摘要： Cu(In,Ga)(S,Se)2 (CIGSe, CIGSSe) has emerged as an attractive thin-film solar cell absorber material owing to its high light absorption coefficient and tunable bandgap. In CIGSSe processing and fabrication, the use of alkali treatments has been implemented as sodium doping is considered a requirement for high efficiency CIGSSe solar cell devices and has been used extensively. One of the more significant developments in recent years has been the discovery of the beneficial effects that potassium post-deposition treatments have on vacuum-processed CIGSSe solar cells as they are responsible for a major increase in CIGSSe solar cell performance. Here, we conduct a study of the effect of potassium treatments to solution-processed CIGSSe films grown from colloidal sulfide-based nanoparticle inks. By adding potassium through e-beam evaporation of KF prior to selenization and grain growth, we find that the grain growth of CIGSSe is enhanced with potassium addition and that a larger-grained film results compared to untreated selenized CIGSSe film, similar to what is observed in sodium-treated films. We also observe through XPS that films treated with K show the presence of the high-bandgap K-In-Se surface phase. Fabricating devices, we find that films that have been subjected simultaneously to both sodium and potassium treatments have enhanced optoelectronic performance mainly manifested in higher open-circuit voltage and higher short-circuit current.