A soft-chemistry route to prepare halide perovskite nanocrystals with tunable emission and high optical performance

Cesium lead halide perovskites constitute a benchmark family of inorganic perovskites for high performance optoelectronic devices. Hot injection is by far the most extended procedure to fabricate CsPbX 3 (X: Cl, Br, and/or I) perovskite nanocrystals (PNCs) of high quality. However, the tedious N 2 -vacuum cycles and fast heating/cooling steps hinder the large-scale production of these materials. This work presents a fast one-step methodology to fabricate small CsPb(Cl x Br 1-x ) 3 nanocrystals with good control of the particle size and shape by using a Soft Chemistry strategy (ligand-mediated controlled growth) and microwave heating. We demonstrate that the procedure can be extended to different mixed halide perovskites, thus providing a fine tuning of the chemical composition and consequently, tunable photoluminescence (PL) emission from 522 nm for pure CsPbBr 3 to 477 nm for CsPb(Cl 0.4 Br 0.6 ) 3 , high photoluminescence quantum yield (PLQY) up to ~86% (for CsPbBr 3 ) and narrow PL full width at half maximum ~18–26 nm. In addition, the protocol was designed in such a way that the chemistry involved in the crystal nucleation and growth of perovskites is as close as possible to that of the hot injection process, which is mechanistically well-understood, to facilitate their adoption by the perovskite research community. Graphical Abstract This manuscript reports a sustainable soft-chemistry route using microwave heating to prepare CsPbX 3 (X:Cl,Br) perovskite nanocrystals with tunable PL emission. Nanocrystals with excellent photoluminescence quantum yields (PLQY, up to 86%), narrow PL FWHM 18–25 nm, defined orthorhombic crystalline phase and average particle size ranging from 15 nm to 25 nm were obtained. This is a promising strategy to reach high quality luminescent NPs, opening the door to prepare low-cost and fast luminescent perovskites for optoelectronics.