Energy transfer in a thin film of TPD fluorescent molecules doped with PtOEP and Ir(ppy)3 phosphorescent molecules

A thin film of triphenylamine dimer, N,N′-bis(3-methylphenyl)-N,N′-bis(phenyl)-benzidine (TPD), doped with fac tris(2-phenylpyridine) iridium (Ir(ppy)3) and platinum octaethyl porphine (PtOEP) is characterized by photoluminescence emission measurements at several excitation wavelengths and photoluminescence excitation measurements at relevant emission wavelengths in the temperature range from 10 K to room temperature. The investigated film is a phosphorescent OLED material with singlet absorbing host (TPD) and triplet emitting guests [Ir(ppy)3 and PtOEP]. At short wavelength excitation simultaneous triple band emission from singlet TPD, triplet Ir(ppy)3 and TPD, and from triplet PtOEP is observed. Förster-type singlet-singlet state energy transfer from TPD to Ir(ppy)3 and PtOEP, intra-component intersystem crossing, and Dexter-type triplet-triplet energy transfer between the substituents are studied.