Rational designs of multifunctional polymers - conjugated photorefractive polymers

Abstract

A novel type of photorefractive polymers, containing a conjugated backbone and a second order NLO chromophore, has been developed. A new polymerization method based on the Stille coupling reaction was explored to synthesize these materials. It was expected that the conjugated backbone would absorb photons in the visible region and play the triple role of charge generator, charge transporter and backbone. Several physical measurements demonstrated this expectation. Two beam coupling experiments clearly indicated an asymmetric optical energy exchange between two beams without applying an external electrical field. This is a conclusive demonstration for photorefractivity. Also, large optical gain of 5.7 cm-1 was observed under zero-field condition, which is comparable to most inorganic photorefractive materials. The versatility of the reaction makes possible the advancement of new polymer structures.