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 language||English (US)|
|Number of pages||10|
|Journal||Physica Status Solidi (A) Applied Research|
|State||Published - May 2002|
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics