While perovskite solar cells have skyrocketed in recent years to power conversion efficiencies competitive with those of silicon and thin-film photovoltaics, the lagging behind stability stands in the way of commercialisation. In this review, we discuss the reasons and factors that induce the degradation in photovoltaic performance of perovskite solar cells, and furthermore, we summarise the most promising strategies to enhance the lifespan. We show that each component of the device, including the charge selective contacts, perovskite layer, and electrodes, can be engineered to reduce the influence of heat, UV light, oxygen, moisture and their synergetic effect on the operating lifetime of devices. We conclude that inorganic contacts and inorganic perovskite compositions are the most promising direction toward stable perovskite solar cells.
