Modeling Transfer of Electrons between Energy States of an Electrolyte and CdS Thin Films using Gerischer Model

Authors

  • Cliff Orori Mosiori Technical University of Mombasa
  • John Maera Maasai Mara University
  • W. Kamande Njoroge Kenyatta University
  • T. Reuben Shikambe Kenyatta University
  • Matthew Munji
  • Robert Magare Maasai Mara University

DOI:

https://doi.org/10.18034/ei.v3i1.197

Keywords:

Fe 3/Fe 2 Oxidant-Reductant electrolyte, cadmium sulfide, Gerischer model, Indium tin oxide, ITO, ITO/CdS interface, Marcus

Abstract

A number of models have been developed to describe electron transfer between electrolytes and group II–VI binary semiconductors. In this report, a study was conducted to describe and model electron transfer between an inorganic semiconductor, (i.e. CdS) and a ferric oxidizing/reducing agent [i.e. K3Fe(CN)6/K4Fe(CN)6]. We describe the interfacial electron transfer using the semi-classical theory approaches as described by Marcus and later developed by Gerischer and therefore called Gerischer model as it is applied to heterogeneous electron transfer in a semiconductor - electrolyte interface. CdS thin films were grown by electro-deposition method on the indium tin oxide (ITO) substrates and were used as electrodes. The data collected was used to determine the kinetic constant rates and re-orientation energies as measured in the solutions with different concentration of redox system, Fe+3/ Fe+2. Experiments showed that when concentration of oxidized species increased and causing an increase in  activity, the kinetic constant rates decreases inversely. Equally light induced current at 0.0V/Ag was higher when the ratio of the oxidant-reductant (i.e. 2/0.02 and 0.2/0.02) was high. EIS studies revealed that for the two ratios of. 2/0.02 and 0.2/0.02, the difference of current density was comparable to the transfer of the charge carriers for the oxidant-reductant electrolyte at 2/0.02 with respect to 0.2/0.02.

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Author Biographies

  • Cliff Orori Mosiori, Technical University of Mombasa

    Department of Mathematics & Physical Sciences, Technical University of Mombasa, Box 90420 – 80100 Mombasa, KENYA

  • John Maera, Maasai Mara University

    Department of Mathematics & Physical Sciences, Maasai Mara University, Box 861 - 20500, Narok , KENYA

  • W. Kamande Njoroge, Kenyatta University

    Department of Physics, Kenyatta University, Box 43844 - 00100, Nairobi, KENYA

  • T. Reuben Shikambe, Kenyatta University

    Department of Physics, Kenyatta University, Box 43844 - 00100, Nairobi, KENYA

  • Matthew Munji

    Department of Physics, Kenyatta University, Box 43844 - 00100, Nairobi, KENYA

  • Robert Magare, Maasai Mara University

    Department of Mathematics & Physical Sciences, Maasai Mara University, Box 861 - 20500, Narok , KENYA

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Published

2015-06-18

Issue

Section

Peer Reviewed Articles

How to Cite

Modeling Transfer of Electrons between Energy States of an Electrolyte and CdS Thin Films using Gerischer Model. (2015). Engineering International, 3(1), 35-44. https://doi.org/10.18034/ei.v3i1.197

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