Polar solvent-mediated direct room temperature synthesis of pure-red-emitting perovskite nanocrystals

Mixed halogen CsPbIxBr3-x nanocrystals (NCs), as indispensable materials for pure red light applications, are widely used in high-definition displays due to their excellent optoelectronic proporties. However, the traditional hot-injection synthesis requires high temperature and inert gas protection, which brings challenges for large-scale development. Herein, we propose a novel spontaneous crystallization approach to synthesize pure-red-emitting perovskite NCs at room temperature using the environmentally friendly strong polar solvent isopropanol (IPA) as an anti-solvent. Meanwhile, 3-aminopropyltriethoxysilane (APTES) surface modifier was introduced to obtain the silica coating layer through spontaneous hydrolysis reaction. The prepared CsPbI2Br/SiO2 composite NCs exhibit a pure red emission peak at 632 nm with a FWHM of 32 nm and a photoluminescence QY of 44%. Furthermore, the use of APTES reduces the sensitivity of iodide ions to moisture and oxygen at room temperature, thereby suppressing phase separation of CsPbI2Br induced by distortion in the perovskite structure and enhancing its stability. Our work provides a meaningful approach for the batch synthesis of perovskite NCs at room temperature in environmentally friendly solvents.