Photovoltaic Devices Using Sublimed Methylammonium Lead Iodide Perovskites: Long‐Term Reproducible Processing

Fully evaporated solar cells using methylammonium iodide (MAI)-based perovskites can reach power conversion efficiencies exceeding 20%. An important point to advance perovskite photovoltaics is ensure reproducibility from batch batch. Sublimation control of organic ammonium halides critical in achieving this for cells. Herein, a reproducible procedure the coevaporation PbI2 and MAI based on an evaporator chamber setup with only two quartz crystal microbalances (QCMs) described. One QCM monitors exclusively precursor (PbI2-QCM) second total amount MAPbI3 mass reaching substrates (MAPbI3-QCM). It shown that evaporation be reliably monitored, indirectly, through MAPbI3-QCM. In way, fluctuating sublimation rates usually observed due variations purity are avoided. This allows one obtain consistently high-performing over period half years.