Deep red donor-acceptor type thermally activated delayed fluorescence emitter with o-carborane as an acceptor

Abstract

o-Carborane is a strong acceptor having a three-dimensional structure of 10 borons and 2 carbons. Thus, this study explores the potential of using o-carborane as a new acceptor in designing donor-acceptor (D-A) type thermally activated delayed fluorescence (TADF) materials. Accordingly, a D-A type TADF emitter was designed using o-carborane as an acceptor and 9,9-dimethyl-9,10-dihydroacridine as a donor. The TADF emitter exhibited deep red emission with a peak wavelength of 642 nm as proven by delayed fluorescence in the transient photoluminescence analysis. Deep red emission with a peak wavelength of 651 nm was also observed in both doped and non-doped devices, as demonstrated using electroluminescence devices. Finally, the maximum external quantum efficiency of DMAC-oCB devices was found to be 5.2% in the doped device and 2.1% in the non-doped device.