Dark signals and photovoltaic properties of Al/chlorophyll a/Ag cells

M. Mabrouki, A. Oueriagli, A. Outzourhit, E. L. Ameziane, S. Hotchandani, R. M. LeBlanc

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3 Scopus citations

Abstract

The electrical characteristics of Al/chlorophyll a/Ag (Al/Chi a/Ag) structures, prepared by electrodeposition of chlorophyll a onto vacuum evaporated aluminum and followed by evaporation of silver (Ag) top electrode, are presented. It was found that these cells present a short-circuit current and an open-circuit voltage in the dark which both evolve with the aging time. An analysis of the I-V characteristics suggests that these dark signals are due to electrochemical reactions at the Al/Chl a interface and to thermally detrapped carriers in the Chi a film. Furthermore, the temperature dependence of the I-V characteristics of these cells revealed a change in the conduction mechanisms in the Chi a film around 15 °C. This is further confirmed by studying the variations of the photocurrent with temperature. The conversion efficiency of these cells was found to be on the order of 0.1%. A comparison of the action spectra of the cells and the absorption spectra of the Chl a films suggested that the photogeneration of free carriers is governed by the ionization of the photogenerated excitons.

Original languageEnglish (US)
Pages (from-to)345-354
Number of pages10
JournalPhysica Status Solidi (A) Applied Research
Volume191
Issue number1
DOIs
StatePublished - May 2002

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ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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