Photoelectric and photorefractive properties of polyvinylcarbazole composites with graphene in the visible spectral range

Journal article, 2013

The photoelectric and photorefractive characteristics of polyvinylcarbazole (PVK) composites with 0.15 wt % graphene at a wavelength of 532 nm have been measured. The dependence of the quantum efficiency of generation of mobile charge carriers as determined from the photocurrent is well approximated by the Onsager equation calculated accurate to E (0) (3) for the quantum yield of thermalized electron-hole pairs of phi(0) = 1 and their initial separation radius of r (0) = 10.9 . The long-wavelength edge of optical absorption for PVK lies at 365 nm. Thus, the photogeneration of mobile carriers during illumination of the composite at 532 nm is due to photoexcitation of graphene. The measurement of the photorefractive properties has revealed that the two-beam coupling gain coefficient is I" = 50 cm(-1) at E (0) = 150 V/mu m and equal intensities of incident beams. It has been found that at E (0) = 83.3 V/mu m, the two-beam coupling gain coefficient increases from 8 to 14 cm(-1) as the ratio of incident beam intensities I (1)(0)/I (2)(0) increases from 1 to 2.4.