OLED Delayed Fluorescent Compound Triplet Exciton Conversion
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Solution Overview
Problem
Current organic light emitting diodes (OLEDs) face challenges in achieving high luminous efficiency and long luminous lifespan, with fluorescent materials showing low efficiency and phosphorescent materials having short lifespan due to the use of metal complexes.
Innovation Solution
An OLED structure incorporating a first compound with delayed fluorescent properties and optionally a second compound as a host, where the emissive layer comprises a first compound with a specific organic structure that efficiently transfers exciton energy, enhancing internal quantum efficiency and luminous efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If fluorescent materials are used in OLEDs, then the device structure is simple, but luminous efficiency is low because only singlet excitons are utilized
Solution Approach 1:
The patent changes the photophysical parameters of the emitting material by using delayed fluorescent materials with specific molecular structures (containing carbazole, triphenylamine, or triarylamine groups) that enable efficient triplet exciton utilization through reverse intersystem crossing, achieving internal quantum efficiency of 100% while maintaining device structure simplicity
Solution Approach 2:
The patent employs composite material design by combining delayed fluorescent materials with specific host materials (such as mCP, TCTA, TAPC for holes; Alq3, BCP, TPBi for electrons) to create an emissive layer that achieves both high luminous efficiency and long lifespan without requiring phosphorescent metal complexes
2Use of energy by moving object
If phosphorescent materials are used in OLEDs, then luminous efficiency is high because triplet excitons are utilized, but luminous lifespan is too short due to metal complexes
Solution Approach 1:
The patent replaces expensive and short-lifespan phosphorescent metal complexes with delayed fluorescent organic materials that have longer operational stability while achieving comparable or superior luminous efficiency through triplet exciton utilization via reverse intersystem crossing mechanisms
Solution Approach 2:
The patent changes the material class from phosphorescent to delayed fluorescent, altering the excited state utilization mechanism while maintaining high internal quantum efficiency through molecular design containing specific electron-donating groups that facilitate triplet-to-singlet conversion
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 achieves improved luminous efficiency and extended lifespan by converting triplet excitons to singlet excitons, realizing 100% internal quantum efficiency and enhanced color purity in OLEDs.
Implementation Method 1
An OLED structure incorporating a first compound with delayed fluorescent properties... converting triplet excitons to singlet excitons
Data Source
AI summary
An organic light diode (OLED) and an organic light emitting device comprising the OLED (e.g., a display device or a lighting device) are described. The OLED can comprise at least one emitting material layer including a first compound where an alkyl group is substituted to a specific position of an electron donor moiety. Luminous properties in the OLED and the device can be improved by applying the first compound with beneficial luminous efficiency.