ZnO Spin-Coating of TiO₂ Photo-Electrodes to Enhance the Efficiency of Associated Dye-Sensitized Solar Cells

Fahd Al-Juaid, Amar Merazga, Fouad Abdel-Wahab, Mohamed Al-Amoudi

Department of Chemistry, Taif University, Taif, KSA.
Department of Physics, Taif University, Taif, KSA.

DOI: 10.4236/wjcmp.2012.24032                

Abstract

Dye-sensitized solar cells (DSSCs) with ZnO spin-coated TiO₂ photo-electrodes are compared to DSSC with a bare TiO₂ photo-electrode. It is demonstrated that the deposited ZnO of controlled amount, by varying the precursor concentration in the coating sol, can indeed enhance the performance of the DSSC. The measured power conversion efficiency shows a maximum around the precursor concentration 0.1 M and falls down sharply to 0% beyond this point. The results are interpreted on the basis of two competing factors: At ZnO concentrations less than 0.1 M, the formation of an energy barrier increases the photocurrent by reducing the rate of interfacial back-recombination. At ZnO concentrations greater than 0.1 M, the screening of the TiO₂ film by thicker ZnO layers decreases the photocurrent through the reduction of TiO₂ dye-adsorption efficiency.

Keywords

TiO₂ Photo-Electrodes; ZnO Sol-Gel Spin-Coating; Dye-Sensitized Solar Cells; Power Conversion Efficiency

Conflicts of Interest

The authors declare no conflicts of interest.

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