A sky blue thermally activated delayed fluorescence emitter to achieve efficient white light emission through in situ metal complex formation

Abstract

We developed two types of 2,6-pyrazine-based sky blue-to-green thermally activated delayed fluorescence (TADF) emitters, of which the green emitter helped realize high-performance organic light-emitting devices (OLEDs) with an external quantum efficiency (η_ext) of over 20%, whereas the sky-blue emitter outperformed conventional fluorescent emitters with an η_ext of over 10%. Moreover, this sky-blue emitter was able to form an in situ metal complex in the form of CuI(I) and it exhibited efficient white light emission with an η_ext,max of 11%. To our best knowledge, this is the first report on TADF emitters realizing the in situ formation of a metal complex.