Facial synthesis of highly stable and bright CsPbX3(X=Cl, Br, I) perovskite nanocrystals via an anion exchange at the water-oil interface

Cesium lead halide perovskite nanocrystals (NCs) have attracted unprecedented attention owing to their compelling properties for optoelectronic applications. Compared with the classical hot-injection method, the room-temperature (RT) synthetic strategy is more facile and tender, but it is hard to obtain stable CsPbI3NCs and it usually uses polar solvents that sometimes reduce the stability and properties of NCs. Here, we reported a simple approach to synthesize highly efficient and stable CsPbI(3)as well as other color-tunable CsPbX3NCs with high quantum efficiency at room temperatureviaan anion exchange at the water-oil interface, in which the as-synthesized pristine CsPbBr3NCs in toluene were treated in aqueous solutions of HX (X=Cl, Br, and I) and protonated oleylamine (OAm) acted as a carrier. The synthesized CsPbI3NCs had an emission at 680 nm and even showed excellent colloidal stability after being stored for 32 d. The high efficiency and stability of the obtained CsPbX3NCs were ascribed to the facts that: (i) the polar reagents were almost removed from the surface of NCs; (ii) the defect-related nonradiative recombination was suppressed efficiently by surface passivation.

Automated summary

A simple and efficient method for synthesizing highly efficient and stable cesium lead halide perovskite nanocrystals at room temperature via anion exchange at the water-oil interface was reported. The obtained CsPbX3NCs showed high quantum efficiency and excellent colloidal stability, attributed to removal of polar reagents from the surface of NCs and efficient suppression of defect-related nonradiative recombination through surface passivation.