Room-Temperature Synthesis of CuInQ2 (Q = S or Se) in Non-Aqueous Solution using an Organoindium Reagent

We have discovered a novel two-phase synthesis of CuInSe2 at 25 °C from Cu2Se and (C5H5)3 In in 4-methylpyridine (4-MePy). An analogous reaction to produce CuInS2 must be run at 140 °C in refluxing 4-MePy in the presence of 2-mercaptopyridine. Microscopy of CuInSe2 produced at 25 °C shows it to be platelet-shaped crystallites with an approximate particle size of 10 microns, less than 2% C and H, with a small amount of unidentified crystalline impurity. Our results demonstrate that it is possible to produce from solution a material that is ordinarily synthesized in bulk or films at much higher temperatures or using extraneous reagents and/or electrons.