Electrodeposited ZnO/CdSe Core-Shell Nanowire Arrays: Building Blocks for Nanostructured Solar Cells

  • Prof Claude Levy-Clement, Institut de Chimie et Matériaux de Paris-Est, CNRS, 94320 Thiais, France
  • Jamil Elias, Institut de Chimie et Matériaux de Paris-Est, CNRS, 94320 Thiais, France
  • Dr Ramon Tena-Zaera, Institut de Chimie et Matériaux de Paris-Est, CNRS, 94320 Thiais, France
  • Dr Ivan Mora-Sero, Departament de Física, Universitat Jaume I, 12071 Castelló, Spain
  • Dr Fran Fabregat-Santiago, Departament de Física, Universitat Jaume I, 12071 Castelló, Spain
  • Prof Juan Bisquert, Departament de Física, Universitat Jaume I, Castelló, Spain

    • Electrodeposited ZnO/CdSe core-shell nanowire arrays present highly interesting properties to be used as building blocks for nanostructured solar cells. ZnO/CdSe/CuSCN ETA (Extremely Thin Absorber)-solar cells based on this nanostructure exhibited promising photovoltaic efficiencies ~2.5% [1]. A strong influence of the annealing temperature on the electronic performance of ZnO/CdSe nanowires has been found, the best results being obtained after annealing in air at 400°C. External quantum efficiency > 70% has been reached for ZnO/CdSe nanowire arrays in ferro/ferricyanide solutions [2]. The annealing effects on the structural properties of ZnO/CdSe nanowires have been analyzed by X-ray diffraction. Electrochemical impedance spectroscopy measurements [3] have been performed in polysulfide solutions to study the influence of the annealing temperature on the charge transfer at ZnO/CdSe interface. The variation of (micro)structural properties and charge transfer will be discussed in the frame of solar cell applications. On the other hand, the effects of dimensions, density and verticality of the ZnO nanowire arrays on the light scattering have been investigated by optical spectroscopy. An overview of the influence on the absorption of solar light by ZnO/CdSe core-shell nanowires will be presented. Some strategies to reduce the thickness of CdSe shell without decreasing the solar light absorption will be discussed, opening new approaches to get nanostructured solar cells less sensitive to the properties of the light absorber layer.

    [1] C. Lévy-Clément et al. Adv. Mater. 17, 1512 (2005)
    [2] R. Tena-Zaera et al. Chem. Mater. 19, 1626 (2007)
    [3] I. Mora-Sero et al. Appl. Physics. Letters 89, 203117 (2006)