Heat-Generating Member for OLED Light-Emitting Layer Efficiency
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Solution Overview
Problem
Conventional organic electroluminescent display devices face challenges in enhancing fluorescence emission efficiency, particularly in the reverse intersystem crossing of light-emitting materials like thermally activated delayed fluorescent materials from the excited triplet state to the excited singlet state.
Innovation Solution
Incorporating a heat-generating member, such as a heat source resistor, to supply heat to the light-emitting layer, which promotes reverse intersystem crossing and improves fluorescence emission efficiency by controlling voltage applied to heat source power supply lines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If thermally activated delayed fluorescent material is used in the light-emitting layer, then the device can achieve phosphorescent-level efficiency, but the fluorescence emission efficiency and reverse intersystem crossing rate remain insufficient
Solution Approach 1:
The patent applies parameter changes by introducing a heat-generating member that supplies thermal energy to the light-emitting layer. This thermal energy increases the temperature of the light-emitting layer, which accelerates the reverse intersystem crossing process from triplet state to singlet state, thereby improving fluorescence emission efficiency and reducing afterimage effects.
2Device complexity
If conventional light-emitting materials are used without additional heat supply, then the device structure remains simple, but afterimages occur and fluorescence emission efficiency is limited
Solution Approach 1:
The patent converts the harmful afterimage effect into a beneficial outcome by using a heat-generating member. The heat supplied accelerates the reverse intersystem crossing process, which eliminates trapped triplet states that cause afterimages. This transforms the previously harmful thermal effects into a useful mechanism for improving display quality and reducing afterimages.
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
The solution enhances fluorescence emission efficiency and reduces the likelihood of afterimages by effectively converting excited triplet states to excited singlet states, thereby improving the overall performance of the light-emitting layer in organic electroluminescent display devices.
Implementation Method 1
a heat-generating member supplying heat to the first light-emitting layer
Implementation Method 2
the efficiency of reverse intersystem crossing of a light-emitting material, such as the thermally activated delayed fluorescent material, used for the light-emitting layer to the excited singlet state after transition to the excited triplet state
Data Source
AI summary
A display device includes: a substrate; a first organic light-emitting diode including a first electrode provided above the substrate for each of pixels, a second electrode, and a first light-emitting layer provided between the first electrode and the second electrode; and a heat-generating member supplying heat to the first light-emitting layer.