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Conical islands of TiO2 nanotube arrays in the photoelectrode of dye-sensitized solar cells.

Kim WR, Park H, Choi WY - Nanoscale Res Lett (2015)

Bottom Line: The resulting conical island structures were anodized in ethylene glycol solution containing 0.25 wt% NH4F and 2 vol% H2O, and conical islands composed of TiO2 nanotubes were successfully formed on the Ti foils.The conical island structure was very effective at improving performances of DSCs based on TiO2 nanotubes.DSCs based on the conical islands of TiO2 nanotube arrays have the potential to achieve higher efficiency levels compared to DSCs based on normal TiO2 nanotubes and TiO2 nanoparticles because the conical islands of TiO2 nanotube arrays enlarge the surface area for dye adsorption.

View Article: PubMed Central - PubMed

Affiliation: Department of Metal and Materials Engineering, Gangneung-wonju National University, Gangneung, 210-720 South Korea.

ABSTRACT
Ti conical island structures were fabricated using photolithography and the reactive ion etching method. The resulting conical island structures were anodized in ethylene glycol solution containing 0.25 wt% NH4F and 2 vol% H2O, and conical islands composed of TiO2 nanotubes were successfully formed on the Ti foils. The conical islands composed of TiO2 nanotubes were employed in photoelectrodes for dye-sensitized solar cells (DSCs). DSC photoelectrodes based on planar Ti structures covered with TiO2 nanotubes were also fabricated as a reference. The short-circuit current (J sc) and efficiency of DSCs based on the conical island structures were higher than those of the reference samples. The efficiency of DSCs based on the conical island structures reached up to 1.866%. From electrochemical impedance spectroscopy and open-circuit voltage (V oc) decay measurements, DSCs based on the conical island structures exhibited a lower charge transfer resistance at the counter cathode and a longer electron lifetime at the interface of the photoelectrode and electrolyte compared to the reference samples. The conical island structure was very effective at improving performances of DSCs based on TiO2 nanotubes. Graphical AbstractConical islands of TiO2 nanotube arrays are fabricated by an anodizing process with Ti protruding dots which have a conical shape. The conical islands are applied for use in DSC photoelectrodes. DSCs based on the conical islands of TiO2 nanotube arrays have the potential to achieve higher efficiency levels compared to DSCs based on normal TiO2 nanotubes and TiO2 nanoparticles because the conical islands of TiO2 nanotube arrays enlarge the surface area for dye adsorption.

No MeSH data available.


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X-ray diffraction patterns of the (a) as-anodized and (b) annealed conical island structures composed of TiO2nanotube arrays.
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Fig4: X-ray diffraction patterns of the (a) as-anodized and (b) annealed conical island structures composed of TiO2nanotube arrays.

Mentions: Figure 4 shows the X-ray diffraction patterns of the as-anodized and annealed conical island structures composed of TiO2 nanotube arrays on Ti substrates. The as-anodized conical island structure composed of TiO2 nanotube arrays, as shown in Figure 4a, has only Ti metal peaks, and there are no crystalline peaks of Ti oxides. The as-anodized conical island structure can be confirmed as amorphous phase. After annealing at 500°C for 1 h, the anatase peaks of TiO2 can be found, as seen in Figure 4b. This reveals that the nanotubes on the conical islands were converted to the anatase phase by the annealing process. The anatase phase has previously shown the best performance when applied in DSCs because the anatase (101) plane provides preferential sites for dye adsorption [54,55].Figure 4


Conical islands of TiO2 nanotube arrays in the photoelectrode of dye-sensitized solar cells.

Kim WR, Park H, Choi WY - Nanoscale Res Lett (2015)

X-ray diffraction patterns of the (a) as-anodized and (b) annealed conical island structures composed of TiO2nanotube arrays.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4384997&req=5

Fig4: X-ray diffraction patterns of the (a) as-anodized and (b) annealed conical island structures composed of TiO2nanotube arrays.
Mentions: Figure 4 shows the X-ray diffraction patterns of the as-anodized and annealed conical island structures composed of TiO2 nanotube arrays on Ti substrates. The as-anodized conical island structure composed of TiO2 nanotube arrays, as shown in Figure 4a, has only Ti metal peaks, and there are no crystalline peaks of Ti oxides. The as-anodized conical island structure can be confirmed as amorphous phase. After annealing at 500°C for 1 h, the anatase peaks of TiO2 can be found, as seen in Figure 4b. This reveals that the nanotubes on the conical islands were converted to the anatase phase by the annealing process. The anatase phase has previously shown the best performance when applied in DSCs because the anatase (101) plane provides preferential sites for dye adsorption [54,55].Figure 4

Bottom Line: The resulting conical island structures were anodized in ethylene glycol solution containing 0.25 wt% NH4F and 2 vol% H2O, and conical islands composed of TiO2 nanotubes were successfully formed on the Ti foils.The conical island structure was very effective at improving performances of DSCs based on TiO2 nanotubes.DSCs based on the conical islands of TiO2 nanotube arrays have the potential to achieve higher efficiency levels compared to DSCs based on normal TiO2 nanotubes and TiO2 nanoparticles because the conical islands of TiO2 nanotube arrays enlarge the surface area for dye adsorption.

View Article: PubMed Central - PubMed

Affiliation: Department of Metal and Materials Engineering, Gangneung-wonju National University, Gangneung, 210-720 South Korea.

ABSTRACT
Ti conical island structures were fabricated using photolithography and the reactive ion etching method. The resulting conical island structures were anodized in ethylene glycol solution containing 0.25 wt% NH4F and 2 vol% H2O, and conical islands composed of TiO2 nanotubes were successfully formed on the Ti foils. The conical islands composed of TiO2 nanotubes were employed in photoelectrodes for dye-sensitized solar cells (DSCs). DSC photoelectrodes based on planar Ti structures covered with TiO2 nanotubes were also fabricated as a reference. The short-circuit current (J sc) and efficiency of DSCs based on the conical island structures were higher than those of the reference samples. The efficiency of DSCs based on the conical island structures reached up to 1.866%. From electrochemical impedance spectroscopy and open-circuit voltage (V oc) decay measurements, DSCs based on the conical island structures exhibited a lower charge transfer resistance at the counter cathode and a longer electron lifetime at the interface of the photoelectrode and electrolyte compared to the reference samples. The conical island structure was very effective at improving performances of DSCs based on TiO2 nanotubes. Graphical AbstractConical islands of TiO2 nanotube arrays are fabricated by an anodizing process with Ti protruding dots which have a conical shape. The conical islands are applied for use in DSC photoelectrodes. DSCs based on the conical islands of TiO2 nanotube arrays have the potential to achieve higher efficiency levels compared to DSCs based on normal TiO2 nanotubes and TiO2 nanoparticles because the conical islands of TiO2 nanotube arrays enlarge the surface area for dye adsorption.

No MeSH data available.


Related in: MedlinePlus