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Energy Express

  • Editor: Bernard Kippelen
  • Vol. 18, Iss. S3 — Sep. 13, 2010
  • pp: A451–A457

Dead zones in colloidal quantum dot photovoltaics: evidence and implications

D. Aaron R. Barkhouse, Illan J. Kramer, Xihua Wang, and Edward H. Sargent  »View Author Affiliations

Optics Express, Vol. 18, Issue S3, pp. A451-A457 (2010)

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In order to fabricate photovoltaic (PV) cells incorporating light-trapping electrodes, flexible foil substrates, or more than one junction, illumination through the top-contact (i.e.: non-substrate) side of a photovoltaic device is desirable. We investigate the relative collection efficiency for illumination through the top vs. bottom of PbS colloidal quantum dot (CQD) PV devices. The external quantum efficiency spectra of FTO/TiO2/PbS CQD/ITO PV devices with various PbS layer thicknesses were measured for illumination through either the top (ITO) or bottom (FTO) contacts. By comparing the relative shapes and intensities of these spectra with those calculated from an estimation of the carrier generation profile and the internal quantum efficiency as a function of distance from the TiO2 interface in the devices, a substantial dead zone, where carrier extraction is dramatically reduced, is identified near the ITO top contact. The implications for device design, and possible means of avoiding the formation of such a dead zone, are discussed.

© 2010 OSA

OCIS Codes
(040.5350) Detectors : Photovoltaic
(230.0230) Optical devices : Optical devices
(250.0250) Optoelectronics : Optoelectronics
(250.5590) Optoelectronics : Quantum-well, -wire and -dot devices

ToC Category:

Original Manuscript: July 1, 2010
Revised Manuscript: August 27, 2010
Manuscript Accepted: August 27, 2010
Published: September 1, 2010

Virtual Issues
Focus Issue: Thin-Film Photovoltaic Materials and Devices (2010) Optics Express

D. Aaron R. Barkhouse, Illan J. Kramer, Xihua Wang, and Edward H. Sargent, "Dead zones in colloidal quantum dot photovoltaics: evidence and implications," Opt. Express 18, A451-A457 (2010)

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