Structural and magnetic properties of microwave-synthesized reduced graphene oxide/VO₂/Fe₂O₃ nanocomposite

• Sumanta Sahoo,
• Ankur Sood and
• Sung Soo Han

Beilstein J. Nanotechnol. 2025, 16, 921–932, doi:10.3762/bjnano.16.70

• gained considerable research attention. In this context, the current work demonstrates a facile rGO-supported solid-state MW synthetic route for fabricating a ternary nanocomposite of VO2, Fe2O3, and rGO. Here, the MW irradiation for 90 s was found to be suitable for the reduction and exfoliation of

• graphite oxide to form rGO, the reduction of V2O5 to form VO2, and the formation of Fe2O3 from ferrocene. X-ray diffraction and X-ray photoelectron spectroscopy analyses confirm the formation of distinct metal oxides in the presence of rGO. Furthermore, the morphological analysis reveals the deposition of

• Fe2O3 nanoparticles and VO2 nanorods on the 2D rGO surface. Notably, the ternary composite displayed good magnetic properties for its potential biomedical applications. Overall, this work explores an efficient and cost-effective synthetic approach for developing graphene-based magnetic nanocomposites

A review of defect engineering, ion implantation, and nanofabrication using the helium ion microscope

• Frances I. Allen

Beilstein J. Nanotechnol. 2021, 12, 633–664, doi:10.3762/bjnano.12.52

• irradiation has been used to introduce lattice defects into VO2 nanowires with which to control the conduction mechanisms of thermal and electrical transport in this material [71]. By performing a dose series and measuring the thermal and electrical conductivities of helium ion-irradiated VO2 around its

• insulator–metal transition temperature, a fundamental study of the contradictorily low electronic thermal conductivity of VO2 in the metallic regime was enabled. Similarly, Bi2Te3 nanoribbons have been irradiated with helium ions in order to defect-tune conduction mechanisms and study the anomalously high

Improvement of the thermoelectric properties of a MoO₃ monolayer through oxygen vacancies

• Wenwen Zheng,
• Wei Cao,
• Ziyu Wang,
• Huixiong Deng,
• Jing Shi and
• Rui Xiong

Beilstein J. Nanotechnol. 2019, 10, 2031–2038, doi:10.3762/bjnano.10.199

• supercell (72 atoms) to construct a neutral defect, such that the stoichiometric proportion is MoO2.94. Since there are three types of O atoms in the primitive cell, we named the three defective structures VO1, VO2 and VO3. Further details of the defect structures are presented in Supporting Information

• oxygen molecules. Then we calculate the formation energies and band gaps of these defect structures. The absolute Ef values are 2.074 eV (VO1), 2.076 eV (VO2) and 4.108 eV (VO3) while the band gaps are 0.837 eV (VO1), 0.797 eV (VO2) and 0.831 eV (VO3). In contrast to the bulk MoO3, the three defective

•  4c. Additionally, the values for VO1 and VO2 are almost the same, which means that they lead to the same structure. The structural dependency of the defective MoO3 monolayer is reflected in the insets of Figure 4b and Figure 4c. Previous theoretical studies show that a narrow and sharp peak in the

Porous N- and S-doped carbon–carbon composite electrodes by soft-templating for redox flow batteries

• Maike Schnucklake,
• László Eifert,
• Jonathan Schneider,
• Roswitha Zeis and
• Christina Roth

Beilstein J. Nanotechnol. 2019, 10, 1131–1139, doi:10.3762/bjnano.10.113

• functional group promotes the VO2+/VO2+ redox reaction the most [18]. The application of templates is a commonly used strategy to introduce porosity into carbon materials. Depending on the utilized template one can distinguish between a hard-templating and a soft-templating approach [19]. In both cases, the

• contributions. Electrochemical characterization The electrocatalytic activity of the composite electrodes for the positive redox reaction VO2+/VO2+ was investigated by CV (Table 3) and EIS. The CV curves of the respective carbon samples are shown in Figure 6 and the Nyquist plots are shown in Figure 7. The

• in higher currents compared to the only carbonized samples. The obtained data suggest that the kinetics regarding the VO2+/VO2+ redox couple follow the order of carbonized < composite (N-doped) < composite (co-doped with N and S). This means that the redox reaction of the vanadium ions proceeds more

Quantitative analysis of annealing-induced instabilities of photo-leakage current and negative-bias-illumination-stress in a-InGaZnO thin-film transistors

• Dapeng Wang and
• Mamoru Furuta

Beilstein J. Nanotechnol. 2019, 10, 1125–1130, doi:10.3762/bjnano.10.112

• higher-energy light irradiation, demonstrating that the generated ionized oxygen vacancies (VO+/VO2+) are neutralized by capturing electrons [8]. However, SS degradation still can be observed in the 300 °C-annealed TFT under the irradiation with short-wavelength light (below 430 nm), indicating that

• results demonstrate that the high concentration of VO defects near EV is excited to VO+/VO2+, located below the bottom of the conduction band [12]. Meanwhile, the photo-excited electron–hole pairs from the EV are separated because of a vertical electric field (VGS = −20 V). Consequently, the transfer

• annealed at 300, 350, and 400 °C, respectively (Figure 4d). In our previous publication [13], the additional positive gate pulse can neutralize the ionized VO+/VO2+ states and release the trapped holes at the GI/IGZO interface, helping to smooth the hump induced by donor-like defect states. When the pulse

Concurrent nanoscale surface etching and SnO₂ loading of carbon fibers for vanadium ion redox enhancement

• Jun Maruyama,
• Shohei Maruyama,
• Tomoko Fukuhara,
• Toru Nagaoka and
• Kei Hanafusa

Beilstein J. Nanotechnol. 2019, 10, 985–992, doi:10.3762/bjnano.10.99

• ions are shown in Figure 5 for TGP and TGP-CSnPc-TAir. The CVs for TGP-550Air are also shown for comparison. The enhancement of the VO2+/VO2+ redox reactions at the TGP-CSnPc-550Air electrode is clearly demonstrated by the negative and positive peak shifts for the oxidation and reduction peaks

• surface (TGP-550Air), which suffered from inhibition by the adsorption of VO2 [23][29]. The excessive exposure of the edge plane led to an activity decrease at TGP-CSnPc-600Air and TGP-CSnPc-650Air due to this inhibition and the optimized activity was attained with TGP-CSnPc-550Air in this study. The

• activity was equivalent to that obtained for the finely etched surface obtained in the previous study [15] without SnO2 nanoparticles. Because the V2+ ions generated by the negative scan could be easily oxidized by VO2+ to generate V3+, a scan rate of 50 mV·s−1 was chosen in order to observe the V2

Exploring the photoleakage current and photoinduced negative bias instability in amorphous InGaZnO thin-film transistors with various active layer thicknesses

• Dapeng Wang and
• Mamoru Furuta

Beilstein J. Nanotechnol. 2018, 9, 2573–2580, doi:10.3762/bjnano.9.239

• required for the transition from VO to VO+ and VO2+, respectively. Moreover, the ionized oxygen vacancies of VO+ and VO2+ are located near the mid-gap and the bottom of the EC [15][29], respectively. It is sufficient to excite high-density VO defects to VO+/VO2+ and then to generate free electrons to EC

• . Simultaneously, the electron–hole pairs are photoexcited from EV, which leads to the neutralization between the ionized VO+/VO2+ and the generated electrons, contributing to free holes in EV [18]. During the NBIS duration with VGS = −30 V, a vertical electric field is exerted along the growth direction of the

• originate from the photoexcited VO+/VO2+. In the forward measurement, the transfer curves exhibit a positive shift in the VGS direction with a hump at the turn-on voltage region when the NBIS duration exceeds 1000 s, which is attributed to the synergistic effects of the generated defect states and the

Synthesis of graphene–transition metal oxide hybrid nanoparticles and their application in various fields

• Arpita Jana,
• Elke Scheer and
• Sebastian Polarz

Beilstein J. Nanotechnol. 2017, 8, 688–714, doi:10.3762/bjnano.8.74

• –TiO2 make use of its photocatalytic activity, there are also some applications of shape-controlled TiO2–graphene hybrids used in pollutant abatement [100], high-performance anodes for microbial fuel cells [101], and self-cleaning applications [102]. Vanadium oxide (VO, V2O3, VO2, V2O5)–graphene hybrids

• Vanadium has oxidation states ranging from −1 to +5. Binary vanadium oxides have already been proven as a potential material for studying superconductivity at high pressures and low-dimensional quantum-spin transitions [103]. VO2 has two crystalline phases, monoclinic and rutile. The monoclinic form of

• vanadium(IV) oxide can be transferred to the rutile form by a thermally induced, reversible treatment at 68 °C [104]. VO2 (M) behaves as a semiconductor whereas VO2(R) behaves as a semimetal. Vanadium pentoxide (V2O5) has very low electronic conductivity due to its low d-band mobility. It also shows a

Multimodal cantilevers with novel piezoelectric layer topology for sensitivity enhancement

• Steven Ian Moore,
• Michael G. Ruppert and
• Yuen Kuan Yong

Beilstein J. Nanotechnol. 2017, 8, 358–371, doi:10.3762/bjnano.8.38

• Vi1, however, for the second transducer Vi2 is combined with a negative polarity to optimally actuate M2. The optimal output voltage for M2, Vo2, results from taking the difference between the outputs of the two instrumentation circuits. This principle can be extended for the design of a piezoelectric

Effect of SiN_x diffusion barrier thickness on the structural properties and photocatalytic activity of TiO₂ films obtained by sol–gel dip coating and reactive magnetron sputtering

• Mohamed Nawfal Ghazzal,
• Eric Aubry,
• Nouari Chaoui and
• Didier Robert

Beilstein J. Nanotechnol. 2015, 6, 2039–2045, doi:10.3762/bjnano.6.207

• dominant crystalline phase [10]. Koo et al. reported that a SiNx diffusion barrier is necessary to crystallize VO2 films [12]. The XRD patterns reveal a preferential [101] orientation for the sol–gel TiO2 films, whereas the reactive sputtered TiO2 films show a [001] preferential orientation. In order to

• film surface), and increasing the thickness up to 1,000 nm does not further reduce the concentration of Na+ ions. Koo et al. [12] showed that the SiNx diffusion barrier contributes to the formation of the VO2 crystalline phase. From XPS results, it was concluded that the amount of sodium ions diffused

• to the top VO2 layer decreases gradually as the thickness decreases from 100 nm to 10 nm. Increasing the SiNx diffusion barrier thickness indirectly induces the decrease in the crystallite size of the SG-TiO2 film. A similar behavior has been observed for TiO2 films grown on various types of glasses

Switching adhesion forces by crossing the metal–insulator transition in Magnéli-type vanadium oxide crystals

• Bert Stegemann,
• Matthias Klemm,
• Siegfried Horn and
• Mathias Woydt

Beilstein J. Nanotechnol. 2011, 2, 59–65, doi:10.3762/bjnano.2.8

• oxygen content by means of a definite mixture of the starting vanadium oxides V2O3 and VO2 [37]. Under such conditions crystals of exclusively one Magnéli phase per tube could be obtained, several of which showed specular surfaces. X-Ray diffraction (XRD) and magnetic susceptibility measurements on