Design and synthesis of yellow- to red-emitting gold(iii) complexes containing isomeric thienopyridine and thienoquinoline moieties and their applications in operationally stable organic light-emitting devices

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. The isomeric effect and extended pi-conjugation of the N-heterocycles have 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 long device operational stability 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.

Automated summary

A new class of yellow- to red-emitting carbazolylgold(iii) complexes with high photoluminescence quantum yields has been designed and synthesized, showing improved operational lifetimes in organic light-emitting devices. This work provides insights into the development of robust and highly luminescent gold(iii) complexes and stable molecular motifs for designing efficient emitters.