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Efficient Performance of Electrostatic Spray-Deposited TiO 2 Blocking Layers in Dye-Sensitized Solar Cells after Swift Heavy Ion Beam Irradiation

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ABSTRACT

A compact TiO2 layer (~1.1 μm) prepared by electrostatic spray deposition (ESD) and swift heavy ion beam (SHI) irradiation using oxygen ions onto a fluorinated tin oxide (FTO) conducting substrate showed enhancement of photovoltaic performance in dye-sensitized solar cells (DSSCs). The short circuit current density (Jsc = 12.2 mA cm-2) of DSSCs was found to increase significantly when an ESD technique was applied for fabrication of the TiO2 blocking layer, compared to a conventional spin-coated layer (Jsc = 8.9 mA cm-2). When SHI irradiation of oxygen ions of fluence 1 × 1013 ions/cm2 was carried out on the ESD TiO2, it was found that the energy conversion efficiency improved mainly due to the increase in open circuit voltage of DSSCs. This increased energy conversion efficiency seems to be associated with improved electronic energy transfer by increasing the densification of the blocking layer and improving the adhesion between the blocking layer and the FTO substrate. The adhesion results from instantaneous local melting of the TiO2 particles. An increase in the electron transport from the blocking layer may also retard the electron recombination process due to the oxidized species present in the electrolyte. These findings from novel treatments using ESD and SHI irradiation techniques may provide a new tool to improve the photovoltaic performance of DSSCs.

No MeSH data available.


X-ray diffraction spectra. (Note that * indicated in the XRD spectra is indicated the crystalline contribution from FTO substrate.) Standard peak position (JCPDS 21-1272) of the TiO2 anatase phase is given in vertical lines.
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Figure 2: X-ray diffraction spectra. (Note that * indicated in the XRD spectra is indicated the crystalline contribution from FTO substrate.) Standard peak position (JCPDS 21-1272) of the TiO2 anatase phase is given in vertical lines.

Mentions: Figure 2 shows the X-ray diffraction spectra of the ESD pristine and the SHI-irradiated TiO2 layers. Hereafter, the SHI-irradiated TiO2 layer is referred to as a layer formed by the ESD first and subsequently SHI-irradiated techniques. The characteristic peak observed at ~25.3° in both the films indicated the presence of an anatase phase of TiO2 (JCPDS 21-1272). The increase in the relative peak intensities observed in the SHI-irradiated sample shows that the SHI irradiation induced crystallization when compared to the as-prepared pristine ESD TiO2 films. The average grain size of the SHI-irradiated TiO2 films was found to be about 47 nm as estimated from Scherrer's equation. The significant additional peak exhibited in the SHI-irradiated sample is not clearly understood.


Efficient Performance of Electrostatic Spray-Deposited TiO 2 Blocking Layers in Dye-Sensitized Solar Cells after Swift Heavy Ion Beam Irradiation
X-ray diffraction spectra. (Note that * indicated in the XRD spectra is indicated the crystalline contribution from FTO substrate.) Standard peak position (JCPDS 21-1272) of the TiO2 anatase phase is given in vertical lines.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211366&req=5

Figure 2: X-ray diffraction spectra. (Note that * indicated in the XRD spectra is indicated the crystalline contribution from FTO substrate.) Standard peak position (JCPDS 21-1272) of the TiO2 anatase phase is given in vertical lines.
Mentions: Figure 2 shows the X-ray diffraction spectra of the ESD pristine and the SHI-irradiated TiO2 layers. Hereafter, the SHI-irradiated TiO2 layer is referred to as a layer formed by the ESD first and subsequently SHI-irradiated techniques. The characteristic peak observed at ~25.3° in both the films indicated the presence of an anatase phase of TiO2 (JCPDS 21-1272). The increase in the relative peak intensities observed in the SHI-irradiated sample shows that the SHI irradiation induced crystallization when compared to the as-prepared pristine ESD TiO2 films. The average grain size of the SHI-irradiated TiO2 films was found to be about 47 nm as estimated from Scherrer's equation. The significant additional peak exhibited in the SHI-irradiated sample is not clearly understood.

View Article: PubMed Central - HTML - PubMed

ABSTRACT

A compact TiO2 layer (~1.1 μm) prepared by electrostatic spray deposition (ESD) and swift heavy ion beam (SHI) irradiation using oxygen ions onto a fluorinated tin oxide (FTO) conducting substrate showed enhancement of photovoltaic performance in dye-sensitized solar cells (DSSCs). The short circuit current density (Jsc = 12.2 mA cm-2) of DSSCs was found to increase significantly when an ESD technique was applied for fabrication of the TiO2 blocking layer, compared to a conventional spin-coated layer (Jsc = 8.9 mA cm-2). When SHI irradiation of oxygen ions of fluence 1 × 1013 ions/cm2 was carried out on the ESD TiO2, it was found that the energy conversion efficiency improved mainly due to the increase in open circuit voltage of DSSCs. This increased energy conversion efficiency seems to be associated with improved electronic energy transfer by increasing the densification of the blocking layer and improving the adhesion between the blocking layer and the FTO substrate. The adhesion results from instantaneous local melting of the TiO2 particles. An increase in the electron transport from the blocking layer may also retard the electron recombination process due to the oxidized species present in the electrolyte. These findings from novel treatments using ESD and SHI irradiation techniques may provide a new tool to improve the photovoltaic performance of DSSCs.

No MeSH data available.