Solution-processing of Cu(In,Ga)(S,Se)2 solar cells from metal chalcogenides: aspects of absorber crystallisation and interface formation

Photovoltaic (PV) solar cells provide a simple and smart way for direct conversion of sunlight into electricity, which is a clean alternative to conventional fossil fuel-based energy conversion methods. As a result of ongoing research, photovoltaic technologies are becoming both more efficient and cheaper. Thin film solar cells, particularly chalcogenides, are a promising area of research as they offer substantial cost savings as a consequence of reduced material usage and cheaper atmospheric fabrication processes.Cu(In,Ga)(S,Se)2(CIGS)solar cells are currently the best performing commercially deployed thin film PV technology. However the best performing CIGS devices are fabricated using sophisticated vacuum-based co-evaporation or co-sputtering systems requiring high capital costs and high energy budgets. Lower costs are achievable using alternative atmospheric deposition methods. These typically involve two step processes consisting of electrodeposition, nanoparticle or molecular solution coatings followed by high temperature annealing in a chalcogen containing atmosphere. [Continues.]