Abstract

A new class of yellow- to red-emitting carbazolylgold(III) complexes containing isomeric thienopyridine or thienoquinoline moieties in the cyclometalating ligand has been designed and synthesized, which showed high photoluminescence quantum yields of over 80 % in solid-state thin films.1 The isomeric effect and extended π-conjugation of the N-heterocycles has been found to remarkably perturb the photophysical, electrochemical and electroluminescence properties of the gold(III) complexes. In particular, the operational lifetimes of organic light-emitting devices based on that incorporated with thieno[2,3-c]pyridine are almost three orders of magnitude longer than that incorporated with thieno[3,2-c]pyridine. This has led to the long device operational stabilities with a LT70 value of up to 63,200 h at a luminance of 100 cd m−2 and a long half-lifetime of 206,800 h, as well as maximum external quantum efficiencies of up to 8.6 % and 14.5 % in the solution-processed and vacuum-deposited devices, respectively. This work provides insights into the development of robust and highly luminescent gold(III) complexes and the identification of stable molecular motifs for designing efficient emitters.

Reference:

1. Li, L.-K.; Au-Yeung, C. C.; Tang, M.-C.; Lai, S.-L.; Cheung, W.-L.; Ng, M.; Chan, M.-Y.; Yam, V. W.-W. Materials Horizons, 2022, 9, 281 – 293.