A biomineralization-inspired strategy of self-encapsulation for perovskite solar cells

Solution-processed perovskite films are promising for the cost-effective fabrication of optoelectronic devices. However, the poor environmental stability of perovskite materials hampers their commercial development, and a challenge remains in the universal technology for self-encapsulating perovskite films through controlling the crystallization. Herein, we designed a strategy of crystal growth assisted by the polymer bottom-up dynamic diffusion and created the self-encapsulated perovskite films with preferred crystalline orientation by mimicking the typical process of biomineralization. Thin polymer distributed at the surface, buried interface, and grain boundaries facilitated the efficient defect passivation and self-encapsulation of the entire film, and also, the coordination interaction between polymer and perovskite aligned the interface energy band. These collaborative advantages endowed perovskite solar cells (PSCs) with power conversion efficiency (PCE) of 22.90 %. In addition, the self-encapsulated perovskite films exhibited negligible decomposition and PCE remained 90 % after being stored in ambient air (30–50 % humidity) for 90 days. This universal strategy of biomineralization-inspired polymer self-encapsulating opens up a new avenue for efficient and stable perovskite optoelectronics.