Preparation method of carbon-based quantum down-conversion material and WOLED device

Abstract

The application discloses a kind of carbon-based quantum light conversion materials and the preparation method of WOLED device, comprising: preparing carbon-based quantum light conversion material;Form a layer of anode on substrate;Hole injection layer, hole transport layer, light emitting layer, electron transport layer, electron injection layer, semi-transparent cathode are deposited in sequence on anode;Carbon-based quantum light material mixed solution is coated on semi-transparent cathode by spin coating to form carbon-based quantum color conversion layer;After color conversion layer solidification, continue to spray carbon-based quantum light conversion material mixed solution on color conversion film layer by inkjet printing, after heating, vacuumizing by reducing pressure makes the second layer color conversion layer solidification and forms semi-circular lens structure plane;Carrying out cover packaging.The WOLED made by the application simplifies process flow, simple structure.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of organic light-emitting device preparation, and particularly relates to a carbon-based quantum down-conversion material and a preparation method of a WOLED device. BACKGROUND

[0002] An organic light-emitting diode (OLED) display has advantages of self-emission, thinness, wide viewing angle, low power consumption and flexible display. A white light OLED, as a kind of organic electroluminescence, is widely concerned in the industry for its application in lighting and display.

[0003] A white organic electroluminescence diode (WOLED) has characteristics of energy saving and high efficiency, thinness, environmental protection and large-area thin film manufacturing, and has a broad application prospect in the field of full-color display. However, the structure of the WOLED is more complex than that of other color OLED devices, which is destined to have the significant disadvantage of complicated preparation process of the WOLED device for white light emission. Therefore, simplifying the preparation process and making the structure and process flow of the WOLED simple have become a research focus.

[0004] The color conversion layer is a method for realizing a white light organic electroluminescence device. The prior art usually adopts yellow or red fluorescent powder pumped by blue light to realize white light emission. The light conversion structure of the white light device has low luminous efficiency. SUMMARY

[0005] One of the technical problems to be solved by the application is to provide a preparation method of a carbon-based quantum light conversion material. The material prepared by the method has a light conversion function, can convert long-wavelength light into short-wavelength light, and can be used for the preparation of a WOLED device.

[0006] The second technical problem to be solved by the application is to provide a preparation method of a WOLED device, which simplifies the process flow and has a simple structure.

[0007] The application is implemented in the following manner.

[0008] A preparation method of a carbon-based quantum light conversion material comprises the following steps.

[0009] Step S1: In a nitrogen environment, a reaction bottle is filled with tetrahydrofuran solution, an ultrasonic oscillator is turned on, and graphite powder is added to the tetrahydrofuran solution, and ultrasonic oscillation is performed for 5 hours to disperse the graphite powder in the tetrahydrofuran solution.

[0010] Step S2: SnCl4.5H2O or ZnCl2.3H2O is weighed and dissolved in an ethanol solution, and after magnetic stirring and uniform mixing, an ethanolamine solution is added, and uniform stirring is performed to obtain a precursor solution.

[0011] Step S3: adding lithium metal into the solution prepared in step S1, adding the solution prepared in step S2 into the obtained mixed solution, and then transferring the solution into a pressure reactor for reaction, heating to 110°C for 24h, cooling to room temperature, and obtaining a crude product;

[0012] Step S4: washing the obtained crude product with deionized water for three times, and drying in an oven to obtain a target product;

[0013] Step S5: under ultrasonic environment, pouring the toluene solution into a reaction bottle, and adding the obtained target product into the toluene solution in batches, and ultrasonic oscillation for 3h to make the target product dispersed in the toluene solution;

[0014] Step S6: dissolving the obtained product in ethylene glycol dimethyl ether, and obtaining a carbon-based quantum light conversion material.

[0015] Further, in step S1, the component ratio of tetrahydrofuran solution and graphite powder is 500ml:10.5g.

[0016] Further, in step S2, the component ratio of SnCl4·5H2O or ZnCl2·3H2O and ethanol is 3.0g:300ml, and the component ratio of ethanol and ethanolamine solution is 6ml:300ml.

[0017] A preparation method of a WOLED device, comprising the following steps:

[0018] forming an anode layer on a substrate;

[0019] evaporating and depositing a hole injection layer HIL on the anode layer;

[0020] evaporating and depositing a hole transport layer HTL on the hole injection layer;

[0021] evaporating and depositing an emitting layer EML on the hole transport layer;

[0022] evaporating and depositing an electron transport layer ETL on the emitting layer;

[0023] evaporating and depositing an electron injection layer EIL on the electron transport layer;

[0024] evaporating and depositing a semi-transparent cathode CT on the electron injection layer;

[0025] mixing the carbon-based quantum light conversion material solution prepared by the preparation method of the carbon-based quantum light conversion material as described above, and coating the solution on the semi-transparent cathode by a spin coating method; promoting volatilization of the solution by a heating function on a spin coating platform and reducing pressure and vacuumizing, to form a carbon-based quantum light conversion layer;

[0026] After the color conversion layer is cured, a carbon-based quantum light conversion material mixed solution is continuously sprayed on the color conversion film layer by inkjet printing, and the second color conversion layer is cured to form a semicircular lens structure plane through heating and vacuumizing under reduced pressure;

[0027] Carrying out cover plate packaging.

[0028] The carbon-based quantum dot down-conversion material is placed on a WOLED semi-transparent cathode film by a spin coating method to form a light conversion film, light conversion is realized, long-wavelength light is self-converted into short-wavelength light, white light OLED lighting is realized, the process flow is simplified, and the structure is simple. BRIEF DESCRIPTION OF DRAWINGS

[0029] The application will be further described below with reference to the drawings and embodiments.

[0030] Figure 1 is a structure schematic diagram when a first light conversion layer of a WOLED device of the application is prepared.

[0031] Figure 2 is a structure schematic diagram when a first light conversion layer of a WOLED device of the application is prepared.

[0032] Figure 3 is a structure schematic diagram of a WOLED device of the application.

[0033] Figure 4 is a color coordinate diagram of a WOLED device of the application. DETAILED DESCRIPTION

[0034] A preparation method of a carbon-based quantum light conversion material, comprising the following steps:

[0035] Step S1: under a nitrogen environment, 500ml of a tetrahydrofuran solution is poured into a reaction bottle, an ultrasonic oscillator is opened, 10.5g of graphite powder is added to the tetrahydrofuran solution, and ultrasonic oscillation is performed for 5h, so that the graphite powder is dispersed in the tetrahydrofuran solution;

[0036] Step S2: 3.0g of SnCl4.·5H2O or ZnCl2.·3H2O is weighed and dissolved in 300ml of an ethanol solution, after magnetic stirring and uniform mixing, 1500ml of an ethanolamine solution is added, and uniform stirring is performed to obtain a precursor solution;

[0037] Step S3: 3.0g of metallic lithium is added to the solution prepared in step S1, the solution in step S2 is added to the obtained mixed solution, and then the mixed solution is transferred to a pressure reaction kettle for reaction, heating is performed to 110℃, and reaction is performed for 24h, and then cooling is performed to room temperature to obtain a crude product;

[0038] Step S4: the obtained crude product is washed with deionized water three times, and dried in an oven to obtain the target product;

[0039] Step S5: under ultrasonic environment, 800ml of toluene solution is poured into a reaction bottle, and the obtained target product is added into the toluene solution in batches, and ultrasonic oscillation is performed for 3h, so that the target product is dispersed in the toluene solution;

[0040] Step S6: the obtained product is dissolved in 200ml of ethylene glycol dimethyl ether, and the carbon-based quantum light conversion material is obtained.

[0041] The application also provides a preparation method of the WOLED device, comprising the following steps:

[0042] forming an anode layer on a substrate;

[0043] depositing a hole injection layer HIL on the anode layer by evaporation;

[0044] depositing a hole transport layer HTL on the hole injection layer by evaporation;

[0045] depositing an emitting layer EML on the hole transport layer by evaporation;

[0046] depositing an electron transport layer ETL on the emitting layer by evaporation;

[0047] depositing an electron injection layer EIL on the electron transport layer by evaporation;

[0048] depositing a semi-transparent cathode CT on the electron injection layer by evaporation;

[0049] mixing the carbon-based quantum light conversion material prepared by the preparation method of the carbon-based quantum light conversion material and a solvent to prepare a carbon-based quantum light conversion material mixed solution, and coating the carbon-based quantum light conversion material mixed solution on the semi-transparent cathode by a spin coating method; the carbon-based quantum light conversion material mixed solution is volatilized to form a carbon-based quantum light conversion layer by a heating function on a spin coating platform and under reduced pressure; Figure 1 as shown in FIG. 4;

[0050] after the light conversion layer is solidified, the carbon-based quantum dot material mixed solution is continuously sprayed on the light conversion film layer by an inkjet printing method, and the second light conversion layer is solidified to form a semi-transparent lens structure plane by heating and vacuumizing under reduced pressure; Figure 2 as shown in FIG. 5;

[0051] performing cover plate packaging.

[0052] Figure 3 FIG. 6 is a structural schematic diagram of the WOLED device of the application.

[0053] The carbon-based quantum light conversion material prepared by the application is placed on a WOLED semi-transparent cathode film by a spin coating method to form a light conversion film, light conversion is realized, long-wavelength light is self-converted into short-wavelength light, and WOLED lighting is realized, which simplifies the process flow and has a simple structure.

[0054] The color coordinates of the WOLED device prepared by the application are CIEx: 0.322 and CIEy: 0.353, that is, the WOLED device emits warm white light. Figure 4

[0055] The EQE (external quantum efficiency) of the WOLED device prepared by the application is 6.8%, which indicates that the carbon-based quantum light conversion material can improve the light extraction efficiency of the device. The light extraction rate is the ratio of the external quantum efficiency (EQE) and the internal quantum efficiency. The internal quantum efficiency is the actual light emission efficiency of the light-emitting layer, the structure of the light-emitting layer of the OLED device is unchanged, so the internal quantum efficiency is considered as a constant value, and the external quantum efficiency is indirectly considered as the judgment of the light extraction rate.

[0056] The above examples and drawings are not limited to the product form and style of the application, and any appropriate changes or modifications made by those skilled in the art to the application should be considered as not departing from the patent scope of the application.​

Claims

1. A method for preparing a carbon-based quantum light conversion material, characterized in that: The method comprises the following steps: Step S1: under the nitrogen environment, pour tetrahydrofuran solution into the reaction bottle, open the ultrasonic oscillator, add graphite powder into the tetrahydrofuran solution, and ultrasonic oscillation for 5 hours to make the graphite powder dispersed in the tetrahydrofuran solution; Step S2: weigh SnCl4·5H2O or ZnCl2·3H2O, dissolve in ethanol solution, magnetically stir to mix uniformly, then add ethanolamine solution, and stir uniformly to obtain a precursor solution; Step S3: add lithium metal into the solution prepared in step S1, add the solution in step S2 into the obtained mixed solution, then transfer into a pressure reaction kettle, react, heat to 110 DEG C for 24 hours, cool to room temperature, and obtain a crude product; Step S4: wash the obtained crude product with deionized water for three times, and place into an oven to dry, to obtain a target product; Step S5: under the ultrasonic environment, pour toluene solution into the reaction bottle, add the obtained target product into the toluene solution in batches, ultrasonic oscillation for 3 hours, to make the target product dispersed in the toluene solution; Step S6: dissolve the obtained product in ethylene glycol dimethyl ether, to obtain a carbon-based quantum light conversion material.

2. The method for preparing a carbon-based quantum light conversion material as described in claim 1, characterized in that: In the step S1, the component ratio of the tetrahydrofuran solution and the graphite powder is 500 ml:10.5 g.

3. The method for preparing a carbon-based quantum light conversion material as described in claim 1, characterized in that: In the step S2, the component ratio of SnCl4·5H2O or ZnCl2·3H2O and ethanol is 3.0 g:300 ml, and the component ratio of the ethanol and the ethanolamine solution is 6 ml:300 ml.

4. A method of fabricating a WOLED device, characterized by: The method comprises the following steps: forming an anode on a substrate; evaporating and depositing a hole injection layer HIL on the anode; evaporating and depositing a hole transport layer HTL on the hole injection layer; evaporating and depositing an emitting layer EML on the hole transport layer; evaporating and depositing an electron transport layer ETL on the emitting layer; evaporating and depositing an electron injection layer EIL on the electron transport layer; evaporating and depositing a semi-transparent cathode CT on the electron injection layer; mixing the carbon-based quantum light conversion material solution prepared by the method for preparing a carbon-based quantum light conversion material according to any one of claims 1 to 3 on the semi-transparent cathode by the way of spin coating; promoting the volatilization of the solution to form a carbon-based quantum color conversion layer by the heating function on the spin coating platform and reducing pressure vacuumization; after the color conversion layer is solidified, continuously spraying the carbon-based quantum light conversion material solution on the color conversion film layer by the way of inkjet printing, and solidifying the second color conversion layer to form a semi-circular lens structure plane by heating and reducing pressure vacuumization; performing cover plate packaging.

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