Improvement of Film Quality in CuInSe2 Thin Films Fabricated by a Non-Vacuum, Nanoparticle-Based Approach

Abstract

To improve the quality of CuInSe2 (CIS) thin films fabricated by a non-vacuum, nanoparticle-based approach, in this study, two categories of nanoparticles, Cu (InGa) Se2 (CIGS) nanoparticles and copper selenide (Cu–Se) with indium selenide (In–Se) nanoparticles are investigated. It is found that the Cu–Se with In–Se nanoparticles show a higher crystallization velocity than CIGS nanoparticles. The films obtained from Cu–Se with In–Se nanoparticles exhibit higher crystallinity with a larger grain size. Thiourea is applied as a sintering additive during the selenization process. It is clarified that the addition of thiourea is very effective for grain growth and the fabrication of a dense CIS layer. The cell performance is measured under Air Mass 1.5 irradiation. The efficiency of the solar cell, fabricated using Cu–Se, In–Se nanoparticles with thiourea, is 2.15%, higher than that of the solar cell fabricated using CIGS nanoparticles, which is 0.28%.