CN107579170A - A kind of crest is OLED of long wavelength and preparation method thereof - Google Patents

Abstract

The invention discloses an OLED device with a long-wavelength peak and a preparation method thereof. The OLED device with a long-wavelength peak is prepared by doping two short-wavelength materials with host and object, and the doped short-wavelength materials are different, and the peak is red-shifted. to varying degrees. Compared with preparing common OLED devices with long-wavelength peaks, the present invention adopts short-wavelength guest materials doped into short-wavelength hosts to prepare OLED devices with long-wavelength peaks in terms of device structure and materials, and the short-wavelength guest does not To emit light, the present invention uses low-cost short-wavelength materials to prepare long-wavelength OLED devices, and does not need to chemically synthesize deep red light objects, which has major breakthroughs in device structure, materials, cost, and wavelength.

Description

A kind of OLED device with long wavelength peak and its preparation method

technical field

The invention belongs to the technical field of OLED device preparation, and more specifically relates to an OLED device with a long wavelength peak and a preparation method thereof.

Background technique

Organic light-emitting diode (Organic Light-Emitting Diode, OLED) is an external electric field to make organic materials excite radiative transitions to emit light. Since Deng Qingyun and others published a research report on organic light-emitting diodes (OLEDs), OLEDs have attracted more and more attention. Organic electroluminescent diodes are known as "dream displays" for their active display, fast response speed, wide viewing angle, low power loss and wide operating temperature range, and have become the main force of the new generation in the field of display technology.

In how to prepare an OLED device, there are mainly the following methods: a) Use the blue fluorescent material CBP doped with the red phosphorescent material R-4B as the light-emitting layer to prepare a red OLED device, and the excitons produced by the fluorescent host material with a large energy gap Through the Forter energy transfer method, the energy is transferred to the red phosphorescent object, and then the radiation transitions to emit red light; b) By using the green Alq ₃ material as the host and the red fluorescent DCJTB material as the object, a red OLED device is prepared, and the object emits The mechanism of red light is the Forster energy transfer between host and guest. With the increase of doping concentration, the luminescence spectrum red shifts from 598nm to 629nm, and the color of luminescence changes from orange to red. This is because when the concentration is low, The energy transfer is insufficient, only a part of the energy is transferred to DCJTB to emit red light, and the rest of the energy is generated in AlQ to produce excitonic radiative transition and emit green light, so orange-red light is seen. When the concentration increases, the energy transfer is sufficient, and DCJTB emits red light; c ) by using the blue fluorescent material CBP as the host and Ir(MDQ) ₂ (acac) as the object to prepare a red OLED device. Forster energy transfer occurs between the host and the guest, and the peak of the luminous spectrum is 614nm, but the efficiency is not high. This is because the energy level difference between the red light and the guest is very small, the probability of non-radiative transition becomes larger, and the luminous efficiency is relatively low; d) TPAF : The exciplex formed by B3PYMPM was used as the host, and Ir(MDQ) ₂ acac was used as the guest, and a red OLED device was prepared. The hole-transport layer TPAF and the electron-transport layer B3PYMPM are mixed in an appropriate ratio to form an exciplex, and then the energy is transferred to the guest red phosphorescent material Ir(MDQ)2acac through Forter energy transfer, thereby radiating a transition to emit red light.

The above-mentioned OLED devices are all made by doping a short-wavelength host with a large energy gap and a long-wavelength guest with a small energy gap. ) is relatively complex, which leads to certain limitations in the preparation of traditional OLED devices.

Contents of the invention

In view of the above defects or improvement needs of the prior art, the present invention provides an OLED device with a long-wavelength peak and a preparation method thereof, thereby solving the problem that the long-wavelength materials used in the preparation process of the existing OLED device are not easy to obtain As a result, there are technical problems of certain limitations in the preparation of traditional OLED devices.

In order to achieve the above object, according to one aspect of the present invention, a method for preparing an OLED device with a wave peak of a long wavelength is provided, comprising:

(1) Clean the ITO glass sheet;

(2) dry the ITO glass flakes after cleaning and dry them in an oven;

(3) Ozone treatment is carried out to the ITO glass sheet after oven treatment;

(4) Put the ITO glass sheet after the ozone treatment into the evaporation chamber, and vacuumize;

(5) When the vacuum degree reaches the preset vacuum degree value, the hole injection layer, the hole transport layer, the exciton blocking layer, the light emitting layer, the electron transport layer, the electron injection layer and the cathode are sequentially evaporated, wherein, with a short The wavelength green light host material is doped with short-wavelength green light or yellow light guest material to evaporate to form a light-emitting layer;

(6) Encapsulation is carried out after the vapor deposition is completed to obtain an OLED device with a wave peak of a long wavelength.

Preferably, in step (5), the evaporation rate of the host material is a first preset rate; the evaporation rate of the guest material is different according to the doping concentration of the guest material, and the higher the doping concentration, the evaporation rate The larger is; the evaporation rate of the cathode is the second preset rate, and the evaporation rates of the remaining layers are the third preset rate.

Preferably, the host material of the light-emitting layer is 4CZIPN, and the guest material is x%Ir(ppy) ₃ , or, the host material of the light-emitting layer is 4CZIPN, and the guest material is x%Ir(ppy) ₂ (acac), Alternatively, the host material of the light-emitting layer is 4CZIPN, and the guest material is x% PO-01, wherein x% represents the doping concentration of the guest material.

Preferably, the first preset rate is 1 angstrom per second, the second preset rate is 3-4 angstrom per second, and the third preset rate is 1 angstrom per second.

Preferably, the preset vacuum value is 7x10 ^-4 Pa.

According to another aspect of the present invention, there is provided an OLED device with a long wavelength peak prepared by any one of the methods described above.

Generally speaking, compared with the prior art, the above technical solutions conceived by the present invention can achieve the following beneficial effects:

(1) Compared with the preparation of common peaks in the present invention, it is a long-wavelength OLED device. In terms of device structure and materials, the short-wavelength guest material is doped into the short-wavelength host to prepare a long-wavelength OLED device with a shorter wavelength. Wavelength objects do not emit light.

(2) The present invention utilizes low-cost short-wavelength materials to prepare long-wavelength OLED devices, wherein the light-emitting wavelength of the device is relatively large, and the maximum light-emitting wavelength can reach 684nm, and does not require chemical synthesis of deep red light objects. In terms of device structure, materials, and cost , wavelength and other aspects have a major breakthrough.

(3) There is no common energy transfer between host and guest materials, the host energy level does not wrap the guest energy level, and the light emitted by the device is not the light emitted by the guest material.

(4) The difference in the guest material and the doping concentration in the present invention lead to a different degree of red shift of the wave peak, and with the increase of the doping concentration of the guest material, the red shift degree of the light emitted by the radiative transition increases.

Description of drawings

FIG. 1 is a schematic structural view of an OLED device disclosed in an embodiment of the present invention;

Fig. 2 is the comparative figure of the luminescence spectrum of the OLED device luminescence spectrum and the corresponding standard OLED device that luminescent layer is 4CZIPN:x%Ir(ppy) ₃ ;

Fig. 3 is a comparison chart of the luminescence spectrum of an OLED device with a light-emitting layer of 4CZIPN:x%Ir(ppy) ₂ (acac) and the corresponding standard OLED device;

Fig. 4 is a comparison chart of the luminescence spectrum of the OLED device whose luminescent layer is 4CZIPN:x%PO-01 and the luminescence spectrum of the corresponding standard OLED device.

detailed description

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not constitute a conflict with each other.

As shown in Figure 1, it is a schematic structural diagram of an OLED device disclosed in an embodiment of the present invention, which are as follows from bottom to top: glass substrate, ITO layer, hole injection layer, hole transport layer, exciton blocking layer, light emitting layer , electron transport layer, electron injection layer and cathode. Among them, the exciton blocking layer is TCTA, the hole injection layer and the electron injection layer are MnO ₃ and LiF respectively, the hole transport layer and the electron transport layer are TAPC and TPBI respectively, and the light emitting layer is 4CZIPN:x%Ir(ppy) ₃ Or 4CZIPN:x%Ir(ppy) ₂ (acac) or 4CZIPN:x%PO-01, compared with the standard green thermal delay fluorescent device structure ITO/MnO ₃ /TAPC/TCTA/CBP:x%4CZIPN/ TPBI/LiF/Al, compared with the standard green phosphorescent device structure is ITO/MnO ₃ /TAPC/TCTA/CBP: x%Ir(ppy) ₃ /TPBI/LiF/Al,ITO/MnO ₃ /TAPC/TCTA /CBP:x%Ir(ppy) ₂ (acac)/TPBI/LiF/Al,ITO/MnO ₃ /TAPC/TCTA/CBP:x%PO-01/TPBI/LiF/Al and monolayer thermally delayed fluorescence The device structure is ITO/MnO ₃ /TAPC/TCTA/4CZIPN/TPBI/LiF/Al.

Wherein, the wave peak in the present invention is the preparation method of the OLED device of long wavelength, comprises:

(1) Clean the ITO glass sheet, including: successively use deionized water, ITO cleaning agent: deionized water (1:5), deionized water, acetone, deionized water, isopropanol to clean the ITO glass sheet;

(2) dry the ITO glass flakes after cleaning and dry them in an oven;

Wherein, after drying the isopropanol on the surface of the ITO glass sheet, the oven treatment can be carried out for 1 hour.

(3) Ozone treatment is carried out to the ITO glass sheet after oven treatment;

(4) Put the ITO glass sheet after the ozone treatment into the evaporation chamber, and vacuumize;

(5) When the vacuum degree reaches the preset vacuum degree value, the hole injection layer, the hole transport layer, the exciton blocking layer, the light emitting layer, the electron transport layer, the electron injection layer and the cathode are sequentially evaporated, wherein, with a short The wavelength green light host material is doped with short-wavelength green light or yellow light guest material to evaporate to form a light-emitting layer;

(6) Encapsulation is carried out after the vapor deposition is completed to obtain an OLED device with a wave peak of a long wavelength.

As an optional embodiment, in step (5), the evaporation rate of the host material is the first preset rate; the evaporation rate of the guest material is different according to the doping concentration of the guest material, and the doping The higher the concentration, the greater the evaporation rate; the evaporation rate of the cathode is the second preset rate, and the evaporation rates of the remaining layers are the third preset rate.

As an optional embodiment, the host material of the light-emitting layer is 4CZIPN, and the guest material is x%Ir(ppy) ₃ , or, the host material of the light-emitting layer is 4CZIPN, and the guest material is x%Ir(ppy) 3 . ) ₂ (acac), or, the host material of the light-emitting layer is 4CZIPN, and the guest material is x% PO-01, wherein, x% represents the doping concentration of the guest material.

As an optional implementation manner, the first preset rate is 1 angstrom per second, the second preset rate is 3-4 angstrom per second, and the third preset rate is 1 angstrom per second.

As an optional implementation manner, the preset vacuum value is 7x10 ^-4 Pa.

Example 1

Step 1. Tear off the protective film on the surface of the taken out ITO glass sheet, put it on a special shelf, and wash it in deionized water for 3 times, then put it into a 1:5 ITO cleaning agent and deionized water, and ultrasonically One hour, after ultrasonication, wash 3 times with deionized water, immerse in acetone solution, and sonicate for 15 minutes, wash 3 times with deionized water after sonication, then immerse in isopropanol solution, and sonicate for 15 minutes;

Step 2. After ultrasonication, dry the isopropanol on the ITO glass with a nitrogen gun, and put it in an oven for 1 hour;

Step 3. Take out the dried ITO glass sheet, select a clean ITO glass sheet and put it on the tray with the ITO face down and the back face up, stick it with high temperature glue, put it into the ozone processor for ozone treatment 40 minute;

Step 4. Put the material into the corresponding furnace source in advance, and clean the crystal oscillator, then put the ozone-treated film into the evaporation chamber, close the nitrogen valve and the chamber door, open the mechanical pump and pre-extraction valve, and vacuum gauge , when the vacuum degree reaches 3.4pa, close the pre-pumping valve, open the front valve, molecular pump, molecular pump valve, and vacuumize;

Step 5. When the vacuum reaches 7x10 ^-4 pa, turn on the corresponding furnace power supply, and sequentially evaporate MnO ₃ , TAPC, TCTA, 4CZIPN, Ir(ppy) ₃ , TPBI, LiF, Al, and 4CZIPN as the main material of the light-emitting layer. The plating rate is about 1 angstrom per second, the guest is Ir(ppy) ₃ , and the rate is different according to the doping concentration. The rate of 4%, 5%, 6%, and 8% doping concentration is 0.8 angstrom per second after being magnified 20 times. seconds, 1 angstrom per second, 1.2 angstrom per second, 1.6 angstrom per second, the evaporation rate of Al is 3-4 angstrom per second, and the other evaporation rates are 1 angstrom per second;

Step 6. After the evaporation is completed, close the valve of the molecular pump and the molecular pump. After 30 minutes, close the front valve, the molecular pump, and the vacuum gauge. The dried cover sheet is sent into the glove box, then sealed with encapsulant, cured with ultraviolet light, and the sealed sheet is taken out for testing.

Figure 2 shows the luminescence spectrum of an OLED device with a luminescent layer of 4CZIPN:x%Ir(ppy) ₃ and the luminescence spectrum of a corresponding standard OLED device. It can be seen from the figure that when the light-emitting layer is CBP:x%4CZIPN and CBP:x%Ir(ppy) ₃ , the host CBP and the guest 4CZIPN, Ir(ppy) ₃ undergo energy transfer, and emit green light at 518nm and 516nm , both are the light emitted by the guest 4CZIPN and Ir(ppy) ₃ , when Ir(ppy) ₃ is doped into 4CZIPN, the device emits deep red light, that is, two short-wavelength green materials produce deep red light, and As the doping concentration of the guest Ir(ppy) ₃ increases, the degree of red shift increases. When the doping concentration of the guest Ir(ppy) ₃ is 8%, the peak of the luminescence spectrum of the device is 684nm, compared with the traditional red light device , There are major breakthroughs in structural design, materials, cost, and wavelength.

Example 2

Step 1. Tear off the protective film on the surface of the taken out ITO glass sheet, put it on a special shelf, and wash it in deionized water for 3 times, then put it into a 1:5 ITO cleaning agent and deionized water, and ultrasonically One hour, after ultrasonication, wash 3 times with deionized water, immerse in acetone solution, and sonicate for 15 minutes, wash 3 times with deionized water after sonication, then immerse in isopropanol solution, and sonicate for 15 minutes;

Step 2. After ultrasonication, dry the isopropanol on the ITO glass with a nitrogen gun, and put it in an oven for 1 hour;

Step 3. Take out the dried ITO glass sheet, select a clean ITO glass sheet and put it on the tray with the ITO face down and the back face up, stick it with high temperature glue, put it into the ozone processor for ozone treatment 40 minute;

Step 4. Put the material into the corresponding furnace source in advance, and clean the crystal oscillator, then put the ozone-treated film into the evaporation chamber, close the nitrogen valve and the chamber door, open the mechanical pump and pre-extraction valve, and vacuum gauge , when the vacuum degree reaches 3.4pa, close the pre-pumping valve, open the front valve, molecular pump, molecular pump valve, and vacuumize;

Step 5. When the vacuum degree reaches 7x10 ^-4 pa, turn on the corresponding furnace power supply, and sequentially evaporate MnO ₃ , TAPC, TCTA, 4CZIPN, Ir(ppy) ₂ (acac), TPBI, LiF, Al, and the main body of the light-emitting layer The evaporation rate of the material 4CZIPN is about 1 angstrom per second, and the rate of the guest Ir(ppy) ₂ (acac) varies according to the doping concentration. The rate of the doping concentration of 5%, 6%, and 8% is amplified 20 times to 1 angstrom Per second, 1.2 angstroms per second, 1.6 angstroms per second, the evaporation rate of Al is 3-4 angstroms per second, and the other evaporation rates are 1 angstroms per second;

Step 6. After the evaporation is completed, close the valve of the molecular pump and the molecular pump. After 30 minutes, close the front valve, the molecular pump, and the vacuum gauge. The dried cover sheet is sent into the glove box, then sealed with encapsulant, cured with ultraviolet light, and the sealed sheet is taken out for testing.

3 shows the luminescence spectrum of an OLED device with a luminescent layer of 4CZIPN:x%Ir(ppy) ₂ (acac) and the luminescence spectrum of a corresponding standard OLED device. It can be seen from the figure that when the light-emitting layer is CBP:x%4CZIPN and CBP:x%Ir(ppy) ₂ (acac), the host CBP and the guest 4CZIPN, Ir(ppy) ₂ (acac) undergo energy transfer and emit The green light at 518nm and 520nm is the light emitted by the guest 4CZIPN, Ir(ppy) ₂ (acac). When Ir(ppy) ₂ (acac) is doped into 4CZIPN, it emits deep red light, and with the guest Ir( When the concentration of ppy) ₂ (acac) increases, the degree of red shift increases. When the doping concentration reaches 8%, the peak of the light emission spectrum of the device is 668nm. Compared with the traditional red light device, the structure design, material, cost, wavelength There is a major breakthrough.

Example 3

Step 1. Tear off the protective film on the surface of the taken out ITO glass sheet, put it on a special shelf, and wash it in deionized water for 3 times, then put it into a 1:5 ITO cleaning agent and deionized water, and ultrasonically One hour, after ultrasonication, wash 3 times with deionized water, immerse in acetone solution, and sonicate for 15 minutes, wash 3 times with deionized water after sonication, then immerse in isopropanol solution, and sonicate for 15 minutes;

Step 2. After ultrasonication, dry the isopropanol on the ITO glass with a nitrogen gun, and put it in an oven for 1 hour;

Step 3. Take out the dried ITO glass sheet, select a clean ITO glass sheet and put it on the tray with the ITO face down and the back face up, stick it with high temperature glue, put it into the ozone processor for ozone treatment 40 minute;

Step 4. Put the material into the corresponding furnace source in advance, and clean the crystal oscillator, then put the ozone-treated film into the evaporation chamber, close the nitrogen valve and the chamber door, open the mechanical pump and pre-extraction valve, and vacuum gauge , when the vacuum reaches 3.4pa, close the pre-pumping valve, open the front valve, molecular pump, molecular pump valve, vacuumize

Step 5. When the vacuum degree reaches 7x10 ^-4 pa, turn on the corresponding furnace power supply, and sequentially evaporate MnO ₃ , TAPC, TCTA, 4CZIPN, PO-01, TPBI, LiF, Al, and the evaporation rate of the main material of the light-emitting layer 4CZIPN It is about 1 angstrom per second, and the rate of guest PO-01 is different according to the doping concentration. The rate of 6%, 7% doping concentration is enlarged 20 times to 1.2 angstrom per second, 1.4 angstrom per second, and the evaporation rate of Al is 3-4 angstroms per second, and the other evaporation rates are 1 angstroms per second;

Step 6. After the evaporation is completed, close the valve of the molecular pump and the molecular pump. After 30 minutes, close the front valve, the molecular pump, and the vacuum gauge. The dried cover sheet is sent into the glove box, then sealed with encapsulant, cured with ultraviolet light, and the sealed sheet is taken out for testing.

4 shows the luminescence spectrum of the OLED device whose luminescent layer is 4CZIPN:x%PO-01 and the luminescence spectrum of the corresponding standard OLED device. When the light-emitting layer is CBP: x% 4CZIPN and CBP: x% PO-01, the host CBP and the guest 4CZIPN, PO-01 undergo energy transfer, and emit light at 518nm and 564nm, both of which are emitted by the guest 4CZIPN, PO-01 Light. When the yellow light material PO-01 is doped into 4CZIPN, it emits orange-red light, and the greater the guest concentration, the greater the red shift. When the doping concentration is 7%, the device emits a spectrum with a wavelength of 624nm, and its spectrum has A shoulder peak is 572nm, and the shoulder peak wavelength is the same as the emission wavelength of single-layer delayed fluorescent OLED. Compared with traditional red light devices, there are major breakthroughs in device structure design, materials, and cost.

Those skilled in the art can easily understand that the above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention, All should be included within the protection scope of the present invention.

Claims (6)

1. a kind of crest is the preparation method of the OLED of long wavelength, it is characterised in that including：

(1) ito glass piece is cleaned；

(2) oven after the ito glass piece after cleaning being dried up and dried up；

(3) ozone processing is carried out to the ito glass piece after oven；

(4) the ito glass piece after ozone is handled is put into evaporation storehouse, is vacuumized；

(5) when vacuum reaches predetermined vacuum angle value, evaporation forms hole injection layer, hole transmission layer, exciton blocking successively Layer, luminescent layer, electron transfer layer, electron injecting layer and negative electrode, wherein, with short wavelength's green glow material of main part, doping short wavelength is green Light or gold-tinted guest materials are deposited to form luminescent layer；

(6) it is packaged to obtain the OLED that crest is long wavelength after the completion of being deposited.

2. according to the method for claim 1, it is characterised in that in step (5), the evaporation rate of material of main part is first Scheduled rate；The evaporation rate of guest materials is according to the difference of the doping concentration of guest materials, and evaporation rate is also different, and doping is dense Degree is higher, and evaporation rate is bigger；The evaporation rate of negative electrode is the second scheduled rate, and the evaporation rate of remaining each layer is the 3rd pre- If speed.

3. according to the method for claim 1, it is characterised in that the material of main part of the luminescent layer is 4CZIPN, object material Expect for x%Ir (ppy)₃, or, the material of main part of the luminescent layer is 4CZIPN, and guest materials is x%Ir (ppy)₂(acac), Or the material of main part of the luminescent layer is 4CZIPN, guest materials x%PO-01, wherein, x% represents mixing for guest materials Miscellaneous concentration.

4. according to the method in claim 2 or 3, it is characterised in that first scheduled rate is 1 angstrom per second, described the Two scheduled rates are 3~4 angstroms per second, and the 3rd scheduled rate is 1 angstrom per second.

5. according to the method for claim 1, it is characterised in that the predetermined vacuum angle value is 7x10^-4pa。

6. the crest prepared such as claim 1 to 5 any one methods described is the OLED of long wavelength.