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 (CeO 2 ) photoanode for dye sensitized solar cell (DSSC) application. CeO 2 nanoparticles were synthesized by simple precipitation route and doctor blade method was employed for CeO 2 photoanode preparation. The X-ray diffraction (XRD) pattern of photoanode confirms nano-crystalline CeO 2 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 ~400 nm and pores size ~10–30 nm useful for dye adsorption. The band gap value for CeO 2 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 CeO 2 photoanode showed open circuit voltage (V OC ) ~400 mV and short circuit photocurrent density (J SC ) ~0.42 mA/cm 2 with fill factor (FF) ~63 % for DAT of 24 h. These results are better as compared with costly ruthenium based dye sensitized CeO 2 photoanode.