TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: The organic thin film covalently bound to the surface comprises molecules that include a functional group at one end and covalently binds to the surface of the fine silicon particle via silicon at the other end. The functional group is a reactive functional group, where the reactive functional group is a functional group with either thermal reactivity or light reactivity, or otherwise radical reactivity or ionic reactivity, preferably thermal reactivity or ionic reactivity. The reactive functional group is either an epoxy group or imino group, or otherwise a chalcone group, preferably epoxy group or imino group. The organic thin film covalently bound to the surface comprises a monomolecular film. The ketimine compound, organic acid, aldimine compound, enamine compound, oxazolidine compound, or an aminoalkylalkoxysilane compound is used instead of the silanol condensation catalyst. Preferred Method: The method comprises cleaning the surface of (I) with an organic solvent to form a monomolecular film covalently bound to the surface of (I). In the method, at least one promoter comprises ketimine compound, organic acid, aldimine compound, enamine compound, oxazolidine compound, or an aminoalkylalkoxysilane compound is mixed with the silanol condensation catalyst. The surface of the base material covered by an organic thin film covalently bound to the surface, the layer of n-type fine silicon particles covered by an organic thin film, and the layer of p-type fine silicon particles covered by an organic thin film are covalently bound with each other via the respective organic thin film to form a hardened film. The method for manufacturing a solar cell prior to the application of the paste to the base material, an organic thin film, comprises a functional group that reacts with the first or second reactive functional group on the surface of (I) covered by an organic film, including the first reactive functional group or of (I) covered by an organic film, including the second reactive functional group, is bound to the surface of the base material. EXAMPLE - Fine silicon particles (p-type) with a particle diameter of 100-10 nm were prepared and dried thoroughly. The p-type fine silicon particles were mixed and stirred in the absorption liquid (comprising alkoxysilane compound of formula (H2N(CH2)3Si-(O(CH3)3)), dibutyltin diacetylacetonate or acetic acid were dissolved into a hexamethyldisiloxane and dimethylformamide) and reacted in a normal atmosphere for two hours. Then, a chlorinated solvent, such as tricren, was added to the mixture and stirred for cleaning and thus p-type fine silicon particles covered by a chemical absorption monomolecular film.