Organic EL Layer Structure for Low-Voltage Long-Life Emission
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Solution Overview
Problem
Existing organic electroluminescence devices face challenges in achieving low driving voltage and long lifetime.
Innovation Solution
The organic electroluminescence device comprises a cathode, an anode, and an organic layer with an emitting layer and a first layer, where the emitting layer contains a compound represented by formula (1) and the first layer contains a compound represented by formula (BE1).
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional organic EL device structures are used, then device functionality is maintained, but driving voltage remains high and lifetime is limited
Solution Approach 1:
The patent applies parameter changes by carefully selecting and optimizing the HOMO and LUMO energy levels of the organic compounds in each layer. The emitting layer uses a compound with HOMO of -5.8 eV and LUMO of -2.0 eV, while the electron transporting layer uses a compound with HOMO of -6.0 eV and LUMO of -2.3 eV. This energy level gradient design enables efficient charge injection and transport, achieving low driving voltage (below 5V) and extended device lifetime simultaneously.
Solution Approach 2:
The patent employs composite materials by combining specific organic compounds with complementary properties in a multi-layer structure. The device integrates a hole transporting layer, an emitting layer with specific anthracene-based compound, and an electron transporting layer with different compound composition. This composite structure optimizes both charge injection efficiency and exciton recombination, resolving the contradiction between low operating voltage and long operational lifetime.
2Reliability
If simple organic layer structures are used, then manufacturing is easier, but device performance in terms of voltage and lifetime is insufficient
Solution Approach 1:
The patent applies segmentation by dividing the organic layer into distinct functional layers: a hole transporting layer, an emitting layer, and an electron transporting layer. Each layer is optimized with specific compound compositions and thicknesses (e.g., emitting layer at 50-200 nm). This segmented structure enables independent optimization of charge injection, recombination, and transport functions, achieving high reliability without excessive manufacturing complexity.
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 enables the organic electroluminescence device to operate at a low driving voltage while maintaining a long lifetime, making it suitable for use in electronic apparatuses.
Implementation Method 1
When voltage is applied to an organic electroluminescence device, 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: a cathode, an anode, and an organic layer disposed between the cathode and the anode, wherein the organic layer comprises an emitting layer and a first layer, the first layer is disposed between the cathode and the emitting layer, the emitting layer comprises a compound represented by the following formula (1), and the first layer comprises a compound represented by the following formula (BE1):