Retarded Crystallization Kinetics of One-Step Deposited MAPbCl₃ Perovskite Enabling Fully Transparent Solar Cells

Transparent photovoltaics (TPVs) with perovskite absorbers have attracted considerable attention, owing to their applicability in buildings, vehicles, and mobile displays. Especially, unlike semitransparent PVs, ultraviolet harvesting TPVs are suitable for developing truly transparent solar cells because of their high transparency, color neutrality, and superior optoelectronic properties. However, fabricating compact perovskite film and controlling the crystallization kinetics of the wide-bandgap MAPbCl3 perovskite are still challenging. In this study, we successfully fabricated a high-quality MAPbCl3 perovskite film by one-step deposition using an anodized aluminum oxide (AAO) template and a PbAc2 salt. PbAc2 was utilized to enhance the solubility of the perovskite precursor because of the strong bonding between PbAc2 and MA+. The AAO template suppressed the crystallization rate by slowing the solvent evaporation induced by the spatial confinement, resulting in an upward growth from the bottom. The resulting TPV device exhibited a high average visible transmittance of 72.5% and a color rendering index of 95 with a power conversion efficiency (PCE) of 0.68%. Furthermore, the scaling potential of the one-step coated TPV was demonstrated by fabricating PSCs with a size of 4 × 4 cm2, and a PCE of 0.6% was obtained from a large-area aperture size of 1.2 cm2.