OLED Emitter Doping Ratio Stabilization via Alcohol Heat Treatment
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Solution Overview
Problem
The existing method of forming an emitting layer in OLEDs using vacuum evaporation often results in a change in the doping ratio of host and dopant materials, leading to reduced light emitting efficiency due to different dissipation rates, which affects the uniform distribution of excitons and the performance and lifespan of OLED devices.
Innovation Solution
A treatment method involving alcohol heat treatment of the host and dopant materials in a vacuum glove box, followed by centrifugation and drying, ensures they are dissipated in the same proportion during vacuum evaporation, maintaining the optimal doping ratio and enhancing light emitting efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If vacuum evaporation is used to form the emitting layer with host and dopant materials, then the emitting layer can be formed efficiently, but the doping ratio changes during the evaporation process due to different dissipation rates, reducing light emitting efficiency
Solution Approach 1:
The patent applies preliminary action by pre-mixing the host and dopant materials in a solvent before evaporation. This pre-mixing ensures that the materials are uniformly distributed at the molecular level before the evaporation process begins, preventing the doping ratio from changing during evaporation due to different dissipation rates. The pre-formed complex maintains the intended doping ratio throughout the layer formation process.
Solution Approach 2:
The patent uses a solvent as an intermediary substance to facilitate uniform mixing and distribution of host and dopant materials. The solvent acts as a mediator that allows the materials to form a stable complex with the desired doping ratio before evaporation, ensuring that the final emitting layer maintains the intended composition without the precision losses that would occur with direct evaporation of pure materials.
2Loss of energy
If the doping ratio is optimized for maximum light emitting efficiency, then the light emitting efficiency is maximized, but the different dissipation rates of host and dopant during vacuum evaporation cause the final doping ratio to deviate from the optimal value
Solution Approach 1:
The patent applies preliminary action by pre-mixing the host and dopant materials in a solvent before evaporation. This pre-mixing ensures that the materials are uniformly distributed at the molecular level before the evaporation process begins, preventing the doping ratio from changing during evaporation due to different dissipation rates. The pre-formed complex maintains the intended doping ratio throughout the layer formation process.
Solution Approach 2:
The patent changes the physical state and interaction parameters of the host and dopant materials by dissolving them in a solvent. This parameter change allows the materials to form a stable complex with a fixed doping ratio, preventing the composition from changing during the evaporation process. The solvent-mediated interaction stabilizes the doping ratio while maintaining the optimal light emitting efficiency.
3Manufacturing precision
If alcohol heat treatment is applied to host and dopant materials before vacuum evaporation, then the doping ratio is maintained uniformly, but the process time and temperature control requirements increase
Solution Approach 1:
The patent changes the physical state and interaction parameters of the host and dopant materials by dissolving them in a solvent and applying controlled heat treatment. This parameter change allows the materials to form a stable complex with a fixed doping ratio, preventing the composition from changing during the evaporation process. The solvent-mediated interaction stabilizes the doping ratio while maintaining the optimal light emitting efficiency.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method maintains the designed optimal doping ratio, improving the light emitting efficiency and service life of OLED devices by ensuring uniform exciton distribution across the emitting layer, with a 20% increase in external quantum efficiency compared to conventional methods.
Implementation Method 1
adding the host, the dopant and anhydrous ethanol into a polytetrafluoroethylene lining to be mixed uniformly to obtain a mixed solution, and putting the lining in a high pressure autoclave to be treated at a temperature of 40 to 60 celsius degree for 18 to 36 hours to obtain a treatment liquid
Implementation Method 2
centrifuging the treatment liquid to collect a precipitate
Implementation Method 3
The treating agent penetrates and diffuses into the host and dopant materials during heat treatment
Implementation Method 4
The vacuum evaporation is a process of placing the material to be film into a vacuum environment for evaporation or sublimation to cause to precipitate on the surface of the substrate
Implementation Method 5
The vacuum evaporation is a process of placing the material to be film into a vacuum environment for evaporation or sublimation to cause to precipitate on the surface of the substrate
Data Source
AI summary
Provided is a treatment method of an emitting layer raw material in an OLED, comprising steps of: (1) providing the emitting layer raw material, and the emitting layer raw material comprising a host and a dopant, and in a vacuum glove box with protective gas, adding the host, the dopant and anhydrous ethanol into a polytetrafluoroethylene lining to be mixed uniformly, and putting the lining in a high pressure autoclave to be treated at a temperature of 40 to 60 celsius degrees for 18 to 36 hours to obtain a treatment liquid; (2) centrifuging the treatment liquid to collect a precipitate, and drying the collected precipitate to obtain the emitting layer raw material after treatment. The resulting treated emitting layer raw material achieves sufficient mixing and dispersion of the host and the dopant, and does not affect the subsequent use of vacuum evaporation method to form an emitting layer.