Accession Number : ADA266073

Title :   Polaronic Charge Separation in Mixed-Halide MX Solids.

Descriptive Note : Professional paper,

Corporate Author : NAVAL COMMAND CONTROL AND OCEAN SURVEILLANCE CENTER RDT AND E DIV SAN DIEGO CA

Personal Author(s) : Saxena, A. ; Bishop, A. R. ; Huang, X. Z. ; Gammel, J. T.

Report Date : APR 1993

Pagination or Media Count : 58

Abstract : We have obtained clear evidence for photoinduced electron hole pair separation in mixed-halide, halogen-bridged transition metal (MX) chain solids. Resonance Raman experiments on doped and photoexcited single crystals of mixed-halide (M = Pt, X=Cl, Br, I) complexes indicate charge separation: electron polarons preferentially locate on the PtBr segment while hole polarons are trapped within PtCl segments. This polaron selectivity, which is potentially very useful for photovoltaic device applications, is demonstrated within theoretical calculations based on a discrete, 3/4-filled, two-band, tight-binding, extended Peierls-Hubbard model, showing strong hybridization of PtCl and PtBr electronic bands as the driving force for separation. In contrast to PtCl(/)x/Brl1-x25 the PtCl(/)/xI1-x system exhibits qualitatively different behavior such as 'self doping'.... Photoinduced electron, Polaron selectivity

Descriptors :   *HALIDES, *SOLIDS, *PLATINUM, *CHARGE DENSITY, CHAINS, ELECTRONICS, ELECTRONS, HALOGENS, HYBRIDIZATION, MODELS, RESONANCE, SEPARATION, SINGLE CRYSTALS, TRANSITION METALS, HOLES(ELECTRON DEFICIENCIES), DOPING, EXCITATION, PHOTOVOLTAIC EFFECT.

Subject Categories : Atomic and Molecular Physics and Spectroscopy
      Optics
      Physical Chemistry

Distribution Statement : APPROVED FOR PUBLIC RELEASE