Organic EL Device Dual Electron-Transporting Layer Carrier Balance
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Solution Overview
Problem
Existing organic electroluminescence devices face challenges in achieving high luminous efficiency and long lifespan due to imbalances in carrier transport and exciton generation.
Innovation Solution
The organic electroluminescence device is configured with an anode, an emitting layer, a first electron-transporting layer, a second electron-transporting layer, and a cathode, where the second electron-transporting layer comprises a specific compound and the emitting layer comprises another compound, optimizing carrier balance and exciton generation for improved performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electron-transporting layers are used in organic EL devices, then device structure is simple, but luminous efficiency and lifespan are insufficient
Solution Approach 1:
The electron-transporting layer is divided into two distinct layers: a first electron-transporting layer adjacent to the emitting layer, and a second electron-transporting layer adjacent to the first layer. This segmentation allows each layer to be optimized for different functions, improving overall device reliability and lifespan while managing complexity through functional specialization.
Solution Approach 2:
Different electron-transporting materials are selected for the first and second layers based on their specific transport characteristics. The first layer uses materials optimized for electron injection from the emitting layer, while the second layer uses materials optimized for electron transport toward the cathode. This local optimization of material properties enhances overall device performance and durability.
2Productivity
If conventional electron-transporting layers are used in organic EL devices, then manufacturing process is simple, but luminous efficiency is insufficient
Solution Approach 1:
The invention optimizes specific parameters of the electron-transporting layers, including material selection, layer thickness, and HOMO/LUMO energy levels. By carefully controlling these parameters, the device achieves high luminous efficiency through improved electron transport and balanced carrier injection, while the systematic approach to parameter optimization maintains manufacturing feasibility.
3Quantity of substance
If carrier balance is not optimized, then device structure is simple, but exciton generation is insufficient
Solution Approach 1:
The dual-layer electron-transporting structure provides feedback optimization for carrier balance. The first layer's electron transport characteristics feed into the emitting layer, affecting hole-electron recombination balance, while the second layer's transport properties feed back to ensure sufficient electron supply. This feedback mechanism enhances exciton generation through improved carrier balance.
Solution Approach 2:
The invention employs composite electron-transporting layer structures with different material compositions optimized for specific functions. The first layer may use materials with higher electron mobility for efficient electron injection, while the second layer uses materials optimized for sustained electron transport. This composite approach maximizes exciton generation through balanced carrier transport.
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 configuration enhances luminous efficiency and extends the lifespan of the organic electroluminescence device by improving carrier balance and exciton generation, resulting in high-performance organic electroluminescent devices with both high efficiency and long life.
Implementation Method 1
When voltage is applied to an organic electroluminescence device (hereinafter, referred to as an organic EL device in several cases), holes and electrons are injected into an emitting layer from an anode and a cathode, respectively. Then, thus injected holes and electrons are recombined in the emitting layer, and excitons are formed therein.
Data Source
AI summary
An organic electroluminescence device, comprising: an anode, an emitting layer, a first electron-transporting layer, a second electron-transporting layer and a cathode in this order, wherein the second electron-transporting layer comprises a compound represented by the following formula (1), and the emitting layer comprises a compound represented by the following formula (10).