Organic Electroluminescence Element with Chrysene Host
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Solution Overview
Problem
Organic electroluminescence devices face issues with insufficient external quantum efficiency, durability, and a significant increase in driving voltage due to temperature variations, which affects their performance and reliability.
Innovation Solution
A light-emitting organic thin film composition incorporating specific compounds represented by Formulas (PQ-1) and (BN-1) is used, which includes a chrysene structure-based host material combined with an iridium complex, reducing the dependency on temperature for driving voltage and enhancing durability and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional host materials and phosphorescent materials are used, then device efficiency can be improved, but driving voltage increases significantly with temperature
Solution Approach 1:
The patent changes the chemical structure parameters of the host material by introducing a chrysene core with specific substituent patterns (Formula BN-1) and combines it with phosphorescent materials of specific structures (Formula PQ-1). This structural parameter change results in a host-guest system that maintains stable driving voltage across different temperatures, resolving the contradiction between efficiency improvement and temperature-dependent voltage increment.
Solution Approach 2:
The patent creates a composite light-emitting layer combining a chrysene-based host material (Formula BN-1) with phosphorescent dopants (Formula PQ-1). This composite material system achieves both high efficiency and thermal stability, where the chrysene host structure provides robust thermal performance that prevents driving voltage increment with temperature while maintaining high external quantum efficiency.
2Loss of energy
If phosphorescent materials are used to improve efficiency, then external quantum efficiency increases, but durability becomes insufficient
Solution Approach 1:
The patent modifies the host material structure parameters by using a chrysene core with specific substituent groups (Formula BN-1) that provide both high triplet energy levels for efficient phosphorescence and enhanced thermal stability. This structural optimization simultaneously improves external quantum efficiency and device durability by preventing material degradation under operating conditions.
Solution Approach 2:
The patent employs a chrysene-based host material structure that is inherently stable and resistant to degradation, effectively creating a durable system where the host material can sustain prolonged operation. The specific molecular structure (Formula BN-1) with its rigid chrysene core provides long-term stability, resolving the durability insufficiency while maintaining high efficiency.
3Ease of manufacture
If conventional materials are used, then device fabrication is straightforward, but performance shows severe dependency on usage temperature
Solution Approach 1:
The patent changes the thermal and electrical parameters of the light-emitting layer by selecting specific host (Formula BN-1) and phosphorescent guest (Formula PQ-1) materials. This parameter optimization reduces the temperature coefficient of the driving voltage, making the device performance less sensitive to temperature variations while maintaining ease of fabrication through conventional vacuum deposition techniques.
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 solution results in an organic electroluminescence device with high external quantum efficiency, low driving voltage, and improved durability, exhibiting minimal voltage increment variations across different temperatures, ensuring stable performance even in high-temperature environments.
Implementation Method 1
utilize, for light emission, energy of the exciton generated as a result of recombination of electrons injected from a cathode and holes injected from an anode in the light emitting layer
Implementation Method 2
Improvention in the efficiency of devices has been recently made by using a phosphorescence emitting material
Data Source
AI summary
A light emitting organic thin film including at least one compound represented by Formula (PQ-1) and at least one compound represented by Formula (BN-1).In Formula (PQ-1), each of Ra, Rb and Rc independently represents a hydrogen atom or an alkyl group, wherein any one of Ra, Rb and Rc represents a hydrogen atom and the remaining two represent an alkyl group. Each of R1 to R5 independently represents a hydrogen atom, an alkyl group, an aryl group, a fluorine atom or a cyano group. Each of Rx and Ry independently represents an alkyl group or a phenyl group. In Formula (BN-1), Ar1 represents an arylene group that may have a substituent Z. Ar2 represents a condensed hydrocarbyl group that may have a substituent Z. Each of R101 to R113 independently represents a phenyl group, or the like.