We show here the first colloidal synthesis of double perovskite Cs₂AgInCl₆ nanocrystals (NCs) with a control over their size distribution. In our approach, metal carboxylate precursors and ligands (oleylamine and oleic acid) are dissolved in diphenyl ether and reacted at 105 °C with benzoyl chloride. The resulting Cs₂AgInCl₆ NCs exhibit the expected double perovskite crystal structure, are stable under air, and show a broad spectrum white photoluminescence (PL) with quantum yield of ∼1.6 ± 1%. The optical properties of these NCs were improved by synthesizing Mn-doped Cs₂AgInCl₆ NCs through the simple addition of Mn-acetate to the reaction mixture. The NC products were characterized by the same double perovskite crystal structure, and Mn doping levels up to 1.5%, as confirmed by elemental analyses. The effective incorporation of Mn ions inside Cs₂AgInCl₆ NCs was also proved by means of electron spin resonance spectroscopy. A bright orange emission characterized our Mn-doped Cs₂AgInCl₆ NCs with a PL quantum yield as high as ∼16 ± 4%.

Zinc blende and wurtzitic GaN films have been epitaxially grown onto (001)Si by electron cyclotron resonance microwave plasma-assisted molecular beam epitaxy, using a two-step growth process. In this process a thin buffer layer is grown at relatively low temperatures followed by a higher temperature growth of the rest of the film. GaN films grown on a single crystalline GaN buffer have the zinc blende structure, while those grown on a polycrystalline or amorphous buffer have the wurtzitic structure.