Nonlinear optoelectronic materials formed by push–pull (bi)thiophene derivatives functionalized with di(tri)cyanovinyl acceptor groups

Abstract

Novel nonlinear optical (NLO) materials based on six novel NLO chromophores featuring di(tri)cyanovinyl acceptor linked to (bi)thiophene heterocyclic donor system were fabricated for the first time in polymethyl methacrylate matrices with a 1,064 nm laser working in the 20 ns time pulse regime. Absorption spectra and DFT calculations were also done. This multidisciplinary study showed that tayloring of the optical (linear and nonlinear) properties in the desired direction can be achieved by increasing the length of the π-conjugated heterocyclic system (thiophene vs. bithiophene), the strength of the electron donor groups (H → MeO/EtO → Et2N) as well as the strength of the electron acceptor moieties (dicyanovinyl vs. tricyanovinyl, two vs. three electron withdrawing cyano groups). Due to the relatively high and tunable second-order susceptibilities (0.08–6.45 pm/V at wavelength 1,064 nm), the studied push–pull chromophores can be denoted as promising second-order NLO chromophores.