Low-Temperature Synthesis of High-Brightness Green-Emitting Silica-Coated CsPbBr3 and Its Application in Light-Emitting Diodes

The all-inorganic cesium lead halide perovskite CsPbBr3 exhibits excellent optical properties such as large absorption cross-section, high fluorescence quantum yield (PLQY), and narrow emission peak. However, how to improve the stability of CsPbBr3 quantum dots has been a major challenge for their optoelectronic application. Here, a room-temperature process for synthesizing CsPbBr3@SiO2 using 3-(dimethoxymethylsilyl)propylamine (DEMSPA) as precursor is reported, being a simple and facile process without inert gas. With the help of DEMSPA, a complete shell structure formed by silane can be coated. The results of x-ray diffraction analysis, transmission electron microscopy, and high-resolution transmission electron microscopy revealed that the prepared CsPbBr3 had good crystallinity with cubic phase structure. The luminescent properties of the products were evaluated by photoluminescence spectroscopy and fluorescence lifetime measurements. DEMSPA contains an amino group (–NH2) that could promote the absorption of light. The prepared CsPbBr3@SiO2 emitted an adjustable green wavelength (521 nm to 533 nm) with high PLQY. The light-emitting diode encapsulated with CsPbBr3@SiO2 showed a cold-white light characteristic.