Novel solution processing of high efficiency earth abundant CZTSSe solar cells

We present a novel solution-based approach to process CZTSSe absorbers with molecular-level homogeneity. These devices have achieved 8.08 % power conversion efficiency using fully dissolved hydrazine-based CZTS precursor complexes in which each of the elemental constituents are mixed on the molecular level. The nature of the newly developed hydrazine precursor complexes enables a kinetically favorable reaction route to form kesterite CZTS at temperatures as low as 250 °C. Structural and optoelectronic characterization of the as-prepared CZTS films indicates the robustness of this approach in forming single phase Kesterite CZTS with the flexibility to tailor the band gap between 1.0 to 1.5 eV. The low processing temperatures and excellent film homogeneity imply that with further development this technology may be suitable for the large-scale manufacturing of uniform films and high performance devices.