Progress towards marketable earth-abundant chalcogenide solar cells

Kesterite-related photovoltaic materials are considered a promising alternative to CdTe and Cu(In,Ga)(S,Se)2 absorbers, primarily because they are not reliant on scarce elements such as indium and tellurium or the heavy metal cadmium. Recently, we reported a performance breakthrough for this materials class, reaching by a simple hydrazine-based deposition technique 9.6% power conversion efficiency for Cu2ZnSn(S,Se)4 devices (40% improvement over vacuum-based methods). Here, more detailed characterization for a hydrazine-prepared device shows the potential of this technology for further efficiency improvement. We also present initial device results for Cu2ZnSn(S,Se)4 films deposited using a mixed water-hydrazine-based solvent, yielding devices with 8.1% efficiency.