Photoelectrochemical Investigations on Hg_xCd_{1-x}Se Thin Film Electrode/Electrolyte System

Authors: VITHAL BHIVABA PUJARI, L. P. DESHMUKH

Abstract: Thin film electrodes of Hg_xCd_{1-x}Se (0 \le x \le 0.2) were prepared in an aqueous alkaline medium (pH \cong 11) on highly conducting stainless steel substrates by chemical bath technique. Use of these films was made as an active photoelectrode in an electrochemical photovoltaic cell, comprising: electrode; sodium polysulphide electrolyte; and impregnated graphite as a counter electrode. The investigations on these cells were made by studying I-V and C-V characteristics in dark, power output, built-in-potential, spectral and photo responses. Cell performance parameters were evaluated: open-circuit photopotential V_{ph}; and short-circuit photocurrent I_{ph}; series and shunt resistances R_{s} and R_{sh}; quantum conversion efficiency \eta ; fill factor ff; junction ideality factor n_d; light quality factor n_L; built-in-potential \Phi _B; and the flat-band potential V_{fb} were evaluated. Careful inspection of calculated values of these parameters revealed that the cell performance has been greatly enhanced with increasing electrode composition. Typically, the quantum conversion efficiency and fill factor are found to be enhanced from 0.056% to 0.31% and 31% to 52% respectively, as the photoelectrode composition varied from zero to 0.01. Incremental changes in the performance parameters, and consequently the enhancement in the cell performance are explained on the basis of electrode materials composition.

Keywords: MCS, P-V cells, efficiency and fill factor

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