Triplet energy back transfer in conjugated polymers with pendant phosphorescent iridium complexes

Abstract

The nature of Dexter triplet energy transfer between bonded systems of a red phosphorescent iridium complex 13 and a conjugated polymer, polyflourene, has been investigated in electrophosphorescent organic light-emitting diodes. Red-emitting phosphorescent iridium complexes based on the [Ir(btp) 2(acac)] fragment (where btp is 2-(2′-benzo[b]thienyl) pyridinato and acac is acetylacetonate) have been attached either directly (spacerless) or through a -(CH2)8-chain (octamethylene-tethered) at the 9-position of a 9-octylfluorene host. The resulting dibromo-functionalized spacerless (8) or octamethylene-tethered (12) flourene monomers were chain extended by Suzuki polycondensations using the bis(..