A visible-light photodetector based on heterojunctions between CuO nanoparticles and ZnO nanorods

• Doan Nhat Giang,
• Nhat Minh Nguyen,
• Duc Anh Ngo,
• Thanh Trang Tran,
• Le Thai Duy,
• Cong Khanh Tran,
• Thi Thanh Van Tran,
• Phan Phuong Ha La and
• Vinh Quang Dang

Beilstein J. Nanotechnol. 2023, 14, 1018–1027, doi:10.3762/bjnano.14.84

• valence bands of CuO are at a more negative potential than those of ZnO to form type-II region bonds between CuO and ZnO, avoiding recombination and accelerating the separation of photogenerated electron–hole pairs [37]. To explore and confirm the effects of combining CuO and ZnO, we developed a

Nanoarchitectonics of photothermal materials to enhance the sensitivity of lateral flow assays

• Elangovan Sarathkumar,
• Rajasekharan S. Anjana and
• Ramapurath S. Jayasree

Beilstein J. Nanotechnol. 2023, 14, 988–1003, doi:10.3762/bjnano.14.82

• nanoparticles: The optical, physical, and chemical properties of plasmonic nanoparticles highly depend on the number of valence electrons. When the oscillating frequency of the electron cloud matches the frequency of the electromagnetic irradiation, LSPR occurs [35]. The excited plasmonic photothermal agent

• nanomaterials. When excited by photons with an energy greater than or equal to the bandgap of the materials, electron–hole pairs are generated. The electrons excited to the conduction band will leave holes in the valence band. The relaxation of these electrons can occur radiatively in the form of photons and

Fragmentation of metal(II) bis(acetylacetonate) complexes induced by slow electrons

• Janina Kopyra and
• Hassan Abdoul-Carime

Beilstein J. Nanotechnol. 2023, 14, 980–987, doi:10.3762/bjnano.14.81

• trapped into a usually unfilled molecular valence orbital (i.e., shape resonance) [20]. Such a process usually arises typically at electron energies below 4 eV. The molecular orbitals into which the excess electron may be trapped are reported in [15][16][17][18][19] for the investigated organometallic

• for large molecules, such as phthalocyanine or tetraphenylporphyrin (up to 7–8 eV), because of the long lifetime of the TNIs [22]. Also, the electron can be trapped by long-range forces to form a “multipole”-bound anion. This bound state may then couple to some dissociative valence states, leading to

Prediction of cytotoxicity of heavy metals adsorbed on nano-TiO₂ with periodic table descriptors using machine learning approaches

• Joyita Roy,
• Souvik Pore and
• Kunal Roy

Beilstein J. Nanotechnol. 2023, 14, 939–950, doi:10.3762/bjnano.14.77

• metals is also time- and dose-dependent. Among many other factors, the valence state plays an important role in toxicokinetics and toxicodynamics. Many studies have shown that an increased concentration of heavy metals is correlated with the severity of hepatotoxicity and nephrotoxicity [37]. Lead causes

Ultralow-energy amorphization of contaminated silicon samples investigated by molecular dynamics

• Grégoire R. N. Defoort-Levkov,
• Alan Bahm and
• Patrick Philipp

Beilstein J. Nanotechnol. 2023, 14, 834–849, doi:10.3762/bjnano.14.68

• in this study. In contrast, the simplicity of the Morse potential allowed us to represent the interactions between the argons atoms with full valence band and the sample atoms. As described in [26], a set of DFT calculations were performed using VASP to compute the Morse potential for argon–silicon

Carboxylic acids and light interact to affect nanoceria stability and dissolution in acidic aqueous environments

• Matthew L. Hancock,
• Eric A. Grulke and
• Robert A. Yokel

Beilstein J. Nanotechnol. 2023, 14, 762–780, doi:10.3762/bjnano.14.63

• on the right was exposed to light. The sample in the citric acid column exposed to light for four weeks showed a color change from yellow to clear, possibly indicating a valence state change from Ce4+ to Ce3+. The citric acid sample exposed to light appears to be completely colorless after four weeks

• representative of particle dissolution, due to the valence state change from Ce4+ to Ce3+ during dissolution. The particles in citric acid exposed to light were completely dissolved after four weeks as indicated by DLS and transmission electron microscopy (TEM), shown in Table 1 and Table 2, respectively. In

• Table 2 of Grulke et al. [34], changes in the valence state at the edge and core of the nanoparticles were shown over twelve weeks of dissolution. The Ce3+ concentration increased as the particle size decreased, but only slightly. Figure 7 of Yokel et al. [33] shows little to no change within four weeks

Cross-sectional Kelvin probe force microscopy on III–V epitaxial multilayer stacks: challenges and perspectives

• Mattia da Lisca,
• José Alvarez,
• James P. Connolly,
• Nicolas Vaissiere,
• Karim Mekhazni,
• Jean Decobert and
• Jean-Paul Kleider

Beilstein J. Nanotechnol. 2023, 14, 725–737, doi:10.3762/bjnano.14.59

• is set at mid-gap, whereas it is moved towards the valence (conduction) band if the ratio of acceptor to donor DOS is larger (smaller) than 1 [24]. Results KPFM cross-sectional investigation under dark conditions The cross section of the sample was first investigated by KPFM under dark conditions

• and increase in potential, respectively). The mismatch of the conduction and valence bands between these materials then leads to the peculiar band energy diagram. Insets have been added to Figure 3a and Figure 3b to zoom in this region. Additionally, KP modelling [13] was used to simulate the VCPD

• reported in Figure 6. In this specific case, the charge neutrality level of surface defects is set at mid-gap. Thus, increasing the surface defect densities will produce a pinning of the Fermi level at the neutrality level of the surface states and the energy of valence and conduction bands will appear

Metal-organic framework-based nanomaterials as opto-electrochemical sensors for the detection of antibiotics and hormones: A review

• Akeem Adeyemi Oladipo,
• Saba Derakhshan Oskouei and
• Mustafa Gazi

Beilstein J. Nanotechnol. 2023, 14, 631–673, doi:10.3762/bjnano.14.52

Titania nanoparticles for photocatalytic degradation of ethanol under simulated solar light

• Evghenii Goncearenco,
• Iuliana P. Morjan,
• Claudiu Teodor Fleaca,
• Florian Dumitrache,
• Elena Dutu,
• Monica Scarisoreanu,
• Valentin Serban Teodorescu,
• Alexandra Sandulescu,
• Crina Anastasescu and
• Ioan Balint

Beilstein J. Nanotechnol. 2023, 14, 616–630, doi:10.3762/bjnano.14.51

• , which are localized in the vicinity of the conduction and the valence bands. There are two ways to obtain such knowledge, that is, from optical and luminescence measurements. The former gives us information about electron transitions from the lower to the higher energy levels and the latter about the

• [62][63]. Indirect transitions are more common in both sample groups. The valence bands are the same in P25 and our TiO2 powders, indirect transitions have almost the same values for all measured samples, and the differences among the values could be due to calculus errors. In the case of direct

Evaluation of electrosynthesized reduced graphene oxide–Ni/Fe/Co-based (oxy)hydroxide catalysts towards the oxygen evolution reaction

• Karolina Cysewska,
• Marcin Łapiński,
• Marcin Zając,
• Jakub Karczewski,
• Piotr Jasiński and
• Sebastian Molin

Beilstein J. Nanotechnol. 2023, 14, 420–433, doi:10.3762/bjnano.14.34

• calculations were determined based on the survey spectra collected in a wide range of binding energies, while valence state calculations were based on the high-resolution spectra. The C 1s peak (285.0 eV) was used to correct the results. Analysis of XPS spectra was performed with the Casa-XPS software using a

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

• phenomenon of surface plasmon resonance results from the interaction between electromagnetic radiation and typically high-valence materials, leading to oscillations of the free electrons in it. The decay of these collective oscillations into heat is the plasmonic photothermal (PPT) effect. The absorption

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

• a nutshell, when exposed to light of the desired wavelength (enough energy), an electron (e−) in the photocatalyst's valence band absorbs photon energy and is excited to the conduction band on a femtosecond scale. This results in the formation of a hole (h+) in the valence band and a charge carrier

• reaction, along with other species such as oxygen, hydrogen peroxide, and persulfate. This excited electron reduces an acceptor, and the acceptor's hole oxidises donor molecules. What happens to the excited electron and hole depends on the relative positions of conduction band and valence band of the

• , nanometre-sized photocatalysts based on bismuth have recently been investigated and evaluated, because the majority of bismuth-based photocatalysts have a bandgap below 3.0 eV, making them usable in visible light. Additionally, their electrical structure produces a valence band with hybrid O 2p and Bi 6s

High–low Kelvin probe force spectroscopy for measuring the interface state density

• Ryo Izumi,
• Masato Miyazaki,
• Yan Jun Li and
• Yasuhiro Sugawara

Beilstein J. Nanotechnol. 2023, 14, 175–189, doi:10.3762/bjnano.14.18

• and the sample, the bulk Fermi level does not change on the semiconductor side, whereas the interface states move up and down with the conduction and valence bands. This causes capture of carriers (electrons and/or holes) from the bulk side by the interface states and, conversely, emission of carriers

Two-step single-reactor synthesis of oleic acid- or undecylenic acid-stabilized magnetic nanoparticles by thermal decomposition

• Mykhailo Nahorniak,
• Pamela Pasetto,
• Jean-Marc Greneche,
• Volodymyr Samaryk,
• Sandy Auguste,
• Anthony Rousseau,
• Nataliya Nosova and
• Serhii Varvarenko

Beilstein J. Nanotechnol. 2023, 14, 11–22, doi:10.3762/bjnano.14.2

• isomeric shift resulting from the monopolar electric interaction is very sensitive to the valence states of Fe. Taking into account the characteristic measurement time of 57Fe Mössbauer spectroscopy, estimated at 10−8 s at the Larmor frequency, the ultrafine structure of magnetite at 300 K (and above the

• ) three magnetic components attributed to blocked Fe3+ moieties, blocked Fe2+ moieties, and Fe ions with intermediate valence state between Fe3+ and Fe2+, as commonly observed in typical magnetite below the Verwey transition; (ii) a quadrupolar component assigned to Fe2+ moieties, probably due to some

• technique is highly sensitive to the valence state of Fe species and thus enables the identification of magnetite and maghemite and the estimation of their respective proportions. Measurements were performed in a transmission geometry with a 925 MBq γ-source of 57Co/Rh mounted using a conventional constant

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

• migrate from the valence band (VB) of TNAs to the VB of MoS2 or g-C3N4. Therefore, the recombination of the photo-generated e−–h+ pairs is reduced. In this contribution, the PEC water splitting reactions take place in a neutral media, which is well known to occur via two processes, including the oxidation

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

• than Bi5+. The earlier compounds have been examined more thoroughly than the latter. The overlap of O 2p and Bi 6s orbitals in the valence band (VB) of Bi3+-containing compounds improves photogenerated charge mobility and, hence, improves photocatalytic activity [22][23]. Furthermore, except for BiOF

• conduction band (CB) through visible light [39]. The holes in the valence band of the catalyst split water to hydroxyl radicals (•OH). Electrons in the CB of a semiconductor photocatalyst can generate the superoxide anion (•O2−) when they interact with oxygen molecules. During the photocatalytic oxidative

Enhanced electronic transport properties of Te roll-like nanostructures

• E. R. Viana,
• N. Cifuentes and
• J. C. González

Beilstein J. Nanotechnol. 2022, 13, 1284–1291, doi:10.3762/bjnano.13.106

• calculations of the band structure of t-Te have been revealed that the strong spin–orbit coupling breaks the fourfold degeneracy of the valence band at the H point of the Brillouin zone, creating two non-degenerated H4 and H5 bands and a doubly degenerated H6 band. The H4 and H5 bands contribute to the

• the mobility is mainly limited by phonon scattering at high temperatures, α is close to 3/2 [33][34]. Nveff is the effective density of states of the valence band, EA is the shallow acceptor ionization energy [33], and kB is Boltzmann’s constant. At lower temperatures, most of the free holes are

• recaptured by acceptors and cannot be thermally excited back to the valence band [30][33]. In this case, the thermally activated conduction of free holes becomes less important, and hole hopping directly between acceptor states in the impurity band becomes the primary conduction mechanism [30][31][32][33

Role of titanium and organic precursors in molecular layer deposition of “titanicone” hybrid materials

• Arbresha Muriqi and
• Michael Nolan

Beilstein J. Nanotechnol. 2022, 13, 1240–1255, doi:10.3762/bjnano.13.103

• )titanium (Ti(DMA)4) inorganic precursors and then ethylene glycol (EG) and glycerol (GL) organic co-reactants. The valence electron–core electron interactions are described by projector augmented wave potentials (PAW) [52] and the valance electron configurations are: Ti: 3d34s1, Al: 3s23p1, O: 2s22p4, Cl

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

• absorbs visible light due to its small bandgap below 2.7 eV. Because of this, it has been consistently regarded as a catalyst with excellent optical properties [14][15]. Unfortunately, its narrow bandgap leads to rapid recombination of electron–hole (e−–h+) pairs, and the valence band potential of g-C3N4

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

• the use of ZnO catalysts occurs when ZnO is illuminated by light. When excited by light with an energy greater than the bandgap of ZnO, electrons from the valence band (VB) are excited to the conduction band (CB) to form photogenerated electrons in the CB and photogenerated holes in the VB [11][12

Recent advances in green carbon dots (2015–2022): synthesis, metal ion sensing, and biological applications

• Aisha Kanwal,
• Naheed Bibi,
• Sajjad Hyder,
• Arif Muhammad,
• Hao Ren,
• Jiangtao Liu and
• Zhongli Lei

Beilstein J. Nanotechnol. 2022, 13, 1068–1107, doi:10.3762/bjnano.13.93

• high QY because nitrogen atom doping helps to stabilize the surface defects of CDs and enhances fluorescence emission. Moreover, owing to its five valence electrons and an atomic size that is similar to carbon, nitrogen is a common dopant and the most frequently employed method of enhancing PL

Spindle-like MIL101(Fe) decorated with Bi₂O₃ nanoparticles for enhanced degradation of chlortetracycline under visible-light irradiation

• Chen-chen Hao,
• Fang-yan Chen,
• Kun Bian,
• Yu-bin Tang and
• Wei-long Shi

Beilstein J. Nanotechnol. 2022, 13, 1038–1050, doi:10.3762/bjnano.13.91

• narrow response region to visible light and fast recombination of photoproduced charge carriers [45]. To improve the photocatalytic activity of Bi2O3, many researchers have attempted to modify Bi2O3. Since Bi2O3 has a relatively positive valence band position, combing Bi2O3 with other semiconductors to

• , FEI-quanta 200, Japan Electronics, Japan), transmission electron microscopy (TEM, FEI-Tecnai F20, USA) and high-resolution transmission electron microscopy (HRTEM, JEOL 2100F, Japan). The element valence and chemical composition was investigated using X-ray photoelectron spectroscopy (XPS, Axis ultra

• photocatalytic mechanism, the band structure was measured by UV–vis DRS and valence band X-ray photoelectron spectroscopy (VB-XPS). UV–vis DRS spectra and the bandgap (Eg) of Bi2O3 and MIL101(Fe) were discussed in Figure 5a, and the obtained bandgap of Bi2O3 and MIL101(Fe) are 2.78 and 2.75 eV, respectively

Numerical study on all-optical modulation characteristics of quantum cascade lasers

• Biao Wei,
• Haijun Zhou,
• Guangxiang Li and
• Bin Tang

Beilstein J. Nanotechnol. 2022, 13, 1011–1019, doi:10.3762/bjnano.13.88

• the valence band electrons to transition to the conduction band and produce electron-hole pairs. The lifetimes of electrons and holes are quite different [22] and result in accumulation of holes, and then, in order to maintain electrical neutrality of the laser, the electrons in the current are added

• noting that, when the wavelength of the modulating light is close to the band gap of the active region of the QCL, most of the injected light energy excites the electrons in the valence band to transition to the conduction band and then to the upper laser subband, thereby increasing the power of the

• modulating light. However, with a decrease in the modulated laser wavelength, its energy becomes greater than the band gap between the valence band and the lower laser subband of the conduction band of the QCL active region, with the excess energy exciting the electrons to a higher energy level or high

Theoretical investigations of oxygen vacancy effects in nickel-doped zirconia from ab initio XANES spectroscopy at the oxygen K-edge

• Dick Hartmann Douma,
• Lodvert Tchibota Poaty,
• Alessio Lamperti,
• Stéphane Kenmoe,
• Abdulrafiu Tunde Raji,
• Alberto Debernardi and
• Bernard M’Passi-Mabiala

Beilstein J. Nanotechnol. 2022, 13, 975–985, doi:10.3762/bjnano.13.85

• and oxidation states of the atom in the sample [30]. In the case of transition metal atoms, L2,3-edge XAS is particularly suitable for probing 3d valence orbitals via the dipole-allowed 2p–3d transitions. Several factors may affect the L2,3-edge spectrum, including the structure of the metal complex

• and spin-down orbitals (Figure 4c). This orbital arrangement suggests that the nickel atom has an oxidation state of +3 and is in high spin-polarization with the valence electron configuration according to ligand field theory (cf. Figure 2). In the case of nickel atom Ni2, the contribution to the O

• -polarization with the valence electron configuration according to the ligand field theory (cf. Figure 2). This is because both e and t2 orbitals participate together in the transitions occurring in the pre-edge region. When the second oxygen vacancy is introduced, that is, structure S2, the antiferromagnetic

Hierarchical Bi₂WO₆/TiO₂-nanotube composites derived from natural cellulose for visible-light photocatalytic treatment of pollutants

• Zehao Lin,
• Zhan Yang and
• Jianguo Huang

Beilstein J. Nanotechnol. 2022, 13, 745–762, doi:10.3762/bjnano.13.66

• , with the optimal 70%−Bi2WO6/TiO2-NT nanocomposite as the photocatalyst. It is apparent that only the addition of AgNO3 suppresses the photocatalytic reduction of Cr(VI), suggesting that e− is the uppermost species present during photocatalysis. The edge potentials of the valence band (EVB) and