A full overview of international standards assessing the long-term stability of perovskite solar cells

Recently organic-inorganic perovskite solar cells (PSCs) have emerged as promising candidates for photovoltaics because of their relatively high efficiency and low processing costs. However, for possible commercialisation, long-term stability remains a key obstacle, especially when compared to silicon or GaAs. Thus, future research will significantly focus on stability. The most relevant industry standards for the stability of solar cells are issued by the International Electrotechnical Commission (IEC), summarized in the so-called IEC 61215 norm. The IEC 61215 is a series of very detailed, time-consuming and interconnected stress tests that provide accelerated aging conditions to extrapolate the potential longterm lifetime of a solar module. Established silicon, for example, passes the full IEC 61215. To gain the confidence of investors and customers, passing the full IEC 61215 is a necessary minimum requirement for the commercialization of perovskites. Interestingly, the IEC 61215 is not openly accessible which may be one reason why there are often references to outdated versions. To remedy this situation, we introduce and analyse the most current IEC 61215 stability standards for solar cells and to which degree perovskites have passed them. We then elaborate on the most pertinent challenges for the long-term stability of PSCs in the coming years. This includes less explored stability tests such as potential-induced degradation (IEC TS 62804-1) and ammonia corrosion (IEC 62716). From this, it is evident that currently underappreciated degradation modes such as mechanical stability, high applied voltages and reverse bias, where especially hot spots could become problematic, must be considered in the coming years when evaluating the long-term stability of PSCs.