In a DOE funded Phase I and Phase II SBIR project, GVD validated the use of the barrier coating in protecting perovskite solar cells from water vapor. By integrating a barrier coating step following application of the back contact during PSC manufacturing a PSC manufacturer could eliminate the need to perform subsequent steps in a dry environment. GVD showed that the barrier coating, applied directly atop methylammonium lead iodide photovoltaic stacks from a U.S. hybrid perovskite-silicon solar cell company, eliminates degradation for up to 2 days at 85% RH with no other encapsulation. The coating is compatible with subsequent manufacturing steps, such as EVA lamination. GVD's coating is transparent in the visible spectrum, including >99.9% transparent in the critical window for perovskite-silicon hybrids (780-1100 nm). It undergoes no yellowing after UV-exposure equivalent to a 25 year field lifetime. Alleviation of dry processing requirements, even for a few major steps, could reduce required CAPEX and would accelerate the global installation of solar energy to meet climate targets. GVD's barrier coatings have a water vapor transmission rate ~100x lower than that of the industry standard encapsulation material for silicon solar cells, ethylene vinylacetate. GVD's process yields coatings with similar performance to that of sputtered or oxide-only CVD processes, but, unlike sputtering or oxide-only depositions, GVD's process inflicts no damage on the solar cell. GVD's coatings have very high thermal stability (up to 200 °C continuous use) and excellent UV-stability, which makes them far more suitable as part of a field-deployed solar cell module than polymer coatings.
