A room temperature ionic liquid crystal, 1-dodecyl-3-ethylimidazolium iodide （C12EImI）, and an ionic liquid, 1-decyl-3- ethylimidazolium iodide （Cl0EImI）, have been synthesized, characterized and employed as the electrolyte for dye-sensitized solar cells （DSSC）. The physicochemical properties show that a smectic A （SmA） phase with a lamellar structure is formed in CIzEImI. Both C^2EImI and Cl0EImI have good electrochemical and thermal stability facilitating their use in DSSC. The steady-state voltammograms reveal that the diffusion coefficient of I3- in C^2EImI is larger than that in CmEImI, which is at- tributed to the existence of the SmA phase in Ca2EImI. Because the iodide species are located between the layers of imidazo- lium cations in CjzEImI, exchange reaction-based diffusion is increased with a consequent increase in, the overall diffusion. The electrochemical impedance spectrum reveals that charge recombination at the dyed TiOJelectrolyte interface of a C12EImI-based DSSC is reduced due to the increase in I3- diffusion, resulting in higher open-circuit voltage. Moreover, both short-circuit current density and fill factor of the Cl2EImI based DSSC increase, as a result of the increasing transport of I3 in C^2EImI. Consequently, the photoelectric conversion efficiency of C^2EImI-based DSSC is higher than that of the Cl0EImI-based DSSC.
PAN XuWANG MengFANG XiaQingZHANG ChangNengHUO ZhiPengDAI SongYuan
A novel supramolecular gel electrolyte formed from two-component low molecular mass organogelators was developed and introduced into quasi-solid-state dye sensitized solar cell(QS-DSSC). This supramolecular gel electrolyte system was prepared by using N,N?-1,5-pentanediylbis-dodecanamide and 4-(Boc-aminomethyl)pyridine as co-gelator. Furthermore, the morphologies of the two-component supramolecular gel electrolyte and single-component gel electrolyte were observed by the polarized optical light microscopy, and the charge transport property of the two-component supramolecular gel electrolyte and the kinetic processes of the electron transport/recombination were investigated by the intensity-modulated photocurrent spectroscopy/intensity-modulated photovoltage spectroscopy(IMPS/IMVS). The polarized optical microscopy(POM) revealed that the single-component gel electrolyte was formed as the rod-like fibers, whereas the fibers changed to branched structure in the two-component supramolecular gel electrolyte. Moreover, comparing with the single-component gel electrolyte based QS-DSSC, the electron transport is faster and the electron recombination at the Ti O2/electrolyte interface is slower in the two-component supramolecular gel electrolyte based QSDSSC. Consequently, an efficiency of 7.04% was obtained by the two-component supramolecular gel electrolyte based QSDSSC, which is higher than that of the single-component gel electrolyte based QS-DSSC(6.59%).
