Spinach extract and Eosin-Y co-sensitized ceria photoanode for dye sensitized solar cell application: effect of dye adsorption time

The present work deals with the study of Spinach extract (SP) and Eosin-Y (EY) co-sensitized Ceria (CeO2) photoanode for dye sensitized solar cell (DSSC) application. CeO2 nanoparticles were synthesized by simple precipitation route and doctor blade method was employed for CeO2 photoanode preparation. The X-ray diffraction (XRD) pattern of photoanode confirms nano-crystalline CeO2 with crystalline size using Scherrer formula as 10 nm. The energy dispersive X-ray spectroscopy (EDS) confirms the presence of Ce and O, which supports the XRD result. The scanning electron microscopy (SEM) images of photoanode show the porous structure with mean particles size similar to 400 nm and pores size similar to 10-30 nm useful for dye adsorption. The band gap value for CeO2 was calculated as 3.18 eV, using diffused reflectance spectroscopy (DRS). The possible transition mechanism at molecular levels in SP, EY and SP + EY dyes were studied using UV-Visible absorption spectroscopy. The effect of dye adsorption time (DAT) on the performance of such DSSCs was also studied. The best performing SP and EY co-sensitized CeO2 photoanode showed open circuit voltage (V-OC) similar to 400 mV and short circuit photocurrent density (J(SC)) similar to 0.42 mA/cm(2) with fill factor (FF) similar to 63 % for DAT of 24 h. These results are better as compared with costly ruthenium based dye sensitized CeO2 photoanode.