Highly efficient carbazolylgold(iii) dendrimers based on thermally activated delayed fluorescence and their application in solution-processed organic light-emitting devices.

Abstract

A new class of C^C^N ligand-containing carbazolylgold(iii) dendrimers has been designed and synthesized. High photoluminescence quantum yields of up to 82% in solid-state thin films and large radiative decay rate constants in the order of 105 s−1 are observed. These gold(iii) dendrimers are found to exhibit thermally activated delayed fluorescence (TADF), as supported by variable-temperature emission spectroscopy, time-resolved photoluminescence decay and computational studies. Solution-processed organic light-emitting diodes (OLEDs) based on these gold(iii) dendrimers have been fabricated, which exhibit a maximum current efficiency of 52.6 cd A−1, maximum external quantum efficiency of 15.8% and high power efficiency of 41.3 lm W−1. The operational stability of these OLEDs has also been recorded, with the devices based on zero- and second-generation dendrimers showing maximum half-lifetimes of 1305 and 322 h at 100 cd m−2, respectively, representing the first demonstration of operationally stable solution-processed OLEDs based on gold(iii) dendrimers.