Synthesis and characterization of a new conjugated polymer bearing pyrazole and thiophene moieties as potent NLO material

Abstract

In this communication we describe the design and synthesis of a new conjugated polymer (P) carrying 3,4-dialkoxythiophene, 1,3,4 oxadiazole and pyrazole units, from its monomers through condensation polymerization method. The structure of newly synthesized polymer was established by FT-IR, 1H NMR, elemental analysis and gel permeation chromatographic techniques. Further, its electrochemical, linear and nonlinear optical properties of the polymer have been investigated. The optical and electrochemical band gap was found to be 2.39 eV. Z-scan results reveal that the polymer exhibits strong optical limiting behavior due to effective three-photon absorption (3PA). The value of 3PA coefficient was found to be 1.1×10-20 m3/W2, which is comparable to that of good optical limiting materials. The fluorescence quantum yield of the polymer in solution was determined using quinine sulfate as standard and it was found to be 42%.