Highly crystalline stannite-phase Cu2XSnS4 (X = Mn, Fe, Co, Ni, Zn and Cd) nanoflower counter electrodes for ZnO-based dye-sensitised solar cells

Quaternary chalcopyrite sulfide semiconductors Cu2XSnS4 (X = Mn, Fe, Co, Ni, Zn and Cd) are successfully prepared by using a solvothermal method. Crystal structure, elemental composition and morphology of the as-synthesized nanoflowers are characterised using XRD, XPS, EDS, TEM and SEM. Photovoltaic and catalytic performances based on prepared samples as counter-electrode (CE) materials in ZnO-based dye-sensitised solar cells (DSSCs) are investigated based on N719 dye and iodide/triiodide electrolyte. Notably, Cu2XSnS4 (X = Mn, Fe, Co, Ni, Zn, Cd) all show excellent catalytic activity for the reduction of I3- to I- in the electrolyte. In addition, Cu2MnSnS4 and Cu2NiSnS4 are explored as CE materials for DSSCs for the first time. Cu2MnSnS4 and Cu2NiSnS4 exhibit power conversion efficiency values of 6.18% and 6.12%, respectively, which are comparable to the photovoltaic performance of the DSSCs using a Pt CE (6.09%). (C) 2016 Elsevier B.V. All rights reserved.