Synthesis and two-photon absorption property of new π -conjugated donor–acceptor polymers carrying different heteroaromatics

In this communication, we report the synthesis of three newly designed fluorescent polymers P1–P3, starting from simple thiophene derivatives through precursor polyhydrazide route. The new polymers, carrying donor and acceptor heterocyclic moieties with different spacer groups were found to be thermally stable and good of nonlinear optical (NLO) materials with two photon absorption property. The structures of newly synthesized monomers and polymers were confirmed by FTIR, NMR spectral and elemental analyses. Further, polymers were characterized by GPC and TGA studies. Their linear optical and electrochemical properties were evaluated by UV-vis, fluorescence spectroscopic and cyclic voltammetric (CV) studies, respectively, whereas their NLO properties were studied by Z-scan technique using Nd: YAG laser at 532 nm with 7 ns pulse. The electrochemical band gap of P1–P3 was determined to be 1.98, 1.91 and 2.05 eV, respectively. The NLO results reveal that polymers P1–P3 show good optical limiting property with TPA coefficient values 2.9 × 10 − 11 m/W, 8.0 × 10 − 11 m/W and 1.4 × 10 − 11 m/W, respectively.