Photoelectrochemical Study of the Ilmenite Polymorph of CdSnO3 and Its Photoanodic Application in Dye-Sensitized Solar Cells
By Natu, Gayatri & Wu, Yiying
Published in The Journal of Physical Chemistry C
2010
Abstract
Knowledge of the electronic band structure of complex (multicationic) metal oxides is essential for their application toward photonic energy conversion. Here we report our findings on the band gap (Eg) and the conduction band (CB) edge of the ilmenite polymorph of cadmium stannate (CdSnO3) and its application in dye-sensitized solar cells. Solvothermally prepared CdSnO3 particles were characterized with use of X-ray diffraction and electron microscopy. Diffuse reflectance spectroscopy was performed on the finely ground powder to obtain an indirect-allowed type band gap of 3.07 ± 0.03 eV. CdSnO3 films were spread onto conductive substrates and their photoelectrochemistry was studied. The flat band potential (Efb) was determined in aqueous and nonaqueous solutions via the onset-of-photocurrent method. The conduction band edge (Ecb) was approximated to Efb, and at pH 0 was found to be at 0.82 ± 0.05 V vs NHE for CdSnO3, which is approximately 0.9 eV lower than the Ecb of anatase TiO2 at the same pH. Dye-sensitized solar cells were constructed with CdSnO3 as photoanodes and a best conversion efficiency of 1.42% was obtained under AM 1.5 sun.