A Silicon-based Imidazolium Ionic Liquid Iodide Source for Dye-Sensitized Solar Cells

Room temperature molten salt 1-methyl-3-(trimethylsilyl)methyl-imidazolium iodide (MSII) was used for iodide sources in dye-sensitized solar cells with an organic sensitizer 2-cyano-3-[5-[4-[3-[4-(4-(N,N-bis(4-methoxyphenyl)amino)phenyl)phenyl]-2,5-di-n-butyl-pyrrolo[3,4-c]pyrrole-1,4-dione]phenyl]furan-2-yl] acrylic acid (DPP-I) as light harvester. With an optimized electrolyte (MSII:I2:BI:GuNCS24:2:2:0.4, BI and GuCNS are short for benzimidazole and guanidine thiocyanate, respectively), photovoltaic parameters (Jsc, Voc, and ff) of device are 8.97 mA·cm−2, 600 mV and 0.61, respectively, yielding a maximum overall photo-to-energy conversion ef?ciency (η) of 3.23%. And then the charge-transfer mechanism of devices was deeply analyzed with electrochemical impedance spectroscopy (EIS) in the dark.