Rose Bengal sensitized bilayered photoanode of nano-crystalline TiO2–CeO2 for dye-sensitized solar cell application

Abstract

The present work deals with the study of TiO 2-CeO 2 bilayered photoanode with low-cost Rose Bengal (RB) dye as sensitizer for dye-sensitized solar cell application. The recombination reactions are reduced in bilayered TiO 2-CeO 2 photoanode as compared to the singlelayered CeO 2 photoanode. Once the electrons get transferred from lowest unoccupied molecular orbital level of RB dye to the conduction band (CB) of TiO 2 , then the possibilities of recombination of electrons with oxidized dye molecules or oxidized redox couple are reduced. This is because the CB position of CeO 2 is higher than that of TiO 2 , which blocks the path of electrons. The electrochemical impedance spectroscopy (EIS) analysis shows negative shift in frequency for bilayered TiO 2-CeO 2 photoanode as compared to CeO 2 photoanode. Hence, in bilayered photoanode lifetime of electrons is more than in single-layered photoanode, confirming reduction in recombination reactions. The X-ray diffraction patterns confirm both anatase TiO 2 and CeO 2 with crystalline size using Scherrer formula as 24 and 10 nm, respectively. The scanning electron microscopy images of photoanode show the porous structure useful for dye adsorption. The presence of Ti and Ce is confirmed by electron diffraction studies. The band gap values for TiO 2 and CeO 2 were calculated as 3.20 and 3.11 eV, respectively, using diffused reflectance spectroscopy. The bilayered TiO 2-CeO 2 photoanode showed open-circuit voltage (V OC) *500 mV and short-circuit photocurrent density (J SC) *0.29 mA/cm 2 with fill factor (FF) *62.17 %. There is increase in V OC and J SC values by 66.67 and 38.10 %, respectively, compared to RB-sensitized CeO 2 photoanode. Keywords Dye-sensitized solar cell Á Photoanode Á Rose Bengal dye Á TiO 2-CeO 2 Electronic supplementary material The online version of this article (

Rose bengal-sensitized nanocrystalline ceria photoanode for dye-sensitized solar cell application

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“…To avoid or suppress these losses researchers are trying to use bi-layered materials such as TiO2-CeO2, [15][16][17] ZnO-CeO2, [18] TiO2-ZrO2, [19] TiO2-Nb2O5, [20] ZnO-Nb2O5 [21] etc.…”