Photocurrent dynamics in a polyÑphenylene vinyleneÖ-based photorefractive composite

Department of Physics, University of Alberta, Edmonton, Alberta T6G 2J1, Canada~Received 23 June 2003; revised manuscript received 4 December 2003; published 25 March 2004!All parameters describing the charge carrier dynamics in a poly~phenylene vinylene!-based photorefractive~PR! composite relevant to PR grating dynamics were determined using photoconductivity studies undervarious illumination conditions. In particular, the values of the coefficients for trap filling and recombination ofcharges with ionized sensitizer molecules could be extracted independently. It is concluded that the PR growthtime without preillumination is mostly determined by the competition between deep trap filling and recombi-nation with ionized sensitizer molecules. Further, the pronounced increase in PR speed upon homogeneouspreillumination ~gating! as reported recently is quantitatively explained by deep trap filling.DOI: 10.1103/PhysRevB.69.125216 PACS number~s!: 71.20.Rv, 42.65.Hw, 42.70.Nq, 72.80.LeI. INTRODUCTION