Efficient Anti-solvent-free Spin-Coated and Printed Sn-Perovskite Solar Cells with Crystal-Based Precursor Solutions

Tin-based perovskite solar cells (PSCs), with more consummate optical band gaps, lower exciton-binding energies, and higher charge-carrier mobility, have not attracted tremendous research efforts compared with the lead-based ones that have a record power conversion efficiency (PCE) of 24.2%. The major challenges for Sn-based research are significantly low open-circuit voltage, poor reproducibility, and environmental instability. It has been identified that the oxidation processes take place during the preparation of precursor solutions and fabrication of films, due to the low redox potential of the stannous absorption layer. Herein, we propose two strategies of crystal-resolving and recrystallization technology to reduce the oxidation process. As a result, PCEs of 8.9% (active area of 0.04 cm²) and 5.5% (active area = 1.01 cm²) are attained using the inverted p-i-n structure, which will lead to a revival of lead-free PSC research.