Perovskite solar cells (PSC) have emerged as an important player in the search for producing c1ean and renewable energy at high efficiencies. However, there exist several bottlenecks to maximise their efficiency and stability. This thesis explores the physical mechanisms related to these limitations in operation and provides a deeper understanding as to how to overcome them. Through systematic experiments based on the small perturbation methods of Impedance Spectroscopy (IS) and Intensity Modulated Photocurrent Spectroscopy (IMPS), the perovskite/selective contact interfaces are identified as a critical factor that controls charge accumulation, recombination ando extraction. Therefore, these interfaces require to be carefully tuned in order to gain control over the device operation. Based on these insights, a robust equivalent circuit of the PSC is developed that provides a strong foundation for further development of these solar cells
