Blue Light Exciplex Layer for OLED Crosstalk Suppression
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Solution Overview
Problem
In organic electroluminescent devices using a hybrid process, the blue light emitting layer inadvertently emits light when the red or green light emitting layers are activated, due to inappropriate selection of materials in the hybrid connecting layer, leading to inefficient light emission.
Innovation Solution
The organic electroluminescent device incorporates a blue light emitting layer with specific proportions of electron transport and hole transport materials that form a blue light exciplex, ensuring electrons and holes recombine within the red or green light emitting layers, preventing unwanted light emission from the blue layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a blue light emitting layer is placed over red and green light emitting layers in a hybrid process, then the device structure is simplified and manufacturing is easier, but unwanted blue light emission occurs when red or green layers are activated
Solution Approach 1:
The blue light emitting layer is designed with spatially varying material composition: the first portion covering the red and green light emitting layers contains electron transport material and hole transport material forming a blue light exciplex, while the second portion has different material proportions. This local quality variation ensures that electrons and holes recombine only in the red or green light emitting layers when those layers are activated, preventing unwanted blue light emission from the first portion, while maintaining simplified device structure
Solution Approach 2:
The material composition parameters of the blue light emitting layer are precisely controlled: the proportions of electron transport material and hole transport material in the first portion are matched to the electron transport abilities of the red and green light emitting layers, while the second portion has different proportions. This parameter change approach allows the blue light emitting layer to serve dual functions: enabling blue light emission when needed and preventing unwanted blue light emission when red or green layers are activated
2Illumination intensity
If the blue light emitting layer uses standard material proportions, then the blue light emission is strong, but electrons and holes recombine in the blue layer causing crosstalk when red or green layers should be emitting
Solution Approach 1:
The blue light emitting layer exhibits different local qualities in its first and second portions. The first portion has electron transport material and hole transport material in proportions matched to the electron transport abilities of the red and green light emitting layers, which suppresses blue light emission when those layers are activated. The second portion has different material proportions that enable strong blue light emission when the blue layer is intended to emit. This local quality differentiation resolves the contradiction between strong blue light emission and prevention of light emission crosstalk
3Ease of manufacture
If the electron transport material and hole transport material proportions in the blue light emitting layer do not match the electron transport abilities of red and green layers, then the device is easier to manufacture with standard materials, but electrons and holes recombine in the blue light emitting layer causing unwanted emission
Solution Approach 1:
The material composition parameters of the blue light emitting layer are precisely adjusted: the proportions of electron transport material and hole transport material in the first portion are matched to the electron transport abilities of the red and green light emitting layers, while the second portion has different proportions. This parameter optimization ensures that electrons and holes recombine only in the intended red or green light emitting layers when those layers are activated, preventing unwanted blue light emission and ensuring reliable light emission control
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 solution ensures that only the red or green light emitting layers emit light, improving light efficiency and eliminating unnecessary blue light emission, thus enhancing the display device's performance and simplifying its structure.
Implementation Method 1
The material of the blue light emitting layer comprises an electron transport material and a hole transport material that can form a blue light exciplex
Implementation Method 2
The blue light emitting layer comprises a first portion and a second portion... so that electrons and holes would not recombine within and at an edge of the first portion of the blue light emitting layer
Data Source
AI summary
The present disclosure provides an organic electroluminescent device and a display device. The material of the blue light emitting layer in the organic electroluminescent device comprises an electron transport material and a hole transport material that can form a blue light exciplex. The proportions respectively occupied by the electron transport material and the hole transport material of the blue light emitting layer in all materials of the blue light emitting layer match with the abilities of the red light emitting layer and the green light emitting layer to transport electrons, so that electrons and holes would not recombine within and at an edge of the portion of the blue light emitting layer that covers the red light emitting layer and the green light emitting layer when the red light emitting layer and/or the green light emitting layer is required to emit light.