Rapid supersonic spraying of Cu(In,Ga)(S,Se)₂ nanoparticles to fabricate a solar cell with 5.49% conversion efficiency

We demonstrate production of high-quality Cu(InGa)(SSe)₂ (CIGSSe) films by high-rate supersonic spray deposition. This technique is unique in creating particle-based films without introducing impurities, because no additives or binders are used. The thin film deposition process was investigated computationally, to understand the pulverization of the incoming particles. These simulations were consistent with experimental observations. Grain growth was improved by adding a 300-nm copper layer atop the CIGSSe film; selenization of the resulting bilayer produced a CuSe liquid flux that assisted the sintering process. The final CIGSSe film-based solar cell had a conversion efficiency of 5.49% with J_sc = 18.73 mA/cm², V_oc = 0.488 V, and FF = 59.99% in an active area of 0.44 cm².