Dual Emitting Layer OLED Structure for Exciton Recombination
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Solution Overview
Problem
Current organic electroluminescence devices face limitations in performance, particularly in luminous efficiency and emission characteristics, due to the inefficiencies in exciton formation and recombination processes.
Innovation Solution
The use of a dual emitting layer structure in organic electroluminescence devices, where the first emitting layer contains a specific host material represented by formula (1) and the second emitting layer contains another host material represented by formula (2), both in direct contact, enhances exciton formation and recombination, leading to improved luminous efficiency and emission properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a conventional single emitting layer structure is used, then the device structure is simple, but the luminous efficiency is limited due to inefficient exciton formation and recombination
Solution Approach 1:
The emitting layer is divided into two distinct layers: a first emitting layer containing a first host material and a second emitting layer containing a second host material. This segmentation allows each layer to perform specific functions in the exciton formation and recombination process, thereby improving luminous efficiency while maintaining reasonable structural complexity.
Solution Approach 2:
The patent employs composite material design by combining different host materials (first host material in formula (1) and second host material in formula (2)) with specific chemical structures and functional groups. These composite materials enable optimized exciton management and energy transfer, resolving the contradiction between structural simplicity and efficiency.
2Loss of energy
If the first emitting layer and second emitting layer are in direct contact, then the exciton formation and recombination is enhanced, but the device structure becomes more complex
Solution Approach 1:
The first emitting layer and second emitting layer are merged through direct contact without intermediate layers, enabling efficient exciton transfer and recombination between the two host materials. This merging approach enhances energy utilization while keeping the structural complexity manageable through the specific molecular designs of the host materials.
3Illumination intensity
If host materials with specific chemical structures (formulas (1) and (2)) are used, then the emission characteristics are improved, but the manufacturing precision requirements increase
Solution Approach 1:
The patent employs systematic parameter changes in the chemical structures of host materials, defined by formulas (1) and (2) with varying substituents R1 to R6 and R11 to R16. These parameter variations allow optimization of emission characteristics while providing clear structural guidelines that can be followed in manufacturing, thereby balancing performance improvement with manufacturing feasibility.
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 significantly enhances the luminous efficiency and emission characteristics of the organic electroluminescence devices by optimizing exciton formation and recombination processes, resulting in improved performance and efficiency.
Implementation Method 1
An organic electroluminescence device has found its application in a full-color display for mobile phones, televisions and the like. When a voltage is applied to an organic EL device, holes and electrons are injected from an anode and a cathode, respectively, into an emitting layer.
Implementation Method 2
The injected electrons and holes are recombined in the emitting layer to form excitons. Specifically, according to the electron spin statistics theory, singlet excitons and triplet excitons are generated at a ratio of 25%:75%.
Data Source
AI summary
An organic electroluminescence device includes an anode, a cathode, a first emitting layer, and a second emitting layer disposed between the first emitting layer and the cathode, the first emitting layer containing a first host material in a form of a first compound represented by a formula (101) below, the second emitting layer containing a second host material in a form of a second compound represented by a formula (2) below, the first emitting layer and the second emitting layer being in direct contact with each other.