Charge trapping in photorefractive polymers

Modification of the trap density of the photorefractive polymer composite poly(N-vinyl carbazole), 2,4,7-trinitro-9-fluorenone, and N,N-diethyl-para-nitrozniline is achieved with the addition of 4-(diethylamino)bensaldehyde diphenylhydrazone (DEH). Measurements of the response time and the phase shift of the photorefractive gratings indicate that at low concentrations DEH acts as a trap, while at higher concentrations a new charge transport pathway through hopping between DEH molecules is established. The transient behavior of these gratings further supports this picture