Self-assembly of silicon nanowires studied by advanced transmission electron microscopy

• Marta Agati,
• Guillaume Amiard,
• Vincent Le Borgne,
• Paola Castrucci,
• Richard Dolbec,
• Maurizio De Crescenzi,
• My Alì El Khakani and
• Simona Boninelli

Beilstein J. Nanotechnol. 2017, 8, 440–445, doi:10.3762/bjnano.8.47

• of silicon nanowires (SiNWs) that were self-assembled during an inductively coupled plasma (ICP) process. The ICP-synthesized SiNWs were found to present a Si–SiO2 core–shell structure and length varying from ≈100 nm to 2–3 μm. The shorter SiNWs (maximum length ≈300 nm) were generally found to

• . Energy-filtered TEM (EFTEM) images, acquired in correspondence to the Si plasmon loss (17 eV) and SiO2 plasmon loss (23 eV), display a common core–shell Si–SiO2 internal structure for both the NSs and the NWs (see Figure 1b and Figure 1c). Further EFTEM investigations conducted on hundreds of NWs

• Visualiser Kai software was used for visualization. (a) Typical SEM image showing the morphology of the as-collected sample; EFTEM images obtained at (b) the Si plasmon loss (17 eV) and (c) the SiO2 plasmon loss (23 eV), revealing the Si–SiO2 core–shell structure and the structural continuity between the Si

Methods for preparing polymer-decorated single exchange-biased magnetic nanoparticles for application in flexible polymer-based films

• Laurence Ourry,
• Delphine Toulemon,
• Souad Ammar and
• Fayna Mammeri

Beilstein J. Nanotechnol. 2017, 8, 408–417, doi:10.3762/bjnano.8.43

• for technological applications is of primary importance. Results: In this work, well-characterized exchange-biased perfectly epitaxial CoxFe3−xO4@CoO core@shell NPs, which were isotropic in shape and of about 10 nm in diameter, were decorated by two different polymers, poly(methyl methacrylate) (PMMA

• magnetic NPs to decrease interparticle interactions, particularly dipolar ones [7][8]. The general strategy for such a purpose consists of forming core–shell hybrid structures in which the shell consists of a corona of polymer chains grafted onto the inorganic NP surface. Among the available polymer

• C 1s peak prior to functionalization indicates that organic residues (polyol and acetate molecules) are present at the core–shell NP surface. The Co 2p and Fe 2p peaks are much weaker after polymerization due the presence of a significant polymer coating. The decomposition of the C 1s peak for

Functionalized TiO₂ nanoparticles by single-step hydrothermal synthesis: the role of the silane coupling agents

• Antoine R. M. Dalod,
• Lars Henriksen,
• Tor Grande and
• Mari-Ann Einarsrud

Beilstein J. Nanotechnol. 2017, 8, 304–312, doi:10.3762/bjnano.8.33

• route was demonstrated, and by selecting the type of silane coupling agent the surface properties of the TiO2 nanoparticles could be tailored. This synthesis route has been further developed into a two-step synthesis to TiO2–SiO2 core–shell nanoparticles. Combustion of the silane coupling agents up to

• 700 °C leads to the formation of a nanometric amorphous SiO2 layer, preventing growth and phase transition of the in situ functionalized nanoparticles. Keywords: core–shell nanoparticles; functionalized nanoparticles; hydrothermal synthesis; oriented attachment; silane coupling agent; Introduction

• , surface coverage, and hydrophobicity. Tuning the surface properties of the nanoparticles for different applications by selecting the silane coupling agent is discussed. We further report the effect of heat treatment of the nanoparticles for the formation of core–shell TiO2–SiO2 nanoparticles. Experimental

Phosphorus-doped silicon nanorod anodes for high power lithium-ion batteries

• Chao Yan,
• Qianru Liu,
• Jianzhi Gao,
• Zhibo Yang and
• Deyan He

Beilstein J. Nanotechnol. 2017, 8, 222–228, doi:10.3762/bjnano.8.24

• the shell and the particles, allowing for the expansion of Si without deforming the carbon shell. Such an anode shows a capacity retention of 74% after 1000 cycles at a rate of C/10 [9]. Yang et al. fabricated a Si-based anode with a core–shell–shell heterostructure of Si nanoparticles as the core

• Figure 1b, it can be seen that the Si layer was totally amorphous. The structural information of the obtained Si anode was further identified by transmission electron microscopy (TEM). Figure 2a clearly shows that the Si was conformally coated on the CuO nanorods, resulting in a core–shell nanorod

• electrochemical performance of the obtained Si anode could be ascribed to the following factors. First, the transport paths for electrons and Li ions were significantly shortened in the nanorod core–shell-structured electrode. Then, the transport velocity for electrons and Li ions was enhanced by the phosphorus

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

• as core–shell particles. Table 1 presents some of the examples of the latest papers dealing with TiO2–SnO2 materials for the detection of different gases. The performance of a resistive-type gas sensor is inherently related to the form and number of oxygen species adsorbed at the surface of the

From iron coordination compounds to metal oxide nanoparticles

• Mihail Iacob,
• Carmen Racles,
• Codrin Tugui,
• George Stiubianu,
• Adrian Bele,
• Liviu Sacarescu,
• Daniel Timpu and
• Maria Cazacu

Beilstein J. Nanotechnol. 2016, 7, 2074–2087, doi:10.3762/bjnano.7.198

• appear as core–shell type materials, where the core has a higher contrast (indicating the presence of metal), and the shell has a lower contrast, characteristic for organic compounds (in this case, the stabilizer). In Figure 3a–c the TEM images are shown and the histograms of the distribution by diameter

•  3d). The core–shell morphology is visible in Figure 3c, with an inorganic core covered by the surfactant. Nanoparticle samples (NPT4) were obtained starting from a FeAc2 ([Fe3O(CH3COO)6(H2O)3]NO3∙4H2O) cluster. TEM observations (Figure 4) revealed particles in the form of spheres with hair-like

Organoclay hybrid materials as precursors of porous ZnO/silica-clay heterostructures for photocatalytic applications

• Marwa Akkari,
• Pilar Aranda,
• Abdessalem Ben Haj Amara and
• Eduardo Ruiz-Hitzky

Beilstein J. Nanotechnol. 2016, 7, 1971–1982, doi:10.3762/bjnano.7.188

• may remain assembled to ZnO particles, perhaps organized even as core–shell structures (Figure 4C). EDX analysis of ZnO/silica-clay heterostructures shows the presence of Zn in a significant amount with respect to the Si content in all the samples. However, it is complicated to estimate the precise

Diameter-driven crossover in resistive behaviour of heavily doped self-seeded germanium nanowires

• Stephen Connaughton,
• Maria Koleśnik-Gray,
• Richard Hobbs,
• Olan Lotty,
• Justin D. Holmes and
• Vojislav Krstić

Beilstein J. Nanotechnol. 2016, 7, 1284–1288, doi:10.3762/bjnano.7.119

• ]. To describe our findings, we first recall that in self-seeded Ge NWs the majority charge carriers are free holes whose concentration depends on the number of charge traps at the NW core/shell interface [11][18]. In particular, for larger diameter NWs those free holes will be predominantly located in

• coordinates [20][21] and for simplicity assuming a constant free-hole concentration nh. One finds the expression [22] where Φ0 is the electrostatic potential at the core/shell interface, ε0 is the vacuum permittivity, εr the dielectric constant of germanium, and e the elementary charge. The confinement of

• free holes into the space-charge region close to the NW surface only, however, cannot remain for all diameters. The available volume for the free holes and the number of charge-traps at the core/shell interface scale with NW diameter. Therefore, with decreasing diameter the holes will extend further

Mesoporous hollow carbon spheres for lithium–sulfur batteries: distribution of sulfur and electrochemical performance

• Anika C. Juhl,
• Artur Schneider,
• Boris Ufer,
• Torsten Brezesinski,
• Jürgen Janek and
• Michael Fröba

Beilstein J. Nanotechnol. 2016, 7, 1229–1240, doi:10.3762/bjnano.7.114

• mg·cm−2 was investigated. Results and Discussion Silica template and hollow carbon spheres Hollow carbon spheres with a mesoporous shell were obtained by impregnation of silica spheres with a core–shell structure with phenol and formaldehyde (first step in Figure 1). Carbonization under inert atmosphere

• [35]. In the second step a mesoporous shell was grown on the spheres by employing tetraethyl orthosilicate in presence of cetyltrimethylammonium bromide (CTAB) as a structure-directing agent. Combustion of CTAB in air generated the core–shell silica spheres. The diameter of the solid core was

• determined to be 380 nm by dynamic light scattering, while the diameter of the core–shell particles was about 515 nm. From SEM images (Figure S1 in Supporting Information File 1) a diameter of about 490 nm was determined for the core–shell spheres. Further characterization of the SCMS silica can be found in

Development of highly faceted reduced graphene oxide-coated copper oxide and copper nanoparticles on a copper foil surface

• Rebeca Ortega-Amaya,
• Yasuhiro Matsumoto,
• Andrés M. Espinoza-Rivas,
• Manuel A. Pérez-Guzmán and
• Mauricio Ortega-López

Beilstein J. Nanotechnol. 2016, 7, 1010–1017, doi:10.3762/bjnano.7.93

• the particle size and shape strongly depend on the process temperature. Characterization with transmission electron microscopy and scanning electron microscopy indicates that Cu or Cu2O nanoparticles take rGO sheets from the rGO network to form core–shell Cu–rGO or Cu2O–rGO nanostructures. It is noted

• ; copper(II) oxide; core–shell; reduced graphene oxide; Introduction In the last years, graphene oxide (GO) and reduced graphene oxide (rGO) have emerged as suitable candidates to prepare graphene-based nanocomposites [1][2], including those based on GO/inorganic nanoparticles [3]. The opportunity to

• or metal oxide nanoparticles [11]. In particular, rGO–Cu core–shell nanostructures have been synthesized by CVD [12][13], hydrothermal synthesis [14] and pyrolysis of an organocopper compound [15][16][17]. In a previous work, the authors reported the effective reduction of chemically exfoliated GO

Selective photocatalytic reduction of CO₂ to methanol in CuO-loaded NaTaO₃ nanocubes in isopropanol

• Tianyu Xiang,
• Feng Xin,
• Jingshuai Chen,
• Yuwen Wang,
• Xiaohong Yin and
• Xiao Shao

Beilstein J. Nanotechnol. 2016, 7, 776–783, doi:10.3762/bjnano.7.69

• irradiation at 25 °C. Ru-Shi Liu and co-workers [19] prepared a series of nanostructured core–shell materials (Ni@NiO/N-doped InTaO4 photocatalysts) for the reduction of CO2 to methanol in pure water. In these structures, the core–shell nanostructure might offer a new reaction center transferred from the

Early breast cancer screening using iron/iron oxide-based nanoplatforms with sub-femtomolar limits of detection

• Dinusha N. Udukala,
• Hongwang Wang,
• Sebastian O. Wendel,
• Aruni P. Malalasekera,
• Thilani N. Samarakoon,
• Asanka S. Yapa,
• Gayani Abayaweera,
• Matthew T. Basel,
• Pamela Maynez,
• Raquel Ortega,
• Yubisela Toledo,
• Leonie Bossmann,
• Colette Robinson,
• Katharine E. Janik,
• Olga B. Koper,
• Ping Li,
• Massoud Motamedi,
• Daniel A. Higgins,
• Gary Gadbury,
• Gaohong Zhu,
• Deryl L. Troyer and
• Stefan H. Bossmann

Beilstein J. Nanotechnol. 2016, 7, 364–373, doi:10.3762/bjnano.7.33

• is a vital strategy for early cancer detection. Water-dispersable Fe/Fe3O4-core/shell based nanoplatforms for protease detection are capable of detecting protease activity down to sub-femtomolar limits of detection. They feature one dye (tetrakis(carboxyphenyl)porphyrin (TCPP)) that is tethered to

• of detecting protease activities over a wide activity range down to sub-femtomolar LOD’s. These nanoplatforms consist of dopamine-covered, water-dispersable iron/iron oxide core/shell nanoparticles, to which one fluorescent dye (TCPP, tetrakis(carboxyphenyl)porphyrin) is tethered via a consensus

• central core/shell nanoparticle. For these specific consensus sequences, this effect exceeds the quenching effects (SET and FRET). Therefore, these two nanoplatforms show decreases of TCPP fluorescence upon cleavage. However, this decrease can still be utilized to measure the activities of uPA and MMP 9

Hydration of magnesia cubes: a helium ion microscopy study

• Ruth Schwaiger,
• Johannes Schneider,
• Gilles R. Bourret and
• Oliver Diwald

Beilstein J. Nanotechnol. 2016, 7, 302–309, doi:10.3762/bjnano.7.28

• , the MgO cubes have expanded presumably due to the formation of MgO/Mg(OH)2 core–shell structures, and a thick Mg(OH)2 layer coats the MgO cubes, leading to a partial fusion of the particles. As shown in Figure 3, the expansion of the MgO cubes is significant. We measured an average edge length

• substrate for imaging. Depending on their size the MgO-based cubes [21] become subject to significant volume expansion effects (up to a factor of 2.5) that are attributed to oxide transformation into hydroxides and the generation MgO/Mg(OH)2 core–shell structures as a result of the Kirkendall effect. These

Case studies on the formation of chalcogenide self-assembled monolayers on surfaces and dissociative processes

• Yongfeng Tong,
• Tingming Jiang,
• Azzedine Bendounan,
• Makri Nimbegondi Kotresh Harish,
• Angelo Giglia,
• Stefan Kubsky,
• Fausto Sirotti,
• Luca Pasquali,
• Srinivasan Sampath and
• Vladimir A. Esaulov

Beilstein J. Nanotechnol. 2016, 7, 263–277, doi:10.3762/bjnano.7.24

• chalcogenized interface layer on which molecules are then adsorbed. One can expect that capping nanoparticles with these molecules would lead to formation of metal–metal chalcogenide, core/shell nanoparticles, which has been shown to have interesting specific properties. In the case of chalcogenophene molecules

pH-Triggered release from surface-modified poly(lactic-co-glycolic acid) nanoparticles

• Manuel Häuser,
• Klaus Langer and
• Monika Schönhoff

Beilstein J. Nanotechnol. 2015, 6, 2504–2512, doi:10.3762/bjnano.6.260

• . We present here the idea of a two-step delivery system consisting of core–shell nanoparticles. The outer shell is susceptible to changes of the pH value, such that the release of a membrane-toxic cationic compound is triggered by a reduced pH value in the endolysosomal compartment of the cells. The

Surface-enhanced Raman scattering by colloidal CdSe nanocrystal submonolayers fabricated by the Langmuir–Blodgett technique

• Alexander G. Milekhin,
• Larisa L. Sveshnikova,
• Tatyana A. Duda,
• Ekaterina E. Rodyakina,
• Volodymyr M. Dzhagan,
• Ovidiu D. Gordan,
• Sergey L. Veber,
• Cameliu Himcinschi,
• Alexander V. Latyshev and
• Dietrich R. T. Zahn

Beilstein J. Nanotechnol. 2015, 6, 2388–2395, doi:10.3762/bjnano.6.245

• previously observed for several CdSe-based NCs, including pure CdSe and core–shell CdSe/CdZnS NCs deposited on Au or Ag substrates of various morphology [20][21][22][23]. Resonant SERS enables the observation of LO phonon modes of the CdSe core in a monolayer of core–shell CdSe/ZnS NCs deposited on

Silica-coated upconversion lanthanide nanoparticles: The effect of crystal design on morphology, structure and optical properties

• Uliana Kostiv,
• Miroslav Šlouf,
• Hana Macková,
• Alexander Zhigunov,
• Hana Engstová,
• Katarína Smolková,
• Petr Ježek and
• Daniel Horák

Beilstein J. Nanotechnol. 2015, 6, 2290–2299, doi:10.3762/bjnano.6.235

• . Compared with the initial 10 nm OM–NaYF4:Yb3+/Er3+ nanoparticles, the TEM micrograph (Figure 9) showed that the size of the NaYF4:Yb3+/Er3+&SiO2 particles had increased to 17 nm due to the presence of the silica shell on the surface. The NaYF4:Yb3+/Er3+&SiO2 nanoparticles had a clear core–shell structure

Mapping bound plasmon propagation on a nanoscale stripe waveguide using quantum dots: influence of spacer layer thickness

• Chamanei S. Perera,
• Alison M. Funston,
• Han-Hao Cheng and
• Kristy C. Vernon

Beilstein J. Nanotechnol. 2015, 6, 2046–2051, doi:10.3762/bjnano.6.208

• an emission wavelength of 655 nm were obtained from invitrogen (Cat. No: Q21321MP). These carboxyl QDs are made from CdSe nanocrystals shelled with a ZnS layer. The core–shell material is further coated with a polymer layer to allow for better dispersion of the QDs in aqueous solution. These QDs have

Simulation of thermal stress and buckling instability in Si/Ge and Ge/Si core/shell nanowires

• Suvankar Das,
• Amitava Moitra,
• Mishreyee Bhattacharya and
• Amlan Dutta

Beilstein J. Nanotechnol. 2015, 6, 1970–1977, doi:10.3762/bjnano.6.201

• employs the method of atomistic simulation to estimate the thermal stress experienced by Si/Ge and Ge/Si, ultrathin, core/shell nanowires with fixed ends. The underlying technique involves the computation of Young’s modulus and the linear coefficient of thermal expansion through separate simulations

• proposed methodology can be extended to other materials and structures and helps with the prediction of the conditions under which a nanowire-based device might possibly fail due to elastic instability. Keywords: atomistic simulation; buckling; core–shell nanowire; thermal stress; Introduction In recent

• years, a drastic rise in the research activities on semiconductor core/shell nanowires (CSNWs) made of silicon and germanium has occurred. Such studies are often motivated by the excellent charge transport properties of the materials [1][2][3][4], for which they are now seen as prospective candidates

Nanofibers for drug delivery – incorporation and release of model molecules, influence of molecular weight and polymer structure

• Jakub Hrib,
• Jakub Sirc,
• Radka Hobzova,
• Zuzana Hampejsova,
• Zuzana Bosakova,
• Marcela Munzarova and
• Jiri Michalek

Beilstein J. Nanotechnol. 2015, 6, 1939–1945, doi:10.3762/bjnano.6.198

• the materials enables to control the final structure of the prepared materials [6][20]. Generally, nanofibers that carry drugs follow several basic designs – nanofibers with homogenous structures in which the drug is dispersed throughout the polymer matrix, core–shell nanofibers for which the matrix

• primary factors that affect the diffusion mechanism and drug release. For homogenous nanofibers, the rate of release decreases with time, because the drug must travel progressively longer distances to diffuse to the fiber periphery, which requires more time. Contrary, the core–shell design provides the

A facile method for the preparation of bifunctional Mn:ZnS/ZnS/Fe₃O₄ magnetic and fluorescent nanocrystals

• Houcine Labiadh,
• Tahar Ben Chaabane,
• Romain Sibille,
• Lavinia Balan and
• Raphaël Schneider

Beilstein J. Nanotechnol. 2015, 6, 1743–1751, doi:10.3762/bjnano.6.178

• , 54001 Nancy Cedex, France 10.3762/bjnano.6.178 Abstract Bifunctional magnetic and fluorescent core/shell/shell Mn:ZnS/ZnS/Fe3O4 nanocrystals were synthesized in a basic aqueous solution using 3-mercaptopropionic acid (MPA) as a capping ligand. The structural and optical properties of the

• diodes [6][7] or solar cells [8]. Conventional QDs systems have a core/shell architecture. The shell, generally constituted of a wide band gap material such as ZnS, prevents degradation and preserves the optical properties [3][4]. Magnetic nanoparticles have many advantages, especially for biological

• shell (CdSe or CdS) of thickness between 2–7 nm resulting in either spherical core/shell nanoparticles or heterodimers [20][21][22]. The PL QY of the resulting bifunctional nanoparticles is generally low (typically <5%) due to the quenching effect of the magnetic domain [20][21]. Herein, we describe a

Radiation losses in the microwave K_u band in magneto-electric nanocomposites

• Talwinder Kaur,
• Sachin Kumar,
• Jyoti Sharma and
• A. K. Srivastava

Beilstein J. Nanotechnol. 2015, 6, 1700–1707, doi:10.3762/bjnano.6.173

• range and their properties become different from those of the bulk material [38]. Surface features Transmission electron microscopy (TEM) has been used to determine the distribution and morphology of hexaferrite nanoparticles and polymer. A clear picture of a core–shell morphology can be seen in the TEM

Synthesis, characterization and in vitro biocompatibility study of Au/TMC/Fe₃O₄ nanocomposites as a promising, nontoxic system for biomedical applications

• Hanieh Shirazi,
• Maryam Daneshpour,
• Soheila Kashanian and
• Kobra Omidfar

Beilstein J. Nanotechnol. 2015, 6, 1677–1689, doi:10.3762/bjnano.6.170

• synthesize and optimize a combined nanocomposite containing both. By using various polymers such as chitosan, some of the problems of classic core–shell structures (such as reduced saturation magnetization and thick coating) have been overcome. In the present study, chitosan and one of its well-known

• steps, it is possible to prepare Au nanoparticles of different sizes and shapes that will enhance their efficacy and usage in different applications [33]. It is expected that the nanocomposites developed herein will have advantages over other hybrid Fe3O4 and gold core–shell structures. This is

• derivatives, TMC. This system not only takes advantage of the combined useful properties of both Fe3O4 and Au nanoparticles, but also has promising characteristics that resolve many of the previously reported shortcomings of classic core–shell structures [34]. Fe3O4 nanoparticles as the magnetic core Among

Structural and magnetic properties of iron nanowires and iron nanoparticles fabricated through a reduction reaction

• Marcin Krajewski,
• Wei Syuan Lin,
• Hong Ming Lin,
• Katarzyna Brzozka,
• Sabina Lewinska,
• Natalia Nedelko,
• Anna Slawska-Waniewska,
• Jolanta Borysiuk and
• Dariusz Wasik

Beilstein J. Nanotechnol. 2015, 6, 1652–1660, doi:10.3762/bjnano.6.167

• nanoparticles reveal core–shell structures and they are composed of crystalline iron cores that are covered by amorphous or highly defected phases of iron and iron oxides. Magnetic properties have been measured using a vibrating sample magnetometer. The obtained values of coercivity, remanent magnetization

• . Both nanomaterials reveal core–shell structures and are constructed of crystalline α-Fe cores, which are covered by a layered structure composed of: amorphous iron, amorphous iron oxides and distorted iron oxides (the layer order from core to surface). Additionally, iron nanowires are built from the

Thermal treatment of magnetite nanoparticles

• Beata Kalska-Szostko,
• Urszula Wykowska,
• Dariusz Satula and
• Per Nordblad

Beilstein J. Nanotechnol. 2015, 6, 1385–1396, doi:10.3762/bjnano.6.143

• and crystallinity, which in turn, was reflected in their thermal durability. The particles were obtained by coprecipitation from Fe chlorides and decomposition of an Fe(acac)3 complex with and without a core–shell structure. Three types of ferrite nanoparticles were produced and their thermal

• analysis of the magnetite and core–shell nanoparticles was performed on a Mettler Toledo differential scanning calorimeter (DSC). A Quantum Design MPMS SQUID magnetometer was used for the magnetization measurements. Mössbauer spectra (MS) were obtained using a conventional spectrometer working in constant