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Effect of compressed TiO2 nanoparticle thin film thickness on the performance of dye-sensitized solar cells.

Tsai JK, Hsu WD, Wu TC, Meen TH, Chong WJ - Nanoscale Res Lett (2013)

Bottom Line: The open-circuit voltage of DSSCs decreases as the thickness increases.One DSSC (sample D) has the highest conversion efficiency while it has the maximum short-circuit current density.The results indicate that the short-circuit current density is a compromise between two conflict factors: enlargement of the surface area by increasing photoanode thickness and extension of the electron diffusion length to the electrode as the thickness increases.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Electronic Engineering, National Formosa University, Yunlin 632, Taiwan. tsaijk@nfu.edu.tw.

ABSTRACT
In this study, dye-sensitized solar cells (DSSCs) were fabricated using nanocrystalline titanium dioxide (TiO2) nanoparticles as photoanode. Photoanode thin films were prepared by doctor blading method with 420 kg/cm2 of mechanical compression process and heat treatment in the air at 500°C for 30 min. The optimal thickness of the TiO2 NP photoanode is 26.6 μm with an efficiency of 9.01% under AM 1.5G illumination at 100 mW/cm2. The efficiency is around two times higher than that of conventional DSSCs with an uncompressed photoanode. The open-circuit voltage of DSSCs decreases as the thickness increases. One DSSC (sample D) has the highest conversion efficiency while it has the maximum short-circuit current density. The results indicate that the short-circuit current density is a compromise between two conflict factors: enlargement of the surface area by increasing photoanode thickness and extension of the electron diffusion length to the electrode as the thickness increases.

No MeSH data available.


Related in: MedlinePlus

The UV–vis absorption spectra of compressed TiO2 NP thin films with various thicknesses. Samples A to F have a photoanode thickness of 12.7, 14.2, 25.0, 26.6, 35.3, and 55.2 μm, respectively, with dye adsorption. Sample D' is the TiO2 NP thin film of 26.6 μm in thickness (the same as sample D) but without dye adsorption.
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Figure 3: The UV–vis absorption spectra of compressed TiO2 NP thin films with various thicknesses. Samples A to F have a photoanode thickness of 12.7, 14.2, 25.0, 26.6, 35.3, and 55.2 μm, respectively, with dye adsorption. Sample D' is the TiO2 NP thin film of 26.6 μm in thickness (the same as sample D) but without dye adsorption.

Mentions: In order to reveal the effect of dyes adsorbed on the TiO2 NPs, a compressed TiO2 NP thin film with a thickness that is the same as that of sample D (26.6 μm) but without dye adsorption was prepared. Its UV–vis adsorption spectrum was compared with those of samples A to F, as shown in Figure 3. The range of spectral absorbance was between 0 and 6 which is related to air, to which 0 absorbance was assigned. The absorbance of the films with dye adsorption (samples A to F) is larger than that of the films without dye adsorption. The absorbance increases as the thickness increases which may be attributed to the increase of the number of absorbed dye molecules in the TiO2 NP thin film. In the short light wavelength region (less than 590 nm), the absorbance is almost the same among samples B to F whose thickness is greater than or equal to 14.2 nm, as shown in the inset of Figure 3. It is because the adsorption characteristic of N3 dye is located at the light wavelength of 540 nm. On the other hand, in the long light wavelength region, the absorbance increases as the thickness increases. The result is shown in the inset of Figure 3 by comparison of the absorbance of samples B to F at 650 nm. It is because long-wavelength light has high transmittance resulting in high absorbance for the thick film.


Effect of compressed TiO2 nanoparticle thin film thickness on the performance of dye-sensitized solar cells.

Tsai JK, Hsu WD, Wu TC, Meen TH, Chong WJ - Nanoscale Res Lett (2013)

The UV–vis absorption spectra of compressed TiO2 NP thin films with various thicknesses. Samples A to F have a photoanode thickness of 12.7, 14.2, 25.0, 26.6, 35.3, and 55.2 μm, respectively, with dye adsorption. Sample D' is the TiO2 NP thin film of 26.6 μm in thickness (the same as sample D) but without dye adsorption.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4228349&req=5

Figure 3: The UV–vis absorption spectra of compressed TiO2 NP thin films with various thicknesses. Samples A to F have a photoanode thickness of 12.7, 14.2, 25.0, 26.6, 35.3, and 55.2 μm, respectively, with dye adsorption. Sample D' is the TiO2 NP thin film of 26.6 μm in thickness (the same as sample D) but without dye adsorption.
Mentions: In order to reveal the effect of dyes adsorbed on the TiO2 NPs, a compressed TiO2 NP thin film with a thickness that is the same as that of sample D (26.6 μm) but without dye adsorption was prepared. Its UV–vis adsorption spectrum was compared with those of samples A to F, as shown in Figure 3. The range of spectral absorbance was between 0 and 6 which is related to air, to which 0 absorbance was assigned. The absorbance of the films with dye adsorption (samples A to F) is larger than that of the films without dye adsorption. The absorbance increases as the thickness increases which may be attributed to the increase of the number of absorbed dye molecules in the TiO2 NP thin film. In the short light wavelength region (less than 590 nm), the absorbance is almost the same among samples B to F whose thickness is greater than or equal to 14.2 nm, as shown in the inset of Figure 3. It is because the adsorption characteristic of N3 dye is located at the light wavelength of 540 nm. On the other hand, in the long light wavelength region, the absorbance increases as the thickness increases. The result is shown in the inset of Figure 3 by comparison of the absorbance of samples B to F at 650 nm. It is because long-wavelength light has high transmittance resulting in high absorbance for the thick film.

Bottom Line: The open-circuit voltage of DSSCs decreases as the thickness increases.One DSSC (sample D) has the highest conversion efficiency while it has the maximum short-circuit current density.The results indicate that the short-circuit current density is a compromise between two conflict factors: enlargement of the surface area by increasing photoanode thickness and extension of the electron diffusion length to the electrode as the thickness increases.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Electronic Engineering, National Formosa University, Yunlin 632, Taiwan. tsaijk@nfu.edu.tw.

ABSTRACT
In this study, dye-sensitized solar cells (DSSCs) were fabricated using nanocrystalline titanium dioxide (TiO2) nanoparticles as photoanode. Photoanode thin films were prepared by doctor blading method with 420 kg/cm2 of mechanical compression process and heat treatment in the air at 500°C for 30 min. The optimal thickness of the TiO2 NP photoanode is 26.6 μm with an efficiency of 9.01% under AM 1.5G illumination at 100 mW/cm2. The efficiency is around two times higher than that of conventional DSSCs with an uncompressed photoanode. The open-circuit voltage of DSSCs decreases as the thickness increases. One DSSC (sample D) has the highest conversion efficiency while it has the maximum short-circuit current density. The results indicate that the short-circuit current density is a compromise between two conflict factors: enlargement of the surface area by increasing photoanode thickness and extension of the electron diffusion length to the electrode as the thickness increases.

No MeSH data available.


Related in: MedlinePlus