Room Temperature Synthesis of Stable Silica-Coated CsPbBr3 Quantum Dots for Amplified Spontaneous Emission

All-inorganic cesium lead bromide (CsPbBr3) perovskite quantum dots (QDs) with excellent optical properties have been regarded as good gain materials for amplified spontaneous emission (ASE). However, the poor stability as the results of the high sensitivity to heat and moisture limits their further applications. Here, we report a facile one-pot approach to synthesize CsPbBr3@SiO2 QDs at room temperature. Due to the effective defects passivation using SiO2, as-prepared CsPbBr3@SiO2 QDs present an enhanced photoluminescence quantum yield (PLQY) and chemical stability. The PLQY of CsPbBr3@SiO2 QDs reaches 71.6% which is higher than 46% in pure CsPbBr3 QDs. The PL intensity of CsPbBr3@SiO2 QDs maintains 84% while remaining 24% in pure CsPbBr3 after 80 min heating at 60°C. The ASE performance of the films is also studied under a two-photon-pumped laser. Compared with the films using pure CsPbBr3 QDs, those with as-prepared CsPbBr3@SiO2 QDs exhibit a reduced threshold of ASE. The work suggests that room-temperature-synthesized SiO2-coated perovskites QDs are promising candidates for laser devices.