Proceedings of Online School on Fundamentals of Emerging Solar Cells (PVSCHOOL)
Publication date: 29th January 2021
Currently in the photovoltaic (PV) field, humidity or H2O is considered the main factor threatening the long-term stability of PV materials and devices during realistic outdoor operation, However, it is an apparent fact that in addition to H2O, there exist various chemical species in the outdoor environment, including atmospheric pollutants such as Cl-, NH4+, SO42- etc. One impactful and well-known outcome induced by these atmospheric pollutants is the chemical corrosion of industrial metals (steel, copper, zinc, aluminum etc.). In this work, we show a case study of how the atmospheric pollutants affect the stability of Al2O3-encapsulated Al:ZnO (AZO, being one of the most common transparent conductive oxides used in thin film solar cells). Inspired by the know-hows in atmospheric corrosion, a novel methodlogy is proposed to introduce the atmosphric pollutants. We observe that despite a thin Al2O3 is proved to be sufficent in protecting AZO thin films against damp heat test (85°C and 85% relative humidity for 1000h) as defiend by IEC standards, it does not suffice to protect AZO when additional atmospheric pollutants are introduced.