학술논문

Indication of Intramolecular Triplet–Triplet Annihilation Upconversion in Organic Light‐Emitting Diodes.
Document Type
Article
Source
Advanced Optical Materials. Jan2024, Vol. 12 Issue 3, p1-7. 7p.
Subject
*LIGHT emitting diodes
*MOLECULAR conformation
*MOLECULAR structure
*EXCITON theory
*PHOTON upconversion
*DOPING agents (Chemistry)
*ORGANIC light emitting diodes
*DELAYED fluorescence
Language
ISSN
2195-1071
Abstract
It is well known that triplet–triplet annihilation upconversion (TTU) can enhance electroluminescence (EL) efficiency by converting two low‐energy triplet excitons into one high‐energy singlet exciton. However, conventional intermolecular TTU requires high doping concentration to activate, limiting device architecture. Here, six dimer molecules comprised of two anthracene units connected by a spacer unit are investigated, which have a possibility of the intramolecular TTU process. As a result, two dimer molecules show high TTU efficiencies close to the theoretical maximum even in dispersed, diluted conditions. By comparing these molecular conformations, a correlation is found between the dimer structures of two anthracene units and the TTU activity in the diluted condition, i.e., the 3D molecular structure with the exciton utilizing efficiency. [ABSTRACT FROM AUTHOR]