New diphenylamine-based donor–acceptor-type conjugated polymers as potential photonic materials

A new series of donor–acceptor-type conjugated polymers ( P1 and P2) carrying a diphenyl amine moiety were synthesized via Wittig condensation technique. The polymers structures were well established by FT-IR, 1H NMR, elemental analysis and gel permeation chromatographic techniques. They exhibited good thermal stability with an onset decomposition temperature of approximately 325 °C under nitrogen atmosphere. The optical and electrochemical properties of the polymers were studied by UV–vis, fluorescence emission spectroscopy and cyclic voltammetry. They exhibited good fluorescence in dilute solutions and showed solvatochromic behavior in various polar solvents. The electrochemical studies revealed that the polymers possess low-lying LUMO energy levels that ranging from −3.47 to −3.73 eV and high-lying HOMO energy levels that ranging from −5.57 to −5.81 eV. The thirdorder nonlinear optical properties of the polymers were investigated using the Z-scan technique. The effective two-photon absorption (TPA) coefficients ( β) of the polymers were found to be 0.645 × 10 −10 and 0.212 × 10 −10 m/W.