Fundamental optical constants and anti-reflection coating of melt-grown, polished CsPbBr3 crystals

Lead halide perovskites are notorious for water-sensitivity and low hardness. Consequently, polishing CsPbBr 3 crystals to achieve high-quality surfaces is challenging. We present a breakthrough mechanical polishing methodology tailored to the specific needs of these soft, moisture-sensitive semiconductors. Three-dimensional optical surface profiles over ~ 1 mm 2 areas demonstrate high-quality surfaces with root-mean-square roughness values (< 10 nm) that are unparalleled for melt-grown CsPbBr 3 . We additionally delve into the polished wafers’ fundamental optical constants and introduce an anti-reflection coating method, setting new standards for short-wave infrared transparency in CsPbBr 3 . These pivotal processing guidelines pave the way for advancing halide perovskite applications beyond academic curiosity.