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Efficiency enhancement in dye-sensitized solar cell using TiO2 /ilmenite-derived nanofiber composite as working electrode
(2014-01-01)
Simpraditpan, Athapon
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Wirunmongkol, Thanakorn
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Pavasupree, Sorapong
;
Pecharapa, Wisanu
TiO<inf>2</inf> nanocomposite films of calcined TiO<inf>2</inf> nanofibers and commercial-grade TiO<inf>2</inf> nanoparticles Degussa (P25) utilized as working electrode of dye-sensitized solar cells (DSSCs) are prepared by a doctor blade method. TiO<inf>2</inf> nanofibers were synthesized from ilmenite mineral by hydrothermal process in combination with calcinations process. The prepared samples are characterized by XRD, XPS and TEM. The photoelectric conversion performance of the DSSC based on nanocomposite film electrode was compared to the device fabricated by pure P25 at the same film thickness. The result shows that as calcination temperature increases, the transformation of nanofibers to nanorods and nanoparticles were observed. The energy conversion efficiency ({eng}) of the device tends to with increasing calcined temperature. The greatest {eng} is 3.90% obtained from DSSC fabricated from nanocomposite film electrode of 5 wt.% nanofibers calcined at 800 °C for 2 h mixed with P25, indicating the significant enhancement in its performance by the incorporation of the nanofibers. This enhancement of DSSCs may correlate to high surface area, higher light scattering and light harvesting, low charge recombination and fast electron-transfer rate by nanofibers. © (2014) Trans Tech Publications, Switzerland.
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Modification of dye-sensitized solar cell working electrode using TiO 2 nanoparticle/N-doped TiO2 nanofiber composites
(2014-01-01)
Mekprasart, Wanichaya
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Suphankij, Sineenart
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Tangcharoen, Thanit
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Simpraditpan, Athapon
;
Pecharapa, Wisanu
Nanocomposite films of N-doped TiO<inf>2</inf> nanofibers (NFs) and commercial-grade TiO<inf>2</inf> nanoparticles Degussa (P25) were utilized as working electrode of typical dye-sensitized solar cells (DSSCs). N-doped TiO<inf>2</inf> NFs were fabricated via electrospinning method using ammonium acetate (CH<inf>3</inf>COONH<inf>4</inf>) as nitrogen source and titanium (IV) isopropoxide (TiP) in ethanol as starting precursor in combination with calcinations process. The electrospun NFs were characterized by XRD, Raman spectroscopy, XPS, SEM, and TEM. The photoelectric conversion performance of the DSSCs with composite film electrode was compared to the device using pure P25 film. The result shows that as calcination temperature increases, the anatase-to-rutile phase transformation and the fiber size reduction of NFs were observed. The energy conversion efficiency (η) of the device tends to increase with increasing calcined temperature with specific nanofiber loading content, indicating the significant enhancement in the device performance by the incorporation of the NFs. This enhancement of DSSCs may attribute to high surface area, higher light scattering and light harvesting, low charge recombination, and fast electron-transfer rate by loaded NFs. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
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Hydrothermal synthesis of nanofibers from natural ilmenite mineral and their utilization for dye-sensitized solar cell
(2013-12-01)
Simpraditpan, Athapon
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Wirunmongkol, Thanakorn
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Pavasupree, Sorapong
;
Pecharapa, Wisanu
Titanate nanofibers were synthesized by a hydrothermal method using a low-cost ilmenite mineral as the starting material. The crystalline structure of the as-synthesized nanofibers demonstrated titanate structure (H <inf>2</inf>Ti<inf>x</inf>O2x+<inf>1</inf>). The bi-crystalline mixture consisting of TiO2 (B) and anatase TiO<inf>2</inf> nanofibers was obtained by heat treatment at 500°C for 2 h. Dye-sensitized solar cells (DSSCs) with photoanode consisting of the nanocomposite of nanoparticles and nanofibers (5%) rendered a light-to-electricity conversion efficiency (η) of 0.28%. In contrast, the cells with photoanodes consisting of only nanoparticles and nanofibers exhibited η of 0.25% and 0.15%, respectively. © 2013 Copyright Taylor and Francis Group, LLC.
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Effect of calcination temperature on structural and photocatalyst properties of nanofibers prepared from low-cost natural ilmenite mineral by simple hydrothermal method
(2013-09-01)
Simpraditpan, Athapon
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Wirunmongkol, Thanakorn
;
Pavasupree, Sorapong
;
Pecharapa, Wisanu
Titanate nanofibers were synthesized via the hydrothermal method (120 C for 72 h) using natural ilmenite mineral (FeTiO<inf>3</inf>) as the starting material. The samples were characterized by X-ray diffraction (XRD), X-ray fluorescent (XRF), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Brunauer-Emmett-Teller (BET) for specific surface area. The nanofibers were 20-90 nm in diameter and 2-7 μm in length. The as-synthesized nanofibers calcined at 300-400 C showed TiO<inf>2</inf> (B) whereas the nanofibers calcined at 500 C revealed a mixture of two phases of TiO<inf>2</inf> (B) and anatase. The nanofibers calcined at high temperature of 600-1000 C showed a mixture of tri-crystalline of anatase, rutile, and Fe <inf>2</inf>O<inf>3</inf>. The rutile phase increased with increasing calcination temperature. The nanofibers calcined at 300-700 C maintained their structure while the morphology of the nanofibers calcined at 800-1000 C transformed into submicron rod-like structure. This increase of calcination temperature led to the phase transformation from thermodynamically metastable anatase to the most stable form of rutile phase. The crystallite size of prepared samples increased with increasing calcination temperature. Interestingly, with increasing calcination temperature, the absorption edge of the prepared samples shows an obvious shift to visible light region due to the change of crystallite phase and increased crystallite size. Therefore, the band gap energy of the prepared samples became narrower with increasing calcination temperature. Furthermore, the photocatalytic activity of the nanofibers calcined at 400 C for 2 h was found to be not merely higher than those of the commercially available TiO<inf>2</inf> nanoparticles powders (P-25, JRC-01, and JRC-03) but also the highest of all the samples in this study. © 2013 Elsevier Ltd. All rights reserved.
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Simple hydrothermal preparation of nanofibers from a natural ilmenite mineral
(2013-04-01)
Simpraditpan, Athapon
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Wirunmongkol, Thanakorn
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Pavasupree, Sorapong
;
Pecharapa, Wisanu
Titanate nanofibers were synthesized by a simple hydrothermal method using a natural ilmenite mineral as the starting material. The chemical composition, crystalline structure, shape, size, and specific surface area of the prepared samples were characterized by X-ray fluorescence (XRF), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and the Brunauer-Emmett-Teller analysis (BET). The crystalline structure of the as-synthesized nanofibers demonstrated a layered titanate form, H <inf>2</inf>Ti<inf>x</inf>O<inf>2x+1</inf>. The length of the prepared nanofibers ranged from 2 to 7 μm with diameters ranging from 20 to 90 nm. The as-synthesized nanofibers were solids with BET surface areas of approximately 50 m<sup>2</sup>/g. This synthetic method provides a simple route for the fabrication of one-dimensional (1-D) nanostructured materials from a low-cost natural mineral. © 2012 Elsevier Ltd and Techna Group S.r.l.
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Characterization of flower-like titanate and titania nanowires on titanium plate substrate
(2013-01-01)
Pavasupree, Sorapong
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Onoda, Kinji
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Yoshikawa, Susumu
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Simpraditpan, Athapon
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Pecharapa, Wisanu
Flower-like structure titanate and titania on titanium plate substrate composed of nanowires were synthesized by hydrothermal method at 150 oC for 2 h using titanium plate substrate as the starting material. The crystalline structure, shape and size of the prepared sample were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). SEM images showed flower-like structure with uniform size about 2 ?m. The flower-like structure composed of nanowires with diameter about 20-50 nm. Titanate and titania could be controlled by washing process and calcination temperature. This synthesis method provides a simple route to fabricate nanostructured titanate and titania on titanium plate substrate for dye-sensitized solar cell and photocatalytic activity applications. © 2013 The Authors. Published by Elsevier B.V.

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