TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Composition: The nano-ink composition (C1) and the copper zinc tin selenide sputtering target (T1) further comprise: the ternary multiphase mixture; and a single element which is copper, zinc, tin or selenium. The nano-ink composition (C2) and the copper zinc tin selenide sputtering target (T2) further comprise a single element which is copper, zinc, tin or selenium.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: The chelating agent further comprises para-phenylenediamine and 3 -dibenzoselenophen-4-yl-phenylamine. The monoamine is alkyl polyalkylene glycol amine, bis(methyl triethylene glycol) amine, butyl triethylene glycol amine, lauryl polypropylene glycol amine, methyl tripropylene glycol amine, phenol polypropylene glycol amine, polypropylene glycol amine, bis(methyl tripropylene glycol) amine, N-methyl methyl propylene glycol amine, methyl polypropylene glycol amine, bis(methyl polypropylene glycol) amine, tris(methyl diglycol)amine or methyl polyalkylene glycol amine with random or blockwise distribution of the ethylene glycol and propylene glycol. The diamine is triethylene glycol diamine, tripropylene glycol diamine, polyethylene glycol diamine, polypropylene glycol diamine, polyalkylene glycol diamine with random or blockwise distribution of ethylene glycol and propylene glycol units, butanediol polyalkylene glycol diamine, or resorcinol polyalkylene glycol diamine. The triamine is glycerol polyalkylene glycol triamine with random or blockwise distribution of ethylene glycol and propylene glycol unit, bis(triethylene glycol amine) amine, or bis(polyalkylene glycol amine) amine. EXAMPLE - Teflon blender was put in the glass reaction flask, then nitrogen gas was introduced into the glass reaction flask, and glass reaction flask was filled with nitrogen gas for 30 minutes. 300 g of polyetheramine liquid was added to the glass reaction flask. Then, 28 g of a copper powder, 14.2 g of a zinc powder, 26 g of a tin powder, and 70 g of a selenium powder were added. Blending was performed for 5 hours to remove water vapor and oxygen gas from the mixture in the glass reaction flask. The reaction mixture was heated in the glass reaction flask at 230-250 degrees C with a heater for 40 hours, then the heater was turn off to allow the temperature to drop spontaneously to room temperature, which is 30 degrees C, to obtain 438 g of a black liquid which is anticipated copper zinc tin selenide nano-ink composition.