A method of producing a printable composition comprises mixing a quantity of particulate semiconductor material with a quantity of a binder. The semiconductor material is typically nanoparticulate silicon with a particle size in the range from 5 nanometers to 10 microns. The binder is a self-polymerizing material comprising a natural oil, or a derivative or synthetic analog thereof. Preferably the binder comprises a natural polymer formed by auto-polymerization of a precursor consisting of a natural oil, or its derivatives including pure unsaturated fatty acids, mono- and di-glycerides, or methyl and ethyl esters of the corresponding fatty acids. The method may include applying the printable composition to a substrate, in single or multiple layers, and allowing the printable composition to cure to define the component or conductor on the substrate.