Large-diameter light-scattering complex multipodal nanotubes with graded refractive index: insights into their formation mechanism and photoelectrochemical performance

Omar, Mostafa M.; Fawzy, Samar M.; El-Shabasy, Adel B.; Allam, Nageh K.

doi:10.1039/c7ta08730f

Cited by 15 publications

(14 citation statements)

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“…Meanwhile, multipodal shape provides a graded refractive index, large Please do not adjust margins Please do not adjust margins surface, and easier charge separation at the core-leg interface enabling to volume ratio and higher scattering. 60 In contrast, the long diameter of the compact nanotube (over 170 nm) can act as a subwavelength structure that scatters light in Rayleigh fashion as reported before. 60 That is furthered proved by measuring the electrochemical Impedance spectroscopy (EIS) under light for TiO 2 NTs and TiON x NTs.…”

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confidence: 78%

“…60 In contrast, the long diameter of the compact nanotube (over 170 nm) can act as a subwavelength structure that scatters light in Rayleigh fashion as reported before. 60 That is furthered proved by measuring the electrochemical Impedance spectroscopy (EIS) under light for TiO 2 NTs and TiON x NTs. The equivalent circuit (E.C.)…”

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confidence: 78%

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Tailoring the defects of sub-100 nm multipodal titanium nitride/oxynitride nanotubes for efficient water splitting performance

2021

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confidence: 78%

Section: Please Do Not Adjust Marginsmentioning

confidence: 78%

Tailoring the defects of sub-100 nm multipodal titanium nitride/oxynitride nanotubes for efficient water splitting performance

2021

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“…In addition, resonances disrupt the dispersion parameters. Moreover, we have previously shown that fabricated multipodal nanotubes (tubes with more than one leg) as well as structures of similar tapered-like geometry possess graded refractive index 27 – 30 . All these reasons explain the slight discrepancy in the resonance frequencies calculated from the averaged s-parameters, as well as the artefacts present in the imaginary parts of ε and µ.…”

Section: Resultsmentioning

confidence: 99%

“…It is important to discuss the fabrication feasibility at this point. We have previously fabricated bipodal and even multipodal nanotubes from an alloy of Titanium–Niobium–Zirconium via facile electrochemical anodization 27 , 28 . Mohammadpour et al as well as Naduvath et al have fabricated multipodal nanotubes of Titanium Dioxide through anodization as well 31 , 32 .…”

Section: Resultsmentioning

confidence: 99%

Novel silicon bipodal cylinders with controlled resonances and their use as beam steering metasurfaces

Fawzy

Mahmoud

Ismail

et al. 2021

Sci Rep

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Metasurfaces have paved the way for high performance wavefront shaping and beam steering applications. Phase-gradient metasurfaces (PGM) are of high importance owing to the powerful and relatively systematic tool they offer for manipulating electromagnetic wave fronts and achieving various functionalities. Herein, we numerically present a novel unit cell known as bipodal cylinders (BPC), made of Silicon (Si) and placed on a Silicon dioxide (SiO2) substrate to be compatible with CMOS fabrication techniques and to avoid field leakage into a high index substrate. Owing to its geometrical structure, the BPC structure provides a promising unit cell for electromagnetic wave manipulation. We show that BPC offers a way to shift the electric dipole mode to a frequency higher than that of the magnetic dipole mode. We investigate the effect of varying different geometrical parameters on the performance of such unit cell. Building on that, a metasurface is then presented that can achieve efficient electromagnetic beam steering with high transmission of 0.84 and steering angle of 15.2°; with very good agreement with the theoretically predicted angle covering the whole phase range from 0 to 2$$\pi$$ π .

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“…Based on the anodization approach, a series of nanotube arrays, including binary, ternary, and multinary metal oxides, have been successfully fabricated. Most of these materials are important photoelectrodes in PEC devices, [70,73] [74,75] In 2001, Grimes' group reported the preparation of vertically oriented, highly ordered TiO 2 nanotube arrays up to 500 nm long on Ti foil using an aqueous electrolyte containing hydrofluoric acid (HF). [76] This method is the typical synthesis pathway for the so-called first generation of TiO 2 nanotube arrays, but the length of the resulting nanotubes is severely limited because of the rapid dissolution of TiO 2 in HF.…”

Section: Preparationmentioning

confidence: 99%

Rational Design of Photoelectrodes with Rapid Charge Transport for Photoelectrochemical Applications

Sheng

Feng

2019

Advanced Materials

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Photoelectrode materials are the heart of photoelectrochemical (PEC) cells, which hold great promise to address global energy and environmental issues by converting solar energy into electricity or chemical fuels. In recent decades, significant research efforts have been devoted to the design and construction of photoelectrodes for the efficient generation and utilization of charge carriers to boost PEC performance. This review presents insights from a literature study on the relationship between the architecture and charge dynamics of photoelectrodes. After briefly introducing the fundamental theories of charge dynamics in nanostructured photoelectrodes, the development of photoelectrode design in one-dimensional (1D) polycrystalline nanotube arrays, 1D single-crystalline nanowire arrays, and 3D hierarchical and mesoporous nanowire arrays is reviewed with a focus on the interplay between architecture and charge transport properties. For each design, commonly used synthetic approaches and the corresponding charge transport properties are summarized, with insights into the relationship between the photoelectrode structure and charge transport properties. Subsequently, the applications of these photoelectrodes in PEC systems is summarized. Finally, this review concludes with future challenges in the rational design of This article is protected by copyright. All rights reserved.3 photoelectrode architecture. The basic relationships between the architectures and charge dynamics of photoelectrode materials summarized in this review are expected to provide pertinent guidance and a reference for future advanced material design targeting improved light energy conversion systems.

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Large-diameter light-scattering complex multipodal nanotubes with graded refractive index: insights into their formation mechanism and photoelectrochemical performance

Abstract: Nanostructuring, morphology tuning, doping, as well as alloying have decisive roles in controlling the performance of functional materials.

Cited by 15 publications

References 86 publications

Tailoring the defects of sub-100 nm multipodal titanium nitride/oxynitride nanotubes for efficient water splitting performance

Tailoring the defects of sub-100 nm multipodal titanium nitride/oxynitride nanotubes for efficient water splitting performance

Novel silicon bipodal cylinders with controlled resonances and their use as beam steering metasurfaces

Rational Design of Photoelectrodes with Rapid Charge Transport for Photoelectrochemical Applications

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