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Proceedings Paper

Quantum dot sensitized semiconductors for solar energy conversion
Author(s): Hitomi Y. Akiyama; Tsukasa Torimoto; Yasuhiro Tachibana; Susumu Kuwabata
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Paper Abstract

Metal sulfide (CdS or PbS) quantum dots were synthesized in nanoporous TiO2 films for applications in solar energy conversion devices. Sandwich type regenerative solar cells, based on the quantum dots sensitized TiO2 film, exhibit a high IPCE over visible wavelengths by optimizing the polysulfide electrolyte composition. The CdS QD shows a higher IPCE, compared to PbS, related to an increased light harvesting efficiency when the number and size of the QDs intensified. In contrast, QD size dependence on the IPCE was observed for the PbS, likely resulting from the QD size dependence on a conduction band edge potential (associated with quantum size effect) relative to the TiO2 conduction band edge, or the kinetic competition between the hot electron injection and the electron relaxation in the PbS conduction band. We also propose that an I3 -/I- redox electrolyte, with NaSCN addition, can be employed to enhance the solar cell performance. SCN- ions may attach to the QD surface forming a shell type structure to prevent the photocorrosion reaction, and act as an intermediate electronic state to induce the sequential step electron transfer reactions for the QD re-reduction.

Paper Details

Date Published: 8 September 2006
PDF: 13 pages
Proc. SPIE 6340, Solar Hydrogen and Nanotechnology, 63400H (8 September 2006); doi: 10.1117/12.679784
Show Author Affiliations
Hitomi Y. Akiyama, Osaka Univ. (Japan)
Tsukasa Torimoto, Nagoya Univ. (Japan)
Yasuhiro Tachibana, Osaka Univ. (Japan)
Susumu Kuwabata, Osaka Univ. (Japan)


Published in SPIE Proceedings Vol. 6340:
Solar Hydrogen and Nanotechnology
Lionel Vayssieres, Editor(s)

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