Printing of tin perovskite solar cells via controlled crystallization†

The urgent need for sustainable electricity has driven progress in solar technologies, with perovskite photovoltaics standing out as a top contender. However, the presence of toxic lead in current perovskite devices necessitates the exploration of alternative materials. This study addresses the challenges associated with tin perovskite fabrication and the industrial scale-up of this lead-free technology. It introduces a new approach to regulate the key process of crystallization, involving a combination of new additives and a gas pulse to trigger and subsequently control nucleation and crystal growth. In situ optical spectroscopy probed the crystallization and enabled the optimization of the printing conditions. Solar cells were fabricated with a power conversion efficiency of 5.38% for 0.1 cm², 4.02% for 1 cm² and 2.31% for 5 cm² devices. They were tested under indoor lighting conditions and functioned at similar efficiency levels, thereby demonstrating the potential of this technology for commercial applications. Our new crystallization control method for printing Sn perovskites enabled the fabrication of the first Sn-based solar cell via slot-die coating, which is ideally suited for roll-to-roll manufacturing. This innovation opens new avenues for the development of fully printed lead-free perovskite photovoltaics, contributing significantly to the advancement of sustainable energy technologies.