NOVELTY - A nanoink composition for forming an absorber layer of a thin film solar cell, comprises: particles containing at least one element selected from IB, IIB, IVA and/or VIA; and a volatile chelating agent mixing with the particles, where the volatile chelating agent is a polyetheramine which is selected from monoamine compounds, diamine compounds and triamine compounds and has a molecular weight of 100-4000.    USE - As nanoink composition for forming an absorber layer of a thin film solar cell (claimed).    ADVANTAGE - The thin film (preferably copper zinc tin selenide (Cu2ZnSnSe4, CZTSe)) can be formed only by a simple coating and printing process without requirement of alternative vacuum processing or complex equipment. The method is applied in a single-stage process instead of the conventional multiple-stage process so that reduction of manufacturing costs is capable of accomplishment. The volatile chelating agent is easily removed without any residues in an absorber layer and provides certain viscosity to act as a binder during coating or printing process, and thus any viscosity increaser can not be added further, even in a coating or printing processes afterward. The method is capable of producing nanoink composition for forming a CZTSe film. The volatile chelating agent is polyetheramine, which easily dissolves the reactant elements or salts, such as selenium and copper, so that the CZTSe film can be produced in a simple single-stage process instead of the conventional multiple-stage process which requires alternative vacuum processing or complex equipment.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for producing a nanoink composition for forming an absorber layer of a thin film solar cell, involving: a) obtaining the particles containing at least one element selected from IB, IIB, IVA and/or VIA; b) adding the volatile chelating agent mixing with the particles; and c) heating the volatile chelating agent to a reflux temperature at which the volatile chelating agent is boiling, and reacting the boiling volatile chelating agent with the particles in an inert gas environment.