Photovoltaic Performance of Ag2Se Quantum Dots Co-sensitized Solid-state Dye-sensitized Solar Cells

Ag2Se quantum dots（QDs） was synthesized by co-deposition method which was further applied as co-sensitizer in solid-state dye-sensitized solar cells（DSSCs）. The effects of different sensitization methods of Ag2Se QDs（TiO2/N719/QDs, TiO2/QDs/N719） and sensitization time（0-5 h） on the performance of QDs/dye co-sensitized solar cells were studied. Structure and optical properties of Ag2Se QDs were characterized by transmission electron microscopy（TEM） and ultraviolet-visible spectroscopy（UV-Vis）. Furthermore, the transmission of charge carriers of solar cell devices was characterized by photo-modulated photocurrent/voltage spectrum（IMPS/VS） and electrochemical impedance spectra（EIS）. It was found that the device with TiO2/QDs/N719 showed higher incident photon-to-current efficiency（IPCE） and photoelectric efficiency than those of TiO2/N719/QDs, which was due to the fact that TiO2/QDs/N719 photoanode adsorbed more QDs and dyes. With the extension of Ag2Se QDs sensitization time,the photovoltaic properties of DSSC