PHOTOVOLTAIC PROPERTIES OF SINTERED CDS/CDTE SOLAR-CELLS WITH AN INDIUM-TIN-OXIDE ELECTRODE

Abstract

Indium-tin-oxide (ITO) electrodes were applied to sintered all-polycrystalline CdS/CdTe solar cells for large area cell fabrication. The CdS and CdTe layers were prepared by sequentially sintering (CdS + CdCl2) slurry at 600 degrees C and (Cd + Te) slurry at 625 degrees C. The length of the cells was fixed at 10 mm and the width was varied from 3 to 9 mm. While the application of ITO did not change the junction properties after a high temperature annealing process, it significantly reduced the series resistance of the cells. As the cell width increased from 3 to 9 mm, the efficiency of CdS/CdTe solar cells with ITO electrode decreased slightly from 10.5 to 9.4%, while that of cells without ITO decreased from 10.4 to 8.4% under the illumination of 50 mW.cm(-2). The efficiency of the cells with ITO were less degraded with increasing cell width because the short-circuit current and fill factor of the cell with ITO changed little. The total area (active + contact area) efficiency of the sintered CdS/CdTe cells without ITO had a maximum value of 6.5% at only 4 mm width. However, that of the cells with ITO electrode increased to 7.6% at 9 mm width. Thus, adopting an ITO electrode enabled us to improve the total area efficiency of the sintered CdS/CdTe solar cells with a large active area.