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

• photoluminescence (PL) band at 373 nm, which is due to the exciton recombination corresponding to the band edge emission, and a green emission peak is most commonly observed that arises from the defect of ZnO NPs such as oxygen vacancies, zinc vacancies, oxygen interstitials, and zinc interstitials [241]. Graphene

Diffusion and surface alloying of gradient nanostructured metals

• Zhenbo Wang and
• Ke Lu

Beilstein J. Nanotechnol. 2017, 8, 547–560, doi:10.3762/bjnano.8.59

• higher binding energy between Mn and vacancies, of which the concentration was much larger in the GNS sample than in the CG sample, also contributed to the quicker formation of Mn-enriched oxide scale [45][96][97]. Conclusion Due to the importance of understanding the diffusion and surface alloying

Impact of air exposure and annealing on the chemical and electronic properties of the surface of SnO₂ nanolayers deposited by rheotaxial growth and vacuum oxidation

• Monika Kwoka and
• Maciej Krzywiecki

Beilstein J. Nanotechnol. 2017, 8, 514–521, doi:10.3762/bjnano.8.55

• to its high and variable electrical conductivity in the range of 100 Ω−1·cm−1 to 102 Ω−1·cm−1 due to the existence of free electrons in oxygen vacancies. This effect has been widely applied for the construction of prototypical gas sensors devices with both thick and thin films [3][4][5][6][7][8]. The

Nanocrystalline ZrO₂ and Pt-doped ZrO₂ catalysts for low-temperature CO oxidation

• Amit Singhania and
• Shipra Mital Gupta

Beilstein J. Nanotechnol. 2017, 8, 264–271, doi:10.3762/bjnano.8.29

• conversion at 240 °C, which is the highest conversion rate reported for ZrO2 in literature to date. It is found that through solution combustion, Pt2+ ions replace Zr4+ ions in the ZrO2 lattice and because of this, oxygen vacancies are formed due to charge imbalance and lattice distortion in ZrO2. 1% Pt was

• oxygen mobility and oxygen vacancies and improves the activity and stability of the catalyst. The effects of gas hourly space velocity (GHSV) and initial CO concentration on the CO oxidation over Pt(1%)-ZrO2 were studied. Keywords: CO oxidation; nanomaterials; platinum; solution combustion method

• CO oxidation by different researchers [13][14][15][16]. The addition of precious metals such as Pd, Pt and Rh increased the reactivity of the support by increasing its oxygen mobility and number of oxygen vacancies (the source of oxygen in CO oxidation) [10][11][12]. In recent years, ZrO2 has been

Nanocrystalline TiO₂/SnO₂ heterostructures for gas sensing

• Barbara Lyson-Sypien,
• Anna Kusior,
• Mieczylaw Rekas,
• Jan Zukrowski,
• Marta Gajewska,
• Katarzyna Michalow-Mauke,
• Thomas Graule,
• Marta Radecka and
• Katarzyna Zakrzewska

Beilstein J. Nanotechnol. 2017, 8, 108–122, doi:10.3762/bjnano.8.12

• which the semiconducting behavior begins to prevail over water desorption/oxygen adsorption depends on the TiO2–SnO2 composition. The higher Tmax for TiO2-rich heterostructures can be explained on the basis of the higher ionic defect concentration (mainly oxygen vacancies) at the surface of TiO2. It is

• well known that oxygen vacancies act as water adsorption centers. Moreover, in the case of SnO2 water adsorption takes place because of the formation of weak van der Waals bonds between water dipoles and lattice ions (Sn4+ and O2−) [19]. This facilitates water desorption from the surface of SnO2-rich

• of oxygen vacancies VO, the following reaction could be proposed: The condition of lattice electroneutrality requires that: where k = 1 or 2 corresponds to singly or doubly ionized defects, respectively. Applying the law of mass action to Equation 11 (with k = 1 or 2) gives power-law coefficients of

Ordering of Zn-centered porphyrin and phthalocyanine on TiO₂(011): STM studies

• Piotr Olszowski,
• Lukasz Zajac,
• Szymon Godlewski,
• Bartosz Such,
• Rémy Pawlak,
• Antoine Hinaut,
• Res Jöhr,
• Thilo Glatzel,
• Ernst Meyer and
• Marek Szymonski

Beilstein J. Nanotechnol. 2017, 8, 99–107, doi:10.3762/bjnano.8.11

• investigation of molecular adsorption is titanium dioxide [11][12]. The most stable and the most studied face of TiO2 is the rutile (110) surface. In the context of adsorption studies, it is important to note that the (110) face of rutile usually contains numerous oxygen vacancies, often filled with hydroxy

Obtaining and doping of InAs-QD/GaAs(001) nanostructures by ion beam sputtering

• Sergei N. Chebotarev,
• Alexander S. Pashchenko,
• Leonid S. Lunin,
• Elena N. Zhivotova,
• Georgy A. Erimeev and
• Marina L. Lunina

Beilstein J. Nanotechnol. 2017, 8, 12–20, doi:10.3762/bjnano.8.2

• occupy Ga vacancies in the course of GaAs layer growth and behave as an acceptor-type impurity partially compensating the concentration of Te+ donors. The formation of neutral SnTe complexes results in a decrease in electrically active donors Sn+ + Te+ incorporated in the GaAs layer. We consider that

Annealing-induced recovery of indents in thin Au(Fe) bilayer films

• Anna Kosinova,
• Ruth Schwaiger,
• Leonid Klinger and
• Eugen Rabkin

Beilstein J. Nanotechnol. 2016, 7, 2088–2099, doi:10.3762/bjnano.7.199

• dislocation loops is non-conservative, it generates a flux of excess vacancies. The vacancies can reach the film-substrate interface and the nearby grain boundary, which both can serve as vacancy sinks. The annihilation of vacancies at the film-substrate interface leads to the slight decrease of the film

• thickness [21], whereas annihilation of vacancies at the grain boundaries helps to relax compressive stresses in the film formed during heating due to the mismatch of thermal expansion coefficients between the film and the substrate. The rim-less shape of the dewetting holes observed far from the indented

• region (see Figure 6) confirms that the film-substrate interface is indeed a potent sink and source of vacancies; the vacancies that originated at the interface are consumed by the expanding hole. Some fraction of the vacancy flux generated by annihilating dislocation loops may lead to the nucleation of

Zigzag phosphorene nanoribbons: one-dimensional resonant channels in two-dimensional atomic crystals

• Carlos. J. Páez,
• Dario. A. Bahamon,
• Ana L. C. Pereira and
• Peter. A. Schulz

Beilstein J. Nanotechnol. 2016, 7, 1983–1990, doi:10.3762/bjnano.7.189

• present work, edge-confined states are supported only by zigzag edges and are absent in armchair or bearded edges [11][12]. Therefore, introducing perturbations to a zigzag edge, such as edge vacancies, would locally destroy these 1D states. The consequences of these perturbations are very relevant in the

• transmission probability as a function of the energy as well as the LDOS associated to selected resonances in the presence of vacancies. Defects are normally seen as mechanisms that hinder the observation of transport properties associated to shape modulation of nanoscopic low-dimensional systems. Indeed, the

• resonance spectra are also dramatically modified in the present case. However, the issue can be seen from an entirely different point of view. The vacancies change locally the character of the edge. Thus, they actually introduce small barriers and further divide the system into smaller segments. The system

Nanostructured TiO₂-based gas sensors with enhanced sensitivity to reducing gases

• Wojciech Maziarz,
• Anna Kusior and
• Anita Trenczek-Zajac

Beilstein J. Nanotechnol. 2016, 7, 1718–1726, doi:10.3762/bjnano.7.164

• ], there are several possible explanations for this phenomenon. The first is related to formation of titanium vacancies, VTi, in the flower-like structure during synthesis. Upon Ti foil oxidation by H2O2, a mesoporous hierarchical structure is formed. The three-step process includes, inter alia

Scanning probe microscopy studies on the adsorption of selected molecular dyes on titania

• Jakub S. Prauzner-Bechcicki,
• Lukasz Zajac,
• Piotr Olszowski,
• Res Jöhr,
• Antoine Hinaut,
• Thilo Glatzel,
• Bartosz Such,
• Ernst Meyer and
• Marek Szymonski

Beilstein J. Nanotechnol. 2016, 7, 1642–1653, doi:10.3762/bjnano.7.156

• either by the formation of oxygen vacancies [36], which are point defects commonly found in TiO2(110) surfaces, or by doping [37], and are redistributed among multiple Ti lattice sites in the subsurface layers [36][37][38][39][40][41]. Thus, a defect state in the band gap is formed. Such delocalized

• to the oxide takes place, and an interface dipole is formed. To further understand the energy level alignment between a semiconducting substrate and an organic adsorbate, Lackinger, Janson and Ho [59] studied interactions between zinc(II) etioporphyrin (ZnEP) and oxygen vacancies, which are point

• defects commonly found in TiO2(110) surfaces. The energy level alignment is of crucial importance for DSSC applications of titania. The authors took special care to prepare a sample with unsaturated oxygen vacancies [59] because it is known that they can be easily passivated even at very low partial

Influence of hydrothermal synthesis parameters on the properties of hydroxyapatite nanoparticles

• Sylwia Kuśnieruk,
• Jacek Wojnarowicz,
• Agnieszka Chodara,
• Tadeusz Chudoba,
• Stanislaw Gierlotka and
• Witold Lojkowski

Beilstein J. Nanotechnol. 2016, 7, 1586–1601, doi:10.3762/bjnano.7.153

• of crystalline structure defects, caused by calcium ion vacancies, increases, diminishing material stability, and as a result, enhancing its solubility [20][21]. A range of various methods have been developed in order to produce HAp powder, among others, combustion preparation [22], and numerous wet

Three-gradient regular solution model for simple liquids wetting complex surface topologies

• Sabine Akerboom,
• Marleen Kamperman and
• Frans A. M. Leermakers

Beilstein J. Nanotechnol. 2016, 7, 1377–1396, doi:10.3762/bjnano.7.129

• approximation) we can evaluate the mixing interaction energy in the system by Umix = NχφV, where we ignored boundary effects and φV = NV/M is the volume fraction of vacancies. The entropy of mixing can be evaluated when we assume once more that the sites are randomly filled by solvent. The total number of ways

• to arrange the fluid and the vacancies is given by and the mixing entropy is found by Smix = −kB·lnΩ = −kB(N·ln φ + NV·ln φV) with φ = N/M and kB the Boltzmann constant. The free energy of mixing is given by Fmix = Umix – T·Smix. Introducing the dimensionless free energy density f = Fmix/(Mb3kBT

• obey scaling relations with respect to the difference to the critical point Δχ = χ − 2. Interestingly, near the critical point there is an analytical route to optimise the free energy F [40]. In short, near the critical point the density of the liquid (and thus also for the vacancies) is never far from

Influence of synthesis conditions on microstructure and phase transformations of annealed Sr₂FeMoO_6−x nanopowders formed by the citrate–gel method

• Marta Yarmolich,
• Nikolai Kalanda,
• Sergey Demyanov,
• Herman Terryn,
• Jon Ustarroz,
• Maksim Silibin and
• Gennadii Gorokh

Beilstein J. Nanotechnol. 2016, 7, 1202–1207, doi:10.3762/bjnano.7.111

• atmosphere with predetermined anionic and cationic defectiveness, is problematic [9]. This is due to several factors: the phase purity within the sample, cation and anion vacancies, sample microstructure, chemical composition and thickness of the grain boundaries [10][11][12][13]. Sol–gel technology is a

Reasons and remedies for the agglomeration of multilayered graphene and carbon nanotubes in polymers

• Rasheed Atif and
• Fawad Inam

Beilstein J. Nanotechnol. 2016, 7, 1174–1196, doi:10.3762/bjnano.7.109

• into vacancies thereby self-repairing holes in the graphene sheet. Faber and Evans, using crack deflection modeling, showed that, among all other nano-reinforcements, maximum enhancement in fracture toughness can be attained by employing graphene as reinforcement. This improvement in fracture toughness

Photocurrent generation in carbon nanotube/cubic-phase HfO₂ nanoparticle hybrid nanocomposites

• Protima Rauwel,
• Augustinas Galeckas,
• Martin Salumaa,
• Frédérique Ducroquet and
• Erwan Rauwel

Beilstein J. Nanotechnol. 2016, 7, 1075–1085, doi:10.3762/bjnano.7.101

• surface-located intrinsic and extrinsic defects arising from Hf3+ and O2− vacancies. The small diameter of the nanoparticles in the present study, 2.6 nm on average, implies a very high surface-to-volume ratio, and consequently, enhanced surface-defect-related luminescence. Furthermore, for the cubic

• -phase HfO2 nanoparticles, oxygen vacancies acting as luminescence trap states are present in large amounts [22]. In the variety of different techniques used to decorate CNTs, the first step is usually the dispersion of the CNTs in a liquid solution as they exist in the form of bundled ropes [23]. Acid

• nanoparticles in the process of CNT decoration. In fact, acid treatment creates defects (vacancies and holes in the side walls) on the CNT surfaces along with carboxyl groups in the case of carboxylic acid treatment [24]. The bond with these carboxyl groups is then created via hydroxyl groups present on the

NO gas sensing at room temperature using single titanium oxide nanodot sensors created by atomic force microscopy nanolithography

• Li-Yang Hong and
• Heh-Nan Lin

Beilstein J. Nanotechnol. 2016, 7, 1044–1051, doi:10.3762/bjnano.7.97

• Figure S1 in Supporting Information File 1.) We discussed the electrical properties of the sensors in our previous report [32]. A TiOx ND behaves like an n-type semiconductor due to oxygen vacancies. When NO molecules (or O2 molecules under ambient environment) adsorb on the ND surface, they become

Microscopic characterization of Fe nanoparticles formed on SrTiO₃(001) and SrTiO₃(110) surfaces

• Miyoko Tanaka

Beilstein J. Nanotechnol. 2016, 7, 817–824, doi:10.3762/bjnano.7.73

• surface is sputter-cleaned, it becomes severely disordered, forming oxygen vacancies in the uppermost layers [28]. Subsequent annealing induces oxygen diffusion and surface recrystallization at the same time, making various superstructures possible to appear. In our experiments, TEM STO(001) substrates

• , especially the presence of oxygen vacancies formed during UHV annealing. Our previous studies found that surfaces of both STO(001) and STO(110) have oxygen-depleted (1 × 1) structures [25]. Surface energies for these may differ from those of fully oxidized ones and may alter above values. Still, the present

Microwave solvothermal synthesis and characterization of manganese-doped ZnO nanoparticles

• Jacek Wojnarowicz,
• Roman Mukhovskyi,
• Elzbieta Pietrzykowska,
• Sylwia Kusnieruk,
• Jan Mizeracki and
• Witold Lojkowski

Beilstein J. Nanotechnol. 2016, 7, 721–732, doi:10.3762/bjnano.7.64

• ., formation of clusters [31]), the precipitation of foreign phases [33][34], the stoichiometry; the presence of oxygen vacancies [35][36], and defects of the crystalline lattice. When the synthesis or calcination of Zn1−xMnxO was carried out in an oxidising environment and the absence of foreign phases was

• ]. But when a reducing environment was selected for sample calcination, also precipitations of ZnMnO3 and ZnMn2O4 phase emerged in Zn1−xMnxO and the material displayed only ferromagnetic properties [36]. Ferromagnetic properties of Zn1−xMnxO are explained by the presence of oxygen vacancies, manganese in

• properties in the case of Zn1−xMnxO is the lack of control over the doping impact on the formation of oxygen vacancies, crystalline lattice defects and dopant clusters [48]. It is presumed that there are several competitive chemical reactions in the reaction of Zn1−xMnxO synthesis, such as the oxidisation of

Orientation of FePt nanoparticles on top of a-SiO₂/Si(001), MgO(001) and sapphire(0001): effect of thermal treatments and influence of substrate and particle size

• Martin Schilling,
• Paul Ziemann,
• Zaoli Zhang,
• Johannes Biskupek,
• Ute Kaiser and
• Ulf Wiedwald

Beilstein J. Nanotechnol. 2016, 7, 591–604, doi:10.3762/bjnano.7.52

• leading to an atomically smooth surface for nanoparticle and film deposition. Since charging of the MgO substrate turned out to deteriorate the RHEED pattern, we further annealed the bare substrate under hydrogen atmosphere at 5·10−6 mbar to create oxygen vacancies, leading to a sufficient surface

Bacteriorhodopsin–ZnO hybrid as a potential sensing element for low-temperature detection of ethanol vapour

• Saurav Kumar,
• Sudeshna Bagchi,
• Senthil Prasad,
• Anupma Sharma,
• Ritesh Kumar,
• Rishemjit Kaur,
• Jagvir Singh and
• Amol P. Bhondekar

Beilstein J. Nanotechnol. 2016, 7, 501–510, doi:10.3762/bjnano.7.44

• crystallization and less oxygen vacancies [53]. As observed from Figure 4, the PL intensity increases with increasing excitation wavelength (i.e., 280 nm and 320 nm), which may be attributed to electron–hole plasma recombination shift by band renormalization [54]. Figure 5 shows the Raman spectra for all the

Plasticity-mediated collapse and recrystallization in hollow copper nanowires: a molecular dynamics simulation

• Amlan Dutta,
• Arup Kumar Raychaudhuri and
• Tanusri Saha-Dasgupta

Beilstein J. Nanotechnol. 2016, 7, 228–235, doi:10.3762/bjnano.7.21

• scales associated with different stages of the evolution process. Our findings suggest a plasticity-mediated mechanism of collapse and recrystallization. This contradicts the prevailing notion of diffusion driven transport of vacancies from the interior to outer surface being responsible for collapse

• with hollow core is thermodynamically unstable due to the internal free surface, and shows the tendency to collapse. The kinetics of the collapse has been assumed to proceed through the slow diffusive route, where the migration of vacancies from the hollow core to the outer surface is considered to be

• the dominating mechanism. Accordingly, analytical theories and Monte Carlo simulations based on the process of thermally activated diffusion process have been developed and carried out [12]. However, the proposed mechanism of collapse via migration of vacancies from the inner core to the outer surface

Fabrication of hybrid graphene oxide/polyelectrolyte capsules by means of layer-by-layer assembly on erythrocyte cell templates

• Joseba Irigoyen,
• Nikolaos Politakos,
• Eleftheria Diamanti,
• Elena Rojas,
• Marco Marradi,
• Raquel Ledezma,
• Layza Arizmendi,
• J. Alberto Rodríguez,
• Ronald F. Ziolo and
• Sergio E. Moya

Beilstein J. Nanotechnol. 2015, 6, 2310–2318, doi:10.3762/bjnano.6.237

• ratio of 0.8. The D resonance corresponds to the vibration of sp2 carbon while G corresponds to sp3 carbon and defects associated with vacancies and grain boundaries [28]. The peaks at higher wavenumbers are also characteristic of graphene oxide. XRD results (Figure 1d) indicate the absence of graphite

Plasma fluorination of vertically aligned carbon nanotubes: functionalization and thermal stability

• Claudia Struzzi,
• Mattia Scardamaglia,
• Axel Hemberg,
• Luca Petaccia,
• Jean-François Colomer,
• Rony Snyders and
• Carla Bittencourt

Beilstein J. Nanotechnol. 2015, 6, 2263–2271, doi:10.3762/bjnano.6.232

• on the surface attracts water adsorption, in contrast to the case of pure fluorinated carbon systems that show strong hydrophobicity [20]. In addition to the presence of oxygen atoms grafted during plasma treatment, we must consider that defects such as vacancies created during the process are

• associated to the A1g-mode breathing vibrations of six-membered sp2 carbon rings. It becomes Raman active after neighboring sp2 carbons are converted to sp3 hybridization in graphitic materials. This can be due to the presence of in-plane substitutional heteroatom vacancies, grain boundaries, or other

A single-source precursor route to anisotropic halogen-doped zinc oxide particles as a promising candidate for new transparent conducting oxide materials

• Daniela Lehr,
• Markus R. Wagner,
• Johanna Flock,
• Julian S. Reparaz,
• Clivia M. Sotomayor Torres,
• Alexander Klaiber,
• Thomas Dekorsy and
• Sebastian Polarz

Beilstein J. Nanotechnol. 2015, 6, 2161–2172, doi:10.3762/bjnano.6.222

• recorded at room temperature (Figure 4c). Furthermore, Cl doping strongly affects the so-called green luminescence, which is associated with electrons trapped at oxygen vacancies (VO•• in Kröger–Vink notation) present in many different types of ZnO materials [63]. It can be seen that the intensity of the