MIT

Thermally Activated Delayed Fluorescence and Aggregation Induced Emission with Through-Space Charge Transfer

Title

Thermally Activated Delayed Fluorescence and Aggregation Induced Emission with Through-Space Charge Transfer

Publication Type
Journal Article
Year of Publication
2017
Journal
Journal of the American Chemical Society
Date Published
Mar-03-2019
ISSN
0002-7863

Keywords

Abstract

Emissive molecules comprising a donor and an acceptor bridged by 9,9-dimethylxanthene, were studied (XPT, XCT, and XtBuCT). The structures position the donor and acceptor with cofacial alignment at distances of 3.3–3.5 Å wherein efficient spatial charge transfer can occur. The quantum yields were enhanced by excluding molecular oxygen and thermally activated delayed fluorescence with lifetimes on the order of microseconds was observed. Although the molecules displayed low quantum yields in solution, higher quantum yields were observed in the solid state. Crystal structures revealed π–π intramolecular interactions between a donor and an acceptor, however, the dominant intermolecular interactions were C—H···π, which likely restrict the molecular dynamics to create aggregation-induced enhanced emission. Organic light emitting devices using XPT and XtBuCT as dopants displayed electroluminescence external quantum efficiencies as high as 10%.

Short Title
J. Am. Chem. Soc.