Electrochemical Mechanical Polishing of Flexible Stainless Steel Substrate for Thin-Film Solar Cells

摘要

The morphology of stainless steel is a key factor that affects the quality and structure of deposited cellmaterial and, thus, the efficiency of flexible solar cells. Electrochemical mechanical polishing (ECMP)combines electrochemical and mechanical actions to reduce surface roughness to the level of tens ofnano-meters for some metals. In this study, a novel ECMP system is introduced and electrochemicalprocess parameters are evaluated. Finally, both stainless steel (SS) 304 and SS430 substrates sized 10cm 10 cm are polished from average roughness (Ra) of 35 nm, and peak roughness (Rp) of 126 nmdown to an Ra of 10 nm and Rp of 65 nm. These roughness values are very close to that of glasssubstrates. Amorphous silicon solar cells are fabricated simultaneously on SS304-Bright Annealing(BA), SS304-ECMP, SS430-BA, and SS430-ECMP substrates in the same run. The substrates treatedwith ECMP have better cell performance than untreated substrates. This ECMP process is an efficientand economical method for producing a super smooth SS surface as the substrate for thin-film solarcells.