Indolocarbazole Delayed Fluorescence Material
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Solution Overview
Problem
The development of delayed fluorescent materials with various molecular structures is hindered by the limited types of electron acceptor units, which restricts the design and efficiency of these materials, particularly in terms of thermal stability and luminous efficiency.
Innovation Solution
Incorporating an indolocarbazole group with at least one acceptor functional group as the electron acceptor unit, allowing for a range of molecular structures that enhance thermal stability and luminous efficiency by reducing the energy gap between singlet and triplet excited states, enabling efficient delayed fluorescence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional electron acceptor units are used in delayed fluorescent materials, then the molecular structure design is limited, but the development process becomes simpler
Solution Approach 1:
The electron acceptor unit is segmented into a core indolocarbazole structure with separate functional groups (electron-withdrawing groups) that can be independently selected and combined. This allows the core structure to provide thermal stability while the functional groups provide structural diversity, resolving the contradiction between design flexibility and development complexity.
Solution Approach 2:
The indolocarbazole core structure serves multiple functions simultaneously: it provides the necessary thermal stability for delayed fluorescence and acts as a versatile platform for attaching various electron-withdrawing functional groups. This multi-functionality allows a single core structure to support diverse molecular designs without increasing overall system complexity.
2Productivity
If the energy gap between singlet and triplet excited states is reduced, then luminous efficiency is improved, but thermal stability may be compromised
Solution Approach 1:
Different parts of the molecule are optimized for different functions: the indolocarbazole core provides thermal stability through its rigid structure, while the attached electron-withdrawing functional groups (such as cyano, carbonyl, or trifluoromethyl groups) are specifically positioned and selected to reduce the energy gap between singlet and triplet states. This local optimization allows simultaneous achievement of thermal stability and high luminous efficiency.
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
This approach enables the creation of thermally stable and highly efficient delayed fluorescent materials that achieve high luminous efficiency and improved electron transfer, overcoming the limitations of conventional materials by allowing for a variety of molecular structures.
Implementation Method 1
a high efficiency green fluorescent material with high external quantum efficiency is achieved. The TADF concept represents the phenomenon that reverse transfer of energy from an excited triplet state to an excited singlet state is caused by thermal activation, leading to fluorescence emission.
Implementation Method 2
Since the light emission is generated via the triplet state in the TADF and, thus, the light emission has a long lifetime, this is generally referred to as delayed fluorescence.
Data Source
AI summary
A delayed fluorescence material is disclosed. The delayed fluorescence material has a molecular structure that includes an electron donor unit that donates electrons; and an electron acceptor unit that is coupled to the electron donor unit and accepts electrons, wherein the electron acceptor unit includes an indolocarbazole group having at least one acceptor functional-group bound to the indolocarbazole group. Thus, the delayed fluorescence material exhibits high structural and thermal stability as well as high quantum efficiency.