Photorefractive polymer composites with improved operational stability and performance

Abstract

This dissertation describes advances in the operational stability and performance of polymer composites that used a new hole-transporting polymer matrix, PATPD. Stable operation is achieved when PATPD provides the transport manifold because it prevents the chromophores to act as hole-traps. Operational stability is combined with video-rate compatible response times and large photorefractive nonlinearities, comparable to those obtained with the commonly used hole-transporting polymer PVK. The advances obtained in understanding the impact of chromophore aggregation to the photorefractive properties of such composites will be presented in the framework of a two-trapping site mode. Numerical simulations of the photogenerated current transients and the sensitizer anion build-up will reveal the intricate nature of the trap dynamics when chromophore aggregates can act as hole-traps in a material. Finally, the photorefractive properties of hybrid polymer composites sensitized with CdSe nanoparticles, that currently define the state-of-the-art for the photorefractive performance of this kind of materials, will be presented. The operational stability of hybrid composites is presented for the first time and the limitations to its performance will be analyzed.