Dicyanobenzene Phosphor Composition for High-Current Delayed Fluorescence
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing delayed fluorescent materials face issues such as low emission efficiency, especially in high-current density regions, and unclear relationships between chemical structures and properties, limiting their practical use in light-emitting devices.
Innovation Solution
A dicyanobenzene derivative substituted with a donor group and specific aryl groups, represented by a general formula, is developed to enhance light-emitting efficiency by utilizing both excited singlet and triplet states for fluorescence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If delayed fluorescent materials are used to utilize both excited singlet and triplet states for fluorescence, then emission efficiency is improved, but emission efficiency reduction occurs in high-current density regions
Solution Approach 1:
The patent modifies molecular parameters by introducing specific donor groups (triazole, tetrazole, pyrimidine, pyridine rings) and adjusting the energy gap between S1 and T1 states to 2.0 eV or less, enabling efficient reverse intersystem crossing while maintaining stability in high-current density regions
Solution Approach 2:
The patent creates composite molecular structures combining electron-donating groups with dicyanobenzene cores, forming compounds that exhibit both delayed fluorescence capability and enhanced operational stability through synergistic electronic effects
2Use of energy by moving object
If conventional delayed fluorescent materials are used, then both excited singlet and triplet states can be utilized for fluorescence, but the chemical structure-property relationship is unclear
Solution Approach 1:
The patent systematically varies molecular parameters including donor group types, substitution positions, and energy gap values to establish structure-property relationships, identifying that ΔEST ≤ 2.0 eV is critical for efficient delayed fluorescence
Solution Approach 2:
The patent employs computational chemistry methods to calculate energy levels and predict delayed fluorescence properties, providing feedback on structure-property relationships that guides further material design and optimization
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 compound achieves high emission efficiency in light-emitting devices by effectively utilizing excited triplet energy, reducing emission efficiency reduction in high-current density regions and providing a generalizable chemical structure for improved performance.
Implementation Method 1
A delayed fluorescent material is a compound which, in an excited state, after having undergone reverse intersystem crossing from an excited triplet state to an excited singlet state, emits fluorescence when returning back from the excited singlet state to a ground state thereof
Implementation Method 2
emits fluorescence when returning back from the excited singlet state to a ground state thereof
Data Source
AI summary
A compound represented by the following general formula is an excellent light-emitting material. R1 to R5 each independently represent a hydrogen atom or a substituent, and one of R1 to R5 is a cyano group, one to three of R1 to R5 each are an aryl group Ar optionally substituted with an alkyl group or an aryl group, and one to three of R1 to R5 each are a donor group D (but excepting one that corresponds to Ar).