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Search for "bandgap energy" in Full Text gives 69 result(s) in Beilstein Journal of Nanotechnology.

Near-infrared photoactive Ag-Zn-Ga-S-Se quantum dots for high-performance quantum dot-sensitized solar cells

  • Roopakala Kottayi,
  • Ilangovan Veerappan and
  • Ramadasse Sittaramane

Beilstein J. Nanotechnol. 2022, 13, 1337–1344, doi:10.3762/bjnano.13.110

Graphical Abstract
  • spectrum of colloidal AZGSSe QDs (Figure 4a) reveals a wide absorption range in the near-infrared (NIR) region. This confirms the NIR photoactive nature of the synthesized QDs. Figure 4b depicts the Tauc plot [30] of the synthesized QDs. From this, the bandgap energy of AZGSSe QDs was found to be 1.37 eV
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Published 14 Nov 2022

Recent trends in Bi-based nanomaterials: challenges, fabrication, enhancement techniques, and environmental applications

  • Vishal Dutta,
  • Ankush Chauhan,
  • Ritesh Verma,
  • C. Gopalkrishnan and
  • Van-Huy Nguyen

Beilstein J. Nanotechnol. 2022, 13, 1316–1336, doi:10.3762/bjnano.13.109

Graphical Abstract
  • dimensionality, it was projected that there would be a significant confinement effect and enlarged bandgap energy. Additionally, an upshift of the CB and a downshift of the VB were also measured [48][50]. The preparation process can be used to modify the electrical structure of Bi-based semiconductors. Most Bi
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Published 11 Nov 2022

Rapid fabrication of MgO@g-C3N4 heterojunctions for photocatalytic nitric oxide removal

  • Minh-Thuan Pham,
  • Duyen P. H. Tran,
  • Xuan-Thanh Bui and
  • Sheng-Jie You

Beilstein J. Nanotechnol. 2022, 13, 1141–1154, doi:10.3762/bjnano.13.96

Graphical Abstract
  • oxide with wide bandgap (3.5–5 eV), high availability, non-toxicity, low cost, and native structural defects [18][19]. The large bandgap energy is the limitation of MgO, reducing the photocatalytic performance and applicability of MgO [20]. Various efforts have been made to enhance the absorption in the
  • −1), and M is the molecular weight of NO (g·mol−1). The photon flux in the photocatalytic experiment is 2.72·1019 cm−2·min−1, the irradiation area for the 12 cm diameter petri dish is 113.1 cm2. In addition, the bandgap energy of materials was calculated by using the Tauc and the Kubelka–Munk
  • equation as described in Equations 5–7 [43]: where E is the photon energy (eV), h is Planck’s constant (4.132·10−15 eV·s), ν is the photon frequency (s−1), c is the velocity of light (nm·s−1), λ is the wavelength (nm), α is the absorption coefficient, B is a constant, and Eg is the bandgap energy (eV), R
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Published 18 Oct 2022

Green synthesis of zinc oxide nanoparticles toward highly efficient photocatalysis and antibacterial application

  • Vo Thi Thu Nhu,
  • Nguyen Duy Dat,
  • Le-Minh Tam and
  • Nguyen Hoang Phuong

Beilstein J. Nanotechnol. 2022, 13, 1108–1119, doi:10.3762/bjnano.13.94

Graphical Abstract
  • dihydrate and synthesized ZnO NPs with sizes in the range of 9–18 nm. UV–vis DRS spectra of ZnO were shown in Figure 6a. ZnO absorbs light in the ultraviolet region. The bandgap energy of synthesized ZnO was determined by extrapolation of the linear part of the curve (α·hν)2 as a function of photon energy
  • (Figure 6b). The bandgap energy of synthesized ZnO was 3.15 eV, which is close to the bandgap value of 3.2 eV of ZnO shown in a previous report [33]. The zeta potential value displays the surface charge and stability of ZnO NPs. In this study, the zeta potential of ZnO NPs was −19 mV (Figure 7
  • irradiation by visible and UV light, the MO degradation efficiency by ZnO NPs reached 33.56 and 82.78%, respectively. ZnO has a rather high bandgap energy; therefore, the degradation efficiency of organic substances under visible light is not as high as that under UV light. Maddu et al. [34] studied the
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Published 07 Oct 2022

Zinc oxide nanostructures for fluorescence and Raman signal enhancement: a review

  • Ioana Marica,
  • Fran Nekvapil,
  • Maria Ștefan,
  • Cosmin Farcău and
  • Alexandra Falamaș

Beilstein J. Nanotechnol. 2022, 13, 472–490, doi:10.3762/bjnano.13.40

Graphical Abstract
  • their wide bandgap energy (3.3–3.7 eV), strong luminescence [4][5], antibacterial properties, and UV-protection properties. Additionally, ZnO nanomaterials can be designed into various morphologies, such as nanoparticles, nanoneedles, nanorods, nanocages, nanocombs, and nanoflowers [5][6][7][8]. Hybrid
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Published 27 May 2022

Selected properties of AlxZnyO thin films prepared by reactive pulsed magnetron sputtering using a two-element Zn/Al target

  • Witold Posadowski,
  • Artur Wiatrowski,
  • Jarosław Domaradzki and
  • Michał Mazur

Beilstein J. Nanotechnol. 2022, 13, 344–354, doi:10.3762/bjnano.13.29

Graphical Abstract
  • shorter wavelengths, from about 370 to 342 nm (Figure 5b). The measured light transmission characteristics were further used to determine the thickness and the optical bandgap energy of the prepared films. For the analysis, the reverse synthesis method was applied. The analysis allowed for simultaneous
  • distance of about 70 mm from the target axis. Therefore, one can conclude that the area for the substrate placement with favorable conditions for the preparation of transparent and well-conductive films is located outside the radial boundary of the target. The analysis of the optical bandgap energy (Eg) as
  • directly above (on-axis geometry) and outside the target surface (off-axis geometry) area have different electrical and optical properties testified by about nine orders difference of resistivity and about 0.4 eV difference of the optical bandgap energy. Thin films with minimum resistance were obtained on
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Published 31 Mar 2022

Investigation of a memory effect in a Au/(Ti–Cu)Ox-gradient thin film/TiAlV structure

  • Damian Wojcieszak,
  • Jarosław Domaradzki,
  • Michał Mazur,
  • Tomasz Kotwica and
  • Danuta Kaczmarek

Beilstein J. Nanotechnol. 2022, 13, 265–273, doi:10.3762/bjnano.13.21

Graphical Abstract
  • spectrum as marked in Figure 7a; it is 1.20 eV below the Fermi level (EF). Taking into consideration the bandgap energy of the thin films equal to 2.80 eV, the thin film surface exhibits p-type conduction. The electron affinity (χ) of the thin film surface was equal to 2.41 eV and was calculated based on
  • the relationship [51][52]: where hν = 21.22 eV is the He (I) photon energy, W = 16.01 eV is the width of the spectrum, that is, the energy difference between the VBM and the photoemission cutoff energy, and Eg = 2.80 eV is the bandgap energy calculated from the transmission spectrum. The work function
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Published 24 Feb 2022

Tin dioxide nanomaterial-based photocatalysts for nitrogen oxide oxidation: a review

  • Viet Van Pham,
  • Hong-Huy Tran,
  • Thao Kim Truong and
  • Thi Minh Cao

Beilstein J. Nanotechnol. 2022, 13, 96–113, doi:10.3762/bjnano.13.7

Graphical Abstract
  • density showed improved photocatalytic performances. Besides, the OV density contributes to the rise of the valence band maximum and a decrease of the bandgap energy of SnO2 materials. Morphology There are many shapes of SnO2, for example, nanoparticles, nanocubes, nanorods, nanosheets, nanospheres
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Published 21 Jan 2022

A Au/CuNiCoS4/p-Si photodiode: electrical and morphological characterization

  • Adem Koçyiğit,
  • Adem Sarılmaz,
  • Teoman Öztürk,
  • Faruk Ozel and
  • Murat Yıldırım

Beilstein J. Nanotechnol. 2021, 12, 984–994, doi:10.3762/bjnano.12.74

Graphical Abstract
  • reflectance graph) and (b) bandgap energy diagram of CuNiCoS4 nanocrystals. The I–V characteristics as well as RR changes of the Au/CuNiCoS4/p-Si photodiode under different illumination intensities. The values of n and ϕb of the Au/CuNiCoS4/p-Si photodiode as functions of the illumination power density. Rj–V
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Published 02 Sep 2021

Nanoporous and nonporous conjugated donor–acceptor polymer semiconductors for photocatalytic hydrogen production

  • Zhao-Qi Sheng,
  • Yu-Qin Xing,
  • Yan Chen,
  • Guang Zhang,
  • Shi-Yong Liu and
  • Long Chen

Beilstein J. Nanotechnol. 2021, 12, 607–623, doi:10.3762/bjnano.12.50

Graphical Abstract
  • , for example, La, Bi, and Ta, which are often rare, toxic, and expensive [6]. Also, expensive noble metal-based cocatalysts (e.g., Pt) are required to improve the photocatalytic performance. As such, an ideal photocatalyst for water splitting reaction should fit the following criteria: suitable bandgap
  • energy, high stability, wide light-absorption range, and sufficient catalytically active sites [7]. Conjugated polymers (CPs) are one of the most promising alternatives to the traditional inorganic photocatalysts. Their geometries and physical (e.g., chemical and thermal stability and solubility
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Published 30 Jun 2021

Impact of GaAs(100) surface preparation on EQE of AZO/Al2O3/p-GaAs photovoltaic structures

  • Piotr Caban,
  • Rafał Pietruszka,
  • Jarosław Kaszewski,
  • Monika Ożga,
  • Bartłomiej S. Witkowski,
  • Krzysztof Kopalko,
  • Piotr Kuźmiuk,
  • Katarzyna Gwóźdź,
  • Ewa Płaczek-Popko,
  • Krystyna Lawniczak-Jablonska and
  • Marek Godlewski

Beilstein J. Nanotechnol. 2021, 12, 578–592, doi:10.3762/bjnano.12.48

Graphical Abstract
  • ), where α is the energy-dependent absorption coefficient, B is the constant and Eg is the bandgap energy [47]. Within the obtained plot, the relevant area of rapid linear absorbance growth was extrapolated accordingly, pointing the value of 3.23 eV (the crossing point with the abscissa) as the bandgap of
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Published 28 Jun 2021

Boosting of photocatalytic hydrogen evolution via chlorine doping of polymeric carbon nitride

  • Malgorzata Aleksandrzak,
  • Michalina Kijaczko,
  • Wojciech Kukulka,
  • Daria Baranowska,
  • Martyna Baca,
  • Beata Zielinska and
  • Ewa Mijowska

Beilstein J. Nanotechnol. 2021, 12, 473–484, doi:10.3762/bjnano.12.38

Graphical Abstract
  • layers. Although Cl doping did not affect the reduction in the bandgap energy, the transient photocurrent response of Cl-PCN was enhanced compared to pristine PCN, indicating a better transport and separation of the photoinduced charges. It indicates that a higher amount of electrons can migrate to the
  • planes, (ii) a non-reduction in the bandgap energy, (iii) a lower recombination rate of the electron–hole pairs, (iv) improved photogenerated charge transport and separation, and (v) an enhanced reducing ability of the photogenerated electrons. Therefore, it is believed that heteroatom doping of pristine
  • (F7000, Hitachi) with an excitation wavelength of 280 nm. The DRS was performed using a Jasco (Japan) spectrometer. The Kubelka–Munk function was used to calculate the bandgap energy. The photocurrent response and electrochemical impedance spectroscopy were measured using the Autolab PGSTAT302 N
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Published 19 May 2021

Nickel nanoparticle-decorated reduced graphene oxide/WO3 nanocomposite – a promising candidate for gas sensing

  • Ilka Simon,
  • Alexandr Savitsky,
  • Rolf Mülhaupt,
  • Vladimir Pankov and
  • Christoph Janiak

Beilstein J. Nanotechnol. 2021, 12, 343–353, doi:10.3762/bjnano.12.28

Graphical Abstract
  • , formation of heterojunctions, or size reduction [18][19]. Doping of WO3 with nickel improves the humidity sensing compared to neat WO3. Attributed to a greater number of electrons donated by Ni atoms, higher surface area, and smaller bandgap energy, Ni-doped WO3 has a faster response, higher sensitivity
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Published 15 Apr 2021

ZnO and MXenes as electrode materials for supercapacitor devices

  • Ameen Uddin Ammar,
  • Ipek Deniz Yildirim,
  • Feray Bakan and
  • Emre Erdem

Beilstein J. Nanotechnol. 2021, 12, 49–57, doi:10.3762/bjnano.12.4

Graphical Abstract
  • and 3D materials will be of utmost benefit to the interested community. Review ZnO as electrode material for supercapacitors Zinc oxide (ZnO) is a highly defective semiconductor material, regardless of its synthesis route, that has a large bandgap energy (Eg) at room temperature. However, defect types
  • environment of the lattice atoms and defects. With the aid of advanced characterization techniques one may get valuable information on site symmetry, atomic bonding, and, in particular, on the bandgap energy of semiconductors. Raman, photoluminescence (PL), UV–vis, and electron paramagnetic resonance (EPR
  • surface-defect signal, in general, increases when the mean crystallite size is reduced because of the changing surface-to-volume ratio. In contrast, PL spectroscopy is highly sensitive to two kinds of emission. One is due to electron–hole (e–h) recombination, which is related to the bandgap energy [4
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Published 13 Jan 2021

Kondo effects in small-bandgap carbon nanotube quantum dots

  • Patryk Florków,
  • Damian Krychowski and
  • Stanisław Lipiński

Beilstein J. Nanotechnol. 2020, 11, 1873–1890, doi:10.3762/bjnano.11.169

Graphical Abstract
  • Fermi velocity (vF ≅ 0.8c), D is the nanotube diameter, and a is the distance between carbon atoms in the A lattice and the B lattice of graphene (a ≅ 0.254 nm). Eg is the bandgap energy, where Θ is the chiral angle, . According to tight-binding calculations the value of β corresponding to the
  • , C(24,21) (n = 24, m = 21, bandgap energy Eg = 0.46 meV, Figure 1a) with the diagram of a dot in a wide-bandgap nanotube, C(24,22) (bandgap Eg = 125 meV, Figure 1b). The insets present field dependencies of single-electron states, which, according to Equation 3, are linear for wide-bandgap nanotubes
  • exhibiting non-zero spin magnetic moment. Kondo SU(3) resonances have non-zero orbital and spin moments, and in the Kondo SU(4) state both moments are quenched. By changing the value of the bandgap energy by stress, one can move high-symmetry points between different Coulomb valleys. The SU(4) point occurs
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Published 23 Dec 2020

Unravelling the interfacial interaction in mesoporous SiO2@nickel phyllosilicate/TiO2 core–shell nanostructures for photocatalytic activity

  • Bridget K. Mutuma,
  • Xiluva Mathebula,
  • Isaac Nongwe,
  • Bonakele P. Mtolo,
  • Boitumelo J. Matsoso,
  • Rudolph Erasmus,
  • Zikhona Tetana and
  • Neil J. Coville

Beilstein J. Nanotechnol. 2020, 11, 1834–1846, doi:10.3762/bjnano.11.165

Graphical Abstract
  • yielded the mSiO2@NiPS/TiO2 composite. The bandgap energy of mSiO2@NiPS and of mSiO2@NiPS/TiO2 were estimated to be 2.05 and 2.68 eV, respectively, indicating the role of titania in tuning the optoelectronic properties of the SiO2@nickel phyllosilicate. As a proof of concept, the core–shell nanostructures
  • the core–shell nanostructure and yielded superior photocatalytic properties. Keywords: bandgap energy; core–shell; dye degradation; nickel phyllosilicate; photocatalysts; Introduction Textile dyes and organic compounds are major water pollutants, which create an environmental hazard to aquatic
  • brookite phases, the anatase phase has been extensively used for photocatalysis owing to its enhanced surface properties [7][8][9][10]. In a typical photocatalytic process, photons of energy greater than the bandgap energy of TiO2 excite electrons to the conduction band leaving holes in the valence band
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Published 09 Dec 2020

Nanocasting synthesis of BiFeO3 nanoparticles with enhanced visible-light photocatalytic activity

  • Thomas Cadenbach,
  • Maria J. Benitez,
  • A. Lucia Morales,
  • Cesar Costa Vera,
  • Luis Lascano,
  • Francisco Quiroz,
  • Alexis Debut and
  • Karla Vizuete

Beilstein J. Nanotechnol. 2020, 11, 1822–1833, doi:10.3762/bjnano.11.164

Graphical Abstract
  • transformed by a Kubelka–Munk model in order to obtain the bandgap energy value [43]. The absorption spectrum of RhB was measured using a UV–vis spectrophotometer GENESYS 30TM with tungsten-halogen light source and silicon photodiode detector. The spectra were fitted with the Thermo Scientific VISIONlite PC
  • –vis spectra were recorded and then transformed with the Kubelka–Munk method to obtain the bandgap energy. The analysis of the optical measurement reveals that the sample can absorb visible light over a wide range. The bandgap energy of the nanoparticles was then calculated from the tangent line in the
  • plot of the square root of the Kubelka–Munk function vs the photon energy (Tauc plot, Figure 6). The observed bandgap energy of 2.07 eV is considerably smaller than that of bulk BiFeO3 and comparable to those found in the literature for similarly sized particles [6][23][29][53]. However, we would like
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Published 07 Dec 2020

Absorption and photoconductivity spectra of amorphous multilayer structures

  • Oxana Iaseniuc and
  • Mihail Iovu

Beilstein J. Nanotechnol. 2020, 11, 1757–1763, doi:10.3762/bjnano.11.158

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  • ), Ge0.09As0.09Se0.82 (2), As0.40S0.30Se0.30 (3), and the HS As0.40S0.30Se0.30/Ge0.09As0.09Se0.82/Ge0.30As0.04S0.66 (4). The thin film layer Ge0.30As0.04S0.66 with the largest bandgap energy, Eg ≈ 3.0 eV [11], which was placed on the top of the multilayer structure, has a thickness of d ≈ 200 nm and was transparent to
  • the incident visible light to reach the other layers with a bandgap energy of Eg ≈ 2.0 eV [12][13] and with a thicknesses of d ≈ 500 nm for Ge0.09As0.09Se0.82 and d ≈ 1000 nm for As0.40S0.30Se0.30. Figure 2 shows that the amorphous film Ge0.30As0.04S0.66 is highly transparent to incident light in the
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Published 20 Nov 2020

Nonadiabatic superconductivity in a Li-intercalated hexagonal boron nitride bilayer

  • Kamila A. Szewczyk,
  • Izabela A. Domagalska,
  • Artur P. Durajski and
  • Radosław Szczęśniak

Beilstein J. Nanotechnol. 2020, 11, 1178–1189, doi:10.3762/bjnano.11.102

Graphical Abstract
  • graphene/hBN heterojunction devices allowed for the detection of the Hofstadter’s butterfly phenomenon [39][40]. In both layer and bulk form, hBN has a large bandgap energy, which makes it an insulator [13][41]. Therefore, for a long time this material was not associated with superconductivity. The
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Published 07 Aug 2020

Excitonic and electronic transitions in Me–Sb2Se3 structures

  • Nicolae N. Syrbu,
  • Victor V. Zalamai,
  • Ivan G. Stamov and
  • Stepan I. Beril

Beilstein J. Nanotechnol. 2020, 11, 1045–1053, doi:10.3762/bjnano.11.89

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  • * = 2.91m0 and mv3*, mv4* = 3.12m0) were estimated [24]. The bandgap was calculated based on the positions of the ground and excited states of the observed excitons. The well-known formula Eg = Ei + Ry/n2 was used for this calculation, where Eg is the bandgap energy, Ei corresponds to the positions of the
  • ground (n = 1) and excited (n = 2, 3, 4…) states of the exciton, Ry is the exciton binding energy (Rydberg constant) and n = 1, 2, 3 … are the main quantum numbers. First, from the positions of the ground and excited states, the Rydberg constant was calculated. Then the bandgap energy is estimated. In
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Published 16 Jul 2020

A new photodetector structure based on graphene nanomeshes: an ab initio study

  • Babak Sakkaki,
  • Hassan Rasooli Saghai,
  • Ghafar Darvish and
  • Mehdi Khatir

Beilstein J. Nanotechnol. 2020, 11, 1036–1044, doi:10.3762/bjnano.11.88

Graphical Abstract
  • integer). This form of classification is based on the relation between the magnitude of the energy gap and the width of the AGNRs. The quantum confinement effect alters the bandgap energy in these nanostructures, which decreases with the increase of AGNR width (within each group). A comparison of the
  • of the supercell have the same bandgap energy. The neck width is another factor determining the GNMs properties. The atoms at the edge of the holes in these materials have been passivated with hydrogen atoms. The results for the gap size with nitrogen passivation are almost the same. In practice
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Published 15 Jul 2020

Hexagonal boron nitride: a review of the emerging material platform for single-photon sources and the spin–photon interface

  • Stefania Castelletto,
  • Faraz A. Inam,
  • Shin-ichiro Sato and
  • Alberto Boretti

Beilstein J. Nanotechnol. 2020, 11, 740–769, doi:10.3762/bjnano.11.61

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  • indirect bandgaps. Bandgap energy values largely varying from 3.6 eV to 7.1 eV have been reported in the literature [84][85][86]. Theoretical calculations for the h-BN band structure also show significant differences in the eV values. Some density functional theory (DFT) in the local-density-approximation
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Published 08 May 2020

Effect of Ag loading position on the photocatalytic performance of TiO2 nanocolumn arrays

  • Jinghan Xu,
  • Yanqi Liu and
  • Yan Zhao

Beilstein J. Nanotechnol. 2020, 11, 717–728, doi:10.3762/bjnano.11.59

Graphical Abstract
  • indirect bandgap semiconductor, since the grains are small and the energy levels are discrete: In Equation 1, h is Plank’s constant (6.626 × 10−34 J s), ν is the frequency of light, and Eg represents the bandgap energy. For the calculation of Eg by the Tauc plot absorbance the value of the absorption (Abs
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Published 05 May 2020
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  • of applications including ultra-fast switching devices, oscillators, frequency multipliers, one-transistor static memories and multi-valued memory circuits [12][17][18][19][20]. In a RTD, a material with low bandgap energy is sandwiched between two materials with larger bandgaps, i.e., a quantum well
  • operation is created by juxtaposing graphene nanoribbons (GNRs) with different widths (utilizing the inverse relation between GNR width and bandgap energy) or by periodically arranging graphene (the well) and boron nitride regions (the barriers). While the performance of conventional RTDs based on bulk
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Published 24 Apr 2020

Interfacial charge transfer processes in 2D and 3D semiconducting hybrid perovskites: azobenzene as photoswitchable ligand

  • Nicole Fillafer,
  • Tobias Seewald,
  • Lukas Schmidt-Mende and
  • Sebastian Polarz

Beilstein J. Nanotechnol. 2020, 11, 466–479, doi:10.3762/bjnano.11.38

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  • band (VB) and conduction band (CB) were determined using solid-state UV–vis measurements in combination with PESA. Similar to the determination of the HOMO, the VB can be determined with PESA. Solid-state reflection spectra of the LHPs give information about the bandgap energy Eg of the semiconductor
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Published 17 Mar 2020
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