Mo(SxOy) thin films deposited by electrochemistry for application in organic photovoltaic cells

Abstract In this study, Mo(S x O y ) thin films were deposited onto fluorine doped tin oxide (FTO) using pulsed electrochemical deposition method. It is shown by scanning electron microscopy, energy-dispersive spectroscopy and X-ray photoelectron spectroscopy that after water cleaning the deposited Mo(S x O y ) film corresponds to a hybrid layer MoS x :MoO 3 . This hybrid is used as anode buffer layer (ABL) in planar organic photovoltaic cells (OPVCs) based on the couple copper-phthalocyanine/fullerene. It is shown that it is necessary to proceed to a soft annealing-5 min at 150 °C- of the anode FTO/Mo(S x O y ) to clean the ABL surface in order to obtain efficient contact with the organic material. The OPVC with the optimum Mo(S x O y ) thickness, 12 nm, showed a power conversion efficiency, PCE = 1.41% under an illumination of AM1.5, which is 12% higher than that achieved with a simple MoO 3 ABL. This improvement is attributed to the fact that using a hybrid MoS 2 :MoO 3 ABL allows to combine the advantages of its both constituents. The MoS x blocks the electrons, while the high work function of MoO 3 induces a high hole extraction efficiency at the interface electron donor/anode.