Effect of a trapping molecule on the monolithic organic photorefractive materials

A peculiar effect of a trapping molecule on two closely related monolithic organic photorefractive (PR) materials was described. It was found that the trapping molecule $\mathbf{C}$ affects the PR performances differently in two materials made from either $\mathbf{A}$ or $\mathbf{B}$ , although the two molecules have similar chemical structures. Detailed studies on the charge mobility with the time-of-flight technique and activation energies for charge transport revealed that the trapping molecule $\mathbf{C}$ plays the role of electron trapper in material $\mathbf{A}$ and bipolar trapping center for both hole and electron in material $\mathbf{B}$ .