OLED Auxiliary Layer Energy-Level Stacking for Charge Balance
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Solution Overview
Problem
Existing organic light-emitting elements face challenges in efficiently balancing electron and hole injection, leading to inefficiencies and reduced lifespan due to limitations in material adjustments for controlling charge balance.
Innovation Solution
Incorporating multiple light-emitting auxiliary layers with adjusted LUMO and HOMO energy levels relative to adjacent layers to improve charge balance, specifically with the LUMO of the auxiliary layers higher than the hole transport layer, enhancing electron and hole management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the material of the organic material layer is changed to control charge balance, then the charge balance between electrons and holes can be adjusted, but there is a limit to material options and development complexity increases
Solution Approach 1:
The patent changes the energy level parameters (HOMO and LUMO) of existing organic materials by introducing electron-withdrawing groups or expanding aromatic rings, rather than searching for entirely new materials. This allows systematic adjustment of charge balance through controlled chemical modifications of known compounds.
Solution Approach 2:
The patent introduces functional groups with specific local properties (electron-withdrawing groups like cyano, nitro, or carbonyl groups) at specific positions in the organic material molecule to locally adjust electron distribution and energy levels, achieving precise control over charge balance without redesigning the entire material structure.
2Reliability
If a single light-emitting auxiliary layer is used, then the device structure is simpler, but the charge balance control is insufficient
Solution Approach 1:
The patent divides the light-emitting auxiliary layer into multiple sub-layers with different energy level characteristics. Each sub-layer is optimized for specific charge transport functions, allowing independent control of electron and hole injection rates to achieve superior charge balance.
Solution Approach 2:
The patent adds the dimension of energy level gradient control by creating multiple layers with progressively varying HOMO and LUMO levels. This energy level staircase structure provides an additional degree of freedom for controlling charge carrier distribution beyond what a single layer can achieve.
Data Source
AI summary
An organic electric element according to an embodiment of the present disclosure includes a first electrode, a second electrode, and an organic material layer formed between the first electrode and the second electrode. The organic material layer may include a plurality of light-emitting auxiliary layers and the LUMO/HOMO energy levels of the plurality of light-emitting auxiliary layers are limited to specific conditions in relation to the neighboring organic material layers, thereby the driving voltage, the luminous efficiency and the lifetime of the organic electric element can be improved.