A facile method for preparing Yb3+-doped perovskite nanocrystals with ultra-stable near-infrared light emission

Colloidal all-inorganic cesium lead halide (CsPbX3, X = Cl, Br, I) nanocrystals (NCs) are very important optoelectronic materials and have been successfully utilized as bright light sources and high efficiency photovoltaics due to their facile solution processability. Recently, rare-earth dopants have opened a new pathway for lead halide perovskite NCs for applications in near-infrared wave bands. However, these materials still suffer from serious environmental instability. In this study, we have successfully developed a facile method for fabricating all-inorganic SiO2-encapsulated Yb3+-doped CsPbBr3 NCs by slowly hydrolyzing the organosilicon precursor in situ. Experimental results showed that the Yb3+ ions were uniformly distributed in the NCs, and the whole NCs were completely encapsulated by a dense SiO2 layer. The as-prepared SiO2-encapsulated NCs can emit a strong near-infrared (985 nm) photoluminescence, which originates from the intrinsic luminescence of Yb3+ in the NCs, pumped by the perovskite host NCs. Meanwhile, the SiO2-encapsulated NCs possessed excellent high PLQYs, narrow FWHM, and excellent environmental stability under a room atmosphere for over 15 days. We anticipate that this work will be helpful for promoting the optical properties and environmental stability of perovskite NCs and expanding their practical applications to near infrared photodetectors and other optoelectronic devices.