Novel photoluminescent polymers containing fluorene and 2,4,6-triphenyl pyridine moieties: Effects of noncoplanar molecular architecture on the electro-optical properties of parent matrix

In order to investigate the electro-optical property variations among the target topology-varied polymers with diverse molecular architectures, a series of polymers (P0-P2), having sterically hindered side chains, based on fluorene and pyridine derivatives were successfully synthesized via simple synthetic route and fully characterized via various spectroscopic methods and cyclic voltammetry measurements. The experiments demonstrate that all polymers with almost equivalent absorption and photoluminescence emission properties take on a wide band gap with blue emission in THF solution and thin solid film. However, their energy levels derived from the onset of electrochemical potential in thin solid films exhibit significant differences, which are considered to be due to the branched molecular frameworks on the basis of theoretical calculations. It is demonstrated that the electro-optical properties of wide band gap rigid noncoplanar copolymers are tunable by the sterically hindered pyridine moieties, and these experiments can serve as an excellent exploratory example for fine band gap and photophysics control principle in the p-n heterostructure polymers through the partial planarization of the π-system.