Fused Polycyclic Compound for OLED Emission Efficiency
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Solution Overview
Problem
Current organic electroluminescent elements face challenges in achieving high emission efficiency and extended lifespan, particularly in reducing driving voltage and improving material stability for efficient phosphorescence, delayed fluorescence, and thermally activated delayed fluorescence applications.
Innovation Solution
Incorporating a fused polycyclic compound represented by specific formulas in the emission layer and an amine compound in the hole transport region, along with a capping layer with a refractive index of 1.6 or more, to enhance emission efficiency and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional materials are used in the emission layer, then the device structure is simple, but the emission efficiency is low
Solution Approach 1:
The emission layer uses a composite material system consisting of a host material and a fused polycyclic compound dopant. The host material provides the structural framework while the dopant (Formula 1) with specific fused ring structures enables efficient light emission through TADF or delayed fluorescence mechanisms, achieving high emission efficiency through material composition rather than structural complexity
Solution Approach 2:
The patent optimizes emission efficiency by changing material parameters including the molecular structure of the fused polycyclic compound (Formula 1 with specific X1-X4, R1-R5 substituents), the host-guest ratio, and energy level alignment between host and dopant materials, allowing efficient triplet exciton utilization without complicating the device structure
2Productivity
If materials for high emission efficiency are used, then the emission efficiency is improved, but the driving voltage increases
Solution Approach 1:
The hole transport region uses a specifically designed amine compound (Formula H-1) with localized functional groups that provide both high hole mobility and appropriate energy levels. The compound's structure (with L1-L2 linkages and Ar1-Ar3 aromatic groups) creates optimal local electronic properties that reduce the energy barrier for charge injection and transport, thereby reducing driving voltage while maintaining high emission efficiency in the emission layer
3Reliability
If conventional emission materials are used, then the material stability is insufficient, but the device structure remains simple
Solution Approach 1:
The emission layer employs a composite system where the host material provides structural stability and the fused polycyclic compound dopant (Formula 1) provides emission functionality. This composite approach allows the host to protect the dopant from degradation while maintaining efficient light emission, thereby improving material stability without significantly complicating the device structure
Solution Approach 2:
The patent uses organic small molecule materials that can be deposited as thin films, replacing less stable conventional phosphorescent materials. The fused polycyclic compound structure (Formula 1) provides inherent stability through its rigid fused ring system, allowing the material to function effectively without requiring complex protective structures
4Productivity
If the emission layer is optimized for efficiency, then the emission efficiency is improved, but the lifespan is shortened
Solution Approach 1:
The host material acts as an intermediary between the fused polycyclic compound dopant and the charge carriers. It facilitates efficient energy transfer to the dopant for light emission while protecting the dopant from direct interaction with charges that could cause degradation. This mediator role allows high emission efficiency to be achieved without compromising the lifespan of the emission 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 proposed configuration improves emission efficiency and extends the lifespan of organic electroluminescent elements by optimizing the use of fused polycyclic compounds in the emission layer and amine compounds in the hole transport region, while the capping layer enhances light management.
Implementation Method 1
the emission layer may be to emit delayed fluorescence
Implementation Method 2
a capping layer disposed on the second electrode and having a refractive index of about 1.6 or more
Data Source
AI summary
An organic electroluminescent element of an embodiment includes an oppositely disposed first electrode and second electrode, and multiple organic layers disposed between the first electrode and the second electrode, wherein at least one among the organic layers includes a fused polycyclic compound represented by Formula 1, thereby showing improved emission efficiency: