Preserving the stoichiometry of triple-cation perovskites by carrier-gas-free antisolvent spraying. Issue 37 (21st February 2022) - Telschow, Oscar
Abstract : The method of antisolvent application used during the fabrication of solution-processed lead halide perovskite layers influences their microstructure, stoichiometry and consequently, their photovoltaic performance. Abstract : The use of antisolvents during the fabrication of solution-processed lead halide perovskite layers is increasingly common. Usually, the antisolvent is applied by pipetting during the spin-coating process, which often irreversibly alters the composition of the perovskite layer, resulting in the formation of PbI2 at the surface and bulk of the perovskite layer. Here, we demonstrate that by applying the antisolvent via carrier-gas free spraying, the stoichiometry of the perovskite layer is far better preserved. Consequently, the photovoltaic performance of triple cation photovoltaic devices fabricated in an inverted architecture is enhanced, mainly due to an increase in the open-circuit voltage. By exploring different volumes of antisolvent, we show that spraying as little as 60 μL results in devices with power conversion efficiencies as high as 21%. Moreover, solar cells with sprayed antisolvent are more stable than those fabricated by pipetting the antisolvent.