“…To overcome this shortcoming, fabrication of the CIGS PVs directly from CIGS NPs would eliminate the need for the selenization step, thus lowering the environmental impact of the solar cell production. In this context, the synthesis of CIGS NPs has attracted considerable interest, and reports based on hot-injection [10,11], heat-up [12,13], solvothermal [14,15], hydrothermal [16,17], or mechanochemical [18,19] methods have appeared, usually delivering crystalline and phase-pure CIGS NPs [20]. Notably, most of the synthesis protocols, regardless of the method employed [21,22], are severely limited to the preparation of CIGS NPs with common tetragonal chalcopyrite-type structure (space group I42d), the most thermodynamically stable phase at room temperature [21,22].…”