title: Sub-Millisecond Response Time in a Photorefractive Composite Operating under CW Conditions.
abstract: Extensive study of photorefractive polymeric composites photosensitized with semiconductor nanocrystals has yielded data indicating that the inclusion of such nanocrystals enhances the charge-carrier mobility, and subsequently leads to a reduction in the photorefractive response time. Unfortunately, the included nanocrystals may also act as a source of deep traps, resulting in diminished diffraction efficiencies as well as reduced two beam coupling gain coefficients. Nonetheless, previous studies indicate that this problem is mitigated through the inclusion of semiconductor nanocrystals possessing a relatively narrow band-gap. Here, we fully exploit this property by doping PbS nanocrystals into a newly formulated photorefractive composite based on molecular triphenyldiamine photosensitized with C60. Through this approach, response times of 399 μs are observed, opening the door for video and other high-speed applications. It is further demonstrated that this improvement in response time occurs with little sacrifice in photorefractive efficiency, with internal diffraction efficiencies of 72% and two-beam-coupling gain coefficients of 500 cm(-1) being measured. A thorough analysis of the experimental data is presented, supporting the hypothesized mechanism of enhanced charge mobility without the accompaniment of superfluous traps. It is anticipated that this approach can play a significant role in the eventual commercialization of this class of materials.
authors.affiliation: Department of Chemistry, Missouri University of Science and Technology, Rolla, MO 65409, USA.|BK21 plus Division of Nano Convergence Technology, Pusan National University, Busan 46241, Korea.
authors.forename: Jong-Sik
authors.initials: JS
authors.lastname: Moon
authors.affiliation: Sandia National Laboratories, P.O. Box 5800, Albuquerque, NM 87112, USA.
authors.forename: Tyler E
authors.initials: TE
authors.lastname: Stevens
authors.affiliation: Sandia National Laboratories, P.O. Box 5800, Albuquerque, NM 87112, USA.
authors.forename: Todd C
authors.initials: TC
authors.lastname: Monson
authors.affiliation: Sandia National Laboratories, P.O. Box 5800, Albuquerque, NM 87112, USA.
authors.forename: Dale L
authors.initials: DL
authors.lastname: Huber
authors.affiliation: Department of Chemistry Education, Graduate Department of Chemical Materials, and Institute for Plastic Information and Energy Materials, Pusan National University, Busan 46241, Korea.
authors.forename: Sung-Ho
authors.initials: SH
authors.lastname: Jin
authors.affiliation: BK21 plus Division of Nano Convergence Technology, Pusan National University, Busan 46241, Korea.|Department of Nano energy Engineering, Pusan National University, Busan 46241, Korea.
authors.forename: Jin-Woo
authors.initials: JW
authors.lastname: Oh
authors.affiliation: Department of Chemistry, Missouri University of Science and Technology, Rolla, MO 65409, USA.
authors.forename: Jeffrey G
authors.initials: JG
authors.lastname: Winiarz