A novel two-stage hybrid processing technique towards industrial manufacturing of the Cu(In,Ga)(S,Se)2 solar cell with materially efficient fabrication

Abstract

The chalcogenide Cu(In,Ga)(S,Se)₂ (CIGSSe) solar cell is very promising because it exhibits one of the highest efficiencies among all thin-film solar cells. However, the expensive and complicated fabrication of these solar cells should be overcome for their successful commercialization. Herein, we investigated a novel fabrication technique that combined both vacuum and non-vacuum processes to minimize the production costs and increase the energy conversion efficiency. A carbon-free CuS nanoparticle precursor was used in the non-vacuum process to save Cu materials and the thermal budget. An (In,Ga)₂Se₃ precursor was formed via vacuum co-evaporation, which provided control over the stoichiometry. The CIGSSe films were fabricated using two different approaches: (1) CuS was deposited on a Mo film, with subsequent co-evaporation of the (In,Ga)₂Se₃ film (hybrid staking A – HSA) and (2) (In,Ga)₂Se₃ was deposited on a Mo film, and then, CuS was formed on top of this with selenization (hybrid stacking B – HSB). The HSA solar cells had a higher quality structure and composition when compared with the HSB cells. The HSA CIGSSe solar cell exhibited the superior energy conversion efficiency of 13.6%. Our novel fabrication technique will contribute to the widespread commercialization of CIGSSe solar cells while minimizing material consumption.