Electric field hotspots of all-inorganic off-stoichiometric APbX3 (A = Cs, Rb and X = Cl, Br, I) perovskite quantum dots

Fully-inorganic perovskite quantum dots (QDs) have emerged as an exciting family of semiconductor materials with outstanding opto-electronic properties. Here, using state-of-the-art time dependent density functional theory calculations, we present a comprehensive study of the absorption cross-sections and the electric field enhancements of fully-inorganic off-stoichiometric APbX₃ (A = Rb, Cs and X = Cl, Br, I) perovskite QDs. We show that the type of halide element is a key parameter in determining the QD optical features. Specifically, we demonstrate the dramatic variations in the electric field enhancements and the significant modifications in the hotspot regions with respect to the halide element, confirming the excellent photo-catalytic activity of perovskite QDs reported by the recent experiments.