Organic Compound for Light-Emitting Device Sublimation
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Solution Overview
Problem
Organic electroluminescence (EL) devices face challenges with high sublimation temperatures of light-emitting materials, leading to deterioration and reduced efficiency and lifetime, especially for higher-wavelength lights like green and red, due to heat exposure during industrial mass production processes.
Innovation Solution
Development of an organic compound with a low sublimation temperature, represented by General Formulae (G1) to (G3), which includes specific structural groups and substituents that reduce molecular weight and intermolecular interaction, allowing for high color purity and efficient light emission while being easy to synthesize and purify.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If light-emitting materials with larger molecular weights are used to achieve higher-wavelength light emission, then color purity is improved, but sublimation temperature increases causing material deterioration
Solution Approach 1:
The patent changes the molecular structure parameters of light-emitting materials by introducing condensed heteroaromatic rings with oxygen or sulfur substitutions. This structural modification reduces molecular weight while maintaining the π-electron conjugated system necessary for high-wavelength light emission, thereby lowering sublimation temperature without sacrificing color purity
Solution Approach 2:
The patent employs composite material design by combining condensed heteroaromatic cores with specific substituents (X1-X4 groups and R1-R14 alkyl groups). This composite structure optimizes both the optical properties for color purity and thermal properties for lower sublimation temperature, resolving the contradiction between these two characteristics
2Productivity
If light-emitting materials are subjected to long-time heating during vacuum evaporation for industrial mass production, then manufacturing efficiency is improved, but material deterioration increases reducing device lifetime
Solution Approach 1:
The patent provides beforehand cushioning by designing light-emitting materials with inherently lower sublimation temperatures through condensed heteroaromatic structures. This structural design anticipates the thermal stress during vacuum evaporation processing and prevents deterioration before it occurs, allowing long-time heating without compromising device lifetime
Solution Approach 2:
The patent changes the thermal stability parameter of light-emitting materials by modifying molecular structure. The condensed heteroaromatic rings with oxygen or sulfur substitutions create a more thermally stable structure that can withstand the heating conditions of industrial mass production without deteriorating, thus maintaining reliability during high-productivity manufacturing
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 organic compound achieves high emission efficiency, long driving lifetime, and reduced power consumption, with improved color purity and manufacturing costs, by utilizing a condensed heteroaromatic structure with oxygen or sulfur substitutions to lower the sublimation temperature and inhibit deterioration.
Implementation Method 1
an organic compound layer containing a photoelectric conversion material (an active layer) is located between a pair of electrodes. This device absorbs light energy to generate carriers
Implementation Method 2
Organic electroluminescence (EL) devices... utilize EL with an organic compound. Carriers are injected by application of voltage to the device, and recombination energy of the carriers is used to obtain light emission
Data Source
AI summary
An organic compound is represented by General Formula (G1). In General Formula (G1), X1 to X4 each independently represent any one of groups represented by General Formulae (g1-1) to (g1-3). Two or three of X1 to X4 represent the group represented by General Formula (g1-1) or (g1-2). R1 to R14 each independently represent any one of hydrogen (including deuterium), a straight-chain alkyl group having 1 to 10 carbon atoms, a branched alkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 12 carbon atoms, a substituted or unsubstituted cycloalkyl group having 4 to 10 carbon atoms and having a bridged structure, a trialkylsilyl group having 3 to 12 carbon atoms, a alkoxy group having 2 to 10 carbon atoms, and a fluoroalkyl group having 1 to 10 carbon atoms. Ar1 to Ar4 each independently represent a substituted or unsubstituted aryl group having 6 to 30 carbon atoms or a substituted or unsubstituted heteroaryl group having 3 to 30 carbon atoms.