Related Experiment Video
Updated: Aug 4, 2025

Scale-up Chemical Synthesis of Thermally-activated Delayed Fluorescence Emitters Based on the Dibenzothiophene-S,S-Dioxide Core
Published on: October 24, 2017
Design of Intramolecular Dihedral Angle between Electronic Donor and Acceptor in Thermally Activated Delayed
Xin Qian1, Feihong Chu1, Wencai Zhou1
1Faculty of Materials and Manufacturing, Faculty of Information Technology, Beijing University of Technology, Beijing 100124, P. R. China.
Abstract:
In order to improve the exciton utilization efficiency (ηexc) of organic light-emitting materials, we addressed the ideal donor-acceptor dihedral angle (θD-A) in the TADF molecule by striking a balance between two photophysical processes. One is the conversion of triplet excitons into singlet excitons, and the other is the radiative process from a low-lying excited state to the ground state. Using a combination of first-principles calculations and molecular dynamics simulations, we investigated the impact of θD-A on the splitting energy and spin-orbit coupling between singlet and triplet excitons as well as the transition dipole moment for carbazole benzonitrile (CzBN) derivatives. By comparison with the reverse intersystem crossing rate (krISC), fluorescence emission rate (kr), and ηexc, we proposed a potential highest ηexc (of 94.4%) with the ideal θD-A of 77° for blue light CzBN derivatives; the calculated results have a good agreement with experimental measurement. The structure-efficiency physical connection between the molecular structure (θD-A) and efficiency provided an ideal parameter for a potential candidate for blue TADF-OLED materials.
Related Concept Videos
Cycloaddition Reactions: MO Requirements for Thermal Activation
Diels–Alder vs Retro-Diels–Alder Reaction: Thermodynamic Factors
[4+2] Cycloaddition of Conjugated Dienes: Diels–Alder Reaction
Deactivation Processes: Jablonski Diagram
Cycloaddition Reactions: MO Requirements for Photochemical Activation
Variables Affecting Phosphorescence and Fluorescence

