Photoconductivity and grating response time of a photorefractive polymer

Authors

Brian E. Jones, University of Nebraska-Lincoln
Stephen Ducharme, University of Nebraska-LincolnFollow
Martin M Liphardt, University of Nebraska - Lincoln
Arosha Goonesekera, University of Nebraska-Lincoln
James M. Takacs, University of Nebraska-LincolnFollow
Lei Zhang, University of Nebraska-Lincoln
Rajan Athalye, University of Nebraska-Lincoln

Date of this Version

6-1994

Comments

Published in Journal of the Optical Society of America B, vol.11, no. 6 (June 1994), pp. 1064-1072. Copyright ©1994 Optical Society of America. Used by permission.

Abstract

We report the photoconductive properties and photorefractive grating response time of a polymer mixture composed of 40-wt. % dissolved diethylamino-benzaldehyde diphenyl hydrazone (DEH) and the non-cross-linking epoxy polymer Bisphenol A 4,4'-nitroaminostilbene. The films have improved photoconductive sensitivities as high as 2.1 × 10^–10 cm/(W Ω) at a wavelength of 650 nm with a corresponding reduction of the grating response time constant to 0.11 ± 0.02 s at an intensity of 1 W/cm². The nitro-aminostilbene chromophore is deduced to be the source of photogenerated charge carriers on the basis of a comparison of the wavelength dependence of the photoconductivity and absorption coefficient. Degradation of the photoconductivity and the dark conductivity as well as of the photorefractive speed with sample age is attributed to precipitation of the DEH; this explanation is supported by x-ray diffraction observations of crystal growth in the polymer.