Novel rubidium lead chloride nanocrystals: Synthesis and characterization

Alkali ternary lead halides have been studied intensively in the past few years, with great interest focussed on perovskite materials. In this paper we report on novel rubidium lead chloride nanocrystals (NCs) with the formula Rb₆Pb₅Cl₁₆, which adopt a tetragonal symmetry. The NCs were characterized and found to be active in the UV region, with a band-gap of ~4.05 eV. The roles of the ligands, oleic acid and oleylamine, were investigated and found to strongly affect the morphology and composition of the NCs, through the stabilization of the facilitated crystallization of the ionic precursors. The effective masses were observed by density functional theory (DFT) calculations, using the dielectric function, and the the Bohr exciton radius and exciton binding energy of the NCs were estimated. Moreover, the results were supported by the DFT calculations of the electronic properties and atomic structure.