Comprehensive kinetic analysis of inverted S 1 – T 1 materials with a dynamic exciton model
Open Access
- 1 February 2026
- journal article
- Published by IOP Publishing in Applied Physics Express
- Vol. 19 (2) , 021008
Abstract
Thermally activated delayed fluorescence materials have attracted attention for organic light-emitting diodes owing to their high efficiency and stability. Accurate evaluation of the singlet–triplet energy gap (Δ E ST ), particularly in near-zero-gap systems, remains a key challenge. Here, we investigate the photophysical properties of HzTFEX 2 , a proposed inverted singlet–triplet (InvE ST ) emitter, using temperature- and solvent-dependent analyses based on a dynamic exciton model. The results show that InvE ST explains the emission decay profiles of HzTFEX 2 in the Marcus normal region. We demonstrate that conventional kinetic analyses are insufficient in the near-zero Δ E ST regime, highlighting the necessity of the dynamic exciton model.Keywords
Funding Information
- Japan Society for the Promotion of Science (23K20039, JP25KJ1945)
- Kyulux, Inc. (N/A)
- the Natural Science and Enginering Council of Canada (N/A)
This publication has 31 references indexed in Scilit:
- Highly Twisted Thermally Activated Delayed Fluorescence (TADF) Molecules and Their Applications in Organic Light‐Emitting Diodes (OLEDs)Angewandte Chemie International Edition, 2023
- Exact Solution of Kinetic Analysis for Thermally Activated Delayed Fluorescence MaterialsThe Journal of Physical Chemistry A, 2021
- Are Heptazine-Based Organic Light-Emitting Diode Chromophores Thermally Activated Delayed Fluorescence or Inverted Singlet–Triplet Systems?The Journal of Physical Chemistry Letters, 2021
- Singlet–Triplet Inversion in Heptazine and in Polymeric Carbon NitridesThe Journal of Physical Chemistry A, 2019
- Multireference Approaches for Excited States of MoleculesChemical Reviews, 2018
- Purely Organic Thermally Activated Delayed Fluorescence Materials for Organic Light‐Emitting DiodesAdvanced Materials, 2017
- Molecular Design Strategy of Organic Thermally Activated Delayed Fluorescence EmittersChemistry of Materials, 2017
- Ultrapure Blue Thermally Activated Delayed Fluorescence Molecules: Efficient HOMO–LUMO Separation by the Multiple Resonance EffectAdvanced Materials, 2016
- Highly Efficient Organic Light‐Emitting Diode Based on a Hidden Thermally Activated Delayed Fluorescence Channel in a Heptazine DerivativeAdvanced Materials, 2013
- Violation of Hund's rule by spin polarization in moleculesTheoretical Chemistry Accounts, 1978