Theoretical and experimental investigation on the photophysical properties of star-shaped monodisperse oligo(9,9-di-n-octylfluorene-2,7-vinylene)s functionalized truxenes

We systemically investigate the photophysical properties of two star-shaped truxene based oligomers with different oligo(fluorene-vinylene) arms (Tr-OFV1 and Tr-OFV3) in solution system. The chemical quantum calculation exhibits that the electronic transition depends on the number of fluorene-vinylene (FV) groups in oligomers. The transient absorption (TA) data exhibits that increasing of FV groups in branch arms could accelerate the relaxation of excited oligomers, and the intensity-dependent exciton–exciton annihilation behavior could appear in the relaxation process of excited Tr-OFV3 and disappear in that of Tr-OFV1, indicating that their photophysical behavior is also closed to the number of FV unit.