Photogeneration of charges in microcrystalline chlorophyll a

Hassan Kassi, Saïd Barazzouk, Marc Brullemans, Roger Leblanc, Surat Hotchandani

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

The electric-field and temperature dependence of hole photogeneration in chlorophyll a (Chla) have been analyzed in terms of electric-field assisted thermal dissociation of charge pairs based on Onsager theory. An excellent agreement between the experimental and theoretical values of the slope-to-intercept ratio, S/I, for the plot of photogeneration efficiency vs. electric field at low field strengths provides a proof for the applicability of the Onsager approach to the photogeneration of charges in Chla. A value of 19 nm has been obtained for Coulomb capture radius, rc, from S/I. From the temperature dependence of photogeneration, the initial separation, r 0, of photogenerated electron-hole has been evaluated, and has a value of 1.24 nm. This smaller r0 compared to rc leads to a feeble dissociation probability of electron-hole pairs into free carriers, and may, among other factors, explain the low power conversion efficiencies of Chla photovoltaic cells.

Original languageEnglish
Pages (from-to)5345-5348
Number of pages4
JournalThin Solid Films
Volume518
Issue number18
DOIs
StatePublished - Jul 1 2010

Fingerprint

chlorophylls
Chlorophyll
Electric fields
electric fields
thermal dissociation
temperature dependence
Electrons
Photovoltaic cells
photovoltaic cells
Conversion efficiency
field strength
plots
dissociation
slopes
Temperature
radii
chlorophyll a

Keywords

  • Electric field
  • Microcrystalline chlorophyll a
  • Onsager approach
  • Photocarrier generation
  • Time-of-flight technique

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Materials Chemistry
  • Metals and Alloys
  • Surfaces, Coatings and Films
  • Surfaces and Interfaces

Cite this

Kassi, H., Barazzouk, S., Brullemans, M., Leblanc, R., & Hotchandani, S. (2010). Photogeneration of charges in microcrystalline chlorophyll a. Thin Solid Films, 518(18), 5345-5348. https://doi.org/10.1016/j.tsf.2010.04.002

Photogeneration of charges in microcrystalline chlorophyll a. / Kassi, Hassan; Barazzouk, Saïd; Brullemans, Marc; Leblanc, Roger; Hotchandani, Surat.

In: Thin Solid Films, Vol. 518, No. 18, 01.07.2010, p. 5345-5348.

Research output: Contribution to journalArticle

Kassi, H, Barazzouk, S, Brullemans, M, Leblanc, R & Hotchandani, S 2010, 'Photogeneration of charges in microcrystalline chlorophyll a', Thin Solid Films, vol. 518, no. 18, pp. 5345-5348. https://doi.org/10.1016/j.tsf.2010.04.002
Kassi, Hassan ; Barazzouk, Saïd ; Brullemans, Marc ; Leblanc, Roger ; Hotchandani, Surat. / Photogeneration of charges in microcrystalline chlorophyll a. In: Thin Solid Films. 2010 ; Vol. 518, No. 18. pp. 5345-5348.
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