Organic Compound for OLED Outcoupling Efficiency
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Solution Overview
Problem
Organic light-emitting devices (OLEDs) face challenges in achieving high outcoupling efficiency due to refractive index differences between layers, leading to reduced device efficiency, as a low refractive index is difficult to achieve without compromising carrier-transport properties and reliability.
Innovation Solution
Development of a novel organic compound with a specific structure, including a triarylamine compound with a fluorenyl group and branched or cyclic alkyl groups, which balances carrier-transport properties, low refractive index, and high heat resistance, used in the EL layer to enhance emission efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a low refractive index material is used in the EL layer, then outcoupling efficiency is improved, but carrier-transport property deteriorates
Solution Approach 1:
The patent changes the chemical structure parameters of the organic compound by introducing specific substituents (fluorenyl group with branched or cyclic alkyl groups) to achieve a low refractive index while maintaining carrier-transport properties through molecular design
Solution Approach 2:
The patent creates a composite molecular structure combining triarylamine core with fluorenyme groups and cyclic alkyl substituents to achieve multiple functions (low refractive index and good carrier transport) in a single material
2Loss of energy
If a low refractive index material is used in the EL layer, then external quantum efficiency is improved, but device reliability deteriorates
Solution Approach 1:
The patent modifies molecular parameters by incorporating fluorenyme groups with cyclic alkyl substituents to achieve low refractive index (1.65-1.75) while maintaining device reliability through stable molecular structure
Solution Approach 2:
The patent uses organic compound molecules with specific structural features that provide both low refractive index and stability, replacing conventional materials that require separate layers for optical and functional properties
3Reliability
If an organic compound with many unsaturated bonds is used, then carrier-transport property is improved, but refractive index increases
Solution Approach 1:
The patent changes the balance between unsaturated bonds and cyclic alkyl groups in the molecular structure to maintain carrier-transport capability while reducing refractive index through the introduction of saturated cyclic structures
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 external quantum efficiency, low driving voltage, and improved reliability in OLEDs by maintaining carrier-transport properties while reducing refractive index, thus enhancing overall device performance.
Implementation Method 1
Light-emitting devices (organic EL devices) including organic compounds and utilizing electroluminescence (EL) have been put to more practical use. Carriers (holes and electrons) are injected by application of voltage to the device, and recombination energy of the carriers is used, whereby light emission can be obtained from the light-emitting material.
Data Source
AI summary
An organic compound having a hole-transport property and a low refractive index is provided. An organic compound represented by General Formula (G1) is provided. In the formula, Ar12 represents an aryl group having 6 to 10 carbon atoms in a ring and includes at least one branched-chain or cyclic alkyl group having 3 to 12 carbon atoms. The total number of carbon atoms of the branched-chain or cyclic alkyl group having 3 to 12 carbon atoms in Ar12 is 6 to 36. Ar11 and Ar21 each represent a substituted or unsubstituted arylene group having 6 to 13 carbon atoms in a ring. Ar22 represents a substituted or unsubstituted aryl group having 6 to 10 carbon atoms in a ring. In addition, n and m each independently represent an integer of 0 or 1. Ar1 represents a phenyl group including at least one alkyl group having 1 to 6 carbon atoms. Ar2 represents a phenyl group including at least one alkyl group having 1 to 6 carbon atoms, or an alkyl group having 1 to 4 carbon atoms.