Electrocatalytically active MoSe2 counter electrode prepared in situ by magnetron sputtering for a dye-sensitized solar cell

Molybdenum selenide is a potential alternative to counter electrode of a platinum-free dye-sensitized solar cell (DSSC). In this work, an in situ magnetron sputtering method is developed to prepare MoSe2 electrodes. The MoSe2 electrodes obtained at various temperatures from 300 and 550 degrees C are used as counter electrode for a dye-sensitized solar cell. Photovoltaic measurement results indicate that the MoSe2 electrodes prepared at 400 degrees C has the optimized performance, and the corresponding DSSCs provide an energy conversion efficiency of 6.83% which is comparable than that of the reference DSSC with platinum as counter electrode (6.51%). With further increas-ing the preparation temperature of the MoSe2 electrodes, the corresponding DSSCs decrease gradu-ally to 5.96% for 550 degrees C. Electrochemical impedance spectra (EIS) reveal that charge transfer resis-tance (R-ct) of MoSe2 electrodes is rising with increase of the temperature from 400 to 500 degrees C, sug-gesting a downward electrocatalytic activity. Though the MoSe2 electrode prepared at 550 degrees C show a reduced Rct, its series resistance (R-s) and diffusion resistance (Z(w)) increase obviously. Considering that MoSe2 phase cannot be formed at 300 degrees C, it can be concluded that the prepared temperature as low as possible is favored for its final electrochemical performance. The results are very significant for developing low-cost and responsible counter electrodes for dye-sensitized solar cells. (C) 2019, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.