Dark Signals and Photovoltaic Properties of Al/Chlorophyll a/Ag Cells

Autor: Abdelkader Outzourhit, Roger M. Leblanc, Mustapha Mabrouki, E.L. Ameziane, A. Oueriagli, S. Hotchandani
Rok vydání: 2002
Předmět:
Zdroj: physica status solidi (a). 191:345-354
ISSN: 1521-396X
0031-8965
DOI: 10.1002/1521-396x(200205)191:1<345::aid-pssa345>3.0.co;2-n
Popis: The electrical characteristics of Al/chlorophyll a/Ag (Al/Chl 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 Chl a film. Furthermore, the temperature dependence of the I-V characteristics of these cells revealed a change in the conduction mechanisms in the Chl 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.
Databáze: OpenAIRE
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