CN110066516A - A kind of preparation method of the composite package matrix for LED encapsulation - Google Patents

Abstract

The invention discloses a kind of preparation methods of graphene quantum dot composite package matrix for LED encapsulation, belong to photoelectric field, comprising the following steps: prepare graphene oxide solution using strong acid and oxidizer treatment crystalline graphite powder；The graphene oxide solution of acquisition purify simultaneously ultrasound, is finally dried；The drying graphene oxide of acquisition is prepared into nano-graphene quantum dot (GQDs) solution by chemical cleavage；Graphene quantum dot solution is purified；Graphene quantum dot is evenly spread in colloid, stable GQDs composite package host material is obtained.The light extraction efficiency of encapsulating material can be effectively promoted with composite package matrix prepared by the present invention and improves the thermal stability of chip and light-emitting phosphor, realizes higher device efficiency, guarantee LED component in high-power lower luminous flux output steady in a long-term.

Description

A kind of preparation method of composite encapsulation matrix for LED encapsulation

technical field

The invention relates to the field of optoelectronic technology, in particular to a preparation method of a composite packaging matrix for LED packaging.

Background technique

LED is short for light emitting diode. Since 1993, major technological breakthroughs have been made in blue GaN-LEDs, and white LEDs have been successfully realized in 1996. In recent years, LED has become the third-generation lighting source after incandescent lamps and fluorescent lamps by virtue of its advantages of low power consumption, no pollution, long life, and low-voltage driving.

So far, there are roughly three types of white LEDs. Phosphor-converted white LEDs (ie pc-LEDs) are the most widely used white LEDs on the market. White light is achieved by coating monochromatic or multi-color phosphors on the chip. At present, the most widely used solution on the market is the blue LED chip + yellow phosphor solution. This solution not only has low cost, relatively simple implementation process, and moderate comprehensive performance, but also can be adjusted by changing the chemical composition of the YAG phosphor (spectral composition adjustment). and adjusting the thickness of the phosphor layer to obtain white light of various colors with a color temperature ranging from 3000K to 10000K.

The radiant light generated by the LED chip and the excitation light of the phosphor need to pass through optical components such as chips, phosphor glue, encapsulation glue and lenses to be radiated into the environment. Considering the absorption of light by the material, the propagation of light in the packaging material is reduced. Optical path, reducing unnecessary scattering, refraction and total reflection, and improving light extraction efficiency are the keys to improving LED light efficiency. In the existing white light pc-LEDs package structure, about 13% of the blue light of the chip cannot be extracted to the phosphor layer, and about 13% of the photons in the phosphor coating cannot be extracted due to color mixing/scattering/absorption loss. come out.

In addition, it is found through experiments that under high power input, the temperature of the phosphor will be much higher than the junction temperature of the chip and cause the ^{carbonization} of the phosphor layer. In polymers such as K ^-1 ) resin and silica gel, the heat generated by it is difficult to transfer out and accumulates continuously, resulting in a decrease in the quantum efficiency of chips and phosphors. The junction temperature of the chip and the temperature of the phosphor directly affect the luminous efficiency of the relevant physical process. For the current 1W power white light pc-LEDs with a luminous efficiency of 33% (corresponding to a thermal power of > 0.66W), if the thermal conductivity can be improved from the current ks=0.2W/mK to ks=1.0W/mK or more , the difference between the chip junction temperature and the ambient temperature can be reduced by nearly 5 times during operation, that is, from 85 degrees to about 35 degrees, and the relative luminous flux can be increased by more than 10%.

SUMMARY OF THE INVENTION

Graphene has excellent properties of high refractive index and high thermal conductivity. In the visible light band, the refractive index of graphene quantum dots (GQDs) is around 3.0, and GQDs of 4 nm absorb little light above 400 nm. For the current packaging matrix materials, adding high refractive index nanofillers is a potential direction in the method of increasing the refractive index of the packaging matrix.

The problem to be solved by the present invention is to realize a composite encapsulation matrix material of graphene quantum dots (GQDs) with high refractive index and high thermal conductivity.

The technical scheme of the present invention is: a preparation method of a composite encapsulation matrix for LED encapsulation, characterized in that it comprises the following steps:

(1), utilize strong acid and oxidant to process flake graphite powder to prepare graphene oxide solution and purify, ultrasonic, finally dry;

(2), preparing graphene oxide quantum dots (GOQDs) solution by chemical cutting method from the dried graphene oxide, and obtaining graphene quantum dots (GQDs) after reduction and purification;

(3), dispersing the GQDs obtained in step (2) into the colloid uniformly to obtain a stable GQDs composite encapsulation matrix material;

(4), coating the encapsulation matrix material obtained in step (3) on the surface of the LED in the light-emitting direction.

In step (1), an improved Hummers method is used for preparing graphene oxide, and it can also be a Staudenmaier method, a Hummers method, an ultrasonic-assisted Hummers method, a Brodie method, or the like.

In step (1), the strong acid refers to concentrated sulfuric acid (H ₂ SO ₄ ), or one or more combinations of concentrated sulfuric acid, concentrated nitric acid, and concentrated phosphoric acid, and the ratio of graphite powder to strong acid is 1g corresponds to 20-40ml of strong acid solution.

In step (1), the oxidant is potassium permanganate, or potassium chlorate under fuming nitric acid environment, and the mass ratio of potassium chlorate to graphite powder is 300% to 500%; or sodium nitrate and potassium permanganate; The mass ratio of sodium nitrate to graphite powder is 30% to 60%, and the mass ratio of potassium permanganate to graphite powder is 300% to 500%.

In step (1), the improved Hummers method adopted has three stages of low temperature, medium temperature and high temperature in total, wherein the low temperature stage is to add graphite powder in the concentrated sulfuric acid and stir for 1 hour, then potassium permanganate is added in batches Fully stirred in the reaction solution for 3 hours, and the temperature of the reaction solution was controlled to be lower than 10 degrees in the whole low temperature stage; in the middle temperature stage, the reaction solution was heated to 35 to 40 degrees for 0.5 to 2 hours, and the middle temperature stage was the main oxidation process of the experiment. Graphene oxide with different degrees of oxidation can be prepared by controlling the reaction time and the amount of potassium permanganate; in the high temperature stage, the reaction solution is heated to 80 degrees, and 40 ml of deionized water is slowly added dropwise and stirred continuously for a duration of 10~ 20 minutes, raise the temperature of the reaction solution to 90 degrees and continue stirring for 10 to 20 minutes, stop heating and add 60 ml of deionized water to terminate the reaction, add 30% hydrogen peroxide solution dropwise and stir until the color of the solution is no longer change.

In the described Hummers method, the graphene oxide of different oxidation degrees can be prepared by controlling the consumption of potassium permanganate and the reaction time in the middle temperature stage, the more potassium permanganate consumption is, the longer the reaction time is. The graphite oxide finally prepared The higher the degree of alkylene oxidation.

In step (1), the purification steps include centrifugal washing and dialysis. In the first three washings, dilute hydrochloric acid needs to be used for washing. Dilute hydrochloric acid is obtained by diluting 37% concentrated hydrochloric acid in a ratio of 1:9, and centrifuging with deionized water for many times. After washing, until the pH value of the solution is close to 7, then use a dialysis bag with a molecular weight cut-off of 8,000 to 14,000 to dialyze for a week, change the water twice a day, or use one or several other purification methods such as suction filtration and high-speed centrifugation.

In step (1), the sonication process refers to sonicating for 30-60 minutes with a sonicator.

In step (1), the drying method is freeze drying, or one of natural shade drying, air drying, infrared heating, and drying in a drying oven.

In step (2), the chemical cutting method refers to using the unzipping effect of H ₂ SO ₄ / KMnO ₄ on GO to cut the prepared graphene oxide into smaller sizes GOQDs.

In step (2), the chemical cutting method has four stages, wherein the graphene oxide solid prepared in (1) is added to the concentrated sulfuric acid and stirred in the low temperature stage, and the temperature of the control reaction solution is lower than 10 degrees, and the duration The normal temperature stage refers to adding potassium permanganate to the reaction solution at about 25 degrees at room temperature and stirring continuously. Every 1 g of graphene oxide needs to add 0.5 to 1 g of potassium permanganate, and the duration is about 2 hours. The medium temperature stage means that the temperature of the reaction solution is raised to 45-50 degrees, and the duration is 1-2 hours; the high-temperature stage is that the temperature of the reaction solution is raised to 90 degrees, and 40ml of deionization is slowly added dropwise, and the duration is 30 minutes; after the solution was cooled to room temperature, 30% hydrogen peroxide solution was added dropwise until the color of the solution no longer changed.

In step (2), graphene oxide quantum dots with different nanometer sizes can be prepared by controlling the experimental duration of chemical cutting and the amount of potassium permanganate and the degree of oxidation of graphene oxide prepared in step (2).

In step (2), reduction refers to the use of chemical reduction, high temperature reduction, electrochemical reduction, solvothermal reduction and other methods for deoxidation treatment to reduce GOQDs to GQDs.

In step (2), the purification step includes suction filtration and dialysis, the reaction solution in step (2) is subjected to suction filtration using a 0.22um filter membrane, and the filtered solution is placed in a 3000-8000 molecular weight solution. Dialysis in a dialysis bag for one week, or one or several purification methods in other forms such as high-speed centrifugation.

In step (3), the colloid is thermosetting adhesive or photosensitive adhesive, wherein the thermosetting adhesive is epoxy resin, silica gel, polymethyl methacrylate (PMMA), polycarbonate (PC); the photosensitive colloid is photosensitive adhesive Agent and film-forming agent, wherein the sensitizer is ammonium dichromate (ADC), chromate, diazo compound or a combination of one or more of azide-based compounds; the film-forming agent is polyvinyl alcohol (PVA) ), gum arabic, polyimide, or a combination of one or more of polyvinyl acetate emulsions.

In step (4), the coating is to directly coat the GQDs composite encapsulation matrix material encapsulation matrix obtained in step (3) on the surface of the LED chip as a light extraction layer, or as a remote layer of a phosphor coating, Improve the light extraction efficiency and thermal stability of the chip; or mix the encapsulation matrix material with the phosphor powder as a phosphor powder layer and coat it on the light-emitting surface of the LED chip, or coat it on any distance in the LED light-emitting direction. On the output surface, the light extraction efficiency and thermal stability of the phosphor layer are improved; the coating method is one or more of spin coating, spray coating, glue dispensing, printing and dipping; the The LED is an organic LED, an inorganic LED or a combination of the two; the LED is a single LED chip, or a plurality of LED chip groups on the same substrate, or a whole wafer.

In step (4), the curing method is one or more combinations of oven heating, electric heating plate or infrared heating, and the curing temperature and time are determined according to the property requirements of the colloid (such as silica gel); For curing, for example, photocurable colloids, photoresist, etc. are used.

Using this technology, the encapsulant can be compounded and modified to realize the double-enhancing LED of the refractive index and thermal conductivity of the encapsulation matrix, thereby improving the light extraction efficiency of the encapsulation structure and improving the efficiency stability in a high-current environment.

The technology of the present invention is not only suitable for the packaging of white light LED devices with blue LED chips + yellow phosphors, but also for the packaging of blue LED chips + multi-color phosphors, ultraviolet LED chips + multi-color phosphors (such as RGB three-color phosphors) , is also suitable for the encapsulation of quantum dot phosphors (QDs) pc-LEDs (QD-pc-LEDs) devices.

Using the composite encapsulation matrix prepared by the invention can effectively improve the light extraction efficiency of the encapsulation material and improve the thermal stability of the chip and the phosphor luminescence (effective reduction of the chip junction temperature and the QDs phosphor body temperature under high current working conditions), so as to achieve a higher efficiency. High device efficiency ensures long-term stable high luminous flux output of LED devices under large working conditions.

Description of drawings

FIG. 1 is a schematic diagram of preparing a composite encapsulation matrix as a phosphor layer coated on the surface of an LED chip in Example 1. FIG. 1 is an LED chip, 2 is a substrate, 3 is a reflector cup, 4 is a graphene quantum dot, 5 is a phosphor particle, and 6 is a filled silica gel.

FIG. 2 is a schematic diagram of preparing a composite encapsulation matrix as a phosphor layer coated on the surface of an LED chip in Example 2. FIG. 1 is an LED chip, 2 is a substrate, 3 is a reflector cup, 4 is a graphene quantum dot, 5 is a phosphor particle, and 6 is a light-curing colloid.

FIG. 3 is a schematic diagram of preparing a composite encapsulation matrix as a remote layer coated on the surface of an LED chip in Example 3. FIG. 1 is an LED chip, 2 is a substrate, 3 is a reflector cup, 4 is a graphene quantum dot, and 5 is a filled silica gel.

Detailed ways

Below in conjunction with accompanying drawing and embodiment, the present invention is further described:

Example 1

Weigh 1g of graphite powder, take 23ml of concentrated sulfuric acid with a mass fraction of 98%, mix the graphite powder and concentrated sulfuric acid in a beaker, put the beaker in an ice-water bath, and stir at a speed of 300rpm for 1 hour; weigh 3g of Potassium permanganate was slowly added to the mixed solution in batches, and stirring was continued for 3 hours; the ice-water bath was removed, replaced with a water bath, the temperature of the water bath was set to 35 degrees, and the reaction time was 30 min; the temperature of the water bath was raised to 80 degrees, Add 40ml of pure or deionized water dropwise for 30min.

Take 10ml of concentrated hydrochloric acid and dilute it at a ratio of 1:9, wash and centrifuge the reaction solution with diluted hydrochloric acid, use deionized water to wash and centrifuge until the pH value of the solution is close to 7, and ultrasonically treat for half an hour; then use molecular weight cut-off Dialyze the dialysis bag of 8000-14000 for one week, and change the water twice a day; dry the dialysis suspension in a freeze dryer, and finally get the graphene oxide powder.

Weigh 1g of graphene oxide powder, measure 25ml of concentrated sulfuric acid with a mass fraction of 98%, mix graphene oxide and concentrated sulfuric acid in a beaker, place the beaker in an ice-water bath, and stir for 1 hour at a speed of 300rpm; remove In an ice-water bath, 0.6 g of potassium permanganate was weighed and added to the mixed solution, and stirring was continued for 2 hours at room temperature; replaced with a water bath, the temperature of the water bath was set to 45 degrees, and the reaction time was 60 min; the temperature of the water bath was raised to 90 degrees , 40ml of pure water or deionized water was added dropwise for 30min.

The reacted graphene oxide quantum dot solution was prepared into a 1 mg/ml solution, and the mass ratio of graphene oxide to hydrazine hydrate was 10:7. After adding hydrazine hydrate, it was placed in a 90-95 degree water bath for reduction, and taken out after 1 hour. .

The suspension after the reaction was filtered with a 0.22um filter membrane, and then dialyzed with a dialysis bag with a molecular weight cut-off of 3000-8000 for a week, and the water was changed twice a day; the dialysis suspension was dried in a freeze dryer, and finally 6nm was obtained. left and right graphene quantum dots;

A stable GQDs/Silicone composite encapsulation matrix material can be formed by adding the graphene quantum dots with a mass fraction of 0.1wt% to 1wt% to the optical silica gel;

Take 0.8g of the composite matrix and add 0.1g of phosphor powder and stir well. After the defoaming machine is evacuated to remove air bubbles, it is coated on the surface of the LED chip by the free dispensing method, and cured by heating at 150 °C for 1 hour in a photoelectric oven. The obtained structure is as attached. Figure 1.

Example 2

Weigh 1g of graphite powder, take 23ml of concentrated sulfuric acid with a mass fraction of 98%, mix the graphite powder and concentrated sulfuric acid in a beaker, put the beaker in an ice-water bath, and stir at a speed of 300rpm for 1 hour; weigh 3g of Potassium permanganate was slowly added to the mixed solution in batches, and stirring was continued for 3 hours; the ice-water bath was removed, replaced with a water bath, the temperature of the water bath was set to 35 degrees, and the reaction time was 30 min; the temperature of the water bath was raised to 80 degrees, Add 40ml of pure or deionized water dropwise for 30min.

Take 10ml of concentrated hydrochloric acid and dilute it at a ratio of 1:9, wash and centrifuge the reaction solution with diluted hydrochloric acid, use deionized water to wash and centrifuge until the pH value of the solution is close to 7, and ultrasonically treat for half an hour; then use molecular weight cut-off Dialyze the dialysis bag of 8000-14000 for one week, and change the water twice a day; dry the dialysis suspension in a freeze dryer, and finally get the graphene oxide powder.

Weigh 1g of graphene oxide powder, measure 25ml of concentrated sulfuric acid with a mass fraction of 98%, mix graphene oxide and concentrated sulfuric acid in a beaker, place the beaker in an ice-water bath, and stir for 1 hour at a speed of 300rpm; remove In an ice-water bath, 0.6 g of potassium permanganate was weighed and added to the mixed solution, and stirring was continued for 2 hours at room temperature; replaced with a water bath, the temperature of the water bath was set to 45 degrees, and the reaction time was 60 min; the temperature of the water bath was raised to 90 degrees , 40ml of pure water or deionized water was added dropwise for 30min.

The reacted graphene oxide quantum dot solution was prepared into a 1 mg/ml solution, and the mass ratio of graphene oxide to hydrazine hydrate was 10:7. After adding hydrazine hydrate, it was placed in a 90-95 degree water bath for reduction, and taken out after 1 hour. .

The suspension after the reaction was filtered with a 0.22um filter membrane, and then dialyzed with a dialysis bag with a molecular weight cut-off of 3000-8000 for a week, and the water was changed twice a day; the dialysis suspension was dried in a freeze dryer, and finally 6nm was obtained. left and right graphene quantum dots;

Mix 0.72ml of PVA aqueous solution and 0.68ml of ADC solution with 0.26% concentration, add 0.01g-0.1g of graphene quantum dots and 0.4g of phosphor powder, and fully stir, and use adaptive coating method for photocuring. The resulting structure is shown in FIG. 2 .

Example 3

Weigh 1g of graphite powder and 0.5g of sodium nitrate, measure 20ml of concentrated sulfuric acid with a mass fraction of 98% and 5ml of concentrated nitric acid with a mass fraction of 69%, put graphite powder, sodium nitrate, concentrated sulfuric acid and concentrated nitric acid in a beaker Mix, place the beaker in an ice-water bath, and stir for 1 hour at a speed of 300 rpm; weigh 3 g of potassium permanganate and slowly add it to the mixture in batches, and continue to stir for 3 hours; remove the ice-water bath and replace it with a water bath, The temperature of the water bath was set to 35 degrees, and the reaction time was 60 minutes; the temperature of the water bath was raised to 80 degrees, and 40 ml of pure water or deionized water was added dropwise for 30 minutes.

Take 10ml of concentrated hydrochloric acid and dilute it at a ratio of 1:9, wash and centrifuge the reaction solution with diluted hydrochloric acid, use deionized water to wash and centrifuge until the pH value of the solution is close to 7, and ultrasonically treat for half an hour; then use molecular weight cut-off Dialyze the dialysis bag of 8000-14000 for one week, and change the water twice a day; dry the dialysis suspension in a freeze dryer, and finally get the graphene oxide powder.

Weigh 1g of graphene oxide powder, measure 25ml of concentrated sulfuric acid with a mass fraction of 98%, mix graphene oxide and concentrated sulfuric acid in a beaker, place the beaker in an ice-water bath, and stir for 1 hour at a speed of 300rpm; remove In an ice-water bath, 0.6 g of potassium permanganate was weighed and added to the mixed solution, and stirring was continued for 2 hours at room temperature; replaced with a water bath, the temperature of the water bath was set to 45 degrees, and the reaction time was 60 min; the temperature of the water bath was raised to 90 degrees , 40ml of pure water or deionized water was added dropwise for 30min.

The reacted graphene oxide quantum dot solution was prepared into a 1 mg/ml solution, and the mass ratio of graphene oxide to hydrazine hydrate was 10:7. After adding hydrazine hydrate, it was placed in a 90-95 degree water bath for reduction, and taken out after 1 hour. .

The suspension after the reaction was filtered with a 0.22um filter membrane, and then dialyzed with a dialysis bag with a molecular weight cut-off of 3000-8000 for a week, and the water was changed twice a day; the dialysis suspension was dried in a freeze dryer, and finally 6nm was obtained. Left and right graphene quantum dots;

Add 0.1wt% to 1wt% graphene quantum dots into the optical silica gel and stir well to form a stable GQDs/Silicone composite encapsulation matrix material;

The composite matrix was diluted with n-hexane, and then the LED was placed on a heating plate by spraying method, and a layer of remote layer was directly sprayed on the surface of the LED chip, and then cured by heating at 150 °C for 1 h in a photoelectric oven. The obtained structure is shown in Figure 3. shown.

Example 4

Weigh 1g of graphite powder, take 23ml of concentrated sulfuric acid with a mass fraction of 98%, mix the graphite powder and concentrated sulfuric acid in a beaker, put the beaker in an ice-water bath, and stir at a speed of 300rpm for 1 hour; weigh 3g of Potassium permanganate was slowly added to the mixed solution in batches, and stirring was continued for 3 hours; the ice-water bath was removed, replaced with a water bath, the temperature of the water bath was set to 35 degrees, and the reaction time was 30 min; the temperature of the water bath was raised to 80 degrees, Add 40ml of pure or deionized water dropwise for 30min.

Take 10ml of concentrated hydrochloric acid and dilute it at a ratio of 1:9, wash and centrifuge the reaction solution with diluted hydrochloric acid, use deionized water to wash and centrifuge until the pH value of the solution is close to 7, and ultrasonically treat for half an hour; then use molecular weight cut-off Dialyze the dialysis bag of 8000-14000 for one week, and change the water twice a day; dry the dialysis suspension in a freeze dryer, and finally get the graphene oxide powder.

Weigh 1g of graphene oxide powder, measure 25ml of concentrated sulfuric acid with a mass fraction of 98%, mix graphene oxide and concentrated sulfuric acid in a beaker, place the beaker in an ice-water bath, and stir for 1 hour at a speed of 300rpm; remove In an ice-water bath, 0.6 g of potassium permanganate was weighed and added to the mixed solution, and stirring was continued for 2 hours at room temperature; replaced with a water bath, the temperature of the water bath was set to 45 degrees, and the reaction time was 60 min; the temperature of the water bath was raised to 90 degrees , 40ml of pure water or deionized water was added dropwise for 30min.

The reacted graphene oxide quantum dot solution was prepared into a 1 mg/ml solution, and the mass ratio of graphene oxide to hydrazine hydrate was 10:7. After adding hydrazine hydrate, it was placed in a 90-95 degree water bath for reduction, and taken out after 1 hour. .

The suspension after the reaction was filtered with a 0.22um filter membrane, and then dialyzed with a dialysis bag with a molecular weight cut-off of 3000-8000 for a week, and the water was changed twice a day; the dialysis suspension was dried in a freeze dryer, and finally 6nm was obtained. left and right graphene quantum dots;

A stable GQDs/Silicone composite encapsulation matrix material can be formed by adding the graphene quantum dots with a mass fraction of 0.1wt% to 1wt% to the optical silica gel;

Take 0.8g of the composite matrix and add 0.1g of phosphor powder and stir it thoroughly. After the bubbles are removed by vacuuming with a defoaming machine, it is coated on the surface of the LED chip by a free dispensing method, and cured by heating at 150 °C for 1 h in a photoelectric oven.

Example 5

Weigh 1g of graphite powder and 0.5g of sodium nitrate, measure 20ml of concentrated sulfuric acid with a mass fraction of 98% and 5ml of concentrated nitric acid with a mass fraction of 69%, put graphite powder, sodium nitrate, concentrated sulfuric acid and concentrated nitric acid in a beaker Mix, place the beaker in an ice-water bath, and stir for 1 hour at a speed of 300 rpm; weigh 3 g of potassium permanganate and slowly add it to the mixture in batches, and continue to stir for 3 hours; remove the ice-water bath and replace it with a water bath, The temperature of the water bath was set to 35 degrees, and the reaction time was 30 minutes; the temperature of the water bath was raised to 80 degrees, and 40 ml of pure water or deionized water was added dropwise for 30 minutes.

Take 10ml of concentrated hydrochloric acid and dilute it at a ratio of 1:9, wash and centrifuge the reaction solution with diluted hydrochloric acid, use deionized water to wash and centrifuge until the pH value of the solution is close to 7, and ultrasonically treat for half an hour; then use molecular weight cut-off Dialyze the dialysis bag of 8000-14000 for one week, and change the water twice a day; dry the dialysis suspension in a freeze dryer, and finally get the graphene oxide powder.

Weigh 1g of graphene oxide powder, measure 25ml of concentrated sulfuric acid with a mass fraction of 98%, mix graphene oxide and concentrated sulfuric acid in a beaker, place the beaker in an ice-water bath, and stir for 1 hour at a speed of 300rpm; remove In an ice-water bath, 0.6 g of potassium permanganate was weighed and added to the mixed solution, and stirring was continued for 2 hours at room temperature; replaced with a water bath, the temperature of the water bath was set to 45 degrees, and the reaction time was 60 min; the temperature of the water bath was raised to 90 degrees , 40ml of pure water or deionized water was added dropwise for 30min.

The reacted graphene oxide quantum dot solution was prepared into a 1 mg/ml solution, and the mass ratio of graphene oxide to hydrazine hydrate was 10:7. After adding hydrazine hydrate, it was placed in a 90-95 degree water bath for reduction, and taken out after 1 hour. .

The suspension after the reaction was filtered with a 0.22um filter membrane, and then dialyzed with a dialysis bag with a molecular weight cut-off of 3000-8000 for a week, and the water was changed twice a day; the dialysis suspension was dried in a freeze dryer, and finally 6nm was obtained. Left and right graphene quantum dots;

Add 0.1wt% to 1wt% graphene quantum dots into the optical silica gel and stir well to form a stable GQDs/Silicone composite encapsulation matrix material;

Take 0.8g of the composite matrix and add 0.1g of phosphor powder and stir it thoroughly. After the bubbles are removed by vacuuming with a defoaming machine, it is coated on the surface of the LED chip by a free dispensing method, and cured by heating at 150 °C for 1 h in a photoelectric oven.

Example 6

Weigh 1g of graphite powder and 0.5g of sodium nitrate, measure 20ml of concentrated sulfuric acid with a mass fraction of 98% and 5ml of concentrated nitric acid with a mass fraction of 69%, put graphite powder, sodium nitrate, concentrated sulfuric acid and concentrated nitric acid in a beaker Mix, place the beaker in an ice-water bath, and stir for 1 hour at a speed of 300 rpm; weigh 3 g of potassium permanganate and slowly add it to the mixture in batches, and continue to stir for 3 hours; remove the ice-water bath and replace it with a water bath, The temperature of the water bath was set to 35 degrees, and the reaction time was 30 minutes; the temperature of the water bath was raised to 80 degrees, and 40 ml of pure water or deionized water was added dropwise for 30 minutes.

Take 10ml of concentrated hydrochloric acid and dilute it at a ratio of 1:9, wash and centrifuge the reaction solution with diluted hydrochloric acid, use deionized water to wash and centrifuge until the pH value of the solution is close to 7, and ultrasonically treat for half an hour; then use molecular weight cut-off Dialyze the dialysis bag of 8000-14000 for one week, and change the water twice a day; dry the dialysis suspension in a freeze dryer, and finally get the graphene oxide powder.

Weigh 1g of graphene oxide powder, measure 25ml of concentrated sulfuric acid with a mass fraction of 98%, mix graphene oxide and concentrated sulfuric acid in a beaker, place the beaker in an ice-water bath, and stir for 1 hour at a speed of 300rpm; remove In an ice-water bath, 0.6 g of potassium permanganate was weighed and added to the mixed solution, and stirring was continued for 2 hours at room temperature; replaced with a water bath, the temperature of the water bath was set to 45 degrees, and the reaction time was 90 min; the temperature of the water bath was raised to 90 degrees , 40ml of pure water or deionized water was added dropwise for 30min.

The reacted graphene oxide quantum dot solution was prepared into a 1 mg/ml solution, and the mass ratio of graphene oxide to hydrazine hydrate was 10:7. After adding hydrazine hydrate, it was placed in a 90-95 degree water bath for reduction, and taken out after 1 hour. .

The suspension after the reaction was filtered with a 0.22um filter membrane, and then dialyzed with a dialysis bag with a molecular weight cut-off of 3000-8000 for a week, and the water was changed twice a day; the dialysis suspension was dried in a freeze dryer, and finally 6nm was obtained. Left and right graphene quantum dots;

Add 0.1wt% to 1wt% graphene quantum dots into the optical silica gel and stir well to form a stable GQDs/Silicone composite encapsulation matrix material;

Take 0.8g of the composite matrix and add 0.1g of phosphor powder and stir it thoroughly. After the bubbles are removed by vacuuming with a defoaming machine, it is coated on the surface of the LED chip by a free dispensing method, and cured by heating at 150 °C for 1 h in a photoelectric oven.

Example 7

Weigh 1g of graphite powder and 21ml of concentrated sulfuric acid with a mass fraction of 98% and 3ml of concentrated phosphoric acid with a mass fraction of 85%. Mix the graphite powder, concentrated sulfuric acid and concentrated phosphoric acid in a beaker, and place the beaker in an ice-water bath. , while stirring at a speed of 300rpm for 1 hour; take 3g of potassium permanganate slowly and add it to the mixture in batches, and continue to stir for 3 hours; remove the ice-water bath, replace it with a water bath, and set the water bath temperature to 35 degrees, The reaction time was 30 minutes; the temperature of the water bath was raised to 80 degrees, and 40 ml of pure water or deionized water was added dropwise for 30 minutes.

Take 10ml of concentrated hydrochloric acid and dilute it at a ratio of 1:9, wash and centrifuge the reaction solution with diluted hydrochloric acid, use deionized water to wash and centrifuge until the pH value of the solution is close to 7, and ultrasonically treat for half an hour; then use molecular weight cut-off Dialyze the dialysis bag of 8000-14000 for one week, and change the water twice a day; dry the dialysis suspension in a freeze dryer, and finally get the graphene oxide powder.

Weigh 1g of graphene oxide powder, measure 25ml of concentrated sulfuric acid with a mass fraction of 98%, mix graphene oxide and concentrated sulfuric acid in a beaker, place the beaker in an ice-water bath, and stir for 1 hour at a speed of 300rpm; remove In an ice-water bath, 0.6 g of potassium permanganate was weighed and added to the mixed solution, and stirring was continued for 2 hours at room temperature; replaced with a water bath, the temperature of the water bath was set to 45 degrees, and the reaction time was 60 min; the temperature of the water bath was raised to 90 degrees , 40ml of pure water or deionized water was added dropwise for 30min.

The reacted graphene oxide quantum dot solution was prepared into a 1 mg/ml solution, and the mass ratio of graphene oxide to hydrazine hydrate was 10:7. After adding hydrazine hydrate, it was placed in a 90-95 degree water bath for reduction, and taken out after 1 hour. .

The suspension after the reaction was filtered with a 0.22um filter membrane, and then dialyzed with a dialysis bag with a molecular weight cut-off of 3000-8000 for a week, and the water was changed twice a day; the suspension after dialysis was dried in a freeze dryer, and finally 7nm was obtained. Left and right graphene quantum dots;

Add 0.1wt% to 1wt% graphene quantum dots into the optical silica gel and stir well to form a stable GQDs/Silicone composite encapsulation matrix material;

Take 0.8g of the composite matrix and add 0.1g of phosphor powder and stir it thoroughly. After the bubbles are removed by vacuuming with a defoaming machine, it is coated on the surface of the LED chip by a free dispensing method, and cured by heating at 150 °C for 1 h in a photoelectric oven.

Example 8

Weigh 1g of graphite powder and 21ml of concentrated sulfuric acid with a mass fraction of 98% and 3ml of concentrated phosphoric acid with a mass fraction of 85%. Mix the graphite powder, concentrated sulfuric acid and concentrated phosphoric acid in a beaker, and place the beaker in an ice-water bath. , while stirring at a speed of 300rpm for 1 hour; take 3g of potassium permanganate slowly and add it to the mixture in batches, and continue to stir for 3 hours; remove the ice-water bath, replace it with a water bath, and set the water bath temperature to 35 degrees, The reaction time was 60 minutes; the temperature of the water bath was raised to 80 degrees, and 40 ml of pure water or deionized water was added dropwise for 30 minutes.

Take 10ml of concentrated hydrochloric acid and dilute it at a ratio of 1:9, wash and centrifuge the reaction solution with diluted hydrochloric acid, use deionized water to wash and centrifuge until the pH value of the solution is close to 7, and ultrasonically treat for half an hour; then use molecular weight cut-off Dialyze the dialysis bag of 8000-14000 for one week, and change the water twice a day; dry the dialysis suspension in a freeze dryer, and finally get the graphene oxide powder.

Weigh 1g of graphene oxide powder, measure 25ml of concentrated sulfuric acid with a mass fraction of 98%, mix graphene oxide and concentrated sulfuric acid in a beaker, place the beaker in an ice-water bath, and stir for 1 hour at a speed of 300rpm; remove In an ice-water bath, 0.6 g of potassium permanganate was weighed and added to the mixed solution, and stirring was continued for 2 hours at room temperature; replaced with a water bath, the temperature of the water bath was set to 45 degrees, and the reaction time was 60 min; the temperature of the water bath was raised to 90 degrees , 40ml of pure water or deionized water was added dropwise for 30min.

The reacted graphene oxide quantum dot solution was prepared into a 1 mg/ml solution, and the mass ratio of graphene oxide to hydrazine hydrate was 10:7. After adding hydrazine hydrate, it was placed in a 90-95 degree water bath for reduction, and taken out after 1 hour. .

The suspension after the reaction was filtered with a 0.22um filter membrane, and then dialyzed with a dialysis bag with a molecular weight cut-off of 3000-8000 for a week, and the water was changed twice a day; the dialysis suspension was dried in a freeze dryer, and finally 6nm was obtained. Left and right graphene quantum dots;

Add 0.1wt% to 1wt% graphene quantum dots into the optical silica gel and stir well to form a stable GQDs/Silicone composite encapsulation matrix material;

Take 0.8g of the composite matrix and add 0.1g of phosphor powder and stir it thoroughly. After the bubbles are removed by vacuuming with a defoaming machine, it is coated on the surface of the LED chip by a free dispensing method, and cured by heating at 150 °C for 1 h in a photoelectric oven.

Example 9

Weigh 1g of graphite powder and 21ml of concentrated sulfuric acid with a mass fraction of 98% and 3ml of concentrated phosphoric acid with a mass fraction of 85%. Mix the graphite powder, concentrated sulfuric acid and concentrated phosphoric acid in a beaker, and place the beaker in an ice-water bath. , while stirring at a speed of 300rpm for 1 hour; take 3g of potassium permanganate slowly and add it to the mixture in batches, and continue to stir for 3 hours; remove the ice-water bath, replace it with a water bath, and set the water bath temperature to 35 degrees, The reaction time was 90 minutes; the temperature of the water bath was raised to 80 degrees, and 40 ml of pure water or deionized water was added dropwise for 30 minutes.

Take 10ml of concentrated hydrochloric acid and dilute it at a ratio of 1:9, wash and centrifuge the reaction solution with diluted hydrochloric acid, use deionized water to wash and centrifuge until the pH value of the solution is close to 7, and ultrasonically treat for half an hour; then use molecular weight cut-off Dialyze the dialysis bag of 8000-14000 for one week, and change the water twice a day; dry the dialysis suspension in a freeze dryer, and finally get the graphene oxide powder.

Weigh 1g of graphene oxide powder, measure 25ml of concentrated sulfuric acid with a mass fraction of 98%, mix graphene oxide and concentrated sulfuric acid in a beaker, place the beaker in an ice-water bath, and stir for 1 hour at a speed of 300rpm; remove In an ice-water bath, 0.6 g of potassium permanganate was weighed and added to the mixed solution, and stirring was continued for 2 hours at room temperature; replaced with a water bath, the temperature of the water bath was set to 45 degrees, and the reaction time was 60 min; the temperature of the water bath was raised to 90 degrees , 40ml of pure water or deionized water was added dropwise for 30min.

The reacted graphene oxide quantum dot solution was prepared into a 1 mg/ml solution, and the mass ratio of graphene oxide to hydrazine hydrate was 10:7. After adding hydrazine hydrate, it was placed in a 90-95 degree water bath for reduction, and taken out after 1 hour. .

The suspension after the reaction was filtered with a 0.22um filter membrane, and then dialyzed with a dialysis bag with a molecular weight cut-off of 3000-8000 for a week, and the water was changed twice a day; the dialysis suspension was dried in a freeze dryer, and finally 6nm was obtained. Left and right graphene quantum dots;

Add 0.1wt% to 1wt% graphene quantum dots into the optical silica gel and stir well to form a stable GQDs/Silicone composite encapsulation matrix material;

Take 0.8g of the composite matrix and add 0.1g of phosphor powder and stir it thoroughly. After the bubbles are removed by vacuuming with a defoaming machine, it is coated on the surface of the LED chip by a free dispensing method, and cured by heating at 150 °C for 1 h in a photoelectric oven.

Example 10

Weigh 1g of graphite powder, take 23ml of concentrated sulfuric acid with a mass fraction of 98%, mix the graphite powder and concentrated sulfuric acid in a beaker, put the beaker in an ice-water bath, and stir at a speed of 300rpm for 1 hour; weigh 3g of Potassium permanganate was slowly added to the mixed solution in batches, and continued stirring for 3 hours; the ice-water bath was removed, replaced with a water bath, the water bath temperature was set to 35 degrees, and the reaction time was 60 min; the water bath temperature was raised to 80 degrees, Add 40ml of pure or deionized water dropwise for 30min.

Take 10ml of concentrated hydrochloric acid and dilute it at a ratio of 1:9, wash and centrifuge the reaction solution with diluted hydrochloric acid, use deionized water to wash and centrifuge until the pH value of the solution is close to 7, and ultrasonically treat for half an hour; then use molecular weight cut-off Dialyze the dialysis bag of 8000-14000 for one week, and change the water twice a day; dry the dialysis suspension in a freeze dryer, and finally get the graphene oxide powder.

Weigh 1g of graphene oxide powder, measure 25ml of concentrated sulfuric acid with a mass fraction of 98%, mix graphene oxide and concentrated sulfuric acid in a beaker, place the beaker in an ice-water bath, and stir for 1 hour at a speed of 300rpm; remove In an ice-water bath, 0.6 g of potassium permanganate was weighed and added to the mixed solution, and stirring was continued for 2 hours at room temperature; replaced with a water bath, the temperature of the water bath was set to 45 degrees, and the reaction time was 60 min; the temperature of the water bath was raised to 90 degrees , 40ml of pure water or deionized water was added dropwise for 30min.

The reacted graphene oxide quantum dot solution was prepared into a 1 mg/ml solution, and the mass ratio of graphene oxide to hydrazine hydrate was 10:7. After adding hydrazine hydrate, it was placed in a 90-95 degree water bath for reduction, and taken out after 1 hour. .

The suspension after the reaction was filtered with a 0.22um filter membrane, and then dialyzed with a dialysis bag with a molecular weight cut-off of 3000-8000 for a week, and the water was changed twice a day; the dialysis suspension was dried in a freeze dryer, and finally 6nm was obtained. Left and right graphene quantum dots;

Add 0.1wt% to 1wt% graphene quantum dots into the optical silica gel and stir well to form a stable GQDs/Silicone composite encapsulation matrix material;

Take 0.8g of the composite matrix and add 0.1g of phosphor powder and stir it thoroughly. After the bubbles are removed by vacuuming with a defoaming machine, it is coated on the surface of the LED chip by a free dispensing method, and cured by heating at 150 °C for 1 h in a photoelectric oven.

Example 11

Weigh 1g of graphite powder, take 23ml of concentrated sulfuric acid with a mass fraction of 98%, mix the graphite powder and concentrated sulfuric acid in a beaker, put the beaker in an ice-water bath, and stir at a speed of 300rpm for 1 hour; weigh 3g of Potassium permanganate was slowly added to the mixed solution in batches, and continued stirring for 3 hours; the ice-water bath was removed, replaced with a water bath, the temperature of the water bath was set to 35 degrees, and the reaction time was 90 min; the temperature of the water bath was raised to 80 degrees, Add 40ml of pure or deionized water dropwise for 30min.

Take 10ml of concentrated hydrochloric acid and dilute it at a ratio of 1:9, wash and centrifuge the reaction solution with diluted hydrochloric acid, use deionized water to wash and centrifuge until the pH value of the solution is close to 7, and ultrasonically treat for half an hour; then use molecular weight cut-off Dialyze the dialysis bag of 8000-14000 for one week, and change the water twice a day; dry the dialysis suspension in a freeze dryer, and finally get the graphene oxide powder.

Weigh 1g of graphene oxide powder, measure 25ml of concentrated sulfuric acid with a mass fraction of 98%, mix graphene oxide and concentrated sulfuric acid in a beaker, place the beaker in an ice-water bath, and stir for 1 hour at a speed of 300rpm; remove In an ice-water bath, weigh 1 g of potassium permanganate and add it to the mixed solution, and continue stirring at room temperature for 2 hours; change to a water bath, set the water bath temperature to 45 degrees, and the reaction time to 60 minutes; increase the water bath temperature to 90 degrees, Add 40ml of pure or deionized water dropwise for 30min.

The reacted graphene oxide quantum dot solution was prepared into a 1 mg/ml solution, and the mass ratio of graphene oxide to hydrazine hydrate was 10:7. After adding hydrazine hydrate, it was placed in a 90-95 degree water bath for reduction, and taken out after 1 hour. .

The suspension after the reaction was filtered with a 0.22um membrane, and then dialyzed with a dialysis bag with a molecular weight cut-off of 3000-8000 for a week, and the water was changed twice a day; the suspension after dialysis was dried in a freeze dryer to obtain 5nm Left and right graphene quantum dots;

Add 0.1wt% to 1wt% graphene quantum dots into the optical silica gel and stir well to form a stable GQDs/Silicone composite encapsulation matrix material;

Take 0.8g of the composite matrix and add 0.1g of phosphor powder and stir it thoroughly. After the bubbles are removed by vacuuming with a defoaming machine, it is coated on the surface of the LED chip by a free dispensing method, and cured by heating at 150 °C for 1 h in a photoelectric oven.

Example 12

Weigh 1g of graphite powder, take 26ml of concentrated sulfuric acid with a mass fraction of 98%, mix the graphite powder and concentrated sulfuric acid in a beaker, put the beaker in an ice-water bath, and stir at a speed of 300rpm for 1 hour; weigh 3g of Potassium permanganate was slowly added to the mixed solution in batches, and stirring was continued for 3 hours; the ice-water bath was removed, replaced with a water bath, the temperature of the water bath was set to 35 degrees, and the reaction time was 30 min; the temperature of the water bath was raised to 80 degrees, Add 40ml of pure or deionized water dropwise for 30min.

Take 10ml of concentrated hydrochloric acid and dilute it at a ratio of 1:9, wash and centrifuge the reaction solution with diluted hydrochloric acid, use deionized water to wash and centrifuge until the pH value of the solution is close to 7, and ultrasonically treat for half an hour; then use molecular weight cut-off Dialyze the dialysis bag of 8000-14000 for one week, and change the water twice a day; dry the dialysis suspension in a freeze dryer, and finally get the graphene oxide powder.

Weigh 1g of graphene oxide powder, measure 25ml of concentrated sulfuric acid with a mass fraction of 98%, mix graphene oxide and concentrated sulfuric acid in a beaker, place the beaker in an ice-water bath, and stir for 1 hour at a speed of 300rpm; remove In an ice-water bath, 0.8 g of potassium permanganate was weighed and added to the mixed solution, and stirring was continued for 2 hours at room temperature; replaced by a water bath, the temperature of the water bath was set to 45 degrees, and the reaction time was 90 min; the temperature of the water bath was raised to 90 degrees , 40ml of pure water or deionized water was added dropwise for 30min.

The reacted graphene oxide quantum dot solution was prepared into a 1 mg/ml solution, and the mass ratio of graphene oxide to hydrazine hydrate was 10:7. After adding hydrazine hydrate, it was placed in a 90-95 degree water bath for reduction, and taken out after 1 hour. .

The suspension after the reaction was filtered with a 0.22um membrane, and then dialyzed with a dialysis bag with a molecular weight cut-off of 3000-8000 for a week, and the water was changed twice a day; the suspension after dialysis was dried in a freeze dryer to obtain 5nm Left and right graphene quantum dots;

Add 0.1wt% to 1wt% graphene quantum dots into the optical silica gel and stir well to form a stable GQDs/Silicone composite encapsulation matrix material;

Take 0.8g of the composite matrix and add 0.1g of phosphor powder and stir it thoroughly. After the bubbles are removed by vacuuming with a defoaming machine, it is coated on the surface of the LED chip by a free dispensing method, and cured by heating at 150 °C for 1 h in a photoelectric oven.

Example 13

Weigh 1g of graphite powder, take 26ml of concentrated sulfuric acid with a mass fraction of 98%, mix the graphite powder and concentrated sulfuric acid in a beaker, put the beaker in an ice-water bath, and stir at a speed of 300rpm for 1 hour; weigh 3g of Potassium permanganate was slowly added to the mixed solution in batches, and stirring was continued for 3 hours; the ice-water bath was removed, replaced with a water bath, the temperature of the water bath was set to 35 degrees, and the reaction time was 30 min; the temperature of the water bath was raised to 80 degrees, Add 40ml of pure or deionized water dropwise for 30min.

Take 10ml of concentrated hydrochloric acid and dilute it at a ratio of 1:9, wash and centrifuge the reaction solution with diluted hydrochloric acid, use deionized water to wash and centrifuge until the pH value of the solution is close to 7, and ultrasonically treat for half an hour; then use molecular weight cut-off Dialyze the dialysis bag of 8000-14000 for one week, and change the water twice a day; dry the dialysis suspension in a freeze dryer, and finally get the graphene oxide powder.

Weigh 1g of graphene oxide powder, measure 25ml of concentrated sulfuric acid with a mass fraction of 98%, mix graphene oxide and concentrated sulfuric acid in a beaker, place the beaker in an ice-water bath, and stir for 1 hour at a speed of 300rpm; remove In an ice-water bath, 0.8 g of potassium permanganate was weighed and added to the mixed solution, and stirring was continued for 2 hours at room temperature; replaced with a water bath, the temperature of the water bath was set to 45 degrees, and the reaction time was 120 min; the temperature of the water bath was raised to 90 degrees , 40ml of pure water or deionized water was added dropwise for 30min.

The reacted graphene oxide quantum dot solution was prepared into a 1 mg/ml solution, and the mass ratio of graphene oxide to hydrazine hydrate was 10:7. After adding hydrazine hydrate, it was placed in a 90-95 degree water bath for reduction, and taken out after 1 hour. .

The suspension after the reaction was filtered with a 0.22um membrane, and then dialyzed with a dialysis bag with a molecular weight cut-off of 3000-8000 for a week, and the water was changed twice a day; the suspension after dialysis was dried in a freeze dryer to obtain 5nm Left and right graphene quantum dots;

Add 0.1wt% to 1wt% graphene quantum dots into the optical silica gel and stir well to form a stable GQDs/Silicone composite encapsulation matrix material;

Take 0.8g of the composite matrix and add 0.1g of phosphor powder and stir it thoroughly. After the bubbles are removed by vacuuming with a defoaming machine, it is coated on the surface of the LED chip by a free dispensing method, and cured by heating at 150 °C for 1 h in a photoelectric oven.

Example 14

Weigh 1g of graphite powder, take 26ml of concentrated sulfuric acid with a mass fraction of 98%, mix the graphite powder and concentrated sulfuric acid in a beaker, put the beaker in an ice-water bath, and stir at a speed of 300rpm for 1 hour; weigh 3g of Potassium permanganate was slowly added to the mixed solution in batches, and continued stirring for 3 hours; the ice-water bath was removed, replaced with a water bath, the temperature of the water bath was set to 35 degrees, and the reaction time was 120 min; the temperature of the water bath was raised to 80 degrees, Add 40ml of pure or deionized water dropwise for 30min.

Take 10ml of concentrated hydrochloric acid and dilute it at a ratio of 1:9, wash and centrifuge the reaction solution with diluted hydrochloric acid, use deionized water to wash and centrifuge until the pH value of the solution is close to 7, and ultrasonically treat for half an hour; then use molecular weight cut-off Dialyze the dialysis bag of 8000-14000 for one week, and change the water twice a day; dry the dialysis suspension in a freeze dryer, and finally get the graphene oxide powder.

Weigh 1g of graphene oxide powder, measure 25ml of concentrated sulfuric acid with a mass fraction of 98%, mix graphene oxide and concentrated sulfuric acid in a beaker, place the beaker in an ice-water bath, and stir for 1 hour at a speed of 300rpm; remove In an ice-water bath, weigh 1 g of potassium permanganate and add it to the mixed solution, and continue stirring at room temperature for 2 hours; change to a water bath, set the temperature of the water bath to 45 degrees, and the reaction time to be 120 minutes; increase the temperature of the water bath to 90 degrees, Add 40ml of pure or deionized water dropwise for 30min.

The reacted graphene oxide quantum dot solution was prepared into a 1 mg/ml solution, and the mass ratio of graphene oxide to hydrazine hydrate was 10:7. After adding hydrazine hydrate, it was placed in a 90-95 degree water bath for reduction, and taken out after 1 hour. .

The suspension after the reaction was filtered with a 0.22um membrane, and then dialyzed with a dialysis bag with a molecular weight cut-off of 3000-8000 for a week, and the water was changed twice a day; the suspension after dialysis was dried in a freeze dryer to obtain 5nm Left and right graphene quantum dots;

Add 0.1wt% to 1wt% graphene quantum dots into the optical silica gel and stir well to form a stable GQDs/Silicone composite encapsulation matrix material;

Take 0.8g of the composite matrix and add 0.1g of phosphor powder and stir it thoroughly. After the bubbles are removed by vacuuming with a defoaming machine, it is coated on the surface of the LED chip by a free dispensing method, and cured by heating at 150 °C for 1 h in a photoelectric oven.

Example 15

Weigh 1g of graphite powder, take 26ml of concentrated sulfuric acid with a mass fraction of 98%, mix the graphite powder and concentrated sulfuric acid in a beaker, place the beaker in an ice-water bath, and stir at a speed of 300rpm for 1 hour; weigh 4g of Potassium permanganate was slowly added to the mixed solution in batches, and continued stirring for 3 hours; the ice-water bath was removed, replaced with a water bath, the water bath temperature was set to 35 degrees, and the reaction time was 60 min; the water bath temperature was raised to 80 degrees, Add 40ml of pure or deionized water dropwise for 30min.

Take 10ml of concentrated hydrochloric acid and dilute it at a ratio of 1:9, wash and centrifuge the reaction solution with diluted hydrochloric acid, use deionized water to wash and centrifuge until the pH value of the solution is close to 7, and ultrasonically treat for half an hour; then use molecular weight cut-off Dialyze the dialysis bag of 8000-14000 for one week, and change the water twice a day; dry the dialysis suspension in a freeze dryer, and finally get the graphene oxide powder.

Weigh 1g of graphene oxide powder, measure 25ml of concentrated sulfuric acid with a mass fraction of 98%, mix graphene oxide and concentrated sulfuric acid in a beaker, place the beaker in an ice-water bath, and stir for 1 hour at a speed of 300rpm; remove In an ice-water bath, 0.6 g of potassium permanganate was weighed and added to the mixed solution, and stirring was continued for 2 hours at room temperature; replaced with a water bath, the temperature of the water bath was set to 45 degrees, and the reaction time was 60 min; the temperature of the water bath was raised to 90 degrees , 40ml of pure water or deionized water was added dropwise for 30min.

The reacted graphene oxide quantum dot solution was prepared into a 1 mg/ml solution, and the mass ratio of graphene oxide to hydrazine hydrate was 10:7. After adding hydrazine hydrate, it was placed in a 90-95 degree water bath for reduction, and taken out after 1 hour. .

The suspension after the reaction was filtered with a 0.22um membrane, and then dialyzed with a dialysis bag with a molecular weight cut-off of 3000-8000 for a week, and the water was changed twice a day; the suspension after dialysis was dried in a freeze dryer to obtain 5nm Left and right graphene quantum dots;

Add 0.1wt% to 1wt% graphene quantum dots into the optical silica gel and stir well to form a stable GQDs/Silicone composite encapsulation matrix material;

Take 0.8g of the composite matrix and add 0.1g of phosphor powder and stir it thoroughly. After the bubbles are removed by vacuuming with a defoaming machine, it is coated on the surface of the LED chip by a free dispensing method, and cured by heating at 150 °C for 1 h in a photoelectric oven.

Example 16

Weigh 1g of graphite powder, take 26ml of concentrated sulfuric acid with a mass fraction of 98%, mix the graphite powder and concentrated sulfuric acid in a beaker, place the beaker in an ice-water bath, and stir at a speed of 300rpm for 1 hour; weigh 4g of Potassium permanganate was slowly added to the mixed solution in batches, and continued stirring for 3 hours; the ice-water bath was removed, replaced with a water bath, the temperature of the water bath was set to 35 degrees, and the reaction time was 90 min; the temperature of the water bath was raised to 80 degrees, Add 40ml of pure or deionized water dropwise for 30min.

Take 10ml of concentrated hydrochloric acid and dilute it at a ratio of 1:9, wash and centrifuge the reaction solution with diluted hydrochloric acid, use deionized water to wash and centrifuge until the pH value of the solution is close to 7, and ultrasonically treat for half an hour; then use molecular weight cut-off Dialyze the dialysis bag of 8000-14000 for one week, and change the water twice a day; dry the dialysis suspension in a freeze dryer, and finally get the graphene oxide powder.

Weigh 1g of graphene oxide powder, measure 25ml of concentrated sulfuric acid with a mass fraction of 98%, mix graphene oxide and concentrated sulfuric acid in a beaker, place the beaker in an ice-water bath, and stir for 1 hour at a speed of 300rpm; remove In an ice-water bath, 0.6 g of potassium permanganate was weighed and added to the mixed solution, and stirring was continued for 2 hours at room temperature; replaced with a water bath, the temperature of the water bath was set to 45 degrees, and the reaction time was 60 min; the temperature of the water bath was raised to 90 degrees , 40ml of pure water or deionized water was added dropwise for 30min.

The reacted graphene oxide quantum dot solution was prepared into a 1 mg/ml solution, and the mass ratio of graphene oxide to hydrazine hydrate was 10:7. After adding hydrazine hydrate, it was placed in a 90-95 degree water bath for reduction, and taken out after 1 hour. .

The suspension after the reaction was filtered with a 0.22um membrane, and then dialyzed with a dialysis bag with a molecular weight cut-off of 3000-8000 for a week, and the water was changed twice a day; the suspension after dialysis was dried in a freeze dryer to obtain 5nm Left and right graphene quantum dots;

Add 0.1wt% to 1wt% graphene quantum dots into the optical silica gel and stir well to form a stable GQDs/Silicone composite encapsulation matrix material;

Take 0.8g of the composite matrix and add 0.1g of phosphor powder and stir it thoroughly. After the bubbles are removed by vacuuming with a defoaming machine, it is coated on the surface of the LED chip by a free dispensing method, and cured by heating at 150 °C for 1 h in a photoelectric oven.

Example 17

Weigh 1g of graphite powder, take 26ml of concentrated sulfuric acid with a mass fraction of 98%, mix the graphite powder and concentrated sulfuric acid in a beaker, place the beaker in an ice-water bath, and stir at a speed of 300rpm for 1 hour; weigh 4g of Potassium permanganate was slowly added to the mixed solution in batches, and continued stirring for 3 hours; the ice-water bath was removed, replaced with a water bath, the temperature of the water bath was set to 35 degrees, and the reaction time was 120 min; the temperature of the water bath was raised to 80 degrees, Add 40ml of pure or deionized water dropwise for 30min.

Take 10ml of concentrated hydrochloric acid and dilute it at a ratio of 1:9, wash and centrifuge the reaction solution with diluted hydrochloric acid, use deionized water to wash and centrifuge until the pH value of the solution is close to 7, and ultrasonically treat for half an hour; then use molecular weight cut-off Dialyze the dialysis bag of 8000-14000 for one week, and change the water twice a day; dry the dialysis suspension in a freeze dryer, and finally get the graphene oxide powder.

Weigh 1g of graphene oxide powder, measure 25ml of concentrated sulfuric acid with a mass fraction of 98%, mix graphene oxide and concentrated sulfuric acid in a beaker, place the beaker in an ice-water bath, and stir for 1 hour at a speed of 300rpm; remove In an ice-water bath, 0.6 g of potassium permanganate was weighed and added to the mixed solution, and stirring was continued for 2 hours at room temperature; replaced with a water bath, the temperature of the water bath was set to 45 degrees, and the reaction time was 60 min; the temperature of the water bath was raised to 90 degrees , 40ml of pure water or deionized water was added dropwise for 30min.

The reacted graphene oxide quantum dot solution was prepared into a 1 mg/ml solution, and the mass ratio of graphene oxide to hydrazine hydrate was 10:7. After adding hydrazine hydrate, it was placed in a 90-95 degree water bath for reduction, and taken out after 1 hour. .

The suspension after the reaction was filtered with a 0.22um membrane, and then dialyzed with a dialysis bag with a molecular weight cut-off of 3000-8000 for a week, and the water was changed twice a day; the suspension after dialysis was dried in a freeze dryer to obtain 5nm Left and right graphene quantum dots;

Add 0.1wt% to 1wt% graphene quantum dots into the optical silica gel and stir well to form a stable GQDs/Silicone composite encapsulation matrix material;

Take 0.8g of the composite matrix and add 0.1g of phosphor powder and stir it thoroughly. After the bubbles are removed by vacuuming with a defoaming machine, it is coated on the surface of the LED chip by a free dispensing method, and cured by heating at 150 °C for 1 h in a photoelectric oven.

Example 18

Weigh 1g of graphite powder, take 30ml of concentrated sulfuric acid with a mass fraction of 98%, mix the graphite powder and concentrated sulfuric acid in a beaker, put the beaker in an ice-water bath, and stir at a speed of 300rpm for 1 hour; weigh 4g of Potassium permanganate was slowly added to the mixed solution in batches, and continued stirring for 3 hours; the ice-water bath was removed, replaced with a water bath, the water bath temperature was set to 35 degrees, and the reaction time was 60 min; the water bath temperature was raised to 80 degrees, Add 40ml of pure or deionized water dropwise for 30min.

Take 10ml of concentrated hydrochloric acid and dilute it at a ratio of 1:9, wash and centrifuge the reaction solution with diluted hydrochloric acid, use deionized water to wash and centrifuge until the pH value of the solution is close to 7, and ultrasonically treat for half an hour; then use molecular weight cut-off Dialyze the dialysis bag of 8000-14000 for one week, and change the water twice a day; dry the dialysis suspension in a freeze dryer, and finally get the graphene oxide powder.

Weigh 1g of graphene oxide powder, measure 25ml of concentrated sulfuric acid with a mass fraction of 98%, mix graphene oxide and concentrated sulfuric acid in a beaker, place the beaker in an ice-water bath, and stir for 1 hour at a speed of 300rpm; remove In an ice-water bath, 0.8 g of potassium permanganate was weighed and added to the mixed solution, and stirring was continued for 2 hours at room temperature; replaced by a water bath, the temperature of the water bath was set to 45 degrees, and the reaction time was 90 min; the temperature of the water bath was raised to 90 degrees , 40ml of pure water or deionized water was added dropwise for 30min.

The suspension after the reaction was filtered with a 0.22um filter membrane, and then dialyzed with a dialysis bag with a molecular weight cut-off of 3000-8000 for a week, and the water was changed twice a day; the dialysis suspension was dried in a freeze dryer, and finally 6nm was obtained. Left and right graphene quantum dots;

The reacted graphene oxide quantum dot solution was prepared into a 1 mg/ml solution, and the mass ratio of graphene oxide to hydrazine hydrate was 10:7. After adding hydrazine hydrate, it was placed in a 90-95 degree water bath for reduction, and taken out after 1 hour. .

Add 0.1wt% to 1wt% graphene quantum dots into the optical silica gel and stir well to form a stable GQDs/Silicone composite encapsulation matrix material;

Take 0.8g of the composite matrix and add 0.1g of phosphor powder and stir it thoroughly. After the bubbles are removed by vacuuming with a defoaming machine, it is coated on the surface of the LED chip by a free dispensing method, and cured by heating at 150 °C for 1 h in a photoelectric oven.

Example 19

Weigh 1g of graphite powder, take 30ml of concentrated sulfuric acid with a mass fraction of 98%, mix the graphite powder and concentrated sulfuric acid in a beaker, put the beaker in an ice-water bath, and stir at a speed of 300rpm for 1 hour; weigh 4g of Potassium permanganate was slowly added to the mixed solution in batches, and continued stirring for 3 hours; the ice-water bath was removed, replaced with a water bath, the water bath temperature was set to 35 degrees, and the reaction time was 60 min; the water bath temperature was raised to 80 degrees, Add 40ml of pure or deionized water dropwise for 30min.

Take 10ml of concentrated hydrochloric acid and dilute it at a ratio of 1:9, wash and centrifuge the reaction solution with diluted hydrochloric acid, use deionized water to wash and centrifuge until the pH value of the solution is close to 7, and ultrasonically treat for half an hour; then use molecular weight cut-off Dialyze the dialysis bag of 8000-14000 for one week, and change the water twice a day; dry the dialysis suspension in a freeze dryer, and finally get the graphene oxide powder.

Weigh 1g of graphene oxide powder, measure 25ml of concentrated sulfuric acid with a mass fraction of 98%, mix graphene oxide and concentrated sulfuric acid in a beaker, place the beaker in an ice-water bath, and stir for 1 hour at a speed of 300rpm; remove In an ice-water bath, 0.8 g of potassium permanganate was weighed and added to the mixed solution, and stirring was continued for 2 hours at room temperature; replaced with a water bath, the temperature of the water bath was set to 45 degrees, and the reaction time was 120 min; the temperature of the water bath was raised to 90 degrees , 40ml of pure water or deionized water was added dropwise for 30min.

The reacted graphene oxide quantum dot solution was prepared into a 1 mg/ml solution, and the mass ratio of graphene oxide to hydrazine hydrate was 10:7. After adding hydrazine hydrate, it was placed in a 90-95 degree water bath for reduction, and taken out after 1 hour. .

The suspension after the reaction was filtered with a 0.22um filter membrane, and then dialyzed with a dialysis bag with a molecular weight cut-off of 3000-8000 for a week, and the water was changed twice a day; the dialysis suspension was dried in a freeze dryer to obtain a final 4nm Left and right graphene quantum dots;

Add 0.1wt% to 1wt% graphene quantum dots into the optical silica gel and stir well to form a stable GQDs/Silicone composite encapsulation matrix material;

Take 0.8g of the composite matrix and add 0.1g of phosphor powder and stir it thoroughly. After the bubbles are removed by vacuuming with a defoaming machine, it is coated on the surface of the LED chip by a free dispensing method, and cured by heating at 150 °C for 1 h in a photoelectric oven.

Example 20

Weigh 1g of graphite powder, take 30ml of concentrated sulfuric acid with a mass fraction of 98%, mix the graphite powder and concentrated sulfuric acid in a beaker, put the beaker in an ice-water bath, and stir at a speed of 300rpm for 1 hour; weigh 5g of Potassium permanganate was slowly added to the mixed solution in batches, and continued stirring for 3 hours; the ice-water bath was removed, replaced with a water bath, the water bath temperature was set to 35 degrees, and the reaction time was 60 min; the water bath temperature was raised to 80 degrees, Add 40ml of pure or deionized water dropwise for 30min.

Take 10ml of concentrated hydrochloric acid and dilute it at a ratio of 1:9, wash and centrifuge the reaction solution with diluted hydrochloric acid, use deionized water to wash and centrifuge until the pH value of the solution is close to 7, and ultrasonically treat for half an hour; then use molecular weight cut-off Dialyze the dialysis bag of 8000-14000 for one week, and change the water twice a day; dry the dialysis suspension in a freeze dryer, and finally get the graphene oxide powder.

Weigh 1g of graphene oxide powder, measure 25ml of concentrated sulfuric acid with a mass fraction of 98%, mix graphene oxide and concentrated sulfuric acid in a beaker, place the beaker in an ice-water bath, and stir for 1 hour at a speed of 300rpm; remove In an ice-water bath, 0.6 g of potassium permanganate was weighed and added to the mixed solution, and stirring was continued for 2 hours at room temperature; replaced with a water bath, the temperature of the water bath was set to 45 degrees, and the reaction time was 60 min; the temperature of the water bath was raised to 90 degrees , 40ml of pure water or deionized water was added dropwise for 30min.

The reacted graphene oxide quantum dot solution was prepared into a 1 mg/ml solution, and the mass ratio of graphene oxide to hydrazine hydrate was 10:7. After adding hydrazine hydrate, it was placed in a 90-95 degree water bath for reduction, and taken out after 1 hour. .

The suspension after the reaction was filtered with a 0.22um filter membrane, and then dialyzed with a dialysis bag with a molecular weight cut-off of 3000-8000 for a week, and the water was changed twice a day; the dialysis suspension was dried in a freeze dryer to obtain a final 4nm Left and right graphene quantum dots;

Add 0.1wt% to 1wt% graphene quantum dots into the optical silica gel and stir well to form a stable GQDs/Silicone composite encapsulation matrix material;

Take 0.8g of the composite matrix and add 0.1g of phosphor powder and stir it thoroughly. After the bubbles are removed by vacuuming with a defoaming machine, it is coated on the surface of the LED chip by a free dispensing method, and cured by heating at 150 °C for 1 h in a photoelectric oven.

Example 21

Weigh 1g of graphite powder, take 30ml of concentrated sulfuric acid with a mass fraction of 98%, mix the graphite powder and concentrated sulfuric acid in a beaker, put the beaker in an ice-water bath, and stir at a speed of 300rpm for 1 hour; weigh 5g of Potassium permanganate was slowly added to the mixed solution in batches, and continued stirring for 3 hours; the ice-water bath was removed, replaced with a water bath, the temperature of the water bath was set to 35 degrees, and the reaction time was 120 min; the temperature of the water bath was raised to 80 degrees, Add 40ml of pure or deionized water dropwise for 30min.

Take 10ml of concentrated hydrochloric acid and dilute it at a ratio of 1:9, wash and centrifuge the reaction solution with diluted hydrochloric acid, use deionized water to wash and centrifuge until the pH value of the solution is close to 7, and ultrasonically treat for half an hour; then use molecular weight cut-off Dialyze the dialysis bag of 8000-14000 for one week, and change the water twice a day; dry the dialysis suspension in a freeze dryer, and finally get the graphene oxide powder.

Weigh 1g of graphene oxide powder, measure 25ml of concentrated sulfuric acid with a mass fraction of 98%, mix graphene oxide and concentrated sulfuric acid in a beaker, place the beaker in an ice-water bath, and stir for 1 hour at a speed of 300rpm; remove In an ice-water bath, 0.6 g of potassium permanganate was weighed and added to the mixed solution, and stirring was continued for 2 hours at room temperature; replaced with a water bath, the temperature of the water bath was set to 45 degrees, and the reaction time was 60 min; the temperature of the water bath was raised to 90 degrees , 40ml of pure water or deionized water was added dropwise for 30min.

The reacted graphene oxide quantum dot solution was prepared into a 1 mg/ml solution, and the mass ratio of graphene oxide to hydrazine hydrate was 10:7. After adding hydrazine hydrate, it was placed in a 90-95 degree water bath for reduction, and taken out after 1 hour. .

The suspension after the reaction was filtered with a 0.22um filter membrane, and then dialyzed with a dialysis bag with a molecular weight cut-off of 3000-8000 for a week, and the water was changed twice a day; the dialysis suspension was dried in a freeze dryer to obtain a final 4nm Left and right graphene quantum dots;

Add 0.1wt% to 1wt% graphene quantum dots into the optical silica gel and stir well to form a stable GQDs/Silicone composite encapsulation matrix material;

Take 0.8g of the composite matrix and add 0.1g of phosphor powder and stir it thoroughly. After the bubbles are removed by vacuuming with a defoaming machine, it is coated on the surface of the LED chip by a free dispensing method, and cured by heating at 150 °C for 1 h in a photoelectric oven.

Example 22

Weigh 1g of graphite powder, take 30ml of concentrated sulfuric acid with a mass fraction of 98%, mix the graphite powder and concentrated sulfuric acid in a beaker, put the beaker in an ice-water bath, and stir at a speed of 300rpm for 1 hour; weigh 5g of Potassium permanganate was slowly added to the mixed solution in batches, and continued stirring for 3 hours; the ice-water bath was removed, replaced with a water bath, the temperature of the water bath was set to 35 degrees, and the reaction time was 90 min; the temperature of the water bath was raised to 80 degrees, Add 40ml of pure or deionized water dropwise for 30min.

Take 10ml of concentrated hydrochloric acid and dilute it at a ratio of 1:9, wash and centrifuge the reaction solution with diluted hydrochloric acid, use deionized water to wash and centrifuge until the pH value of the solution is close to 7, and ultrasonically treat for half an hour; then use molecular weight cut-off Dialyze the dialysis bag of 8000-14000 for one week, and change the water twice a day; dry the dialysis suspension in a freeze dryer, and finally get the graphene oxide powder.

Weigh 1g of graphene oxide powder, measure 25ml of concentrated sulfuric acid with a mass fraction of 98%, mix graphene oxide and concentrated sulfuric acid in a beaker, place the beaker in an ice-water bath, and stir for 1 hour at a speed of 300rpm; remove In an ice-water bath, 0.8 g of potassium permanganate was weighed and added to the mixed solution, and stirring was continued for 2 hours at room temperature; replaced by a water bath, the temperature of the water bath was set to 45 degrees, and the reaction time was 90 min; the temperature of the water bath was raised to 90 degrees , 40ml of pure water or deionized water was added dropwise for 30min.

The reacted graphene oxide quantum dot solution was prepared into a 1 mg/ml solution, and the mass ratio of graphene oxide to hydrazine hydrate was 10:7. After adding hydrazine hydrate, it was placed in a 90-95 degree water bath for reduction, and taken out after 1 hour. .

The suspension after the reaction was filtered with a 0.22um filter membrane, and then dialyzed with a dialysis bag with a molecular weight cut-off of 3000-8000 for one week, and the water was changed twice a day; the suspension after dialysis was dried in a freeze dryer, and finally 3nm was obtained. Left and right graphene quantum dots;

Add 0.1wt% to 1wt% graphene quantum dots into the optical silica gel and stir well to form a stable GQDs/Silicone composite encapsulation matrix material;

Take 0.8g of the composite matrix and add 0.1g of phosphor powder and stir it thoroughly. After the bubbles are removed by vacuuming with a defoaming machine, it is coated on the surface of the LED chip by a free dispensing method, and cured by heating at 150 °C for 1 h in a photoelectric oven.

Example 23

Weigh 1g of graphite powder, take 26ml of concentrated sulfuric acid with a mass fraction of 98%, mix the graphite powder and concentrated sulfuric acid in a beaker, place the beaker in an ice-water bath, and stir at a speed of 300rpm for 1 hour; weigh 4g of Potassium permanganate was slowly added to the mixed solution in batches, and continued stirring for 3 hours; the ice-water bath was removed, replaced with a water bath, the temperature of the water bath was set to 35 degrees, and the reaction time was 120 min; the temperature of the water bath was raised to 80 degrees, Add 40ml of pure or deionized water dropwise for 30min.

Take 10ml of concentrated hydrochloric acid and dilute it at a ratio of 1:9, wash and centrifuge the reaction solution with diluted hydrochloric acid, use deionized water to wash and centrifuge until the pH value of the solution is close to 7, and ultrasonically treat for half an hour; then use molecular weight cut-off Dialyze the dialysis bag of 8000-14000 for one week, and change the water twice a day; dry the dialysis suspension in a freeze dryer, and finally get the graphene oxide powder.

Weigh 1g of graphene oxide powder, measure 25ml of concentrated sulfuric acid with a mass fraction of 98%, mix graphene oxide and concentrated sulfuric acid in a beaker, place the beaker in an ice-water bath, and stir for 1 hour at a speed of 300rpm; remove Ice water bath, take 0.6g of potassium permanganate and add it to the mixed solution, continue stirring for 2 hours at room temperature; change to a water bath, set the water bath temperature to 45 degrees, and the reaction time is 120min; the water bath temperature is raised to 90 degrees , 40ml of pure water or deionized water was added dropwise for 30min.

The reacted graphene oxide quantum dot solution was prepared into a 1 mg/ml solution, and the mass ratio of graphene oxide to hydrazine hydrate was 10:7. After adding hydrazine hydrate, it was placed in a 90-95 degree water bath for reduction, and taken out after 1 hour. .

The suspension after the reaction was filtered with a 0.22um membrane, and then dialyzed with a dialysis bag with a molecular weight cut-off of 3000-8000 for a week, and the water was changed twice a day; the suspension after dialysis was dried in a freeze dryer to obtain 5nm Left and right graphene quantum dots;

Add 0.1wt% to 1wt% graphene quantum dots into the optical silica gel and stir well to form a stable GQDs/Silicone composite encapsulation matrix material;

Take 0.8g of the composite matrix and add 0.1g of phosphor powder and stir it thoroughly. After the bubbles are removed by vacuuming with a defoaming machine, it is coated on the surface of the LED chip by a free dispensing method, and cured by heating at 150 °C for 1 h in a photoelectric oven.

Example 24

Weigh 1g of graphite powder, take 23ml of concentrated sulfuric acid with a mass fraction of 98%, mix the graphite powder and concentrated sulfuric acid in a beaker, put the beaker in an ice-water bath, and stir at a speed of 300rpm for 1 hour; weigh 3g of Potassium permanganate was slowly added to the mixed solution in batches, and stirring was continued for 3 hours; the ice-water bath was removed, replaced with a water bath, the temperature of the water bath was set to 35 degrees, and the reaction time was 30 min; the temperature of the water bath was raised to 80 degrees, Add 40ml of pure or deionized water dropwise for 30min.

Take 10ml of concentrated hydrochloric acid and dilute it at a ratio of 1:9, wash and centrifuge the reaction solution with diluted hydrochloric acid, use deionized water to wash and centrifuge until the pH value of the solution is close to 7, and ultrasonically treat for half an hour; then use molecular weight cut-off Dialyze the dialysis bag of 8000-14000 for one week, and change the water twice a day; dry the dialysis suspension in a freeze dryer, and finally get the graphene oxide powder.

Weigh 1g of graphene oxide powder, measure 25ml of concentrated sulfuric acid with a mass fraction of 98%, mix graphene oxide and concentrated sulfuric acid in a beaker, place the beaker in an ice-water bath, and stir for 1 hour at a speed of 300rpm; remove In an ice-water bath, 0.6 g of potassium permanganate was weighed and added to the mixed solution, and stirring was continued for 2 hours at room temperature; replaced with a water bath, the temperature of the water bath was set to 45 degrees, and the reaction time was 60 min; the temperature of the water bath was raised to 90 degrees , 40ml of pure water or deionized water was added dropwise for 30min.

The reacted graphene oxide quantum dot solution was prepared into a 1 mg/ml solution, and the mass ratio of graphene oxide to hydrazine hydrate was 10:7. After adding hydrazine hydrate, it was placed in a 90-95 degree water bath for reduction, and taken out after 1 hour. .

The suspension after the reaction was filtered with a 0.22um filter membrane, and then dialyzed with a dialysis bag with a molecular weight cut-off of 3000-8000 for a week, and the water was changed twice a day; the dialysis suspension was dried in a freeze dryer, and finally 6nm was obtained. Left and right graphene quantum dots;

Add 0.1wt% to 1wt% graphene quantum dots into epoxy resin and fully stir to form a stable graphene/epoxy resin composite encapsulation matrix material;

Take 0.8g of the composite matrix and add 0.1g of phosphor powder and stir it thoroughly. After the bubbles are removed by vacuuming with a defoaming machine, it is coated on the surface of the LED chip by a free dispensing method, and cured by heating at 150 °C for 1 h in a photoelectric oven.

Example 25

Weigh 1g of graphite powder, take 23ml of concentrated sulfuric acid with a mass fraction of 98%, mix the graphite powder and concentrated sulfuric acid in a beaker, put the beaker in an ice-water bath, and stir at a speed of 300rpm for 1 hour; weigh 3g of Potassium permanganate was slowly added to the mixed solution in batches, and stirring was continued for 3 hours; the ice-water bath was removed, replaced with a water bath, the temperature of the water bath was set to 35 degrees, and the reaction time was 30 min; the temperature of the water bath was raised to 80 degrees, Add 40ml of pure or deionized water dropwise for 30min.

Take 10ml of concentrated hydrochloric acid and dilute it at a ratio of 1:9, wash and centrifuge the reaction solution with diluted hydrochloric acid, use deionized water to wash and centrifuge until the pH value of the solution is close to 7, and ultrasonically treat for half an hour; then use molecular weight cut-off Dialyze the dialysis bag of 8000-14000 for one week, and change the water twice a day; dry the dialysis suspension in a freeze dryer, and finally get the graphene oxide powder.

Weigh 1g of graphene oxide powder, measure 25ml of concentrated sulfuric acid with a mass fraction of 98%, mix graphene oxide and concentrated sulfuric acid in a beaker, place the beaker in an ice-water bath, and stir for 1 hour at a speed of 300rpm; remove In an ice-water bath, 0.6 g of potassium permanganate was weighed and added to the mixed solution, and stirring was continued for 2 hours at room temperature; replaced with a water bath, the temperature of the water bath was set to 45 degrees, and the reaction time was 60 min; the temperature of the water bath was raised to 90 degrees , 40ml of pure water or deionized water was added dropwise for 30min.

The reacted graphene oxide quantum dot solution was prepared into a 1 mg/ml solution, and the mass ratio of graphene oxide to hydrazine hydrate was 10:7. After adding hydrazine hydrate, it was placed in a 90-95 degree water bath for reduction, and taken out after 1 hour. .

The suspension after the reaction was filtered with a 0.22um filter membrane, and then dialyzed with a dialysis bag with a molecular weight cut-off of 3000-8000 for a week, and the water was changed twice a day; the dialysis suspension was dried in a freeze dryer, and finally 6nm was obtained. Left and right graphene quantum dots;

Add 0.1wt% to 1wt% graphene quantum dots into polymethyl methacrylate and stir well to form a stable GQDs/PMMA composite encapsulation matrix material;

Take 0.8g of the composite matrix and add 0.1g of phosphor powder and stir it thoroughly. After the bubbles are removed by vacuuming with a defoaming machine, it is coated on the surface of the LED chip by a free dispensing method, and cured by heating at 150 °C for 1 h in a photoelectric oven.

Example 26

Weigh 1g of graphite powder, take 23ml of concentrated sulfuric acid with a mass fraction of 98%, mix the graphite powder and concentrated sulfuric acid in a beaker, put the beaker in an ice-water bath, and stir at a speed of 300rpm for 1 hour; weigh 3g of Potassium permanganate was slowly added to the mixed solution in batches, and stirring was continued for 3 hours; the ice-water bath was removed, replaced with a water bath, the temperature of the water bath was set to 35 degrees, and the reaction time was 30 min; the temperature of the water bath was raised to 80 degrees, Add 40ml of pure or deionized water dropwise for 30min.

Take 10ml of concentrated hydrochloric acid and dilute it at a ratio of 1:9, wash and centrifuge the reaction solution with diluted hydrochloric acid, use deionized water to wash and centrifuge until the pH value of the solution is close to 7, and ultrasonically treat for half an hour; then use molecular weight cut-off Dialyze the dialysis bag of 8000-14000 for one week, and change the water twice a day; dry the dialysis suspension in a freeze dryer, and finally get the graphene oxide powder.

Weigh 1g of graphene oxide powder, measure 25ml of concentrated sulfuric acid with a mass fraction of 98%, mix graphene oxide and concentrated sulfuric acid in a beaker, place the beaker in an ice-water bath, and stir for 1 hour at a speed of 300rpm; remove In an ice-water bath, 0.6 g of potassium permanganate was weighed and added to the mixed solution, and stirring was continued for 2 hours at room temperature; replaced with a water bath, the temperature of the water bath was set to 45 degrees, and the reaction time was 60 min; the temperature of the water bath was raised to 90 degrees , 40ml of pure water or deionized water was added dropwise for 30min.

The reacted graphene oxide quantum dot solution was prepared into a 1 mg/ml solution, and the mass ratio of graphene oxide to hydrazine hydrate was 10:7. After adding hydrazine hydrate, it was placed in a 90-95 degree water bath for reduction, and taken out after 1 hour. .

The suspension after the reaction was filtered with a 0.22um filter membrane, and then dialyzed with a dialysis bag with a molecular weight cut-off of 3000-8000 for a week, and the water was changed twice a day. Finally, graphene quantum dots with a size of about 6 nm and a concentration of 10 mg/mL were obtained. solution.

After dissolving the optical silica gel B glue with tetrahydrofuran, adding 10wt% to 100wt% graphene quantum dot solution and fully stirring, heating and drying excess water and tetrahydrofuran, the GQDs/Silicone composite encapsulation matrix can be formed;

Take 0.8g of the composite matrix and add 0.1g of phosphor powder and stir it thoroughly. After the bubbles are removed by vacuuming with a defoaming machine, it is coated on the surface of the LED chip by a free dispensing method, and cured by heating at 150 °C for 1 h in a photoelectric oven.

Claims (10)

1. a kind of preparation method of the composite package matrix for LED encapsulation, which comprises the following steps:

(1), graphene oxide solution is prepared using strong acid and oxidizer treatment crystalline graphite powder and purified, ultrasound, finally It is dry；

(2), dried graphene oxide is prepared into graphene oxide quantum dot (GOQDs) solution by chemical cleavage, and Graphene quantum dot (GQDs) is obtained after restoring, purifying；

(3), the GQDs for obtaining step (2), then evenly spreads in colloid, obtains stable GQDs composite package matrix material Material；

(4), the matrix of packages material that step (3) obtain is coated in the light direction surface of LED and solidified.

2. a kind of preparation method of the composite package matrix for LED encapsulation according to claim 1, it is characterised in that: In step (1), graphene oxide is prepared using improved Hummers method or Staudenmaier method, Hummers Method, ultrasonic wave added Hummers method and Brodie method etc..

3. a kind of preparation method of the composite package matrix for LED encapsulation according to claim 1, it is characterised in that: In step (1), the strong acid refers to the concentrated sulfuric acid (H₂SO₄), be also possible to one of the concentrated sulfuric acid, concentrated nitric acid, concentrated phosphoric acid or Several combinations of person, and the ratio of graphite powder and nitration mixture is the corresponding 20~40ml mixed acid solution of 1g.The permanganic acid that the oxidant refers to The mass ratio of potassium chlorate under potassium (KMnO4) or fuming nitric aicd environment, potassium chlorate and graphite powder is 300%~500%； Either sodium nitrate and potassium permanganate；Wherein the mass ratio of sodium nitrate and graphite powder is 30%~60%, potassium permanganate and graphite The mass ratio of powder is 300%~500%.

4. a kind of preparation method of the composite package matrix for LED encapsulation according to claim 1, it is characterised in that: In step (1), the improved Hummers method of use shares low temperature, medium temperature, high temperature three phases according to reaction sequence, it is desirable that low Thermophase reacting liquid temperature is lower than 10 degree, and the time continues 3 hours or more；Medium temperature elementary reaction liquid temperature between 35~40 degree, Time was at 0.5~2 hour；Wherein middle thermophase is the main oxidation process of experiment, passes through control reaction time and potassium permanganate Amount can prepare the graphene oxides of different degree of oxidation；Hot stage requires reacting liquid temperature between 80~90 degree, instead It is half an hour between seasonable.

5. a kind of preparation method of the composite package matrix for LED encapsulation according to claim 1, it is characterised in that: In step (1), the purification step includes centrifuge washing, dialysis, is wherein needed three times before centrifuge washing using dilute hydrochloric acid Washing, dilute hydrochloric acid obtains by 37% concentrated hydrochloric acid according to the dilution proportion of 1:9, with after the multiple centrifuge washing of deionized water until molten Liquid pH value is close to 7, and dialysis bag retention molecular weight used is 8000~14000, and dialysis time changed water 2 times daily at one week or more； The ultrasonic procedure refers to that the drying referred to freezing drying, or dries in the shade naturally with Ultrasound Instrument ultrasound 30~60 minutes, Perhaps it air-dries or is dried by infrared heating or drying box.

6. a kind of preparation method of the composite package matrix for LED encapsulation according to claim 1, it is characterised in that: Chemical cleavage described in step (2) (chemical cutting) method refers to utilizing H₂SO₄/KMnO₄To the open chain of GO (Unzipping) effect will prepare GO and be cut into smaller size of GOQDs, by the experiment duration for controlling chemical cleavage The GOQDs that different nano-scales can be prepared with the amount of potassium permanganate, the available various sizes of GQDs after reduction.

7. a kind of preparation method of the composite package matrix for LED encapsulation according to claim 1, it is characterised in that: Reduction described in step (2) refers to carrying out using the methods of electronation, high temperature reduction, electrochemical reduction, solvothermal Deoxidation treatment, repairs its conjugated structure, and GOQDs is reduced into GQDs；Purification refers to restore using the filter membrane of 0.22um Reaction solution in afterwards is filtered, and dialysis bag retention molecular weight used is 3000~8000, can also be using high speed centrifugation etc. Other forms one or several kinds purify mode.

8. a kind of preparation method of the composite package matrix for LED encapsulation according to claim 1, it is characterised in that: Colloid described in step (3) is the combination of one or more of hot-setting adhesive or photoresists, and hot-setting adhesive is epoxy resin, silicon One or more kinds of combinations of glue, polymethyl methacrylate (PMMA), polycarbonate (PC)；Photosensitive colloid includes emulsion And film forming agent, wherein emulsion be bichromate, chromate, diazonium compound either one of azido cpd or A variety of combinations；Film forming agent is polyvinyl alcohol (PVA), gum arabic, one in polyimides or polyvinyl acetate emulsion Kind or a variety of combinations.

9. a kind of preparation method of the composite package matrix for LED encapsulation according to claim 1, it is characterised in that: The coating of matrix of packages material described in step (4) is directly to coat the GQDs composite package host material of the acquisition of step (3) On LED chip surface as pumping photosphere, or the remote layer as fluorescent coating；Or by the matrix of packages material It mixes and is coated in as phosphor powder layer on the light-emitting area of LED chip with fluorescent powder, or be coated in LED light direction the preceding paragraph In any output face of distance；(coating) mode of coating is in spin-coating method, spray coating method, dotting glue method, print process and infusion process It is one or several kinds of.

10. a kind of preparation method of the composite package matrix for LED encapsulation according to claim 1, it is characterised in that: LED described in step (4) is the combination of organic LED, inorganic LED or both；The LED is single LED chip, either The plurality of LEDs chipset or whole wafer of same substrate；The curing mode is oven heat, electric boiling plate or red One or more combinations of external heat, cured temperature and time is depending on the Property requirements of colloid (such as silica gel)；Or Using photocuring, such as use Photosetting colloid, photoresists etc..