Preparation of CuInSe2 solar cell films using CuInSe2/InSe nano-particle ink

A non-vacuum process for the fabrication of a CISe absorber layer from nano-particle ink is described. CISe and InSe nano-particles were prepared via sonochemical synthesis by reacting the starting materials. We prepared nano-particle inks by using an organic binder or various solvents to obtain high-quality thin films. The nano-particle ink was used for the deposition process of precursor thin films; the selenization of the precursor thin films was performed. In order to control the composition of volatile Se in the CISe absorber layer, a bi-layer structure of the precursor thin films is proposed. By using an additional top-layer containing elemental Se, the composition of Se in the CISe absorber layer was maintained after the selenization process. In the case of the bi-layer precursor thin films, unnecessary elements in the top-layer were unfavorable for grain growth and the morphology of the CISe absorber layer.