Photocatalytic degradation of methylene blue under visible light by cobalt ferrite nanoparticles/graphene quantum dots

• Vo Chau Ngoc Anh,
• Le Thi Thanh Nhi,
• Le Thi Kim Dung,
• Dang Thi Ngoc Hoa,
• Nguyen Truong Son,
• Nguyen Thi Thao Uyen,
• Nguyen Ngoc Uyen Thu,
• Le Van Thanh Son,
• Le Trung Hieu,
• Tran Ngoc Tuyen and
• Dinh Quang Khieu

Beilstein J. Nanotechnol. 2024, 15, 475–489, doi:10.3762/bjnano.15.43

• that the resulting composite can enhance the absorption capacity [11]. This observation is an agreement with previous works [11]. In addition, a slight shift of the PL emission peak is also observed because of the blue shift in the UV–vis spectrum, which is consistent with their bigger bandgap energy

Controllable physicochemical properties of WO_x thin films grown under glancing angle

• Rupam Mandal,
• Aparajita Mandal,
• Alapan Dutta,
• Rengasamy Sivakumar,
• Sanjeev Kumar Srivastava and
• Tapobrata Som

Beilstein J. Nanotechnol. 2024, 15, 350–359, doi:10.3762/bjnano.15.31

• within the forbidden gap. These states lead to a reduction in bandgap energy and an upward shift of the Fermi level [41][42]. This is the reason behind the observed reduction in bandgap with higher thicknesses (Figure 2b,c) [43]. To probe the Fermi level position, KPFM is a useful tool to acquire

The microstrain-accompanied structural phase transition from h-MoO₃ to α-MoO₃ investigated by in situ X-ray diffraction

• Zeqian Zhang,
• Honglong Shi,
• Boxiang Zhuang,
• Minting Luo and
• Zhenfei Hu

Beilstein J. Nanotechnol. 2023, 14, 692–700, doi:10.3762/bjnano.14.55

• from +2 to +6 [1][2], leading to a range of molybdenum oxides. Molybdenum oxides include the fully stoichiometric MoO3 with a large bandgap above 2.7 eV, the reduced oxides MoO3−x with oxygen vacancies, and the semimetal MoO2. The degree of reduction influences the bandgap energy of molybdenum oxides

Conjugated photothermal materials and structure design for solar steam generation

• Chia-Yang Lin and
• Tsuyoshi Michinobu

Beilstein J. Nanotechnol. 2023, 14, 454–466, doi:10.3762/bjnano.14.36

• semiconductor materials, optical absorption significantly varies with the wavelength, depending on the bandgap energy. When semiconductor materials are irradiated with light, electron–hole pairs with energies close to the bandgap are produced. The excited electrons eventually return to a lower energy state and

Plasmonic nanotechnology for photothermal applications – an evaluation

• A. R. Indhu,
• L. Keerthana and
• Gnanaprakash Dharmalingam

Beilstein J. Nanotechnol. 2023, 14, 380–419, doi:10.3762/bjnano.14.33

Bismuth-based nanostructured photocatalysts for the remediation of antibiotics and organic dyes

• Akeem Adeyemi Oladipo and
• Faisal Suleiman Mustafa

Beilstein J. Nanotechnol. 2023, 14, 291–321, doi:10.3762/bjnano.14.26

• ][104][110][144][145][146][147][148][149][150]. Doping reduces the bandgap energy, introduces intermediate energy levels to overcome constraints, creates trap sites to capture photogenerated charge carriers, and increases the absorption of visible light. Additionally, after doping, oxygen vacancies or

Electrical and optical enhancement of ITO/Mo bilayer thin films via laser annealing

• Abdelbaki Hacini,
• Ahmad Hadi Ali,
• Nurul Nadia Adnan and
• Nafarizal Nayan

Beilstein J. Nanotechnol. 2022, 13, 1589–1595, doi:10.3762/bjnano.13.133

• transmittance of 94% and increased the bandgap energy from 2.76 to 2.88 eV at 120 mJ. The annealing treatment decreased the resistivity from 15.63 × 10−4 to 1.73 × 10−4 Ω/cm−1. Additionally, the figure of merit of the ITO/Mo structure improved significantly from 6.63 × 10−4 Ω−1 of the as-deposited sample to

• crystalline improvement leads to less light scattering in the metal layer [29][30]. Moreover, laser annealing reduces the defects, including grain boundaries and impurities, reducing light scattering and photon–electron interactions [29][30][31]. The optical bandgap energy Eg of ITO/Mo thin film was studied

• before and after laser annealing. The bandgap energy Eg was determined using the following equation (Tauc relation) [28]: where α is the absorption coefficient, hν is the photon energy; A is a constant, Eg is the bandgap energy, n = 0.5 for a direct bandgap, and n = 2 for an indirect bandgap. The bandgap

Photoelectrochemical water oxidation over TiO₂ nanotubes modified with MoS₂ and g-C₃N₄

• Phuong Hoang Nguyen,
• Thi Minh Cao,
• Tho Truong Nguyen,
• Hien Duy Tong and
• Viet Van Pham

Beilstein J. Nanotechnol. 2022, 13, 1541–1550, doi:10.3762/bjnano.13.127

• spectroscopy (DRS) was carried out to measure the optical bandgap of the semiconductor materials through the Tauc method using the absorption coefficient α of the material, according to Equation 1 [42]: where h, ν, Eg, and B are the Planck constant, the frequency of the photon, the bandgap energy, and a

• visible-light range in comparison to that of the remaining samples. To evaluate the optical bandgap energy of TNAs and g-C3N4, Tauc plots were extrapolated in Figure 4b. The bandgap values of TNAs, g-C3N4, and MoS2 were calculated as about 3.15, 2.67, and 1.47 eV, respectively. These results are agreement

• has been demonstrated. The ability to enhance the optical interaction of the heterostructures was presented through the reduction of the bandgap energy. The outstanding application performance of g-C3N4/TNAs and MoS2/TNAs combinations was presented. In detail, the excellent water-splitting ability of

Non-stoichiometric magnetite as catalyst for the photocatalytic degradation of phenol and 2,6-dibromo-4-methylphenol – a new approach in water treatment

• Joanna Kisała,
• Anna Tomaszewska and
• Przemysław Kolek

Beilstein J. Nanotechnol. 2022, 13, 1531–1540, doi:10.3762/bjnano.13.126

• determine x for the catalysts under study (Table 1). The determined x-values indicate that the catalysts were non-stoichiometric magnetites. M1 with a larger grain diameter is less oxidized while M2 is highly oxidized. This is also reflected in the electron bandgap energy. These values show that the tested

• higher than the bandgap energy generates holes and electrons, which, after moving to the catalyst surface, may participate in redox processes. In a basic medium, the photocatalytic process may proceed by oxygen reduction at the surface of the particles (electron transfer only) [37]. A similar electron

LED-light-activated photocatalytic performance of metal-free carbon-modified hexagonal boron nitride towards degradation of methylene blue and phenol

• Nirmalendu S. Mishra and
• Pichiah Saravanan

Beilstein J. Nanotechnol. 2022, 13, 1380–1392, doi:10.3762/bjnano.13.114

• nitrogen vacancies and formation of energy sub-bands which help in overall reduction of the bandgap energy (Eg) [14]. At the same time, the incorporation of carbon into the HBN lattice results in the delocalization of electrons with simultaneous reduction in bandgap and is directly dependent upon the

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

• 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

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

• 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

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

• 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

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

• 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

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