TECHNOLOGY FOCUS - IMAGING AND COMMUNICATION - Preferred Components: The ink comprises at least 1x 10-5 volume fraction of the partially halide-terminated nanocrystals of silicon or its alloy.    TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: The partially halide-terminated nanocrystals are halide- and hydrogen-terminated nanocrystals of silicon or its alloy. The partially halide-terminated nanocrystals are partially chloride-terminated nanocrystals of silicon or its alloy. The partially halide-terminated nanocrystals are chloride- and hydrogen-terminated nanocrystals of silicon or its alloy. The film is cast on a wafer having a largest dimension of at least 4 inches. The nanocrystals comprise silicon or its alloy and are free of oxides. The film has an area of at least 9 cm2.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: The organic solvent is a dipolar and has hard donor group, without a strongly acidic site, and does not chemically react with the nanocrystal surface. The solvent has a largest dimension of at most 1.5 nm. The organic solvent is halogenated aromatics, ketones, esters, N-substituted pyrrolidinones and/or nitriles. The organic solvent is 1,2-dichlorobenzene, methyl alkyl ketones, N-methylpyrrolidinone and/or benzonitrile. Preferred Method: The solution coating comprises a method comprising drop casting, spin coating, dip coating, meyer rod coating, doctor blade coating, inkjet printing, screen printing and/or contact printing. The method (M1) further comprises: allowing the organic solvent to evaporate at a temperature of at most 250 degrees C; and heating the film to at most 350 degrees C to remove the halide. The conditions comprise gentle mixing or sonication at room temperature. EXAMPLE - 30 sccm Argon, 20 sccm hydrogen, and 4 sccm silicon tetrachloride vapor were injected into a three-fourth-inch outer diameter alumina tube. The precursors were dissociated, and the products chemically were nucleated to form nanocrystals. The pressure in the reactor was maintained at 5.5 ton to give silica nanocrystals.