A thermodynamic model for determining pressure and temperature effects on the bandgap energies and other properties of some semiconductors

Ünlü, Hilmi

doi:10.1016/0038-1101(92)90170-h

Cited by 91 publications

(24 citation statements)

References 13 publications

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“…Consequently, it seems that different band gap values for the prepared BiOBr nanostructures is attributed to their different shape and sizes. It is also proved that morphology, size and defects, the proportions of constituents of the semiconductor, i.e., Bi, O and X, affect the band gap and, hence, the photocatalytic performance [27,50,59,60]. Therefore, the photocatalytic activities of A15, A30 and A60 toward RhB photodegradation were studied to ascertain the important factors that influence the photocatalytic performance.…”

Section: Resultsmentioning

confidence: 99%

Solid state preparation and photocatalytic activity of bismuth oxybromide nanoplates

et al. 2015

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A mechanochemical method was applied to prepare bismuth oxybromide (BiOBr) nanoplates using bismuth nitrate pentahydrate and potassium bromide for 15 (A15), 30 (A30) and 60 (A60) minutes. Scanning electron microscopy studies showed that all the products were comprised of nanoplates. Aggregated nanoplates along with microblocks were observed for A15 and A30 and the entire morphology was not homogenous. The morphology of A60 was uniform and consisted of thin and isolated nanoplates. Evaluation of the X-ray diffraction patterns showed that the purity and crystallinity of the products improved by increasing the milling time. The energy dispersive X-ray analysis confirmed the high purity of the products. Fourier transform infrared spectroscopy, photoluminescence spectroscopy and nitrogen adsorption-desorption analysis using the Brunauer-Emmett-Teller technique were also used to study the products. Diffuse reflectance spectroscopy studies clarified that all the samples were indirect band gap semiconductors with the band gap of 3.25 eV for A15 and the narrow band gap of 2.74 eV for A30 and A60. Photocatalytic studies revealed that A30 has the highest photocatalytic activity among the products. The effect of oxygen vacancies, surface defects, morphology and band gap of products on the photocatalytic or photosensitized degradation of rhodamine B (RhB) and pentachlorophenol (PCP) aqueous solutions were studied.

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Section: Resultsmentioning

confidence: 99%

Solid state preparation and photocatalytic activity of bismuth oxybromide nanoplates

et al. 2015

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“…For instance, when the size of substances decreases, as a consequence of phonon confinement effects, a decrease or increase in the band gap energies of the nanostructured materials will be examined [23,49]. To investigate the effect of these factors exactly, the photocatalytic activities of B15, B30, and B60 in photodegradation of RhB were evaluated.…”

Section: Resultsmentioning

confidence: 99%

Mechanochemically prepared BiOCl nanoplates for removal of rhodamine B and pentachlorophenol

et al. 2015

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BiOCl was synthesized using bismuth nitrate pentahydrate and sodium chloride via ball milling for 15 (B15), 30 (B30), and 60 (B60) min. Scanning electron microscopy studies revealed the isolated nanoplate morphology for B15, an aggregated structure composed of nanoplates for B30, and a special three-dimensional morphology for B60. The X-ray diffraction patterns showed the purity and crystallinity of the products improved by increasing the milling time. Fourier transform infrared spectroscopy, photoluminescence spectroscopy, and nitrogen adsorption-desorption analysis using the BrunauerEmmett-Teller technique were also used to study the products. Diffuse reflectance spectroscopy studies revealed the band gap value of 3.27 eV for B30, B60 and a narrow band gap of 2.77 eV for B15. Photocatalytic studies toward rhodamine B degradation confirmed that the narrow band gap B15 was a stable and recyclable photocatalyst with the highest activity among the products. The effects of factors such as oxygen vacancies, surface defects, morphology, and band gap of products on the photocatalytic activities were studied. Comparison of rhodamine B and pentachlorophenol photodegradation processes revealed that both direct and indirect (dye-photosensitized) photocatalytic pathways could influence the removal results. Graphical abstract

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“…Lattice vibrations and volume change with temperature, strain and pressure, will alter the conduction and valence offsets, which can be obtained by using the Gibbs equilibrium condition for the formation of free electrons and holes in intrinsic semiconductors [7]:…”

Section: Introductionmentioning

confidence: 99%

“…The conduction and valence band energies, defined as the standard state chemical potentials, at any temperature and pressure can be written as [7] The conduction and valence band energies, defined as the standard state chemical potentials, at any temperature and pressure can be written as [7] …”

Section: Introductionmentioning

confidence: 99%

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Tight Binding Modeling of Heterojunction Band Offsets as a Function of Pressure and Composition

2001

phys. stat. sol. (b)

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A thermodynamic model for determining pressure and temperature effects on the bandgap energies and other properties of some semiconductors

Cited by 91 publications

References 13 publications

Solid state preparation and photocatalytic activity of bismuth oxybromide nanoplates

Solid state preparation and photocatalytic activity of bismuth oxybromide nanoplates

Mechanochemically prepared BiOCl nanoplates for removal of rhodamine B and pentachlorophenol

Tight Binding Modeling of Heterojunction Band Offsets as a Function of Pressure and Composition

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