Magnetic properties of Fe₃O₄ antidot arrays synthesized by AFIR: atomic layer deposition, focused ion beam and thermal reduction

• Juan L. Palma,
• Alejandro Pereira,
• Raquel Álvaro,
• José Miguel García-Martín and
• Juan Escrig

Beilstein J. Nanotechnol. 2018, 9, 1728–1734, doi:10.3762/bjnano.9.164

• tendency changes. It is important to point out that the coercivities obtained by the AFIR technique are almost twice as high as those obtained with other techniques, considering similar geometrical and magnetic parameters [39]. From a magnetic viewpoint each nanohole may be considered as a defect since

• they act as pinning centers for the domain wall motion during magnetization reversal. If a is the lattice constant (nearest neighbor center-to-center distance) and d is the hole diameter, the defect volume density (DVD), which is the ratio of the surface covered by holes to the total surface, is given

• applying the external magnetic field along the first and second neighbors directions. (b) Coercivity as a function of the defect volume density (DVD). Coercivity (red squares) and normalized remanence (blue dots) as a function of the angle θ at which the external magnetic field is applied for a square

Multimodal noncontact atomic force microscopy and Kelvin probe force microscopy investigations of organolead tribromide perovskite single crystals

• Yann Almadori,
• David Moerman,
• Jaume Llacer Martinez,
• Philippe Leclère and
• Benjamin Grévin

Beilstein J. Nanotechnol. 2018, 9, 1695–1704, doi:10.3762/bjnano.9.161

• (enabling discrimination between extrinsic surface contamination and intrinsic defect formation). Here, our primary goal is to check if the surface photovoltage and crystal photostriction can be simultaneously and reliably probed by nc-AFM/KPFM. The discussion will be thus focused on the analysis of the

Evaluation of replicas manufactured in a 3D-printed nanoimprint unit

• Manuel Caño-García,
• Morten A. Geday,
• Manuel Gil-Valverde,
• Xabier Quintana and
• José M. Otón

Beilstein J. Nanotechnol. 2018, 9, 1573–1581, doi:10.3762/bjnano.9.149

• features below 10 nm, but increases significantly the defect rate from contaminating particles and air bubbles. Soft NIL employs molds of elastomeric materials such as polydimethylsiloxanes (PDMS) or polyimides at the expense of lower resolution [5]. Hybrid NIL adopts an intermediate position by utilizing

Absence of free carriers in silicon nanocrystals grown from phosphorus- and boron-doped silicon-rich oxide and oxynitride

• Daniel Hiller,
• Julian López-Vidrier,
• Keita Nomoto,
• Michael Wahl,
• Wolfgang Bock,
• Tomáš Chlouba,
• František Trojánek,
• Sebastian Gutsch,
• Margit Zacharias,
• Dirk König,
• Petr Malý and
• Michael Kopnarski

Beilstein J. Nanotechnol. 2018, 9, 1501–1511, doi:10.3762/bjnano.9.141

• context, it is also likely that for samples with >1 atom % P the P-concentration peak found at the Si/SiO2 interface (cf. Figure 2b) reaches a level where a highly enriched P-shell forms on the NC-surface that enables efficient formation of non-radiative defect states. For boron, strong PL-quenching is

• doping, i.e., the generation of free carriers from dopants on substitutional lattice sites, requires thermal ionization, typically provided by the thermal energy at room temperature. Ignoring all the evidence of a defect-related PL-quenching of Si NCs containing P- or B-atoms, we would anticipate from

• temperature. Hence, a freeze-out effect of dopant-induced free carriers that quench the PL is not observed in accordance with dopant-induced defect states deep within the fundamental gap of the NCs. Figure 4b plots the PL peak shift with reference to 300 K, i.e., where a maximum of dopant-induced free

Cr(VI) remediation from aqueous environment through modified-TiO₂-mediated photocatalytic reduction

• Rashmi Acharya,
• Brundabana Naik and
• Kulamani Parida

Beilstein J. Nanotechnol. 2018, 9, 1448–1470, doi:10.3762/bjnano.9.137

• place by the sulfate redox couple attached to nitrogen-doped TiO2 [63]. Hydrogenated defect-promoted black titania exhibits much higher absorption and photocatalytic activity [94][95]. The recombination and charge transfer efficiency can be understood from PL spectra. The PL emission intensity is

Understanding the performance and mechanism of Mg-containing oxides as support catalysts in the thermal dry reforming of methane

• Nor Fazila Khairudin,
• Mohd Farid Fahmi Sukri,
• Mehrnoush Khavarian and
• Abdul Rahman Mohamed

Beilstein J. Nanotechnol. 2018, 9, 1162–1183, doi:10.3762/bjnano.9.108

• , Yan et al. [101] confirmed that plasma treated catalysts can improve the interaction between Ni and the SiO2 support and produces less defect sites on the Ni particles. The authors further remarked that this plasma treatment could suppress inactive carbon deposition and enhance catalyst performance

• for Ni catalysts were treated via thermal decomposition recorded with a great number of defect sites, which consist of Ni (100) and Ni (101) surfaces. These surfaces could increase carbon deposition rate. Table 3 summarizes the development and process conditions of Mg-containing oxide catalysts used

Semi-automatic spray pyrolysis deposition of thin, transparent, titania films as blocking layers for dye-sensitized and perovskite solar cells

• Hana Krýsová,
• Josef Krýsa and
• Ladislav Kavan

Beilstein J. Nanotechnol. 2018, 9, 1135–1145, doi:10.3762/bjnano.9.105

• ,FTO is the current density peak measured at a bare FTO electrode. The actual values are listed in Table 2. As suggested in a previous work [3], there are two types of defects in the barrier film: (i) “defect A” – the partially blocked electrode behaves like a “clean” FTO but with a relatively smaller

• effective area. The relative increase of voltammetric peaks separation (ΔEpp) on the BL normalized to that for pure FTO is smaller than 3. (ΔEpp is defined as the difference between the peak potentials for the Fe(CN)64− oxidation and Fe(CN)63− reduction). (ii) “defect B” – a more complex situation, where

• the defect causes not only the delamination of the titania film from FTO, but also the slowdown of charge transfer kinetics (accompanied by a strong increase in ΔEpp). The barrier properties after post calcination were fairly good for the 0.05 M TAA precursor and the largest layer thickness (200 SCs

Room-temperature single-photon emitters in titanium dioxide optical defects

• Kelvin Chung,
• Yu H. Leung,
• Chap H. To,
• Aleksandra B. Djurišić and
• Snjezana Tomljenovic-Hanic

Beilstein J. Nanotechnol. 2018, 9, 1085–1094, doi:10.3762/bjnano.9.100

• observing its photon statistics. Once a single-photon emitter was identified, the defect was characterised by obtaining its PL spectrum and recording the photodynamics of its count trace. Fluorescence was observed in all the morphologies. However, single-photon emission was only observed in two morphologies

• acquired and can be seen in Figure 4a. The PL spectrum of the defect shows red fluorescence between 600 and 700 nm. There were three resolvable peaks at 610, 619 and 630 nm. Red fluorescence has been attributed to under-coordinated Ti3+ ions in atomic layer deposited films [41], electrons trapped at

• surface defect sites [59] and surface oxygen vacancies on anatase nanocrystal films [60]. Similar photoluminescence in the red was also observed from ZnO defects [7][8][9]. The photodynamics of D1 was also recorded and can be seen for a pump power of 82 μW in Figure 4b. The time trace shows photostability

Fatigue crack growth characteristics of Fe and Ni under cyclic loading using a quasi-continuum method

• Ren-Zheng Qiu,
• Yi-Chen Lin and
• Te-Hua Fang

Beilstein J. Nanotechnol. 2018, 9, 1000–1014, doi:10.3762/bjnano.9.93

• holes, followed by the expansion of the crack tip toward the defect area (Figure 3c). Moreover, at a tension distance of 3 nm, where the crack length increased from 44 Å to 131 Å, the crack tip easily grew along the slip orientation of [110] [4][6] (Figure 3d). Next, the microstructure evolution around

• the crack tip for compression is shown in Figure 3e,f, assuming that the loading distance starts from 3 nm to 6 nm. The results indicated that the originally split parts of the sample coalesce, and defect holes are still present inside the crack tip even if the sample is compressed to the initial

• tip and the suppression of the crack growth for Fe. This observation is in good agreement with that of Ma et al. [11]. Previously, Vatne et al. [18] have indicated that a blunting of the crack tip and the growth of the defect holes are observed during tension loading. This result is similar to that

Electro-optical interfacial effects on a graphene/π-conjugated organic semiconductor hybrid system

• Karolline A. S. Araujo,
• Luiz A. Cury,
• Matheus J. S. Matos,
• Thales F. D. Fernandes,
• Luiz G. Cançado and
• Bernardo R. A. Neves

Beilstein J. Nanotechnol. 2018, 9, 963–974, doi:10.3762/bjnano.9.90

• defect density is already small in such well-organized monolayer films and, thus, defect-mediated nonradiative recombination plays a minor role. As a consequence, there should be no substantial increase in recombination efficiency as the temperature decreases, as observed in Figure 3c. Besides RA SAM

Cyclodextrin inhibits zinc corrosion by destabilizing point defect formation in the oxide layer

• Abdulrahman Altin,
• Maciej Krzywiecki,
• Adnan Sarfraz,
• Cigdem Toparli,
• Claudius Laska,
• Philipp Kerger,
• Aleksandar Zeradjanin,
• Karl J. J. Mayrhofer,
• Michael Rohwerder and
• Andreas Erbe

Beilstein J. Nanotechnol. 2018, 9, 936–944, doi:10.3762/bjnano.9.86

• interface, closely resembling the energy level alignment in an n–p junction. The energy level shift is too large to permit further electron transfer through the layer, inhibiting corrosion. Adsorption hence changes the defect density in the protecting ZnO layer. This mechanism of corrosion inhibition shows

• that affecting the defect chemistry of passivating films by molecular inhibitors maybe a viable strategy to control corrosion of metals. Keywords: band diagram; defect chemistry; organic corrosion inhibitors; X-ray photoelectron spectroscopy; zinc corrosion; Introduction Organic corrosion inhibitors

• reactions, forming precipitates such as hydrated zinc oxide [15]. ZnO is naturally an n-type semiconductor with a band gap of 3.4 eV [20]. Oxides formed in an aerated corrosion process are typically defect-rich oxides [21], especially in the presence of Cl− [15]. Consequently, the products remain initially

Optical orientation of nematic liquid crystal droplets via photoisomerization of an azodendrimer dopant

• Sergey A. Shvetsov,
• Alexander V. Emelyanenko,
• Natalia I. Boiko,
• Alexander S. Zolot'ko,
• Yan-Song Zhang,
• Jui-Hsiang Liu and
• Alexei R. Khokhlov

Beilstein J. Nanotechnol. 2018, 9, 870–879, doi:10.3762/bjnano.9.81

• in the droplets resting on the solid substrate [30]. The NLC director distribution with boojum defect on the top of the droplet (Figure 1a) can be reversibly changed to almost homeotropic NLC alignment (Figure 1b). The interest in these geometries of NLC droplets is explained by their better

• distribution with one bujoom defect on the top (Figure 1a). These droplets are visualized in crossed polarizers as slightly twisted Maltese crosses, while the smaller droplets between them are the previously described droplets in the bulk of glycerol (Figure 3a). A twist can be explained by the difference

• conditions with glycerol (Figure 1b), and the droplet structure becomes almost homogeneous with the director being preferably oriented normally to the substrate and visualized as dark regions (Figure 3b). The UV illumination with λmax = 365 nm (or 384 nm) provides the boojum defect formation due to planar

Surface-plasmon-enhanced ultraviolet emission of Au-decorated ZnO structures for gas sensing and photocatalytic devices

• T. Anh Thu Do,
• Truong Giang Ho,
• Thu Hoai Bui,
• Quang Ngan Pham,
• Hong Thai Giang,
• Thi Thu Do,
• Duc Van Nguyen and
• Dai Lam Tran

Beilstein J. Nanotechnol. 2018, 9, 771–779, doi:10.3762/bjnano.9.70

• the band gap of the ZnO particles slightly decreases when decorated with the Au NPs. Photoluminescence measurements of ZnO and Au NP/ZnO samples were performed at room temperature, as shown in Figure 3c. The PL spectra exhibit an intense, narrow UV band edge emission at 385 nm, and a defect-related

• defect-related emission band of ZnO. The electron–hole (e–h) pairs near the Au NP/ZnO interface generated by the laser source are extracted by the local electric field in the region of the energy barrier of the Au NP/ZnO structure, thus increasing the free carrier density and reducing the energy barrier

• . The inset of Figure 3c shows the band bending, the Fermi energy level of the ZnO and the electron transfer from Au to ZnO. The e–h recombination in Au NP/ZnO structures can be promoted and leads to an enhanced UV emission. The strong electronic interaction between Au NPs and the defect sites of ZnO

A review of carbon-based and non-carbon-based catalyst supports for the selective catalytic reduction of nitric oxide

• Shahreen Binti Izwan Anthonysamy,
• Syahidah Binti Afandi,
• Mehrnoush Khavarian and
• Abdul Rahman Bin Mohamed

Beilstein J. Nanotechnol. 2018, 9, 740–761, doi:10.3762/bjnano.9.68

• groups for the attachment of metal nanoparticles. It is believed that the oxidative treatment may create defects to the hexagonal or pentagonal structures of the GR sheet in the nanotubes. The functional groups can be introduced at the bent parts, defect sites, and at the sidewall of the MWCNTs. Acid

Dynamics and fragmentation mechanism of (C₅H₄CH₃)Pt(CH₃)₃ on SiO₂ surfaces

• Kaliappan Muthukumar,
• Harald O. Jeschke and
• Roser Valentí

Beilstein J. Nanotechnol. 2018, 9, 711–720, doi:10.3762/bjnano.9.66

• higher than those when using the 3 × 3 × 4 slabs, owing to the enhanced concentration of the hydroxyl groups and defect sites, and the closer packing of the molecules. On the 50% dehydroxylated cells, where two surface active sites are located adjacent to each other, one of the methyl groups, which was

The effect of atmospheric doping on pressure-dependent Raman scattering in supported graphene

• Egor A. Kolesov,
• Mikhail S. Tivanov,
• Olga V. Korolik,
• Olesya O. Kapitanova,
• Xiao Fu,
• Hak Dong Cho,
• Tae Won Kang and
• Gennady N Panin

Beilstein J. Nanotechnol. 2018, 9, 704–710, doi:10.3762/bjnano.9.65

• -controlled box (pressure ranged from 1000 to about 5 × 10−5 mbar). A laser power of 2 mW was used, and the laser spot diameter was about 1.5 µm. Pressure-dependent measurements were carried out in a typical graphene monolayer and a bilayer low-defect region. Raman spectra of graphene on various substrates

Sensing behavior of flower-shaped MoS₂ nanoflakes: case study with methanol and xylene

• Maryam Barzegar,
• Masoud Berahman and
• Azam Iraji zad

Beilstein J. Nanotechnol. 2018, 9, 608–615, doi:10.3762/bjnano.9.57

• charge transfer from xylene to MoS2. Since only defect sites can aquire charges from xylene, we expect only one mechanism for gas detection of this kind. Figure 7 illustrates the interaction of methanol on pristine and sulfur-vacancy MoS2 and the electron density of these materials. As can be seen

• , methanol can transfer charge via van der Waals interactions both toward the pristine and the defect-containing MoS2. These two different detection sites for methanol can result in two distinct mechanisms that are observed in our experiments. The fast process is related to charge transfer on the pristine

• Mulliken population shows that the charge transfer in the case of xylene on pristine and the defect-containing MoS2 is almost 0.001e and 0.027e (average of different isomers), respectively, in the area of study. In the case of methanol, the Mulliken population is 0.04e and 0.071e in the pristine and the

Anchoring Fe₃O₄ nanoparticles in a reduced graphene oxide aerogel matrix via polydopamine coating

• Błażej Scheibe,
• Radosław Mrówczyński,
• Natalia Michalak,
• Karol Załęski,
• Michał Matczak,
• Mateusz Kempiński,
• Zuzanna Pietralik,
• Mikołaj Lewandowski,
• Stefan Jurga and
• Feliks Stobiecki

Beilstein J. Nanotechnol. 2018, 9, 591–601, doi:10.3762/bjnano.9.55

• material is an amorphous carbon. However, the use of other excitation energies leads to completely different conclusions. The calculated ID/IG ratios and mean defect distance (LD) together with full-widths-at-half-maximum (FWHM) of D and G peaks of rGO-based aerogels probed with different laser sources are

• reference rGO aerogel, the rGO-Fe3O4 and rGO-PDA@Fe3O4 aerogel structures have less defects and higher structural order. The first effect is related to a k-selective resonant Raman scattering process observed in graphite-based materials, where the defect-activated D mode is excitation laser-dependent due to

• reference rGO aerogel, is related to the stabilization of rGO aerogel structure by Fe3O4 nanoparticles that anchor at the GO defect sites via monodente or bidentate coordination of iron with carboxylic groups during hydrogel formation [49]. In the case of the rGO-PDA@Fe3O4 sample, this effect is even more

Green synthesis of fluorescent carbon dots from spices for in vitro imaging and tumour cell growth inhibition

• Nagamalai Vasimalai,
• Vânia Vilas-Boas,
• Juan Gallo,
• María de Fátima Cerqueira,
• Mario Menéndez-Miranda,
• José Manuel Costa-Fernández,
• Lorena Diéguez,
• Begoña Espiña and
• María Teresa Fernández-Argüelles

Beilstein J. Nanotechnol. 2018, 9, 530–544, doi:10.3762/bjnano.9.51

• months without any loss of their optical properties. Typically, C-dots exhibit an interesting excitation-dependent photoluminescence, entirely different from other luminescent materials such as semiconductor quantum dots, gold or silver nanoclusters. This luminescence is attributed to defect states of

• the C-dots (surface defect emission) and intrinsic defects (zig-zag site emission) [8]. Figure 2 illustrates the emission profile of black pepper C-dots at different excitation wavelengths. The emission spectra were recorded at excitation wavelengths ranging from 290 to 600 nm, and a red shift of the

Sugarcane juice derived carbon dot–graphitic carbon nitride composites for bisphenol A degradation under sunlight irradiation

• Lan Ching Sim,
• Jing Lin Wong,
• Chen Hong Hak,
• Jun Yan Tai,
• Kah Hon Leong and
• Pichiah Saravanan

Beilstein J. Nanotechnol. 2018, 9, 353–363, doi:10.3762/bjnano.9.35

• with previous reports [4][56]. Although the origin of the PL luminescence in CDs is not fully elucidated, the excitation-dependent PL behavior of CDs is usually correlated to the size distribution of CDs, the recombination of photogenerated charges at surface-confined defect states and the different

Wafer-scale bioactive substrate patterning by chemical lift-off lithography

• Chong-You Chen,
• Chang-Ming Wang,
• Hsiang-Hua Li,
• Hong-Hseng Chan and
• Wei-Ssu Liao

Beilstein J. Nanotechnol. 2018, 9, 311–320, doi:10.3762/bjnano.9.31

• pattern feature and size, large-area fabrication, high resolution and fidelity control, and the ability to functionalize versatile bioarrays. With the interface-contact-induced reaction, a preformed alkanethiol self-assembled monolayer on a Au surface is ruptured and a unique defect-rich diluted matrix is

• behavior compared to other SAM systems. Here, the lift-off process creates a diluted molecular matrix environment which is expected to be due to partial Au thiolate removal in SAMs. With the appropriate adjustment of the experimental conditions, this “diluted artificial defect-rich” matrix provides an

• abundance of opportunities to create different bioactive substrates via a straightforward one-step SAM defect control. Compared to conventional biological platform generation, this matrix provides the advantages of wide probe compatibility, minimized nonspecific biospecies adhesion, versatile platform

The nanofluidic confinement apparatus: studying confinement-dependent nanoparticle behavior and diffusion

• Stefan Fringes,
• Felix Holzner and
• Armin W. Knoll

Beilstein J. Nanotechnol. 2018, 9, 301–310, doi:10.3762/bjnano.9.30

• 15 s. The gap distance can be stabilized to ≈1 nm (1σ). The stability of the setup in lateral direction was measured by observing the drift of a surface defect in the tool. A lateral drift of ≈100 nm/h was observed. We note that this drift is slow compared to the observed particle motion and does not

Al₂O₃/TiO₂ inverse opals from electrosprayed self-assembled templates

• Arnau Coll,
• Sandra Bermejo,
• David Hernández and
• Luís Castañer

Beilstein J. Nanotechnol. 2018, 9, 216–223, doi:10.3762/bjnano.9.23

• top-down approaches based on lithography or holography), the present state of the current techniques [8][9][10][11][12][13] either leads to various randomly oriented domains [14] or to limited defect-free areas, and furthermore, they are typically very slow fabrication processes. In addition, a review

Liquid-crystalline nanoarchitectures for tissue engineering

• Baeckkyoung Sung and
• Min-Ho Kim

Beilstein J. Nanotechnol. 2018, 9, 205–215, doi:10.3762/bjnano.9.22

• cells and surrounding tissues is required. [116]. LC nanoarchitectures formed by hydrated lipids are also an important class that is to be investigated for tissue engineering purposes [117][118][119][120][121][122][123][124][125][126][127]. Biophysical roles of defect structures appearing in biological

Dopant-stimulated growth of GaN nanotube-like nanostructures on Si(111) by molecular beam epitaxy

• Alexey D. Bolshakov,
• Alexey M. Mozharov,
• Georgiy A. Sapunov,
• Igor V. Shtrom,
• Nickolay V. Sibirev,
• Vladimir V. Fedorov,
• Evgeniy V. Ubyivovk,
• Maria Tchernycheva,
• George E. Cirlin and
• Ivan S. Mukhin

Beilstein J. Nanotechnol. 2018, 9, 146–154, doi:10.3762/bjnano.9.17

• defect-free structures on highly mismatched substrates, e.g., GaN NWs on Si [7][8]. NWs usually possess high crystal quality due to the effective mechanical stress relaxation at a distance of about one NW base diameter from the substrate. Nanowires synthesized on Si are very promising nanostructures in