Organic Host Compound for High-Efficiency Light-Emitting Elements
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Solution Overview
Problem
Current host materials for phosphorescent compounds in light-emitting elements have limitations in emission efficiency, reliability, light-emitting characteristics, synthesis efficiency, and cost, necessitating the development of more effective compounds for use in light-emitting elements with high electron-transport properties and low voltage operation.
Innovation Solution
A novel organic compound represented by General Formula (G1) and (G2) is introduced, which can serve as a host material in light-emitting layers and electron-transport layers, featuring high electron-transport properties and a wide energy gap, allowing for high current efficiency and low driving voltage in light-emitting elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional host materials are used in light-emitting elements, then the structure is simple and ease of manufacture is maintained, but emission efficiency and current efficiency are limited
Solution Approach 1:
The patent applies parameter changes by modifying the molecular structure of host materials through systematic variations in chemical composition. Specifically, it introduces compounds with different structural motifs (dibenzo[f,h]quinoxaline, dibenzofuran, dibenzothiophene, carbazole units) and substituent patterns to optimize triplet energy levels and electron-transport properties, thereby achieving higher emission efficiency while maintaining manufacturability through established synthesis routes
Solution Approach 2:
The patent employs composite materials by designing host compounds that combine multiple functional units within a single molecular structure. The host materials integrate electron-transport moieties (carbazole, dibenzofuran, dibenzothiophene) with the core dibenzo[f,h]quinoxaline framework, creating composite molecular structures that simultaneously provide high triplet energy levels and superior electron-transport capabilities for enhanced light-emitting performance
2Reliability
If conventional host materials are used, then manufacturing cost is controlled, but reliability and lifetime of light-emitting elements are insufficient
Solution Approach 1:
The patent improves reliability by changing chemical parameters of host materials to achieve higher thermal stability and operational stability. The designed compounds feature elevated triplet energy levels (T1) exceeding 2.85 eV and optimized HOMO-LUMO energy gaps, which prevent triplet-triplet annihilation and concentration quenching, thereby extending light-emitting element lifetime while maintaining synthesis feasibility through stepwise chemical reactions
3Ease of operation
If conventional host materials are used, then device structure is simple, but electron-transport properties are insufficient for low voltage operation
Solution Approach 1:
The patent achieves low voltage operation by changing the electron-transport parameters of host materials. The designed compounds exhibit optimized electron mobility and appropriate LUMO energy levels through incorporation of electron-deficient dibenzo[f,h]quinoxaline cores with electron-rich carbazole and heterocyclic units, enabling efficient electron injection and transport at reduced driving voltages while maintaining structural clarity for manufacturing
Solution Approach 2:
The patent enhances electron-transport properties through composite molecular design combining multiple electron-transport functional units. The host materials integrate dibenzo[f,h]quinoxaline cores with carbazole, dibenzofuran, and dibenzothiophene moieties, creating composite structures with synergistic electron-transport capabilities that enable low voltage operation without excessive structural complexity
4Productivity
If phosphorescent compounds are used to achieve high internal quantum efficiency, then emission efficiency improves, but concentration quenching and triplet-triplet annihilation occur
Solution Approach 1:
The patent resolves the contradiction between high internal quantum efficiency and emission stability by changing the triplet energy level parameter of host materials. The designed hosts exhibit T1 levels exceeding 2.85 eV, which are sufficiently higher than the phosphorescent guest materials, preventing triplet energy back-transfer and triplet-triplet annihilation. This energy level mismatch stabilizes phosphorescent emission while maintaining high internal quantum efficiency through effective triplet exciton confinement in the host
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 novel organic compound enhances the performance of light-emitting elements by achieving high current efficiency, long lifetime, and reduced power consumption, while being suitable for use with phosphorescent compounds, thereby improving overall light-emitting characteristics.
Implementation Method 1
a light-emitting element which is driven at a low voltage and has high current efficiency
Implementation Method 2
a compound capable of converting a triplet excited state into luminescence (hereinafter, referred to as a phosphorescent compound) exhibits luminescence from the triplet excited state (phosphorescence)
Implementation Method 3
since intersystem crossing (i.e., transition from a singlet excited state to a triplet excited state) easily occurs in a phosphorescent compound
Data Source
AI summary
Provided is a novel organic compound that is used as a host material in which a light-emitting substance is dispersed. The organic compound is represented by General Formula (G1). In the formula, A represents a substituted or unsubstituted dibenzofuran-diyl group, a substituted or unsubstituted dibenzothiophene-diyl group, a substituted or unsubstituted N-aryl-9H-carbazole-diyl group, or a substituted or unsubstituted N-alkyl-9H-carbazole-diyl group; Ar1 and Ar2 each independently represent a single-bond or a substituted or unsubstituted arylene group; R11 to R19 and R21 to R29 each independently represent hydrogen, an alkyl group having 1 to 6 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 13 carbon atoms; X1 and X2 each independently represent a carbon atom or a nitrogen atom; and the carbon atom is bonded to hydrogen, an alkyl group having 1 to 6 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 13 carbon atoms.