CN110718648A - In-situ synthesis manufacturing method of perovskite quantum dot light-emitting diode based on inorganic hole transport material - Google Patents

Abstract

The patent of the present invention discloses a method for in-situ synthesis of perovskite quantum dot light-emitting diodes based on inorganic hole transport materials, which uses a multi-step spin coating method on an ITO glass substrate coated with PEDOT: PSS and CuI in sequence. In situ synthesis of light-emitting layer CsPbBr3 _perovskite quantum dots. The multi-step spin-coating in-situ synthesis technology of the present invention provides a new method for preparing high-performance, high-stability all-inorganic perovskites, which avoids purification, re-dissolution and exposure to conventional synthesis methods after synthesis. The problem of rapid decline in the optical properties of quantum dots in the air environment; and by optimizing the various functional layers of perovskite light-emitting diodes, inorganic materials with high light transmittance and good charge transport properties are used instead of commonly used organic materials as hole transport layers. The high-efficiency light-emitting device is prepared, and the problem of poor stability of organic materials is solved; the process is simple, the production difficulty is small, and the practicability is strong.

Description

In situ synthesis of perovskite quantum dot light-emitting diodes based on inorganic hole transport materials Production Method

technical field

The invention belongs to the field of light-emitting diode material synthesis and light-emitting diode device preparation, in particular to an in-situ synthesis and production method of a light-emitting diode based on an inorganic hole transport material perovskite quantum dot.

Background technique

With the rapid development of the lighting and display industries, the advantages of perovskite quantum dots as light-emitting materials have been gradually discovered and applied. Compared with traditional light-emitting materials, perovskite quantum dots have more excellent characteristics, such as wide excitation spectrum, narrow and symmetrical emission spectrum, tunable color, high electron-hole mobility, which can produce higher energy conversion efficiency. optics, etc. Moreover, LEDs using perovskite quantum dots as light-emitting bodies can achieve a nearly continuous emission spectrum, which is unmatched by other types of LEDs and fluorescent lamps. At present, the preparation methods of perovskite quantum dots CsPbX ₃ (X=Cl, I, Br) mainly include high temperature thermal injection method and room temperature reprecipitation method. High-temperature hot injection method can obtain CsPbX3 (X=Cl, I, Br) quantum dot products with high yield and high crystallinity, but it needs to be synthesized at high temperature (140-160 °C) and inert gas environment. The room temperature reprecipitation method can synthesize CsPbX ₃ (X=Cl, I, Br) in the atmospheric environment at room temperature. However, it is difficult to control its growth process kinetically and further adjust its luminescence properties due to the excessively intense and rapid reaction. The above synthesis method is applied to the light-emitting diode by dissolving the product in a solution and spin-coating it on the device as a light-emitting layer after synthesis, which is complicated in process and is not conducive to large-scale and commercial production. In the selection of functional layers, Ploy-TFB and Ploy-TPD are mostly used as hole transport layers in quantum dot light-emitting diodes, but as organic materials, their sensitivity to water and air is still in the development of quantum dot light-emitting diodes. problems that need to be solved urgently.

SUMMARY OF THE INVENTION

In order to solve the above technical problems, the present invention provides a method for in-situ synthesis of perovskite quantum dot light-emitting diodes based on inorganic hole transport materials. On this basis, a method for preparing high-efficiency and stable perovskite quantum dot light-emitting devices with CuI as the hole-transporting layer.

The technical solution of the present invention is as follows, based on the in-situ synthesis method of perovskite quantum dot light-emitting diodes based on inorganic hole transport materials, characterized in that the steps are as follows:

1) Take the ITO glass and put it into a beaker containing deionized water + detergent, deionized water, acetone, and isopropanol in turn, so that the liquid level does not cover all the ITO glass, and then use an ultrasonic machine to sonicate for 15 minutes. Finally, immerse the cleaned ITO glass in a beaker filled with alcohol and save it for later use.

2) Take out the ITO glass soaked in alcohol and wipe both sides of the glass with lens paper until there is no dust. The wiped ITO glass was placed in a glass dish in turn, and the lid was removed and placed in an ultraviolet ozone machine for 20 min.

3) Dissolve 1.25-2.5 mmol of PbBr in 10 mL of dimethylformamide, use a magnetic stirrer to heat to 90°C at a speed of 800 rpm, and continuously stir for 1-2.5 h to prepare a PbBr-dimethylformamide solution.

4) Dissolve 0.35-0.7 mmol CsBr in 10 mL of methanol, and use a magnetic stirrer at 600 rpm to stir continuously for 30 min at 25 ℃ to 35 ℃ to prepare a CsBr-methanol solution.

5) Dissolve 0.2 g of CuI in 10 mL of dipropyl sulfide, and use a magnetic stirrer at 600 rpm for continuous stirring for 30 min at 50 °C to prepare a CuI-dipropyl sulfide solution.

6) Dissolve 0.125g ZnO:Mg in 5mL ethanol, shake to dissolve for 20s, and prepare a ZnO:Mg-ethanol solution.

7) Use a 5 mL syringe to draw 2 mL of PEDOT:Pss aqueous solution, and install the filter head on the syringe.

8) Put the ITO glass treated by the UV ozone machine on the spin coater, add 50 μL to 70 μL of the PEDOT:PSS aqueous solution dropwise, and use the spin coater to spin at 2000rpm for 30s; then spin-coat the PEDOT:PSS aqueous solution. The ITO glass was annealed on a heating table at 120 °C for 30 min.

9) After the annealing in step 8), after the ITO glass was cooled to 25°C to 35°C, 20 μL of CuI-dipropyl sulfide solution was added dropwise onto the PEDOT:PSS layer, and the spin coater was used for spin coating at 2000 rpm. 30s, then annealed on a heating table at 120 °C for 20min;

10) After the annealing in step 9), after the ITO glass is cooled to 25℃～35℃, take 20～30μL of PbBr-dimethylformamide solution dropwise onto the CuI layer, and spin coat at 2500rpm using a spin coater 30 s, and then annealed on a heating table at 90 °C for 30 min.

11) After the annealing in step 10), after the ITO glass was cooled to 25°C to 35°C, 20 μL of CsBr-methanol solution was added dropwise onto the PbBr layer, and spin-coated at 3500 rpm for 30 s using a spin coater, and then placed on the PbBr layer. Annealed on a heating table at 250 °C for 5 min.

12) After the annealing in step 11), repeat step 11) four times to obtain CsPbBr3 _perovskite quantum dots by in-situ synthesis;

13) Dissolve 5 mg of PMMA in 10 mL of chloroform, and use a magnetic stirrer to continuously stir at 500 rpm for 6 hours at 50°C to prepare a PMMA-chloroform solution.

14) Add 50 μL of PMMA-chloroform solution dropwise to the quantum dot layer of step 12), spin-coat at 4000 rpm for 60 s using a spin coater, and then place it on a heating table at 90 °C for 30 min.

15) After the annealing in step 14), 60 μL of ZnO:Mg was added dropwise onto the PMMA layer, spin-coated at 2000 rpm for 40 s using a spin coater, and then placed on a heating table at 70 °C for 30 min.

16) Put the ITO glass spin-coated with each functional layer in step 15) into the evaporation box to evaporate the aluminum negative electrode, take it out and encapsulate it with UV curing glue on the side where the functional layer is spun to complete the production.

First, we carry out multi-step strict cleaning of the ITO glass with special patterns, put them in a container with deionized water + detergent, deionized water, acetone, isopropyl alcohol in turn, and use an ultrasonic machine to clean The instrument will ultrasonically vibrate it sufficiently so that its surface is free of stains. Afterwards, we gently wiped the surface of the ITO glass with lens tissue to remove possible residual dust, etc., and irradiated with an ultraviolet ozone machine to improve its surface work function and improve the charge transfer performance. Then, we sequentially prepared a certain concentration of each functional layer solution: PEDOT: Pss aqueous solution, CuI-dipropyl sulfide solution, CsBr-methanol solution, PbBr-dimethylformamide solution, ZnO: Mg-ethanol solution, and They are sequentially applied with a specific spin coating speed, dosage and annealing temperature to form a film of uniform thickness layer by layer. Among them, PEDOT:Pss is used as hole injection layer, CuI is used as hole transport layer, CsBr and PbBr are involved in the reaction to synthesize CsPbBr3 _perovskite quantum dots as light-emitting layer, ZnO:Mg is used as electron transport layer, and Al is used as negative electrode. The prepared perovskite quantum dot light-emitting diodes emit bright green light with a wavelength of about 600 nm.

The beneficial effects of the present invention are: 1. The multi-step spin-coating in-situ synthesis technology of the present invention provides a new method for preparing high-performance, high-stability all-inorganic perovskites, avoiding the use of traditional synthesis methods to synthesize After purification, re-dissolution, and exposure to air environment, the optical properties of quantum dots are rapidly degraded. 2. By optimizing each functional layer of the perovskite light-emitting diode, the inorganic material CuI with high light transmittance and good charge transport performance is used to replace the commonly used organic materials such as Ploy-TFB and Ploy-TPD as the hole transport layer. The light-emitting device solves the problem that the poor stability of organic materials affects the performance of the device. 3. The present invention has the advantages of simple process, low production difficulty, strong practicability and stable performance, and can be further commercialized to provide high-quality lighting and display equipment for human life.

Description of drawings

FIG. 1 is a schematic structural diagram of ITO glass and various functional coatings.

Detailed ways

The present invention is further described below with reference to the examples, by controlling the amount of PbBr and CsBr to control the thickness of the film of the perovskite quantum dot light-emitting layer, so as to achieve the effect of regulating the charge transport of the device.

Embodiment 1: As a preferred specific implementation case of the present invention, an in-situ synthesis and fabrication method of a perovskite quantum dot light-emitting diode based on an inorganic hole transport material, the steps are as follows (the coating sequence is shown in Figure 1) :

1) Take the ITO glass and put it into a beaker containing deionized water + detergent, deionized water, acetone, and isopropanol in turn, so that the liquid level does not cover all the ITO glass, and then use an ultrasonic machine to sonicate for 15 minutes. Finally, immerse the cleaned ITO glass in a beaker filled with alcohol and save it for later use.

2) Take out the ITO glass soaked in alcohol and wipe both sides of the glass with lens paper until there is no dust. The wiped ITO glass was placed in a glass dish in turn, and the lid was removed and placed in an ultraviolet ozone machine for 20 min.

3) Dissolve 1.25 mmol of PbBr in 10 mL of dimethylformamide, use a magnetic stirrer to heat to 90°C at 800 rpm, and continuously stir for 1 h to prepare a PbBr-dimethylformamide solution.

4) Dissolve 0.35 mmol of CsBr in 5 mL of methanol, and use a magnetic stirrer at 600 rpm for continuous stirring for 30 min at 30 °C to prepare a CsBr-methanol solution.

5) Dissolve 0.2 g of CuI in 10 mL of dipropyl sulfide, and use a magnetic stirrer at 600 rpm for continuous stirring for 30 min at 50 °C to prepare a CuI-dipropyl sulfide solution.

6) Dissolve 0.125g of ZnO:Mg in 5mL of ethanol, shake to dissolve for 20s, and prepare a ZnO:Mg-ethanol solution.

7) Use a 5mL syringe to draw 2mL of PEDOT:PSS aqueous solution, and install the filter head on the syringe.

8) Put the ITO glass treated with the UV ozone machine on the spin coater, add 60 μL of PEDOT:PSS aqueous solution dropwise, and use the spin coater to spin at 2000rpm for 30s; then spin the ITO glass with the PEDOT:PSS aqueous solution. Placed on a heating table at 120°C for 30min annealing.

9) After the annealing in step 8), after the ITO glass was cooled to 30°C, 20 μL of CuI-dipropyl sulfide solution was added dropwise onto the PEDOT:PSS layer, and the spin coater was used for spin coating at 2000 rpm for 30 s, and then It was annealed on a heating table at 120 °C for 20 min;

10) After the annealing in step 9), after the ITO glass was cooled to 30 °C, 30 μL of PbBr-dimethylformamide solution was added dropwise onto the CuI layer, and spin-coated at 2500 rpm for 30 s using a spin coater, and then the It was annealed on a heating table at 90°C for 30min.

11) After the annealing in step 10), after the ITO glass was cooled to 30°C, 40 μL of CsBr-methanol solution was added dropwise onto the PbBr layer, spin-coated at 3500rpm for 30s using a spin coater, and then placed at 250°C Annealed on a heating table for 5 min.

12) After the annealing in step 11), repeat step 11) four times to obtain CsPbBr3 _perovskite quantum dots by in-situ synthesis

13) Dissolve 5 mg of PMMA in 10 mL of chloroform, and use a magnetic stirrer to continuously stir at 500 rpm for 6 hours at 50°C to prepare a PMMA-chloroform solution.

14) Add 50 μL of PMMA-trichloromethane solution dropwise to the quantum dot layer of step 12), use a spin coater at 4000 rpm for 60 s, and then place it on a heating table at 90 °C for 30 min.

15) After the annealing in step 14), drop 60 μL of ZnO:Mg onto the PMMA layer, spin it with a spin coater at 2000 rpm for 40 s, and then place it on a heating table at 70 °C for 30 min.

16) Put the ITO glass spin-coated with each functional layer in step 15) into the evaporation box to evaporate the aluminum negative electrode, take it out and encapsulate it with UV curing glue on the side where the functional layer is spun to complete the production.

Embodiment 2: As another specific implementation case of the present invention, an in-situ synthesis and fabrication method of a perovskite quantum dot light-emitting diode based on an inorganic hole transport material, the steps are as follows (the coating sequence is shown in Figure 1):

1) Take the ITO glass and put it into a beaker containing deionized water + detergent, deionized water, acetone, and isopropanol in turn, so that the liquid level does not cover all the ITO glass, and then use an ultrasonic machine to sonicate for 15 minutes. Finally, immerse the cleaned ITO glass in a beaker filled with alcohol and save it for later use.

2) Take out the ITO glass soaked in alcohol and wipe both sides of the glass with lens paper until there is no dust. The wiped ITO glass was placed in a glass dish in turn, and the lid was removed and placed in an ultraviolet ozone machine for 20 min.

3) Dissolve 5 mmol of PbBr in 10 mL of dimethylformamide, use a magnetic stirrer to heat to 90°C at 800 rpm, and continue stirring for 2 h to prepare a PbBr-dimethylformamide solution.

4) Dissolve 0.7 mmol of CsBr in 10 mL of methanol, and use a magnetic stirrer to continuously stir for 30 min at 600 rpm at 25 °C to prepare a CsBr-methanol solution.

5) Dissolve 0.25 g of CuI in 10 mL of dipropyl sulfide, and use a magnetic stirrer at 600 rpm for continuous stirring for 30 min at 50 °C to prepare a CuI-dipropyl sulfide solution.

6) Dissolve 0.125g ZnO:Mg in 5mL ethanol, shake to dissolve for 20s, and prepare a ZnO:Mg-ethanol solution.

7) Use a 5mL syringe to draw 2mL of PEDOT:PSS aqueous solution, and install the filter head on the syringe.

8) Put the ITO glass treated by the UV-ozone machine on the spin coater, drop 50 μL of PEDOT:PSS aqueous solution, and use the spin coater to spin at 2000 rpm for 30 s. Then, the ITO glass spin-coated with the PEDOT:PSS aqueous solution was annealed on a heating table at 120 °C for 30 min.

9) After the annealing in step 8), after the ITO glass was cooled to 25°C, 20 μL of CuI-dipropyl sulfide solution was added dropwise onto the PEDOT:PSS layer, and spin-coated at 2000 rpm for 30 s using a spin coater. It was then annealed on a heating table at 120 °C for 20 min.

10) After the annealing in step 9), after the ITO glass was cooled to 25°C, 20 μL of PbBr-dimethylformamide solution was added dropwise onto the CuI layer, spin-coated at 2500 rpm for 30 s using a spin coater, and then the It was annealed on a heating table at 90°C for 30min.

11) After the annealing in step 10), after the ITO glass was cooled to 25°C, 20 μL of CsBr-methanol solution was added dropwise onto the PbBr layer, spin-coated at 3500rpm for 30s using a spin coater, and then placed at 250°C Annealed on a heating table for 5 min.

12) After the annealing in step 11), repeat step 11) four times to obtain CsPbBr3 _perovskite quantum dots by in-situ synthesis

13) Dissolve 5 mg of PMMA in 10 mL of chloroform, and use a magnetic stirrer to continuously stir at 500 rpm for 6 hours at 50°C to prepare a PMMA-chloroform solution.

14) Add 50 μL of PMMA-trichloromethane solution dropwise to the quantum dot layer of step 12), use a spin coater at 4000 rpm for 60 s, and then place it on a heating table at 90 °C for 30 min.

15) After the annealing in step 14), 60 μL of ZnO:Mg was added dropwise onto the PMMA layer, spin-coated at 2000 rpm for 40 s using a spin coater, and then placed on a heating table at 70 °C for 30 min.

16) Put the ITO glass spin-coated with each functional layer in step 15) into the evaporation box to evaporate the aluminum negative electrode, take it out and encapsulate it with UV curing glue on the side where the functional layer is spun to complete the production.

Embodiment 3: As another specific implementation case of the present invention, an in-situ synthesis and fabrication method of a perovskite quantum dot light-emitting diode based on an inorganic hole transport material, the steps are as follows (the coating sequence is shown in Figure 1):

1) Take the ITO glass and put it into a beaker containing deionized water + detergent, deionized water, acetone, and isopropanol in turn, so that the liquid level does not cover all the ITO glass, and then use an ultrasonic machine to sonicate for 15 minutes. Finally, immerse the cleaned ITO glass in a beaker filled with alcohol and save it for later use.

2) Take out the ITO glass soaked in alcohol and wipe both sides of the glass with lens paper until there is no dust. The wiped ITO glass was placed in a glass dish in turn, and the lid was removed and placed in an ultraviolet ozone machine for 20 min.

3) Dissolve 10 mmol of PbBr in 10 mL of dimethylformamide, use a magnetic stirrer to heat to 90°C at 800 rpm, and continuously stir for 2.5 h to prepare a PbBr-dimethylformamide solution.

4) Dissolve 0.7 mmol of CsBr in 10 mL of methanol, and use a magnetic stirrer to continuously stir for 30 min at 600 rpm at 35 °C to prepare a CsBr-methanol solution.

5) Dissolve 0.2 g of CuI in 10 mL of dipropyl sulfide, and use a magnetic stirrer at 600 rpm for continuous stirring for 30 min at 50 °C to prepare a CuI-dipropyl sulfide solution.

6) Dissolve 0.25g ZnO:Mg in 5mL ethanol, shake to dissolve for 20s, and prepare a ZnO:Mg-ethanol solution.

7) Use a 5mL syringe to draw 2mL of PEDOT:PSS aqueous solution, and install the filter head on the syringe.

8) Put the ITO glass treated with the UV-ozone machine on the spin coater, add 70 μL PEDOT:PSS aqueous solution dropwise, and use the spin coater to spin at 2000rpm for 30s. Then, the ITO glass spin-coated with the PEDOT:PSS aqueous solution was annealed on a heating table at 120 °C for 30 min.

9) After the annealing in step 8), after the ITO glass was cooled to 35°C, 20 μL of CuI-dipropyl sulfide solution was added dropwise onto the PEDOT:PSS layer, and the spin coater was used for spin coating at 2000 rpm for 30 s. It was then annealed on a heating table at 120 °C for 20 min

10) After the annealing in step 9), after the ITO glass was cooled to 35°C, 30 μL of PbBr-dimethylformamide solution was added dropwise onto the PEDOT:PSS layer, and the spin coater was used for spin coating at 3000 rpm for 30 s, and then It was annealed on a heating table at 90 °C for 30 min.

11) After the annealing in step 10), after the ITO glass was cooled to 35°C, 20 μL of CsBr-methanol solution was added dropwise onto the PbBr layer, spin-coated at 3500rpm for 30s using a spin coater, and then placed at 250°C Annealed on a heating table for 5 min.

112) After the annealing in step 11), repeat step 11) four times to obtain CsPbBr3 _perovskite quantum dots by in-situ synthesis

13) Dissolve 5 mg of PMMA in 10 mL of chloroform, and use a magnetic stirrer to continuously stir at 500 rpm for 6 hours at 50°C to prepare a PMMA-chloroform solution.

14) Add 50 μL LPMMA-trichloromethane solution dropwise to the quantum dot layer of step 12), spin-coat at 4000rpm for 60s using a spin coater, and then place it on a heating table at 90°C for 30min annealing.

15) After the annealing in step 14), 60 μL of ZnO:Mg was dropped onto the PMMA layer, spin-coated at 2500 rpm for 40 s using a spin coater, and then placed on a heating table at 70 °C for 30 min.

16) Put the ITO glass spin-coated with each functional layer in step 15) into the evaporation box to evaporate the aluminum negative electrode, take it out and encapsulate it with UV curing glue on the side where the functional layer is spun to complete the production.

Claims (1)

1. based on the in-situ synthesis method of inorganic hole transport material perovskite quantum dot light-emitting diode, it is characterized in that, its steps are as follows: 1) Take the ITO glass and put it into a beaker containing deionized water + detergent, deionized water, acetone, and isopropanol in turn, so that the liquid level does not cover all the ITO glass, and then use the ultrasonic machine to sonicate for 15 minutes; Immerse the cleaned ITO glass in a beaker filled with alcohol and save it for later use; 2) Take out the ITO glass soaked in alcohol, and wipe both sides of the glass with lens paper until there is no dust; put the wiped ITO glass into a glass dish in turn, remove the cover and place it in an ultraviolet ozone machine for 20 minutes; 3) Dissolve 1.25-2.5 mmol PbBr in 10 mL of dimethylformamide, use a magnetic stirrer to heat to 90°C at a speed of 800 rpm, and continuously stir for 1-2.5 h to prepare a PbBr-dimethylformamide solution; 4) Dissolve 0.35-0.7 mmol CsBr in 10 mL of methanol, and use a magnetic stirrer to continuously stir for 30 min at 600 rpm at 25 °C to 35 °C to prepare a CsBr-methanol solution; 5) Dissolve 0.2 g of CuI in 10 mL of dipropyl sulfide, and use a magnetic stirrer at 600 rpm for continuous stirring for 30 min at 50°C to prepare a CuI-dipropyl sulfide solution; 6) Dissolve 0.125g ZnO:Mg in 5mL of ethanol, shake and dissolve for 20s to prepare a ZnO:Mg-ethanol solution; 7) Use a 5mL syringe to draw 2mL of PEDOT:Pss aqueous solution, and install the filter head on the syringe; 8) Put the ITO glass treated by the UV ozone machine on the spin coater, add 50 μL to 70 μL of the PEDOT:PSS aqueous solution dropwise, and use the spin coater to spin at 2000rpm for 30s; then spin-coat the PEDOT:PSS aqueous solution. The ITO glass was annealed on a heating table at 120°C for 30min; 9) After the annealing in step 8), after the ITO glass was cooled to 25°C to 35°C, 20 μL of CuI-dipropyl sulfide solution was added dropwise onto the PEDOT:PSS layer, and the spin coater was used for spin coating at 2000 rpm. 30s, then annealed on a heating table at 120 °C for 20min; 10) After the annealing in step 9), after the ITO glass is cooled to 25℃～35℃, take 20～30μL of PbBr-dimethylformamide solution dropwise onto the CuI layer, and spin coat at 2500rpm using a spin coater 30s, then annealed on a heating table at 90°C for 30min; 11) After the annealing in step 10), after the ITO glass was cooled to 25°C to 35°C, 20 μL of CsBr-methanol solution was added dropwise onto the PbBr layer, and spin-coated at 3500 rpm for 30 s using a spin coater, and then placed on the PbBr layer. Annealed on a heating table at 250°C for 5min; 12) After the annealing in step 11), repeat step 11) four times to obtain CsPbBr3 _perovskite quantum dots by in-situ synthesis; 13) Dissolve 5 mg of PMMA in 10 mL of chloroform, and use a magnetic stirrer to continuously stir at 500 rpm for 6 hours at 50°C to prepare a PMMA-chloroform solution; 14) Add 50 μL PMMA-trichloromethane solution dropwise to the quantum dot layer of step 12), spin-coat at 4000rpm for 60s using a spin coater, and then place it on a heating table at 90°C for 30min annealing; 15) After the annealing in step 14), 60 μL of ZnO:Mg was dropped onto the PMMA layer, spin-coated at 2000 rpm for 40 s using a spin coater, and then placed on a heating table at 70 °C for 30 min of annealing; 16) Put the ITO glass spin-coated with each functional layer in step 15) into the evaporation box to evaporate the aluminum negative electrode, take it out and encapsulate it with UV curing glue on the side where the functional layer is spun to complete the production.

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