Development of Copper Sulfide/Cadmium Sulfide Thin-Film Solar Cells. Final Report, 13 July 1979-31 May 1983

摘要

Four major issues were addressed and resolved by the work on this program: process transferability, identification and control of key steps for high cell performance, low-cost grid electrodes giving high cell efficiency, and elucidation and suppression of performance-degrading mechanisms. Cell fabrication was shown to be transferable, with adequate attention given to the details of the CdS film deposition. Accurate and reliable monitoring of substrate temperature during CdS deposition can be accomplished by using thermocouples which are welded to molybdenum foil tabs, rather than directly to the copper foil substrate itself. The control of the wet-processing steps for surface texturing and barrier-layer formation can be improved to eliminate subtle operator influences. A special apparatus was designed and tested with a gas knife to dry the cell surface and an enclosure to provide a flowing argon atmosphere for transfers to and from etch, barrier-formation, and rise baths. Provisions of gold grid electrodes by selective electroplating of gold resulted in cell efficiency values up to 30% higher than for a standard processing with thick evaporated gold electrodes. This should be an important avenue for reducing fabrication costs and improving cell performance. Better understanding was gained of factors which affect the degradation of cell performance in atmospheres containing moisture and air. Nonthermal effects of laser treatment were shown to suppress or delay degradation of cell performance. Such modifications should be important for low-cost encapsulation techniques which allow some influence of air and moisture on the cells. (ERA citation 09:037446)