Synthesis and characterization of a main-chain polymer for single component photorefractive materials

A novel bifunctional chromophore was synthesized by using tolyldiphenylamine (TDPA) and N-(4-nitrophenyl)-piperidine (NPP) units as a hole transporting and a second-order nonlinear optical (NLO) materials, respectively. The chromophore was reacted with paraformaldehyde (FA) using p-toluenesulfonic acid as a catalyst to prepare a main-chain polymer for single component photorefractive (PR) materials. This polymer was mixed with C60 (charge generating agents) and tricrecyl phosphate (plasticizer) to provide PR devices. The device showed a high photoconductive (PC) sensitivity of 10−9 cm Ω−1 W−1 and the response time of 4 ms by a four-wave mixing (FWM) measurements at an applied electric field of 80 V/μm using writing intensity of 150 mW/cm2, which is the fastest value reported for the organic PR device to date. PR composites consisting of hole transporting polymer showed shorter response times than one consisting of the low molecular weight chromophore.