Improved light absorption and charge transport for perovskite solar cells with rough interfaces by sequential deposition

Recently, highly efficient solar cells based on organic-inorganic perovskites have been intensively reported for developing fabricating methods and device structures. Additional power conversion efficiency should be gained without increasing the thickness and the complexity of the devices to accord with practical applications. In this paper, a rough interface between perovskite and HTM was fabricated in perovskite solar cells to enhance the light scattering effect and improve the charge transport. The parameters related to the morphology have been systematically investigated by sequential deposition. Simultaneous enhancements of short-circuit current and power conversion efficiency were observed in both CH3NH3PbI3 and CH3NH3PbI3-xClx devices containing the rough interface, with power conversion efficiencies of 10.2% and 10.8%, respectively. Our finding provides an efficient and universal way to control the morphology and further optimize perovskite solar cells for devices by sequential deposition with various structures.