Holistic Strategies Lead to Enhanced Efficiency and Stability of Hybrid Chemical Vapor Deposition Based Perovskite Solar Cells and Modules

Hybrid chemical vapor deposition (HCVD) is a promising method for the up-scalable fabrication of perovskite solar cells/modules (PSCs/PSMs). However, the efficiency of the HCVD-based perovskite solar cells still lags behind the solution-processed PSCs/PSMs. In this work, the oxygen loss of the electron transport layer of SnO2 in the HCVD process and its negative impact on solar cell device performance are revealed. As the counter-measure, potassium sulfamate (H2KNO3S) is introduced as the passivation layer to both mitigate the oxygen loss issue of SnO2 and passivate the uncoordinated Pb2+ in the perovskite film. In parallel, N-methylpyrrolidone (NMP) is used as the solvent to dissolve PbI2 by forming the intermediate phase of PbI2 center dot NMP, which can greatly lower the energy barrier for perovskite nucleation in the HCVD process. The perovskite seed is employed to further modulate the kinetics of perovskite crystal growth and improve the grain size. The resultant solar cells yield a champion power conversion efficiency (PCE) of 21.98% (0.09 cm(2)) with a stable output performance of 21.15%, and the PCEs of the mini-modules are 16.16% (22.4 cm(2), stable output performance of 14.72%) and 12.12% (91.8 cm(2)). Furthermore, the unencapsulated small area device shows an outstanding operational stability with a T80 lifetime exceeding 4000 h.