Water-assisted synthesis of stable and multicolored CsPbX@SiO core-shell nanoparticles as fluorescent probes for biosensing.

Colloidal lead halide perovskite nanocrystals are highly luminescent materials with great promise as fluorescent probes in biosensing as long as their intrinsic instability in aqueous media is effectively addressed. In this study, we successfully prepared stable and multicolored CsPbX@SiO (X = Cl/Br, Br and I) core-shell nanoparticles through a simple method based on the water-induced transformation of CsPbX into CsPbX, combined with sol-gel procedures. We observed that the concentration of the CsPbX precursor plays a crucial role in the formation of isolated nanospheres with uniform silica coating and in controlling the number of core-free particles.

Highly Emitting Perovskite Nanocrystals with 2-Year Stability in Water through an Automated Polymer Encapsulation for Bioimaging.

Lead-based halide perovskite nanocrystals are highly luminescent materials, but their sensitivity to humid environments and their biotoxicity are still important challenges to solve. Here, we develop a stepwise approach to encapsulate representative CsPbBr nanocrystals into water-soluble polymer capsules. We show that our protocol can be extended to nanocrystals coated with different ligands, enabling an outstanding high photoluminescence quantum yield of ∼60% that is preserved over two years in capsules dispersed in water.

Monodispersed CsPbBr@SiO Core-Shell Nanoparticles as Luminescent Labels for Biosensing.

Despite the rising advances in the field of metal halide perovskite nanocrystals (NCs), the exploitation of such nanoparticles as luminescent labels for imaging and biosensing is still unclear and in the early stages of investigation. One of the major challenges toward the implementation of metal halide perovskite NCs in biosensing applications is to produce monodispersed nanoparticles with desired surface characteristics and compatible with aqueous environments. Here, we report the synthesis of monodispersed spherical CsPbBr@SiO core-shell nanoparticles by post-synthetic chemical transformation of 3D CsPbBr NCs in the presence of tetraethyl orthosilicate and a critical water/ammonia ratio.