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

Mixed halogen CsPbI x Br 3-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 CsPbI 2 Br/SiO 2 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 CsPbI 2 Br 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.