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Craig A Grimes - One of the best experts on this subject based on the ideXlab platform.
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vertically aligned wo3 nanowire arrays grown directly on Transparent Conducting Oxide coated glass synthesis and photoelectrochemical properties
Nano Letters, 2011Co-Authors: Jinzhan Su, Xinjian Feng, Jennifer D Sloppy, Craig A GrimesAbstract:Photocorrosion stable WO(3) nanowire arrays are synthesized by a solvothermal technique on fluorine-doped tin Oxide coated glass. WO(3) morphologies of hexagonal and monoclinic structure, ranging from nanowire to nanoflake arrays, are tailored by adjusting solution composition with growth along the (001) direction. Photoelectrochemical measurements of illustrative films show incident photon-to-current conversion efficiencies higher than 60% at 400 nm with a photocurrent of 1.43 mA/cm(2) under AM 1.5G illumination. Our solvothermal film growth technique offers an exciting opportunity for growth of one-dimensional metal Oxide nanostructures with practical application in photoelectrochemical energy conversion.
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long vertically aligned titania nanotubes on Transparent Conducting Oxide for highly efficient solar cells
Nature Nanotechnology, 2009Co-Authors: Oomman K Varghese, Maggie Paulose, Craig A GrimesAbstract:Dye-sensitized solar cells consist of a random network of titania nanoparticles that serve both as a high-surface-area support for dye molecules and as an electron-transporting medium. Despite achieving high power conversion efficiencies, their performance is limited by electron trapping in the nanoparticle film. Electron diffusion lengths can be increased by transporting charge through highly ordered nanostructures such as titania nanotube arrays. Although titania nanotube array films have been shown to enhance the efficiencies of both charge collection and light harvesting, it has not been possible to grow them on Transparent Conducting Oxide glass with the lengths needed for high-efficiency device applications (tens of micrometres). Here, we report the fabrication of Transparent titania nanotube array films on Transparent Conducting Oxide glass with lengths between 0.3 and 33.0 µm using a novel electrochemistry approach. Dye-sensitized solar cells containing these arrays yielded a power conversion efficiency of 6.9%. The incident photon-to-current conversion efficiency ranged from 70 to 80% for wavelengths between 450 and 650 nm. Transparent films of titania nanotubes up to 30-μm long are fabricated on Transparent Conducting Oxide glass, and used to make dye-sensitized solar cells.
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vertically aligned single crystal tio2 nanowire arrays grown directly on Transparent Conducting Oxide coated glass synthesis details and applications
Nano Letters, 2008Co-Authors: Xinjian Feng, Oomman K Varghese, Maggie Paulose, Karthik Shankar, Thomas J Latempa, Craig A GrimesAbstract:Single-crystal one-dimensional (1D) semiconductor architectures are important in materials-based applications requiring a large surface area, morphological control, and superior charge transport. Titania has widespread utility in applications including photocatalysis, photochromism, photovoltaics, and gas sensors. While considerable efforts have focused on the preparation of 1D TiO2, no methods have been available to grow crystalline nanowire arrays directly onto Transparent Conducting Oxide (TCO) substrates, greatly limiting the performance of TiO2 photoelectrochemical devices. Herein, we present a straightforward low temperature method to prepare single crystal rutile TiO2 nanowire arrays up to 5 μm long on TCO glass via a non-polar solvent/hydrophilic substrate interfacial reaction under mild hydrothermal conditions. The as-prepared densely packed nanowires grow vertically oriented from the TCO glass substrate along the (110) crystal plane with a preferred (001) orientation. In a dye sensitized solar c...
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vertically aligned single crystal tio2 nanowire arrays grown directly on Transparent Conducting Oxide coated glass synthesis details and applications
Nano Letters, 2008Co-Authors: Xinjian Feng, Oomman K Varghese, Maggie Paulose, Karthik Shankar, Thomas J Latempa, Craig A GrimesAbstract:Single-crystal one-dimensional (1D) semiconductor architectures are important in materials-based applications requiring a large surface area, morphological control, and superior charge transport. Titania has widespread utility in applications including photocatalysis, photochromism, photovoltaics, and gas sensors. While considerable efforts have focused on the preparation of 1D TiO2, no methods have been available to grow crystalline nanowire arrays directly onto Transparent Conducting Oxide (TCO) substrates, greatly limiting the performance of TiO2 photoelectrochemical devices. Herein, we present a straightforward low temperature method to prepare single crystal rutile TiO2 nanowire arrays up to 5 microm long on TCO glass via a non-polar solvent/hydrophilic substrate interfacial reaction under mild hydrothermal conditions. The as-prepared densely packed nanowires grow vertically oriented from the TCO glass substrate along the (110) crystal plane with a preferred (001) orientation. In a dye sensitized solar cell, N719 dye, using TiO2 nanowire arrays 2-3 microm long we achieve an AM 1.5 photoconversion efficiency of 5.02%.
Tadatsugu Minami - One of the best experts on this subject based on the ideXlab platform.
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present status of Transparent Conducting Oxide thin film development for indium tin Oxide ito substitutes
Thin Solid Films, 2008Co-Authors: Tadatsugu MinamiAbstract:Abstract This paper describes the present status and prospects for further development of Transparent Conducting Oxide materials for use as Indium-Tin-Oxide (ITO) substitutes in the thin-film Transparent electrodes of liquid crystal displays (LCDs), currently the largest use of ITO, and, thus, of indium. The best substitute material for the ITO Transparent electrodes used in LCDs is impurity-doped ZnO, e.g., Al- and Ga-doped ZnO (AZO and GZO). From resource and environmental points of view, AZO is the best candidate. The most important problems associated with substituting impurity-doped ZnO for the ITO used in LCDs have already been resolved in laboratory trials. Under the present circumstances, (rf and dc)-magnetron sputtering (rf + dc-MS) deposition, both with and without H 2 gas introduction, has been found to be the best deposition method to prepare impurity-doped ZnO thin films for practical use; AZO thin films with a resistivity on the order of 10 − 4 Ω cm were prepared on glass substrates with an approximately uniform resistivity spatial distribution and a thickness above 100 nm. In order to improve the resistivity stability, AZO and GZO thin films co-doped with another impurity have been newly developed. A 50 nm-thick V-co-doped AZO (AZO:V) thin film was stable enough to be acceptable for use in practical Transparent electrode applications. However, it seems likely that obtaining a stability comparable to that of ITO using impurity-doped ZnO will be difficult for thin films with a thickness below approximately 30 nm.
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substitution of Transparent Conducting Oxide thin films for indium tin Oxide Transparent electrode applications
Thin Solid Films, 2008Co-Authors: Tadatsugu MinamiAbstract:Abstract The present status and prospects for further development of reduced or indium-free Transparent Conducting Oxide (TCO) materials for use in practical thin-film Transparent electrode applications such as liquid crystal displays are presented in this paper: reduced-indium TCO materials such as ZnO-In 2 O 3 , In 2 O 3 -SnO 2 and Zn-In-Sn-O multicomponent Oxides and indium-free materials such as Al- and Ga-doped ZnO (AZO and GZO). In particular, AZO thin films, with source materials that are inexpensive and non-toxic, are the best candidates. The current problems associated with substituting AZO or GZO for ITO, besides their stability in oxidizing environments as well as the non-uniform distribution of resistivity resulting from dc magnetron sputtering deposition, can be resolved. Current developments associated with overcoming the remaining problems are also presented: newly developed AZO thin-film deposition techniques that reduce resistivity as well as improve the resistivity distribution uniformity using high-rate dc magnetron sputtering depositions incorporating radio frequency power. In addition, stability tests of resistivity in TCO thin films evaluated in air at 90% relative humidity and 60 °C have demonstrated that sufficiently moisture-resistant AZO thin films can be produced at a substrate temperature below 200 °C when the film thickness was approximately 200 nm. However, improving the stability of AZO and GZO films with a thickness below 100 nm remains a problem.
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Transparent Conducting Oxide semiconductors for Transparent electrodes
Semiconductor Science and Technology, 2005Co-Authors: Tadatsugu MinamiAbstract:The present status and prospects for further development of polycrystalline or amorphous Transparent Conducting Oxide (TCO) semiconductors used for practical thin-film Transparent electrode applications are presented in this paper. The important TCO semiconductors are impurity-doped ZnO, In2O3 and SnO2 as well as multicomponent Oxides consisting of combinations of ZnO, In2O3 and SnO2, including some ternary compounds existing in their systems. Development of these and other TCO semiconductors is important because the expanding need for Transparent electrodes for optoelectronic device applications is jeopardizing the availability of indium-tin-Oxide (ITO), whose main constituent, indium, is a very expensive and scarce material. Al- and Ga-doped ZnO (AZO and GZO) semiconductors are promising as alternatives to ITO for thin-film Transparent electrode applications. In particular, AZO thin films, with a low resistivity of the order of 10−5 Ω cm and source materials that are inexpensive and non-toxic, are the best candidates. However, further development of the deposition techniques, such as magnetron sputtering or vacuum arc plasma evaporation, as well as of the targets is required to enable the preparation of AZO and GZO films on large area substrates with a high deposition rate.
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high rate deposition of Transparent Conducting Oxide thin films by vacuum arc plasma evaporation
Thin Solid Films, 2002Co-Authors: Tadatsugu Minami, Satoshi Ida, Toshihiro MiyataAbstract:Transparent Conducting Oxide (TCO) thin films have been deposited at a high rate above 370 nm/min by vacuum arc plasma evaporation (VAPE) using sintered Oxide fragments as the source material. It was found that the deposition rate of TCO films was strongly dependent on the deposition pressure, whereas the obtained electrical properties were relatively independent of the pressure. Resistivities of 5.6×10−4 and 2.3×10−4 Ω·cm and an average transmittance above 80% (with substrate included) in the visible range were obtained in Ga-doped ZnO (GZO) thin films deposited at 100 and 350 °C, respectively. In addition, a resistivity as low as 1.4×10−4 Ω·cm and an average transmittance above 80% were also obtained in indium-tin-Oxide (ITO) films deposited at 300 °C. The deposited TCO films exhibited uniform distributions of resistivity and thickness on large area substrates.
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high sensitivity chlorine gas sensors using multicomponent Transparent Conducting Oxide thin films
Sensors and Actuators B-chemical, 2000Co-Authors: Toshihiro Miyata, Tomohiro Hikosaka, Tadatsugu MinamiAbstract:Abstract Newly developed semiconductor thin-film gas sensors with a high sensitivity for chlorine (Cl2) gas using multicomponent Transparent Conducting Oxide (TCO) thin films such as MgO–In2O3, ZnO–In2O3 and Zn2In2O5–MgIn2O4 are described. The multicomponent Oxide thin-film gas sensors used in this work exhibited an increase in resistance with exposure to Cl2 gas. The sensitivity of multicomponent TCO thin-film gas sensors could be controlled by altering the chemical composition of the thin-films. The highest sensitivity for Cl2 gas was obtained in sensors using a Zn2In2O5–MgIn2O4 thin film prepared with Zn2In2O5 contents of about 60 mol%; when operated at 300°C in air, they were able to detect Cl2 gas at a minimum concentration of 0.01 ppm. The sensitivity or resistance of these (Zn2In2O5)0.6–(MgIn2O4)0.4 thin-film gas sensors was increased by a factor of about 100 when exposed to Cl2 gas with a concentration of 7 ppm. An increase of resistivity in multicomponent TCO thin-film sensors with exposure to Cl2 gas resulted from a simultaneous decrease of both carrier concentration and Hall mobility. The increase in resistivity is attributed to the trapping of free electrons resulting from Cl2 being adsorbed on grain boundaries and/or the thin film surface, the same as that produced by adsorption of oxygen. The sensitivity and resistance of Zn2In2O5–MgIn2O4 thin-film gas sensors exhibited very stable long-term operation in air containing a high concentration of Cl2 gas.
Xinjian Feng - One of the best experts on this subject based on the ideXlab platform.
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vertically aligned wo3 nanowire arrays grown directly on Transparent Conducting Oxide coated glass synthesis and photoelectrochemical properties
Nano Letters, 2011Co-Authors: Jinzhan Su, Xinjian Feng, Jennifer D Sloppy, Craig A GrimesAbstract:Photocorrosion stable WO(3) nanowire arrays are synthesized by a solvothermal technique on fluorine-doped tin Oxide coated glass. WO(3) morphologies of hexagonal and monoclinic structure, ranging from nanowire to nanoflake arrays, are tailored by adjusting solution composition with growth along the (001) direction. Photoelectrochemical measurements of illustrative films show incident photon-to-current conversion efficiencies higher than 60% at 400 nm with a photocurrent of 1.43 mA/cm(2) under AM 1.5G illumination. Our solvothermal film growth technique offers an exciting opportunity for growth of one-dimensional metal Oxide nanostructures with practical application in photoelectrochemical energy conversion.
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vertically aligned single crystal tio2 nanowire arrays grown directly on Transparent Conducting Oxide coated glass synthesis details and applications
Nano Letters, 2008Co-Authors: Xinjian Feng, Oomman K Varghese, Maggie Paulose, Karthik Shankar, Thomas J Latempa, Craig A GrimesAbstract:Single-crystal one-dimensional (1D) semiconductor architectures are important in materials-based applications requiring a large surface area, morphological control, and superior charge transport. Titania has widespread utility in applications including photocatalysis, photochromism, photovoltaics, and gas sensors. While considerable efforts have focused on the preparation of 1D TiO2, no methods have been available to grow crystalline nanowire arrays directly onto Transparent Conducting Oxide (TCO) substrates, greatly limiting the performance of TiO2 photoelectrochemical devices. Herein, we present a straightforward low temperature method to prepare single crystal rutile TiO2 nanowire arrays up to 5 μm long on TCO glass via a non-polar solvent/hydrophilic substrate interfacial reaction under mild hydrothermal conditions. The as-prepared densely packed nanowires grow vertically oriented from the TCO glass substrate along the (110) crystal plane with a preferred (001) orientation. In a dye sensitized solar c...
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vertically aligned single crystal tio2 nanowire arrays grown directly on Transparent Conducting Oxide coated glass synthesis details and applications
Nano Letters, 2008Co-Authors: Xinjian Feng, Oomman K Varghese, Maggie Paulose, Karthik Shankar, Thomas J Latempa, Craig A GrimesAbstract:Single-crystal one-dimensional (1D) semiconductor architectures are important in materials-based applications requiring a large surface area, morphological control, and superior charge transport. Titania has widespread utility in applications including photocatalysis, photochromism, photovoltaics, and gas sensors. While considerable efforts have focused on the preparation of 1D TiO2, no methods have been available to grow crystalline nanowire arrays directly onto Transparent Conducting Oxide (TCO) substrates, greatly limiting the performance of TiO2 photoelectrochemical devices. Herein, we present a straightforward low temperature method to prepare single crystal rutile TiO2 nanowire arrays up to 5 microm long on TCO glass via a non-polar solvent/hydrophilic substrate interfacial reaction under mild hydrothermal conditions. The as-prepared densely packed nanowires grow vertically oriented from the TCO glass substrate along the (110) crystal plane with a preferred (001) orientation. In a dye sensitized solar cell, N719 dye, using TiO2 nanowire arrays 2-3 microm long we achieve an AM 1.5 photoconversion efficiency of 5.02%.
Oomman K Varghese - One of the best experts on this subject based on the ideXlab platform.
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long vertically aligned titania nanotubes on Transparent Conducting Oxide for highly efficient solar cells
Nature Nanotechnology, 2009Co-Authors: Oomman K Varghese, Maggie Paulose, Craig A GrimesAbstract:Dye-sensitized solar cells consist of a random network of titania nanoparticles that serve both as a high-surface-area support for dye molecules and as an electron-transporting medium. Despite achieving high power conversion efficiencies, their performance is limited by electron trapping in the nanoparticle film. Electron diffusion lengths can be increased by transporting charge through highly ordered nanostructures such as titania nanotube arrays. Although titania nanotube array films have been shown to enhance the efficiencies of both charge collection and light harvesting, it has not been possible to grow them on Transparent Conducting Oxide glass with the lengths needed for high-efficiency device applications (tens of micrometres). Here, we report the fabrication of Transparent titania nanotube array films on Transparent Conducting Oxide glass with lengths between 0.3 and 33.0 µm using a novel electrochemistry approach. Dye-sensitized solar cells containing these arrays yielded a power conversion efficiency of 6.9%. The incident photon-to-current conversion efficiency ranged from 70 to 80% for wavelengths between 450 and 650 nm. Transparent films of titania nanotubes up to 30-μm long are fabricated on Transparent Conducting Oxide glass, and used to make dye-sensitized solar cells.
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vertically aligned single crystal tio2 nanowire arrays grown directly on Transparent Conducting Oxide coated glass synthesis details and applications
Nano Letters, 2008Co-Authors: Xinjian Feng, Oomman K Varghese, Maggie Paulose, Karthik Shankar, Thomas J Latempa, Craig A GrimesAbstract:Single-crystal one-dimensional (1D) semiconductor architectures are important in materials-based applications requiring a large surface area, morphological control, and superior charge transport. Titania has widespread utility in applications including photocatalysis, photochromism, photovoltaics, and gas sensors. While considerable efforts have focused on the preparation of 1D TiO2, no methods have been available to grow crystalline nanowire arrays directly onto Transparent Conducting Oxide (TCO) substrates, greatly limiting the performance of TiO2 photoelectrochemical devices. Herein, we present a straightforward low temperature method to prepare single crystal rutile TiO2 nanowire arrays up to 5 μm long on TCO glass via a non-polar solvent/hydrophilic substrate interfacial reaction under mild hydrothermal conditions. The as-prepared densely packed nanowires grow vertically oriented from the TCO glass substrate along the (110) crystal plane with a preferred (001) orientation. In a dye sensitized solar c...
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vertically aligned single crystal tio2 nanowire arrays grown directly on Transparent Conducting Oxide coated glass synthesis details and applications
Nano Letters, 2008Co-Authors: Xinjian Feng, Oomman K Varghese, Maggie Paulose, Karthik Shankar, Thomas J Latempa, Craig A GrimesAbstract:Single-crystal one-dimensional (1D) semiconductor architectures are important in materials-based applications requiring a large surface area, morphological control, and superior charge transport. Titania has widespread utility in applications including photocatalysis, photochromism, photovoltaics, and gas sensors. While considerable efforts have focused on the preparation of 1D TiO2, no methods have been available to grow crystalline nanowire arrays directly onto Transparent Conducting Oxide (TCO) substrates, greatly limiting the performance of TiO2 photoelectrochemical devices. Herein, we present a straightforward low temperature method to prepare single crystal rutile TiO2 nanowire arrays up to 5 microm long on TCO glass via a non-polar solvent/hydrophilic substrate interfacial reaction under mild hydrothermal conditions. The as-prepared densely packed nanowires grow vertically oriented from the TCO glass substrate along the (110) crystal plane with a preferred (001) orientation. In a dye sensitized solar cell, N719 dye, using TiO2 nanowire arrays 2-3 microm long we achieve an AM 1.5 photoconversion efficiency of 5.02%.
Maggie Paulose - One of the best experts on this subject based on the ideXlab platform.
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long vertically aligned titania nanotubes on Transparent Conducting Oxide for highly efficient solar cells
Nature Nanotechnology, 2009Co-Authors: Oomman K Varghese, Maggie Paulose, Craig A GrimesAbstract:Dye-sensitized solar cells consist of a random network of titania nanoparticles that serve both as a high-surface-area support for dye molecules and as an electron-transporting medium. Despite achieving high power conversion efficiencies, their performance is limited by electron trapping in the nanoparticle film. Electron diffusion lengths can be increased by transporting charge through highly ordered nanostructures such as titania nanotube arrays. Although titania nanotube array films have been shown to enhance the efficiencies of both charge collection and light harvesting, it has not been possible to grow them on Transparent Conducting Oxide glass with the lengths needed for high-efficiency device applications (tens of micrometres). Here, we report the fabrication of Transparent titania nanotube array films on Transparent Conducting Oxide glass with lengths between 0.3 and 33.0 µm using a novel electrochemistry approach. Dye-sensitized solar cells containing these arrays yielded a power conversion efficiency of 6.9%. The incident photon-to-current conversion efficiency ranged from 70 to 80% for wavelengths between 450 and 650 nm. Transparent films of titania nanotubes up to 30-μm long are fabricated on Transparent Conducting Oxide glass, and used to make dye-sensitized solar cells.
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vertically aligned single crystal tio2 nanowire arrays grown directly on Transparent Conducting Oxide coated glass synthesis details and applications
Nano Letters, 2008Co-Authors: Xinjian Feng, Oomman K Varghese, Maggie Paulose, Karthik Shankar, Thomas J Latempa, Craig A GrimesAbstract:Single-crystal one-dimensional (1D) semiconductor architectures are important in materials-based applications requiring a large surface area, morphological control, and superior charge transport. Titania has widespread utility in applications including photocatalysis, photochromism, photovoltaics, and gas sensors. While considerable efforts have focused on the preparation of 1D TiO2, no methods have been available to grow crystalline nanowire arrays directly onto Transparent Conducting Oxide (TCO) substrates, greatly limiting the performance of TiO2 photoelectrochemical devices. Herein, we present a straightforward low temperature method to prepare single crystal rutile TiO2 nanowire arrays up to 5 μm long on TCO glass via a non-polar solvent/hydrophilic substrate interfacial reaction under mild hydrothermal conditions. The as-prepared densely packed nanowires grow vertically oriented from the TCO glass substrate along the (110) crystal plane with a preferred (001) orientation. In a dye sensitized solar c...
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vertically aligned single crystal tio2 nanowire arrays grown directly on Transparent Conducting Oxide coated glass synthesis details and applications
Nano Letters, 2008Co-Authors: Xinjian Feng, Oomman K Varghese, Maggie Paulose, Karthik Shankar, Thomas J Latempa, Craig A GrimesAbstract:Single-crystal one-dimensional (1D) semiconductor architectures are important in materials-based applications requiring a large surface area, morphological control, and superior charge transport. Titania has widespread utility in applications including photocatalysis, photochromism, photovoltaics, and gas sensors. While considerable efforts have focused on the preparation of 1D TiO2, no methods have been available to grow crystalline nanowire arrays directly onto Transparent Conducting Oxide (TCO) substrates, greatly limiting the performance of TiO2 photoelectrochemical devices. Herein, we present a straightforward low temperature method to prepare single crystal rutile TiO2 nanowire arrays up to 5 microm long on TCO glass via a non-polar solvent/hydrophilic substrate interfacial reaction under mild hydrothermal conditions. The as-prepared densely packed nanowires grow vertically oriented from the TCO glass substrate along the (110) crystal plane with a preferred (001) orientation. In a dye sensitized solar cell, N719 dye, using TiO2 nanowire arrays 2-3 microm long we achieve an AM 1.5 photoconversion efficiency of 5.02%.
