Aqueous solvent-regulated crystallization and interfacial modification in perovskite solar cells with enhanced stability and performance

Crystal orientation of perovskite film and interface modification plays an important role in the efficient operation and stability of perovskite solar cells (PSC). Herein, a high quality perovskite film with large grain size, high crystallinity and preferred crystal orientation on (100) plane is deposited on an aqueous solvent (H2O and DMF) pretreated nickel oxide (NiOx) substrate (HDP). The aqueous solvent treatment increases the wettability and conductivity of NiOx layer during perovskite growth. Steady-state and time-resolved photoluminescences reveals a significantly increased charge extraction efficiency in the HDP perovskite films. In addition, the HDP devices exhibit impressively improved photovoltaic performance as well as enhanced long-term stability under high moisture, UV irradiation and thermal stress. Therefore, our work provides a versatile strategy to introduce preferred orientation and interfacial modification to enhance the crystal quality and stability of halide perovskite thin films and related optoelectronic devices.