Photocurrent kinetics (in the microsecond time range) of chlorophyll a, chlorophyll b and stilbazolium merocyanine solutions in a nematic liquid crystal located in an electrochemical cell

A. Ptak, A. Der, R. Toth-Boconadi, N. S. Naser, D. Fra̧ckowiak

Research output: Contribution to journalArticle

22 Citations (Scopus)

Abstract

The photosynthetic pigments chlorophyll a and chlorophyll b solutions in a nematic liquid crystal were located between semiconducting and metallic transparent electrodes and illuminated by lamp or laser light. Cells with two semiconducting electrodes were also investigated. Such systems represent models of biological membranes simulating their fluid and oriented structure. The kinetics of photocurrent generation in the time range from microseconds to minutes were measured. The action spectrum of the photocurrent effect was established. The kinetics of the photocurrent generated by laser flash photolysis in the chlorophyll solutions are complex and to some extent similar to the kinetics reported for thylakoids. For comparison, the photocurrent kinetics of stilbazolium merocyanine, a highly protonated dye, were also measured. In this case, on flash illumination, only one photocurrent peak was observed. This peak is due to electron tunnelling to the semiconducting electrode. In the case of chlorophylls, several effects, such as charge displacement and migration of the ions, are superimposed giving a complex photocurrent generation. The results suggest that, in the case of chloroplasts, the kinetics of photopotential generation may be partially dependent on the membrane structure and fluidity.

Original languageEnglish
Pages (from-to)133-139
Number of pages7
JournalJournal of Photochemistry and Photobiology A: Chemistry
Volume104
Issue number1-3
DOIs
Publication statusPublished - Apr 1997

Keywords

  • Chlorophyll
  • Electrochemical cell
  • Liquid crystal
  • Merocyanine
  • Photocurrent

ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)
  • Physics and Astronomy(all)

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