The hybrid organic-inorganic perovskite solar cells have garnered considerable attention, achieving very high efficiencies exceeding 25%. However, the stability of perovskite solar cells represents a significant obstacle towards the widespread commercialization of this technology. In-depth research towards understanding the fundamental mechanisms responsible for the degradation of perovskite materials is urgently required. The present PhD thesis aims to provide novel strategies towards overcoming the degradation of perovskite solar cells by replacing the conventionally used costly and unstable gold electrode with low-cost and stable electrodes; and by additive engineering of active perovskite absorber material.