A quasi-quantum well sensitized solar cell with accelerated charge separation and collection

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review

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Author(s)

  • Keyou Yan
  • Lixia Zhang
  • Jianhang Qiu
  • Yongcai Qiu
  • Jiannong Wang
  • Shihe Yang

Detail(s)

Original languageEnglish
Pages (from-to)9531-9539
Journal / PublicationJournal of the American Chemical Society
Volume135
Issue number25
Online published3 Jun 2013
Publication statusPublished - 26 Jun 2013
Externally publishedYes

Abstract

Semiconductor-sensitized solar cell (SSSC) represents a new generation of device aiming to achieve easy fabrication and cost-effective performance. However, the power of the semiconductor sensitizers has not been fully demonstrated in SSSC, making it actually overshadowed by dye-sensitized solar cell (DSSC). At least part of the problem is related to the inefficient charge separation and severe recombination with the current technologies, which calls on rethinking about how to better engineer the semiconductor sensitizer structure in order to enhance the power conversion efficiency (PCE). Herein we report on using for the first time a quasi-quantum well (QW) structure (ZnSe/CdSe/ZnSe) as the sensitizer, which is quasi-epitaxially deposited on ZnO tetrapods. Such a novel photoanode architecture has attained 6.20% PCE, among the highest reported to date for this type of SSSCs. Impedance spectra have revealed that the ZnSe/CdSe/ZnSe QW structure has a transport resistance only a quarter that of, but a recombination resistance twice that of the ZnSe/CdSe heterojunction (HJ) structure, yielding much longer electron diffusion length, consistent with the resulting higher photovoltage, photocurrent, and fill factor. Time-resolved photoluminescence spectroscopy indicates dramatically reduced electron transfer from ZnO to the QW sensitizer, a feature which is conducive to charge separation and collection. This study together with the impedance spectra and intensity modulated photocurrent spectroscopies supports a core/shell two-channel transport mechanism in this type of solar cells and further suggests that the electron transport along sensitizer can be considerably accelerated by the QW structure employed.

Citation Format(s)

A quasi-quantum well sensitized solar cell with accelerated charge separation and collection. / Yan, Keyou; Zhang, Lixia; Qiu, Jianhang et al.

In: Journal of the American Chemical Society, Vol. 135, No. 25, 26.06.2013, p. 9531-9539.

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review