Citranox Corrosion for Photovoltaic Application

Q. We use Citranox for cleaning glass coated with tin oxide. We use the cleaned glass to deposit thin film CdS/CdTe photovoltaic devices. We use your citranox detergent and use a stainless steel ultrasonic cleaner. Is there a concern that the citranox could corrode stainless and deposit metallic ions on the glass surface? Which can be detrimental to the semiconductor films of the photovoltaic devices? Should we use a PTFE ultrasonic cleaner?

A. Citranox will not corrode stainless steel. Citranox will chelate traces of iron that may be present on the surface at locations where the passivation might be degraded from scratches or abrasion. We are familiar with thin film silicon deposition on tin oxide coated glass, and there have not been any reported contamination issues even when cleaned with highly ionic cleaners. Citranox is very free rinsing and even if there were traces of chelated iron, the chelating agents would sequester them in solution and inhibit their deposition on the glass surface and facilitate their being rinsed away. Frankly a PTFE ultrasonic cleaner sounds like overkill. PTFE might absorb some of the ultrasound. I am familiar with a startup CdSe photovoltaic manufacturer making photovoltaics that uses simple ultrasonic tanks to clean their substrates with Citranox.

Visit our Photovoltaic and Solar Cleaning industry page for more information on the cleaners recommended for different surfaces and soils. You can also ask our cleaning experts a technical cleaning question at Ask Alconox.