Surface Contamination Removal from Si PV Substrates Using a Biodegradable Chelating Agent and Detection of Cleaning Endpoints Using UV/VIS Spectroscopy

摘要

The continued pressure for increasing c-Si solar efficiency is generating many innovative and novel approaches. In this manuscript we present the results of a chemical cleaning approach for targeted removal of efficiency degrading metallic contaminants. The application of this cleaning approach, in both alkaline and acidic cleaning processes has demonstrated 0.2 to 0.3% absolute cell efficiency improvement for both mc-Si and c-Si production lines. This improvement is not dependent on cell architectures, but addresses a universal complication arising from crystalline silicon photovoltaic wafering manufacture. We also disclose the potential of utilizing this chemistry to enable a spectroscopic method for real time monitoring of trace metal loading in the cleaning baths. And by extension a method to provide process endpoint detection based on metallic loading levels in aqueous solutions.