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Ag nanoparticle-deposited TiO2 nanotube arrays for electrodes of Dye-sensitized solar cells.

Kawamura G, Ohmi H, Tan WK, Lockman Z, Muto H, Matsuda A - Nanoscale Res Lett (2015)

Bottom Line: Efficient charge transportation through the ordered nanostructure of TNT arrays should be carried out compared to conventional particulate TiO2 electrodes.In this work, we deposited Ag nanoparticles (NPs) on the wall of TNT arrays to enhance light-harvesting property.Dye-sensitized solar cells with these Ag NP-deposited TNT arrays yielded a higher power conversion efficiency (2.03 %) than those without Ag NPs (1.39 %). 06.60.Ei Sample preparation, 81.05.Bx Metals, Semimetals, Alloys, 81.07.De Nanotubes.

View Article: PubMed Central - PubMed

Affiliation: Department of Electrical and Electronic Information Engineering, Toyohashi University of Technology, 1-1 Hibarigaoka, Tempaku-cho, Toyohashi, 441-8580 Aichi Japan.

ABSTRACT

Abstract: Dye-sensitized solar cells composed of a photoanode of Ag nanoparticle (NP)-deposited TiO2 nanotube (TNT) arrays were fabricated. The TNT arrays were prepared by anodizing Ti films on fluorine-doped tin oxide (FTO)-coated glass substrates. Efficient charge transportation through the ordered nanostructure of TNT arrays should be carried out compared to conventional particulate TiO2 electrodes. However, it has been a big challenge to grow TNT arrays on FTO glass substrates with the lengths needed for sufficient light-harvesting (tens of micrometers). In this work, we deposited Ag nanoparticles (NPs) on the wall of TNT arrays to enhance light-harvesting property. Dye-sensitized solar cells with these Ag NP-deposited TNT arrays yielded a higher power conversion efficiency (2.03 %) than those without Ag NPs (1.39 %).

Pacs codes: 06.60.Ei Sample preparation, 81.05.Bx Metals, Semimetals, Alloys, 81.07.De Nanotubes.

No MeSH data available.


Related in: MedlinePlus

Current-voltage and power-voltage characteristics of DSSC fabricated using TNT arrays without (a) and with (b) Ag nanoparticles. The blue line (power, P) was given by P = I × V
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Fig6: Current-voltage and power-voltage characteristics of DSSC fabricated using TNT arrays without (a) and with (b) Ag nanoparticles. The blue line (power, P) was given by P = I × V

Mentions: Figure 6a shows the current-voltage characteristics of DSSC fabricated with annealed TNT arrays on FTO. The power conversion efficiency of the DSSC was 1.39 % (open-circuit voltage VOC = 0.73 V, short-circuit density JSC = 4.2 mA cm−2, fill factor FF = 0.44). On the other hand, the DSSC fabricated from Ag nanoparticle-deposited TNT arrays yielded a conversion efficiency of 2.03 % (VOC = 0.76 V, JSC = 5.0 mA cm−2, FF = 0.54) (Fig. 6b). The improvement of JSC caused by depositing Ag nanoparticles should mainly be due to enhanced light-harvesting ability. LSPR of Ag nanoparticles strongly absorb and scatter photons compared to almost all materials including dyes, thus more photons are captured by the DSSC with Ag nanoparticles [16]. Additionally, since the electric field near Ag nanoparticles becomes very strong when LSPR is induced, the electrons of dyes are effectively excited by the enhanced local field. Therefore, the improved JSC is reasonably explained in terms of the abovementioned LSPR effects, because more excited electrons are generated by depositing Ag nanoparticles on the arrays. The deposition of Ag nanoparticles on TNTs should also have negative effects on DSSC performance, for example, the excited electrons are captured by Ag nanoparticles leading to deteriorated electron conductivity of the TNTs. However, the negative effects were hidden by the positive effect of improved light-harvesting ability. On the other hand, the reason why FF was improved by Ag deposition is still unclear. Presumably, the deposition of Ag nanoparticles occurred predominantly at the defect sites because of the higher surface energy of the sites. Thus, Ag nanoparticles got rid of the defect sites where charge recombination often occurs. Considering that as-purchased N719 was used without further purification process in this work, higher conversion efficiency should be obtainable by using properly purified or recently developed dyes [17]. A surface treatment of TiO2 electrode by TiCl4, which is often employed to improve JSC and FF [18, 19], was also not carried out in this work. Moreover, optimization of the length of TNT arrays should also be effective for enhancement of our DSSC performance.Fig. 6


Ag nanoparticle-deposited TiO2 nanotube arrays for electrodes of Dye-sensitized solar cells.

Kawamura G, Ohmi H, Tan WK, Lockman Z, Muto H, Matsuda A - Nanoscale Res Lett (2015)

Current-voltage and power-voltage characteristics of DSSC fabricated using TNT arrays without (a) and with (b) Ag nanoparticles. The blue line (power, P) was given by P = I × V
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4440869&req=5

Fig6: Current-voltage and power-voltage characteristics of DSSC fabricated using TNT arrays without (a) and with (b) Ag nanoparticles. The blue line (power, P) was given by P = I × V
Mentions: Figure 6a shows the current-voltage characteristics of DSSC fabricated with annealed TNT arrays on FTO. The power conversion efficiency of the DSSC was 1.39 % (open-circuit voltage VOC = 0.73 V, short-circuit density JSC = 4.2 mA cm−2, fill factor FF = 0.44). On the other hand, the DSSC fabricated from Ag nanoparticle-deposited TNT arrays yielded a conversion efficiency of 2.03 % (VOC = 0.76 V, JSC = 5.0 mA cm−2, FF = 0.54) (Fig. 6b). The improvement of JSC caused by depositing Ag nanoparticles should mainly be due to enhanced light-harvesting ability. LSPR of Ag nanoparticles strongly absorb and scatter photons compared to almost all materials including dyes, thus more photons are captured by the DSSC with Ag nanoparticles [16]. Additionally, since the electric field near Ag nanoparticles becomes very strong when LSPR is induced, the electrons of dyes are effectively excited by the enhanced local field. Therefore, the improved JSC is reasonably explained in terms of the abovementioned LSPR effects, because more excited electrons are generated by depositing Ag nanoparticles on the arrays. The deposition of Ag nanoparticles on TNTs should also have negative effects on DSSC performance, for example, the excited electrons are captured by Ag nanoparticles leading to deteriorated electron conductivity of the TNTs. However, the negative effects were hidden by the positive effect of improved light-harvesting ability. On the other hand, the reason why FF was improved by Ag deposition is still unclear. Presumably, the deposition of Ag nanoparticles occurred predominantly at the defect sites because of the higher surface energy of the sites. Thus, Ag nanoparticles got rid of the defect sites where charge recombination often occurs. Considering that as-purchased N719 was used without further purification process in this work, higher conversion efficiency should be obtainable by using properly purified or recently developed dyes [17]. A surface treatment of TiO2 electrode by TiCl4, which is often employed to improve JSC and FF [18, 19], was also not carried out in this work. Moreover, optimization of the length of TNT arrays should also be effective for enhancement of our DSSC performance.Fig. 6

Bottom Line: Efficient charge transportation through the ordered nanostructure of TNT arrays should be carried out compared to conventional particulate TiO2 electrodes.In this work, we deposited Ag nanoparticles (NPs) on the wall of TNT arrays to enhance light-harvesting property.Dye-sensitized solar cells with these Ag NP-deposited TNT arrays yielded a higher power conversion efficiency (2.03 %) than those without Ag NPs (1.39 %). 06.60.Ei Sample preparation, 81.05.Bx Metals, Semimetals, Alloys, 81.07.De Nanotubes.

View Article: PubMed Central - PubMed

Affiliation: Department of Electrical and Electronic Information Engineering, Toyohashi University of Technology, 1-1 Hibarigaoka, Tempaku-cho, Toyohashi, 441-8580 Aichi Japan.

ABSTRACT

Abstract: Dye-sensitized solar cells composed of a photoanode of Ag nanoparticle (NP)-deposited TiO2 nanotube (TNT) arrays were fabricated. The TNT arrays were prepared by anodizing Ti films on fluorine-doped tin oxide (FTO)-coated glass substrates. Efficient charge transportation through the ordered nanostructure of TNT arrays should be carried out compared to conventional particulate TiO2 electrodes. However, it has been a big challenge to grow TNT arrays on FTO glass substrates with the lengths needed for sufficient light-harvesting (tens of micrometers). In this work, we deposited Ag nanoparticles (NPs) on the wall of TNT arrays to enhance light-harvesting property. Dye-sensitized solar cells with these Ag NP-deposited TNT arrays yielded a higher power conversion efficiency (2.03 %) than those without Ag NPs (1.39 %).

Pacs codes: 06.60.Ei Sample preparation, 81.05.Bx Metals, Semimetals, Alloys, 81.07.De Nanotubes.

No MeSH data available.


Related in: MedlinePlus