Nano Research

, Volume 4, Issue 12, pp 1181–1190 | Cite as

Sensitization of hydrothermally grown single crystalline TiO2 nanowire array with CdSeS nanocrystals for photovoltaic applications

  • Akshay Kumar
  • Kuan-teh Li
  • Anuj R. Madaria
  • Chongwu Zhou
Research Article

Abstract

An oriented array of electron transporting nanowires, grown directly on a transparent conductor constitutes an optimal architecture for efficient photovoltaic applications. In addition, semiconductor nanocrystals can work as efficient light absorbers because of their tunable optical properties. In this paper, we use an oriented array of TiO2 nanowires grown directly on a transparent conductive electrode and subsequently sensitized with colloidally grown CdSeS nanocrystal quantum dots (QDs), using an efficient bi-linker assisted methodology, to demonstrate photovoltaic cells. Upon excitation with light, exciton dissociation takes place at the nanowire-nanocrystal interface, after which, electrons are transported to the fluorine-doped tin oxide (FTO) electrode via single-crystalline TiO2 nanowire channels. We demonstrate that an ex situ ligand exchange of QDs followed by sensitization on oxygen-plasma treated TiO2 nanowires results in enhanced loading of QDs, as compared to the in situ ligand exchange approach. An array of 1 μm long TiO2 nanowire sensitized with CdSeS nanocrystals exhibits photovoltaic effects with a short-circuit current of 2–3 mA/cm2, an open circuit voltage of 0.6–0.7 V and a fill factor of 52–65%, resulting in devices with efficiencies of up to 0.6%.

Keywords

TiO2 nanowire semiconductor nanocrystals solar cells hydrothermal growth 

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Copyright information

© Tsinghua University Press and Springer-Verlag Berlin Heidelberg 2011

Authors and Affiliations

  • Akshay Kumar
    • 1
  • Kuan-teh Li
    • 1
  • Anuj R. Madaria
    • 1
  • Chongwu Zhou
    • 1
  1. 1.Department of Electrical Engineering and Center for Energy Nanoscience and TechnologyUniversity of Southern CaliforniaLos AngelesUSA

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