Water-induced MAPbBr3@PbBr(OH) with enhanced luminescence and stability.

Poor stability has long been one of the key issues that hinder the practical applications of lead-based halide perovskites. In this paper, the photoluminescence (PL) quantum yield (QY) of bromide-based perovskites can be increased from 2.5% to 71.54% by introducing water, and the PL QY of a sample in aqueous solution decreases minimally over 1 year. The enhanced stability and PL QY can be attributed to the water-induced methylamino lead bromide perovskite (MAPbBr3)@PbBr(OH). We note that this strategy is universal to MAPbBr3, formamidine lead bromide perovskite (FAPbBr3), inorganic lead bromide perovskite (CsPbBr3), etc. Light-emitting devices (LEDs) are fabricated by using the as-prepared perovskite as phosphors on a 365 nm UV chip. The luminance intensity of the LED is 9549 cd/m2 when the driven current is 200 mA, and blemishes on the surface of glass are clearly observed under the illumination of the LEDs. This work provides a new strategy for highly stable and efficient perovskites. Inexpensive crystals useful for applications including display devices can be manufactured with exceptional environmental stability by following a new synthetic technique. Lead halide perovskites are materials that emit light with a range of colors, but also suffer from poor moisture stability. Kai-Kai Liu, Lin Dong, Chong-Xin Shan from China’s Zhengzhou University and colleagues now report that adding a dose of water to lead halide perovskites enables them to emit bright fluorescent light, even when submerged underwater for more than a year. The team’s experiments revealed that controlled hydration of the perovskite’s outer surface helped remove defects that decrease light output, as well as protected against further incursions by air and water molecules. Successful fabrication of the hydrated crystals as phosphors within light-emitting devices (LEDs) indicates their potential for industrial purposes.