Nitrogen-Containing Compound for OLED Emission Layer
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Solution Overview
Problem
Current organic electroluminescence devices face challenges in achieving high emission efficiency and long device life due to limitations in materials that can efficiently recombine holes and electrons, leading to suboptimal light emission and increased driving voltage.
Innovation Solution
Incorporating a nitrogen-containing compound with a heterocyclic moiety and two carbazole moieties linked via a phenylene group in the emission layer, which acts as an electron accepting and donating group, respectively, to facilitate thermally activated delayed fluorescence and enhance emission efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional materials are used in the emission layer, then device structure is simple, but emission efficiency is low and device life is short
Solution Approach 1:
The patent employs composite materials by combining a heterocyclic moiety (electron-accepting group) with two carbazole moieties (electron-donating groups) in a single molecular structure. This composite approach enables the material to simultaneously achieve high emission efficiency through effective charge carrier recombination and extended device life, while the molecular design integrates multiple functional groups into one compound rather than using separate layers.
2Illumination intensity
If materials with high emission efficiency are used, then light emission is improved, but driving voltage increases
Solution Approach 1:
The patent changes the chemical and electronic parameters of the emission layer material by incorporating specific functional groups with defined electron-donating and electron-accepting properties. The carbazole moieties provide electron-donating capability while the heterocyclic moiety provides electron-accepting capability, creating a balanced electronic structure that enables efficient recombination at lower driving voltages while maintaining high light emission intensity.
3Duration of action of stationary object
If conventional emission materials are used, then device manufacturing is simple, but device life is limited
Solution Approach 1:
The patent applies segmentation by dividing the molecular structure into distinct functional segments: a heterocyclic moiety (electron-accepting group) and two carbazole moieties (electron-donating groups). Each segment performs a specific function, and their combination creates a material with enhanced stability and longevity. The linker connecting these segments provides structural flexibility while maintaining overall molecular stability, contributing to extended device life.
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 use of this nitrogen-containing compound in the emission layer results in improved emission efficiency, reduced driving voltage, and extended device life by enabling efficient recombination of charge carriers and promoting thermally activated delayed fluorescence.
Implementation Method 1
facilitate thermally activated delayed fluorescence and enhance emission efficiency
Implementation Method 2
An organic electroluminescence display is different from a liquid crystal display and is so called a self-luminescent display that accomplishes display by recombining holes and electrons injected from a first electrode and a second electrode in an emission layer and emitting light from a luminescent material
Data Source
AI summary
An organic electroluminescence device includes a first electrode, a hole transport region, an emission layer including a nitrogen-containing compound, an electron transport region, and a second electrode. The nitrogen-containing compound may include a heterocyclic moiety and two carbazole moieties, the heterocyclic moiety may be a substituted pyridine, a substituted pyrimidine, or a substituted 1,3,5-triazine, each of two carbons among carbons of 2-, 4-, and 6-positions of the substituted pyridine, the substituted pyrimidine, or the substituted 1,3,5-triazine may be substituted with a phenylene group, a carbon in an ortho position of each phenylene group may be linked with a nitrogen at a 9-position of one of the carbazole moieties, and the remaining carbon among the carbons of the 2-, 4-, and 6-positions may be substituted with a substituted or unsubstituted aromatic group, and the carbazole moieties may be linked together by a linker.