The enhancement of photovoltaic parameters in dye-sensitized solar cells of nano-crystalline SnO2 by incorporating with large SrTiO3 particles

• Published in: Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy Molecular and biomolecular spectroscopy, 2013-05, Vol.109, p.37-41
• Main Authors: Aponsu, G.M.L.P., Wijayarathna, T.R.C.K., Perera, I.K., Perera, V.P.S., Siriwardhana, A.C.P.K.
• Format: Article
• Language: English
• Subjects: Dye-sensitized solar cells; High band gap semiconductor; Mott–Schottky plot; Nano-crystalline films
• ISSN: 1386-1425
• DOI: 10.1016/j.saa.2013.02.016

[Display omitted] ► Dye sensitized solar cells made of SrTiO3/SnO2 attribute improved photovoltaic parameters compared to bare SnO2 electrodes. ► Wider charge separation through minibands of SrTiO3/SnO2 structure better suppress recombination channels. ► The shifting up of the CB edge of SnO2 in the composite film to a higher level improves the photovoltage of the cells. In this paper, the performance of nano-porous electrodes made of a composite material of SrTiO3 and SnO2 are compared with those made of bare SnO2. When these particular devices are analyzed in a comparative mode the results confirmed the enhancement of photovoltaic parameters in the former device. The performance of respective cells were examined by several methods including I−V characteristic measurements, photocurrent action spectra, dark I−V measurements, Mott−Schottky measurements and X-ray diffraction measurements. Even though such improvements in this particular cell could be explicated by the formation of a potential energy barrier of SrTiO3 particles of comparably large width at the SrTiO3/SnO2 interface, the passivation of voids in the SnO2 film by SrTiO3 particles to a certain extent could not be totally ruled out. Besides, high energetic electrons injected by dye molecules move more credibly through mini-bands formed in the chain of nano-crystalline SnO2 particles to the back contact. The blocking of the recombination path and the shifting up of the uppermost electron occupied level of SnO2 accompanying the conduction band edge in the SrTiO3/SnO2 composite film, may have lead to the observed enhancement of the fill factor and photovoltage, respectively.