Abstract

In our laboratory, we developed an electrochemical photovoltaic cell (EPC) that directly converts solar energy into electricity. The cell contains a polycrystalline n-CdSe semiconducting electrode, a gel electrolyte and a transparent counter electrode (indium-tin-oxide). In order to improve the performance of this cell, CdSe thin layers were gown by a low cost process, the liquid-metal vapor reaction. This technique has the important advantage of producing layers with a highly textured surface, leading to enhance light-harvesting capabilities. The present work involves the preparation of polycrystalline CdSe by liquid-metal vapor reaction, in which the Se vapors react with the surface of a heated Cd substrate under constant argon flow. The electrodes are characterized using: X-ray diffraction, energy dispersive analysis of x-ray, scanning electron microscopy and cyclic voltammetry. It is observed that CdSe thin films present good porosity. All the electrodes prepared in this work are of an n-type semiconductor. The gel electrolyte is composed of the redox couple CsT/T 2 (CsT is 5-mercapto-1-methyltetrazole cesium salt, T 2 is di-5-91-methyltetrazole disulfide) dissolved in a mixture of DMSO/DMF and incorporated in polyvinylidene fluoride. The use of gel electrolyte was chosen because of its large electrochemical stability domain and its ability to eliminate the photocorrosion of low band gap n-type semiconductors usually observed when using aqueous electrolytes.