White OLED Blue Emission Layer for Higher Color Purity
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Solution Overview
Problem
Existing white light organic light-emitting devices (OLEDs) suffer from low light-emitting efficiency and color purity issues due to the poor performance of blue light-emitting materials, leading to yellowish emission of white light.
Innovation Solution
The use of a blue light-emitting layer doped with a first dopant material having a triplet-triplet annihilation effect, where the triplet energy level of the first dopant material is higher than that of the second dopant material in the adjacent light-emitting layer, prevents triplet energy transfer and enhances exciton utilization, thereby improving blue light-emitting efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If blue light-emitting materials are used in white light OLEDs, then the device can emit white light, but the light-emitting efficiency is low and color purity deteriorates causing yellowish emission
Solution Approach 1:
The patent changes the energy level parameter of the dopant material, specifically setting the triplet energy level of the first dopant material (in blue light-emitting layer) to be higher than that of the second dopant material (in green light-emitting layer). This parameter change prevents triplet energy transfer from green to blue layer, thereby improving both light-emitting efficiency and color purity of the white light OLED
Solution Approach 2:
The patent uses composite doping strategy by combining different dopant materials in different light-emitting layers. The first dopant material is doped in the blue light-emitting layer while the second dopant material is doped in the green light-emitting layer, creating a composite structure that optimizes both efficiency and color purity through material composition control
2Use of energy by moving object
If triplet energy transfer occurs from green light-emitting layer to blue light-emitting layer, then energy utilization improves, but the triplet state of blue light-emitting material is quenched reducing light-emitting efficiency
Solution Approach 1:
The patent applies preliminary anti-action by designing the energy level structure in advance to prevent harmful triplet energy transfer. By setting the triplet energy level of the blue light-emitting layer dopant higher than that of the green light-emitting layer dopant before device operation, the patent preemptively blocks the quenching pathway, ensuring efficient energy utilization without triplet state loss
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 approach significantly enhances the light-emitting efficiency and color purity of blue light in white OLEDs, leading to more stable and efficient device performance under high brightness conditions.
Implementation Method 1
The first dopant material includes a blue light-emitting material with triplet-triplet annihilation effect
Implementation Method 2
at least two light-emitting layers include a first light-emitting layer and a second light-emitting layer that are stacked alternately; the first light-emitting layer is a blue light-emitting layer
Data Source
AI summary
An organic light-emitting device, a manufacturing method and a display device are provided. The organic light-emitting device includes: a first electrode and a second electrode that are arranged oppositely; at least two light-emitting layers located between the first electrode and the second electrode, the at least two light-emitting layers include a first light-emitting layer and a second light-emitting layer that are stacked alternately. The first light-emitting layer is a blue light-emitting layer, the first light-emitting layer is doped with a first dopant material, and the second light-emitting layer is doped with a second dopant material. The first dopant material includes a blue light-emitting material with triplet-triplet annihilation effect, and the triplet energy level of the first dopant material is higher than the triplet energy level of the second dopant material.