Molecular Iodine for a General Synthesis of Binary and Ternary Inorganic and Hybrid Organic–Inorganic Iodide Nanocrystals

We report the synthesis of various binary and ternary inorganic and hybrid organic–inorganic iodide nanocrystals (NCs) starting from molecular iodine (I2). The synthesis described herein utilizes a reaction between I2 and oleylamine, which results in oleylammonium iodide, an iodide precursor that can be directly used in the preparation of iodide-based NCs. The generality of the synthesis was demonstrated by synthesizing KI, RbI, CsI, AgI, CsPbI3, FAPbI3, Cs4PbI6, Cs3Bi2I9, FA3Bi2I9, and RbAg4I5 NCs. Furthermore, the syntheses are facile and are carried out in vials heated on a hot plate in air. They exhibit not only narrow size distributions, but also, in the case of lead-based perovskites NCs, 70–80% photoluminescence quantum yields. To further prove the high quality of the CsPbI3 and FAPbI3 perovskite NCs, red and infrared bright light-emitting diodes were fabricated, with external quantum efficiencies (EQEs) exceeding 3%, without following any extensive washing procedures.