Organic OLED Compound Structure for Quenching-Resistant Delayed Fluorescence
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Solution Overview
Problem
Existing organic light emitting elements face issues with concentration quenching, reduced light emission efficiency, and short lifespan due to exciton accumulation and degradation, particularly in non-doped layers using delayed fluorescence materials.
Innovation Solution
The introduction of a heteraborin skeleton with a selenium or tellurium atom and bulky aryl group, along with a bulky donor type substituent, enhances the reverse intersystem crossing rate and suppresses concentration quenching, leading to improved roll-off characteristics and extended lifespan in non-doped elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a light emitting material is used at high concentration in a non-doped layer, then the light emission intensity increases, but concentration quenching occurs and light emission efficiency decreases
Solution Approach 1:
The patent changes the molecular structure parameters of the light emitting material by introducing a heteraborin skeleton with selenium or tellurium atoms and bulky aryl groups. This structural modification enables the material to maintain high light emission efficiency even at high concentrations by suppressing concentration quenching through the unique electronic properties and steric effects of the modified structure.
2Loss of energy
If a donor acceptor type delayed fluorescence material is used, then the reverse intersystem crossing rate increases and light emission efficiency improves, but exciton accumulation occurs leading to roll-off and reduced lifespan
Solution Approach 1:
The patent modifies the molecular structure by introducing a heteraborin skeleton with selenium or tellurium atoms, which changes the electronic parameters of the material. This structural change enables efficient exciton management that prevents accumulation while maintaining high reverse intersystem crossing rates, thereby improving both light emission efficiency and element lifespan without the roll-off problem.
3Speed
If a heavy atom such as bromine is introduced to increase the reverse intersystem crossing rate, then the reverse intersystem crossing rate increases, but light emission efficiency decreases
Solution Approach 1:
Instead of using traditional heavy atoms like bromine, the patent employs a heteraborin skeleton with selenium or tellurium atoms integrated into the molecular framework. This structural modification achieves enhanced reverse intersystem crossing rates through the heavy atom effect while simultaneously maintaining high light emission efficiency by preserving the multiple resonance effect and optimizing the electronic structure, avoiding the efficiency loss associated with conventional heavy atom approaches.
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 proposed organic compound achieves high light emission efficiency and longevity by maintaining a high reverse intersystem crossing rate while preventing concentration quenching, even in non-doped layers, thereby enhancing the performance of organic light emitting elements.
Implementation Method 1
A donor acceptor type delayed fluorescence material in an excited state causes reverse intersystem crossing from an excited triplet state to an excited singlet state, and then radiates fluorescence when returning from the excited singlet state to the ground state.
Implementation Method 2
the organic EL element emits light when the excitons return to the ground state
Implementation Method 3
A delayed fluorescence material generally has a structure in which a donor moiety and an acceptor moiety are bound
Data Source
AI summary
An organic compound is represented by formula (1-1) or (1-2) below,in formulas (1-1) and (1-2), D1 is a group represented by any one of formulas (2-1) to (2-5), and D2 is a hydrogen atom or a group represented by any one of formulas (2-1) to (2-5).