Colloidal APbX3 nanocrystals [A=Cs+, CH3NH3 +, CH(NH2)2 +, X=Cl, Br, I] with bright photoluminescence spanning from ultraviolet to near-infrared spectral regions

Chemically synthesized inorganic nanocrystals (NCs) are considered to be promising building blocks for a broad spectrum of applications including electronic, thermoelectric, and photovoltaic devices. We have synthesized monodisperse colloidal nanocubes (4-15 nm edge lengths) of fully inorganic cesium lead halide perovskites (CsPbX3, X=Cl, Br, and I or mixed halide systems Cl/Br and Br/I) using inexpensive commercial precursors [1]. Their bandgap energies and emission spectra are readily tunable over the entire visible spectral region of 410-700 nm. The photoluminescence of CsPbX3NCs is characterized by narrow emission line-widths of 12-42 nm, wide color gamut covering up to 140% of the NTSC color standard, high quantum yields of up to 90% and also low thresholds for stimulated emission [2]. Post-synthestic chemical transformations of colloidal NCs, such as ion-exchange reactions, provide an avenue to compositional fine tuning or to otherwise inaccessible materials and morphologies [3]. Similar synthesis methodologies are well suited also for hybrid perovskite nanocrystals based on methylammonium (MA) and for mamidiniumcations (FA): MAPbX3[4], FAPbBr3 [5], Cs1-xFAxPbI3and FAPbI3[6]. In particular, Cs- and FA-based NCs (Figure below) are highly promising for luminescence downconversion (bright and narrow emission at 530 and 640 nm), for infrared light-emitting diodes and as precursors/inks for perovskite solar cells. In this talk, we will discuss the synthesis methodologies and optical properties of these novel APbX3NCs.