Hysteresis in organic-inorganic hybrid perovskite solar cells

Organic-inorganic hybrid perovskite solar cells (HPSCs) are considered to be the most rapidly developed photovoltaic technology ever till date, portraying promising potential to replace the traditional silicon photovoltaics. In spite of such impressive growth, this technology is inundated with numerous challenges impeding the progress towards commercial viability. It is mainly due to the fact that the advancements in terms of performance efficiency were not equally matched with the fundamental understanding of inherent electronic and physio-chemical properties, modulating the photovoltaic parameters of the devices. Anomalous hysteresis observed in the current-voltage response of HPSCs is one of such major elusive issues prevalent in perovskite photovoltaics. Such hysteresis phenomenon could lead to erroneous estimation of the solar cell device efficiency, thereby its reliability during actual performance becomes questionable; serving as a serious obstacle for progress from both research as well as commercialization perspective. Hence, a detailed understanding of the origin of hysteresis and its associated mechanisms are highly indispensable. Though numerous theories have been proposed to elucidate the underlying causes of hysteresis, its origin is a highly debated topic till date and the most convincing answer is yet to be unraveled. The presented review takes an opportunity to elaborate various governing mechanisms or origins affecting the hysteresis phenomenon from a comprehensive yet insightful standpoint. This report also provides a concise synthesis of intricate interdependencies among the factors influencing hysteresis and highlights potential research strategies to develop hysteresis-free devices; rendering possible pathways to facilitate the viable commercialization of perovskite solar cells.