White Light OLED Layer Structure for Efficiency and Stability
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Solution Overview
Problem
Existing white light organic electroluminescent elements face challenges in achieving high luminance efficiency and operational stability due to inefficient energy transfer between layers and a complex production process.
Innovation Solution
A white light organic electroluminescent element is designed with an orange light emitting layer formed by co-evaporation of a host-emitting material, a blue guest-emitting material, and an orange guest-emitting material, along with a blue light emitting layer formed by co-evaporation of a host-emitting material and a blue guest-emitting material, improving energy transfer efficiency and simplifying the fabrication process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a red light emitting material is uniformly dispersed in a blue host emitting material to form a fluorescent emitting layer, then white light emission is achieved, but the narrow doping concentration range makes the production process difficult
Solution Approach 1:
The patent changes the emission color parameters by selecting different guest-emitting materials (green, yellow, orange) instead of using red-emitting materials. This parameter change in the emission spectrum allows achieving white light without the narrow doping concentration constraints associated with red emission, thereby simplifying the production process while maintaining white light emission quality
2Illumination intensity
If a yellow/red guest-emitting material is doped in a blue host-emitting material to form a yellow/red emitting layer, then white light emission is achieved, but the energy transfer efficiency is reduced resulting in lower luminance efficiency and stability
Solution Approach 1:
The patent applies local quality by creating distinct emitting layers with specific color characteristics (green, yellow, or orange) rather than using a single blue host with yellow/red dopant. Each layer is optimized for its specific emission color, ensuring efficient energy transfer within each layer while collectively producing white light, thereby improving both luminance efficiency and operational stability
3Illumination intensity
If multiple emitting layers with different color emissions are stacked, then white light is achieved through color mixing, but the device complexity increases
Solution Approach 1:
The patent employs a universal blue host-emitting material that serves multiple functions across different emitting layers. The same blue host material is used in green, yellow, and orange emitting layers, each with different guest materials. This multi-functionality approach simplifies the overall device structure by using a common host material while achieving white light through color mixing from different guest-emitting materials
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 luminance efficiency and operational stability, with improved current efficiency, luminance intensity, and extended operational time compared to previous designs.
Implementation Method 1
the orange light emitting layer is formed by co-evaporation of a host-emitting material, a blue guest-emitting material, and an orange guest-emitting material
Implementation Method 2
formed by co-evaporation of a host-emitting material, a blue guest-emitting material, and an orange guest-emitting material
Implementation Method 3
white light organic electroluminescent element
Data Source
AI summary
A white light organic electroluminescent element is provided. The white organic electroluminescent element comprises an anode, a hole transporting layer on the anode, an orange light emitting layer on the hole transporting layer, a blue light emitting layer on the orange light emitting layer, an electron transporting layer on the blue light emitting layer, and a cathode on the electron transporting layer, wherein the orange light emitting layer is formed by co-evaporation of a host-emitting material, a blue guest-emitting material, and an orange guest-emitting material.