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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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FESEM images of the conical island structure of the Ti surface fabricated by dry etching. At magnifications of (a) × 20,000 and (b) × 8,000.
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Fig2: FESEM images of the conical island structure of the Ti surface fabricated by dry etching. At magnifications of (a) × 20,000 and (b) × 8,000.

Mentions: Figure 2 shows the FESEM images of the conical islands formed on the Ti surface by the RIE method. In our previous report, we fabricated arrays of protruding Ti cylinders [30]. By increasing the etching time, the morphology of the Ti surface can be converted from protruding cylinders to conical islands, as shown in Figure 2. In this process, negative photoresists were first spin-coated on the Ti metal surface. Usually, when photoresists are exposed to UV light, they are cross-linked and so block reactive etching ions during the RIE process. The cross-linked photoresist layer protects the Ti surface from physical and chemical etching.Figure 2


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

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

FESEM images of the conical island structure of the Ti surface fabricated by dry etching. At magnifications of (a) × 20,000 and (b) × 8,000.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Fig2: FESEM images of the conical island structure of the Ti surface fabricated by dry etching. At magnifications of (a) × 20,000 and (b) × 8,000.
Mentions: Figure 2 shows the FESEM images of the conical islands formed on the Ti surface by the RIE method. In our previous report, we fabricated arrays of protruding Ti cylinders [30]. By increasing the etching time, the morphology of the Ti surface can be converted from protruding cylinders to conical islands, as shown in Figure 2. In this process, negative photoresists were first spin-coated on the Ti metal surface. Usually, when photoresists are exposed to UV light, they are cross-linked and so block reactive etching ions during the RIE process. The cross-linked photoresist layer protects the Ti surface from physical and chemical etching.Figure 2

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