Blue OLED Emitting Layer Composition for Longer Pixel Lifespan
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Solution Overview
Problem
The blue pixel in OLEDs does not provide sufficient emitting efficiency and lifespan, limiting the overall performance of organic light emitting display devices.
Innovation Solution
Incorporating a first emitting material layer with a non-deuterated anthracene derivative and a deuterated anthracene derivative as hosts, along with an electron blocking layer using a heteroaryl-substituted amine derivative and a hole blocking layer using an azine or benzimidazole derivative, enhances the efficiency and lifespan of the OLED.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional single host material is used in the emitting layer, then the device structure is simple, but the emitting efficiency and lifespan are insufficient
Solution Approach 1:
The patent employs a composite emitting layer comprising two different host materials (first host and second host) with different triplet energy levels. This composite structure enables improved lifespan by reducing exciton-polaron annihilation while maintaining emitting efficiency through the synergistic interaction of the two host materials.
Solution Approach 2:
The patent introduces different host materials with specific local functions: the first host (with higher triplet energy) and the second host (with lower triplet energy) are distributed in specific regions or ratios within the emitting layer to optimize both lifespan and emitting efficiency locally.
2Reliability
If conventional hole blocking materials are used, then the manufacturing process is simple, but the lifespan is limited
Solution Approach 1:
The patent modifies the chemical structure and electronic properties of hole blocking materials by introducing specific substituents and functional groups. This parameter change enables the hole blocking layer to achieve superior lifespan performance while maintaining compatibility with standard manufacturing processes.
3Productivity
If conventional electron blocking materials are used, then the device structure is simple, but the emitting efficiency is reduced
Solution Approach 1:
The patent utilizes composite electron blocking materials that combine multiple functional groups or molecules to achieve both high emitting efficiency and appropriate device complexity. The composite structure enables optimized electron transport and blocking characteristics.
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 combination of specific materials in the emitting material layer and blocking layers improves the emitting efficiency and lifespan of the OLED, providing better performance in blue pixel regions.
Implementation Method 1
the second host is a deuterated anthracene derivative
Implementation Method 2
The OLED emits light by injecting electrons from a cathode as an electron injection electrode and holes from an anode as a hole injection electrode into an emitting material layer (EML), combining the electrons with the holes, generating an exciton, and transforming the exciton from an excited state to a ground state
Implementation Method 3
a first electron blocking layer including an electron blocking material of a heteroaryl-substituted amine derivative and positioned between the first electrode and the first emitting material layer
Implementation Method 4
a first hole blocking layer including at least one of a first hole blocking material and a second hole blocking material and positioned between the second electrode and the first emitting material layer, wherein the first hole blocking material is an azine derivative, and the second hole blocking material is a benzimidazole derivative
Data Source
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AI summary
The present disclosure relates to an OLED that includes a first electrode; a second electrode facing the first electrode; a first emitting material layer including a first host, a second host and a blue dopant and positioned between the first and second electrodes; a first electron blocking layer including an electron blocking material of a heteroaryl-substituted amine derivative and positioned between the first electrode and the first emitting material layer; and a first hole blocking layer including at least one of a first hole blocking material and a second hole blocking material and positioned between the second electrode and the first emitting material layer, wherein the first host is an anthracene derivative, and the second host is a deuterated anthracene derivative, and wherein the first hole blocking material is a azine derivative, and the second hole blocking material is a benzimidazole derivative.