TECHNOLOGY FOCUS - IMAGING AND COMMUNICATION - Preferred Composition: The ink composite contains metal chosen copper, tin and zinc, and nanoparticles including sulfur or selenium chosen from zinc sulfide, tin sulfide, tin(IV) sulfide, copper sulfide (CuS, CuyS, where y is 0.5-2), zinc selenide, tin selenide, tin diselenide, copper selenide (CuSe and CuySe). In ink composite, the ratio of content of copper and total content of tin and zinc is 0.5-1.5, and the ratio of content of zinc and content of tin is 0.5-2.    TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Composition: The salt is chosen from chloride, bromide, iodide, nitrate, nitrite, sulfate, acetate, sulfite, acetylacetoante, and hydroxide. The mole ratio of reducing agent and salt in the mixture is 1:1-1:20. The metal nanoparticles is copper-tin bimetallic metal nanoparticles, copper-zinc bimetallic metal nanoparticles, tin-zinc bimetallic metal nanoparticles and copper-tin-zinc intermetallic metal nanoparticles, copper-tin bimetallic metal nanoparticles. The reducing agent is organic reductant and/or inorganic reducing agent, preferably lithium borohydride, sodium borohydride, potassium borohydride, calcium borohydride (Ca(BH4)2), magnesium borohydride (Mg(BH4)2), sodium cyanoborohydride, sodium triacetoxyborohydride, ascorbic acid?and triethanolamine.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Composition: The solvent of the solution (S2 and S1) is chosen from water, diethylene glycol, methanol, oleylamine, ethylene glycol, triethylene glycol, dimethyl sulfoxide, dimethylformamide, and N-methyl-2-pyrrolidone. The solution (S2) further contains capping agent chosen from sodium L-tartrate dibasic dehydrate, potassium sodium tartrate, sodium acrylate, trisodium citrate, disodium citrate, sodium gluconate, sodium ascorbate, sorbitol, trimethyl phosphate, ethylenediamine, propylene diamine, 1,2-ethanedithiol and ethanethiol. The content of capping agent in the solutions (S1 and S2) is 0-20 %mol with respect to 1 mol metal salt solution in the mixture. The organic solvent (A) utilized during manufacture of thin film is chosen from alkane, alkyne, aromatics, ketone, nitrile, ether, ester, organic halide, alcohol, amine, thiol, carboxylic acid, phosphine, phosphate, sulfoxide and amide.    TECHNOLOGY FOCUS - POLYMERS - Preferred Composition: The thin-film is obtained using organic solvent (A), additive, and hydrogen sulfide gas or hydrogen selenide gas. The additive is chosen from polyvinylpyrrolidone Polyvinylpyrrolidone, polyvinyl alcohol, Anti-terra 204 (RTM: solution of polycarboxylic acid salt of polyamine amide), Anti-terra 205 (RTM: solution of polycarboxylic acid salt of polyamine amide), ethyl cellulose, and DisperseBYK 110 (RTM: solution of copolymer with acidic group).