Abstract
We report unprecedented phase stability of cubic CsPbBr(3) quantum dots in ambient air obtained by using Br(2) as halide precursor. Mechanistic investigation reveals the decisive role of temperature-controlled in situ generated, oleylammonium halide species from molecular halogen and amine for the long term stability and emission tunability of CsPbX(3) (X = Br, I) nanocrystals.