Spacer dependence of exciplex dynamics in donor/spacer/acceptor layers

Exciplexes are crucial in organic optoelectronic devices since well-elaborated charge-transfer (CT) complexes exhibit unique exciton generation behavior. Thus, understanding the CT energy structures with exciton dynamics depending on donor–acceptor separation distances is essential for extracting their full potential. In this study, we investigated a long-range exciplex behavior between the electron donor of tris(4-carbazoyl-9-ylphenyl)amine (TCTA) and the electron acceptor of 2,4,6-tris[3-(diphenylphosphinyl)phenyl]-1,3,5-triazine (PO-T2T) by finely controlling their distance with 1,4-bis(triphenylsilyl)benzene (UGH-2) as a spacer layer. We report the characteristic exciplex photophysical kinetic behavior with time-dependent dynamics in terms of the donor–acceptor distance associated with the singlet–triplet energy gap and activation energy variation.