A. Grunnetjepsen et al., SPECTROSCOPIC DETERMINATION OF TRAP DENSITY IN C-60-SENSITIZED PHOTOREFRACTIVE POLYMERS, Chemical physics letters, 291(5-6), 1998, pp. 553-561
A new and simple method for the determination of the trap density in C
-60-sensitized photonfractive polymers is presented. We show that the
radical anion of C-60 acts as the primary photorefractive hole trap, u
sing the strong near-infrared absorption of C-60(-) to quantify the an
ion concentration in situ. The spectroscopically determined concentrat
ion correlates well with the photorefractive trap density obtained fro
m analysis of the photorefractive performance. In our model, optical i
rradiation is needed to activate the trapping sites, and the nonlinear
optical chromophore acts as a temporary reservoir for the photogenera
ted holes (compensator). This model is further clarified using cyclic
voltammetry. (C) 1998 Elsevier Science B.V. All rights reserved.