title: Photorefractive performance of a CdSe/ZnS core/shell nanoparticle-sensitized polymer.
abstract: We report the photorefractive performance of a polymer composite sensitized by CdSe/ZnS core/shell nanoparticles, and also comprising poly(N-vinylcarbazole) and an electro-optic chromophore. The nanoparticles are characterized by absorption and photoluminescence spectroscopy, elemental analysis, transmission electron microscopy, and powder x-ray diffraction. The electro-optic response of the composite is measured independently of the photorefractive effect by transmission ellipsometry. An asymmetric two-beam coupling gain of 30.6+/-0.4 cm(-1) is obtained, confirming photorefractivity. Degenerate four-wave mixing is used to assess photorefractive performance and, at a poling field of 70 V microm(-1), yields a diffraction efficiency of 4.21%+/-0.03%, a holographic contrast of 3.05 x 10(-4)+/-1 x 10(-6), a space-charge rise time of 25+/-2 s, and a sensitivity of 4.7 x 10(-5)+/-4 x 10(-6) cm3 J(-1). These results constitute a significant improvement on the performance of previous nanoparticle-sensitized photorefractive polymer composites.
authors.affiliation: Department of Physics and Astronomy, University of Manchester, Manchester M13 9PL, United Kingdom. farzana@fs2.ph.man.ac.uk
authors.forename: Farzana
authors.initials: F
authors.lastname: Aslam
authors.forename: David J
authors.initials: DJ
authors.lastname: Binks
authors.forename: Mark D
authors.initials: MD
authors.lastname: Rahn
authors.forename: David P
authors.initials: DP
authors.lastname: West
authors.forename: Paul
authors.initials: P
authors.lastname: O'Brien
authors.forename: Nigel
authors.initials: N
authors.lastname: Pickett
authors.forename: Steve
authors.initials: S
authors.lastname: Daniels