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

• 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

Selected properties of Al_xZn_yO 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

• 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

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

• 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

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

• 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

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

• 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

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

• , 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

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

• ), 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

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

• 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

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

• , 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

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

• 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

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

• 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

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

• 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

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

• 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

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

• ), 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

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

• 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

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

• * = 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

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

• 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

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

• 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

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

• 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

Effect of substitutional defects on resonant tunneling diodes based on armchair graphene and boron nitride nanoribbons lateral heterojunctions

• Majid Sanaeepur

Beilstein J. Nanotechnol. 2020, 11, 688–694, doi:10.3762/bjnano.11.56

• 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

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

• 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

First principles modeling of pure black phosphorus devices under pressure

• Ximing Rong,
• Zhizhou Yu,
• Zewen Wu,
• Junjun Li,
• Bin Wang and
• Yin Wang

Beilstein J. Nanotechnol. 2019, 10, 1943–1951, doi:10.3762/bjnano.10.190

• conducting material. Figure 3d shows the bandgap energy of a partially relaxed monolayer BP as a function of RC indicated by the blue solid circles. For comparison, the bandgap energy of a fully relaxed BP is also plotted with red solid squares. The bandgap energy increases first and then decreases with

• relaxed BP show qualitatively consistent behaviors of bandgap variation and even the same phase transition points, although the bandgap energy of the fully relaxed BP decreases faster when RC increases from 10% to 25%. Conductance of pure BP devices under pressure In this subsection, we show the pressure

• = 0, 15% and 30%, respectively. (d) Bandgap energy Eg as a function of RC for partially relaxed (blue circles) and fully relaxed (red squares) 2D BP. The black horizontal line at Eg = 0 indicates the Fermi level. Conductance G from first principles calculations (solid symbols) and GWKB fitted by the

Fabrication and characterization of Si_1−xGe_x nanocrystals in as-grown and annealed structures: a comparative study

• Muhammad Taha Sultan,
• Adrian Valentin Maraloiu,
• Ionel Stavarache,
• Jón Tómas Gudmundsson,
• Andrei Manolescu,
• Valentin Serban Teodorescu,
• Magdalena Lidia Ciurea and
• Halldór Gudfinnur Svavarsson

Beilstein J. Nanotechnol. 2019, 10, 1873–1882, doi:10.3762/bjnano.10.182

• to surface polarization effects due to local fields, which play a crucial role in systems characterized by strong charge inhomogeneity. Further, the development of strain in the structure influences the size and shape of the NCs, thus resulting in a change of the bandgap energy. A common method to

Rapid thermal annealing for high-quality ITO thin films deposited by radio-frequency magnetron sputtering

• Petronela Prepelita,
• Ionel Stavarache,
• Doina Craciun,
• Florin Garoi,
• Catalin Negrila,
• Beatrice Gabriela Sbarcea and
• Valentin Craciun

Beilstein J. Nanotechnol. 2019, 10, 1511–1522, doi:10.3762/bjnano.10.149

• energy of the oscillator, E0, and dispersion energy, Ed [44] as: where ν is the photon frequency. From the graphical representation (n2 − 1)−1 = f [(hν)2] we get the slope (E0Ed)−1, where E0 is considered to be an average of the bandgap energy of semiconductor and has the expression E0 ≈ 2Eg. The optical

Synthesis of P- and N-doped carbon catalysts for the oxygen reduction reaction via controlled phosphoric acid treatment of folic acid

• Rieko Kobayashi,
• Takafumi Ishii,
• Yasuo Imashiro and
• Jun-ichi Ozaki

Beilstein J. Nanotechnol. 2019, 10, 1497–1510, doi:10.3762/bjnano.10.148

• ]. Strelko et al. used theoretical methods to establish an interesting relationship between the bandgap energy of a given catalyst and its ability to promote reactions involving electron transfer [21]. Moreover, P-doping of graphitic layers was revealed to have an effect similar to that of N-doping and hence