Optical Properties of β-Bi2O3 Thin Films

George, Jino; Pradeep, B.; Joseph, K. S.

doi:10.1002/pssa.2211030234

Cited by 18 publications

(8 citation statements)

References 20 publications

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“…The direct energy gaps of the four samples are in accordance with George's report [26] but narrower than the β-Bi 2 O 3 nanowires reported [12]. Figure 4 indicates that the band gap decreases with increasing film thickness.…”

Section: Uv-visible Absorbance Spectrasupporting

confidence: 86%

Enhanced photocatalytic performance: a β-Bi₂O₃ thin film by nanoporous surface

Yang¹,

Lian²,

Shang-Jun³

et al. 2012

J. Phys. D: Appl. Phys.

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Beta-Bi 2 O 3 film photoanodes with different surface structures were prepared by oxidizing bismuth films. The physical properties were characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM), UV-visible absorbance spectra and atomic force microscopy (AFM). XRD shows that all films are beta phase crystal structure except the thinnest 12 nm film. SEM and AFM characterizations indicate that a nanoporous surface structure is generated on the surface after the film is annealed for 3 h, while the films annealed for 1 h show a dense surface. The direct band gaps vary from 2.63 to 2.88 eV, with the film thickness decreasing from 500 to 12 nm. The nanoporous surface structure film exhibits better light harvesting ability and incident photon-to-electron conversion efficiency (IPCE) than the dense surface films. The IPCE (61% at 350 nm and 43% at 400 nm, 0.197 V NHE ) is the highest ever reported. The photocurrent density reaches 0.45 mA cm −2 when illuminated with a bias of 1.23 V NHE in 0.5M Na 2 SO 3 .

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Section: Uv-visible Absorbance Spectrasupporting

confidence: 86%

Enhanced photocatalytic performance: a β-Bi₂O₃ thin film by nanoporous surface

Yang¹,

Lian²,

Shang-Jun³

et al. 2012

J. Phys. D: Appl. Phys.

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“…Figure 4 shows the experimental pressure dependence of the indirect bandgap energy in β-Bi 2 O 3 upon increasing (solid symbols) and decreasing (open symbols) pressure, as obtained from the extrapolation noted in the previous paragraph. Our estimated indirect bandgap is around 2.12(1) eV at room pressure, which is a value in between those given in the literature (between 1.75 and 2.6 eV) [45][46][47]. Note that ab initio-calculated bandgaps obtained within the DFT approximation are considerably underestimated, although the pressure dependence of the bandgap is well described [49].…”

Section: A Optical Absorption Measurementssupporting

confidence: 76%

“…The optical absorption edge of β-Bi 2 O 3 at room temperature and pressure has been measured in several works; however, there is no clear conclusion about the value of the indirect and direct bandgaps reported between 1.75 and 2.6 eV [45][46][47]. For this reason, we have calculated the electronic band structure and electronic DOS of β-Bi 2 O 3 at room pressure [see Fig.…”

Section: A Optical Absorption Measurementsmentioning

confidence: 99%

β−Bi2O3under compression: Optical and elastic properties and electron density topology analysis

et al. 2016

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We report a joint experimental and theoretical study of the optical properties of tetragonal bismuth oxide (β-Bi 2 O 3 ) at high pressure by means of optical absorption measurements combined with ab initio electronic band structure calculations. Our results are consistent with previous results that show the presence of a second-order isostructural phase transition in Bi 2 O 3 (from β to β ) around 2 GPa and a phase transition above 15 GPa combined with a pressure-induced amorphization above 17-20 GPa. In order to further understand the pressure-induced phase transitions and amorphization occurring in β-Bi 2 O 3 , we theoretically studied the mechanical and dynamical stability of the tetragonal structures of β-and β -Bi 2 O 3 at high pressure through calculations of their elastic constants, elastic stiffness coefficients, and phonon dispersion curves. The pressure dependence of the elastic stiffness coefficients and phonon dispersion curves confirms that the isostructural phase transition near 2 GPa is of ferroelastic nature. Furthermore, a topological study of the electron density shows that the ferroelastic transition is not caused by a change in number of critical points (cusp catastrophe), but by the equalization of the electron densities of both independent O atoms in the unit cell due to a local rise in symmetry. Finally, from theoretical simulations, β -Bi 2 O 3 is found to be mechanically and dynamically stable at least up to 26.7 GPa under hydrostatic conditions; thus, the pressure-induced amorphization reported above 17-20 GPa in powder β -Bi 2 O 3 using methanol-ethanol-water as pressure-transmitting medium could be related to the frustration of a reconstructive phase transition at room temperature and the presence of mechanical or dynamical instabilities under nonhydrostatic conditions.

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“…[23] Calculations involving the 32 oxygen atoms exclusively taken from the inner core of the oxido cluster 1 a result in a weighted root mean square deviation of 0. [21,24] and 2.60 eV, [25] respectively, were reported.…”

Section: Resultsmentioning

confidence: 94%

Hydrolysis of a Basic Bismuth Nitrate—Formation and Stability of Novel Bismuth Oxido Clusters

Miersch

Schlesinger

Troff

et al. 2011

Chemistry A European J

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The synthesis of the nanoscaled bismuth oxido clusters [Bi(38)O(45)(NO(3))(20)(DMSO)(28)](NO(3))(4)·4DMSO (1a) and [Bi(38)O(45)(OH)(2)(pTsO)(8)(NO(3))(12)(DMSO)(24)](NO(3))(2)·4DMSO·2H(2)O (2) starting from the basic bismuth nitrate [Bi(6)O(4)(OH)(4)](NO(3))(6)·H(2)O is reported herein. Single-crystal X-ray diffraction analysis, ESI mass spectrometry, thermogravimetric analysis, and molecular dynamics simulation were used to study the formation, structure, and stability of these large metal oxido clusters. Compounds 1a and 2 are based on a [Bi(38)O(45)](24+) core, which is structurally related to δ-Bi(2)O(3). Examination of the fragmentation pathways of 1a and 2 by infrared multi-photon dissociation (IRMPD) tandem MS experiments allows the identification of novel bismuth oxido cluster species in the gas phase.

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Optical Properties of β-Bi2O3 Thin Films

Cited by 18 publications

References 20 publications

Enhanced photocatalytic performance: a β-Bi₂O₃ thin film by nanoporous surface

Enhanced photocatalytic performance: a β-Bi₂O₃ thin film by nanoporous surface

β−Bi2O3under compression: Optical and elastic properties and electron density topology analysis

Hydrolysis of a Basic Bismuth Nitrate—Formation and Stability of Novel Bismuth Oxido Clusters

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Optical Properties of β-Bi2O3 Thin Films

Cited by 18 publications

References 20 publications

Enhanced photocatalytic performance: a β-Bi2O3 thin film by nanoporous surface

Enhanced photocatalytic performance: a β-Bi2O3 thin film by nanoporous surface

β−Bi2O3under compression: Optical and elastic properties and electron density topology analysis

Hydrolysis of a Basic Bismuth Nitrate—Formation and Stability of Novel Bismuth Oxido Clusters

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Product

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Enhanced photocatalytic performance: a β-Bi₂O₃ thin film by nanoporous surface

Enhanced photocatalytic performance: a β-Bi₂O₃ thin film by nanoporous surface