An ambipolar 3,3′-dimethyl-9,9′-bianthracene derivative as a blue host material for high-performance OLEDs

Abstract

A new ambipolar deep blue fluorophore with a non-donor-acceptor structure, MBAn-(4)-tBu (10,10′-bis-(4-tert-butyl-phenyl)-3,3′-dimethyl-9,9′-bianthracene), was designed and synthesized based on 3,3′-dimethyl-9,9′-bianthracene. The twisted conformation of the two anthracene units and the bulky end group substituted with a tert-butyl group in MBAn-(4)-tBu prevented π-conjugation effectively. In particular, MBAn-(4)-tBu in a non-doped device exhibited a maximum external quantum efficiency (EQE) of 3.94% with Commission Internationale de l'Éclairage (CIE) coordinates of (0.16, 0.07) and a narrow full width at half maximum of 49 nm, which was close to the CIE of high definition television standard blue. Furthermore, MBAn-(4)-tBu worked as an excellent fluorescent host for BD1 and DSA-ph dopants to obtain high performance OLEDs with excellent EQEs of 5.26% and 6.96%, respectively. These results demonstrate that the ambipolar 3,3′-dimethyl-9,9′-bianthracene molecule with a non-donor-acceptor structure is advantageous for the fabrication of highly efficient blue fluorescent OLEDs.