Performance of colloidal CdS sensitized solar cells with ZnO nanorods/nanoparticles

• Anurag Roy,
• Partha Pratim Das,
• Mukta Tathavadekar,
• Sumita Das and
• Parukuttyamma Sujatha Devi

Beilstein J. Nanotechnol. 2017, 8, 210–221, doi:10.3762/bjnano.8.23

• , we have reported the advantages of using 1D ZnO nanorods compared to nanoparticles in DSSCs using N719 as a photosensitizer [31]. Due to the reduced grain boundaries and direct conjunction pathway, 1D nanorods can diffuse electrons faster than nanoparticles and other morphologies. However

• surface area of the nanoparticles, more CdS was loaded on them than on the nanorods but uncontrolled agglomeration may result in random electron conduction and further may enhance the recombination rate. Whereas, the nanorods (due to their superior one-dimensional structure and reduced grain boundaries

Laser irradiation in water for the novel, scalable synthesis of black TiO_x photocatalyst for environmental remediation

• Massimo Zimbone,
• Giuseppe Cacciato,
• Mohamed Boutinguiza,
• Vittorio Privitera and
• Maria Grazia Grimaldi

Beilstein J. Nanotechnol. 2017, 8, 196–202, doi:10.3762/bjnano.8.21

• surface morphology, as reported by SEM, reveals that after irradiation, the black surface is uniformly covered by small structures (Figure 2 centre). A high magnification image (Figure 2 right) shows that they consist of cavities and grain boundaries. It is worth noting that the nanostructure of the film

• appears similar to the case of irradiation under 1064 nm wavelength [22]. However, in the present condition, the holes on the surface of the irradiated sample appear to be concentrated at the grain boundaries generated on the surface by the laser annealing. RBS spectra clearly show the presence of oxygen

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

• dissipation and the formation of shallow depressions nearby after subsequent annealing treatments. This annealing-induced evolution of nanoindents was interpreted in terms of annihilation of dislocation loops generated during indentation, accompanied by the formation of nanopores at the grain boundaries and

• film behavior at elevated temperatures. This is because these films exhibit only one type of grain boundaries (Σ3 twin boundary, where Σ is a reciprocal density of coincident sites) and are intrinsically stable against dewetting. The interdiffusion coefficients in the Au(Fe) system have been determined

• which all grain boundaries are of the exact <111>Σ3 type, so-called mazed bicrystalline films [18][19], exhibit a special type of microstructure without triple junctions. The electron backscatter diffraction data obtained on the as-deposited film (not shown here) confirmed that only the near-<111>Σ3

Solvent-mediated conductance increase of dodecanethiol-stabilized gold nanoparticle monolayers

• Patrick A. Reissner,
• Jean-Nicolas Tisserant,
• Antoni Sánchez-Ferrer,
• Raffaele Mezzenga and
• Andreas Stemmer

Beilstein J. Nanotechnol. 2016, 7, 2057–2064, doi:10.3762/bjnano.7.196

• hexagonally ordered within grain boundaries. Small voids between grains result from the self-assembly process. We masked voids in five SEM images at different sample locations, neglecting voids smaller than 25 nm2, as an upper limit for tolerances in interparticle distance variations. On average, these voids

Ferromagnetic behaviour of ZnO: the role of grain boundaries

• Boris B. Straumal,
• Svetlana G. Protasova,
• Andrei A. Mazilkin,
• Eberhard Goering,
• Gisela Schütz,
• Petr B. Straumal and
• Brigitte Baretzky

Beilstein J. Nanotechnol. 2016, 7, 1936–1947, doi:10.3762/bjnano.7.185

• that ferromagnetism is not an intrinsic property of the ZnO crystalline lattice but is that of ZnO/ZnO grain boundaries. If a ZnO polycrystal contains enough grain boundaries, it can transform into the ferromagnetic state even without doping with “magnetic atoms” such as Mn, Co, Fe or Ni. However, such

• doping facilitates the appearance of ferromagnetism in ZnO. It increases the saturation magnetisation and decreases the critical amount of grain boundaries needed for FM. A drastic increase of the total solubility of dopants in ZnO with decreasing grain size has been also observed. It is explained by the

• multilayer grain boundary segregation. Keywords: ferromagnetism; grain boundaries; zinc(II) oxide (ZnO); Review Introduction In 2000 the seminal work of Tomasz Dietl et al. appeared [1]. In this work it was predicted theoretically that many semiconductor oxides can become ferromagnetic (FM) if one dopes

A new approach to grain boundary engineering for nanocrystalline materials

• Shigeaki Kobayashi,
• Sadahiro Tsurekawa and
• Tadao Watanabe

Beilstein J. Nanotechnol. 2016, 7, 1829–1849, doi:10.3762/bjnano.7.176

• boundary microstructures have been seriously considered according to the almost established approach to GBE. This approach has been increasingly recognized for the development of high performance nanocrystalline materials with an extremely high density of grain boundaries and triple junctions. The

• structure, and conventional grain size range. It is evident that the much higher strength of nanocrystalline materials compared to ordinary polycrystals originates from the extensive interaction between grain boundaries and dislocations. On the other hand, poor ductility and severe brittleness of

• grain boundaries and triple junctions. This is often associated with the nonequilibrium deformation of microstructures introduced by severe plastic deformation (SPD) with less thermal stability, excess structural defects and chemical composition by segregation to grain boundaries and interfaces [12][15

Effect of triple junctions on deformation twinning in a nanostructured Cu–Zn alloy: A statistical study using transmission Kikuchi diffraction

• Silu Liu,
• Xiaolong Ma,
• Lingzhen Li,
• Liwen Zhang,
• Patrick W. Trimby,
• Xiaozhou Liao,
• Yusheng Li,
• Yonghao Zhao and
• Yuntian Zhu

Beilstein J. Nanotechnol. 2016, 7, 1501–1506, doi:10.3762/bjnano.7.143

• mechanisms that can simultaneously improve both strength and ductility [5][6][9][10][11]. Consequently, deformation twinning in nanostructured metals has received extensive attention in recent years [10]. Among all of the twinning mechanisms in nanocrystalline materials, partial mission from grain boundaries

• has been found as the primary mechanism from both simulations [12][13] and experiments [14][15]. However, it still remains unclear whether such emissions from grain boundaries have any preference for sites with specific character such as triple junctions. This problem is of significant importance to

• studies revealed that triple junctions were energetically more active than grain boundaries [18] and they were able to emit and absorb free volumes upon deformation, which promotes partial emission [12]. Therefore, one may reasonably hypothesize that triple junctions may promote deformation twinning in

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

Efficient electron-induced removal of oxalate ions and formation of copper nanoparticles from copper(II) oxalate precursor layers

• Kai Rückriem,
• Sarah Grotheer,
• Henning Vieker,
• Paul Penner,
• André Beyer,
• Armin Gölzhäuser and
• Petra Swiderek

Beilstein J. Nanotechnol. 2016, 7, 852–861, doi:10.3762/bjnano.7.77

• MUA SAM (Figure 4a). The grain boundaries between the gold crystallites are clearly visible and the facets are smooth and free of apparent defects. An image of a sample covered with copper(II) oxalate after 16 deposition cycles (Figure 4b) reveals that the material grows as needle-like structures

In situ observation of deformation processes in nanocrystalline face-centered cubic metals

• Aaron Kobler,
• Christian Brandl,
• Horst Hahn and
• Christian Kübel

Beilstein J. Nanotechnol. 2016, 7, 572–580, doi:10.3762/bjnano.7.50

• ]. Modified or even unexpected deformation mechanisms are ascribed to the increasing influence of grain boundaries (GBs) on mechanical properties [3][4][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. GB-mediated deformation mechanisms, such as GB sliding and migration, grain growth and rotation [21

• until fracture (Figure 1d). This procedure allows the assignment of the fracture site to the microstructural features (i.e., grain boundaries) (Figure 1c). The direct overlay reveals that the crack behavior is a combination of intragranular fracture with the crack path through a crystallite (white lines

• in Figure 1c) and intergranular fracture with the crack path along grain boundaries (red lines in Figure 1c). The observation of grain growth, fragmentation and recrystallization next to the crack path (Figure 1c,d) suggests that the deformation is both a result of intragranular deformation (related

Determination of the compositions of the DIGM zone in nanocrystalline Ag/Au and Ag/Pd thin films by secondary neutral mass spectrometry

• Gábor Y. Molnár,
• Shenouda S. Shenouda,
• Gábor L. Katona,
• Gábor A. Langer and
• Dezső L. Beke

Beilstein J. Nanotechnol. 2016, 7, 474–483, doi:10.3762/bjnano.7.41

• Figure 2 that there is an intensive intermixing, due to diffusion along the grain boundaries, on both sides and the average concentrations at saturation are below 50%. Furthermore, the saturation values of Au in Ag are lower than that of Ag in Au and their values increase with increasing the annealing

Organized films

• Maurizio Canepa and
• Helmuth Möhwald

Beilstein J. Nanotechnol. 2016, 7, 406–408, doi:10.3762/bjnano.7.35

• . On one hand, the domain structure causes grain boundaries, which are almost impossible to remove. Furthermore, the tight packing of alkane chains in classical LB films prohibits the incorporation of foreign molecules with high precision. This fact is a significant disadvantage if one aims to arrange

Synthesis and applications of carbon nanomaterials for energy generation and storage

• Marco Notarianni,
• Jinzhang Liu,
• Kristy Vernon and
• Nunzio Motta

Beilstein J. Nanotechnol. 2016, 7, 149–196, doi:10.3762/bjnano.7.17

• coming from the gas source to diffuse into the metal. The process is very difficult to control, and especially so in polycrystalline metals where the grain boundaries act as nucleation sites for multilayer growth [141]. For this reason, single crystal and atomically smooth metals are usually preferred to

• quality. In fact, the graphene produced is mostly polycrystalline with aperiodic heptagon/pentagon pairs [143] or overlapped bilayer regions [144] at the grain boundaries (Figure 22b). It has also been demonstrated that the presence of grain boundaries can reduce the mechanical and electrical properties

Evaluation of gas-sensing properties of ZnO nanostructures electrochemically doped with Au nanophases

• Elena Dilonardo,
• Michele Penza,
• Marco Alvisi,
• Cinzia Di Franco,
• Francesco Palmisano,
• Luisa Torsi and
• Nicola Cioffi

Beilstein J. Nanotechnol. 2016, 7, 22–31, doi:10.3762/bjnano.7.3

• possibly related to transducer function. Rai et al. [5] reported that the presence of a great number of grain boundaries in ZnO nanospheres acts as a highly resistive barrier, inducing the increase of the overall device resistance, since the electrical conductivity is equally influenced by the density and

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

• 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

• portion of grain boundaries. To get further information about the influence of doping on the conductivity, measurements of the complex dielectric function in the THz frequency range were performed. Time-domain THz spectroscopy [56][57] is a method to investigate the transmission and/or reflection of a

• could be proven by several methods, that the desired materials were obtained, due to the current, powder-like nature, the electronic properties are yet dominated by grain boundary effects. Therefore, future research in this field will address the synthesis of thin films minimizing the amount of grain

• boundaries. Furthermore, we could not yet realize a F-containing precursor. F@ZnO materials are also expected to be interesting TCO candidates and potential ITO substitutes. 1H NMR spectra (Zn–CH3 region) for the reaction of I2 with [MeZnOiPr]4 before (a) and after purification (b), and for the reaction with

High I_on/I_off current ratio graphene field effect transistor: the role of line defect

• Mohammad Hadi Tajarrod and
• Hassan Rasooli Saghai

Beilstein J. Nanotechnol. 2015, 6, 2062–2068, doi:10.3762/bjnano.6.210

• the best candidates for changing the hexagon structure of graphene with acceptable C–C distances and angles for sp2 hybridization [7]. These defects play a remarkable role in graphene and nano-structured devices. One controlled defect in graphene are grain boundaries. The electrical and thermal

• conductivity decrease with grain boundaries in materials [8][9]. By studying the grain boundaries in graphite, extended line defects become visible in the STM analysis [10]. The first experimental report of the extended line defect (ELD), which was studied through alternating Stone–Thrower–Wales defects, was

Nitrogen-doped graphene films from chemical vapor deposition of pyridine: influence of process parameters on the electrical and optical properties

• Andrea Capasso,
• Theodoros Dikonimos,
• Francesca Sarto,
• Alessio Tamburrano,
• Giovanni De Bellis,
• Maria Sabrina Sarto,
• Giuliana Faggio,
• Angela Malara,
• Giacomo Messina and
• Nicola Lisi

Beilstein J. Nanotechnol. 2015, 6, 2028–2038, doi:10.3762/bjnano.6.206

• [17]. Besides, the electron mobility itself can be greatly affected by the presence of substitutional atoms (which are a kind of lattice defects, such as vacancies, and grain boundaries) [18]. Graphene can be doped through surface proximity by layering it with other materials (such as metals [19

• the lattice or along grain boundaries. In Figure 2a, the influence of temperature and hydrogen flow on the G and 2D Raman bands is further investigated. When lowering the CVD temperature, the position of the G peak is observed to slightly upshift, while the 2D peak position downshifts. Raman

Surface engineering of nanoporous substrate for solid oxide fuel cells with atomic layer-deposited electrolyte

• Sanghoon Ji,
• Waqas Hassan Tanveer,
• Wonjong Yu,
• Sungmin Kang,
• Gu Young Cho,
• Sung Han Kim,
• Jihwan An and
• Suk Won Cha

Beilstein J. Nanotechnol. 2015, 6, 1805–1810, doi:10.3762/bjnano.6.184

• . Results and Discussion Highly dense ALD thin film electrolyte Thin films fabricated via low-temperature vacuum deposition techniques typically have lower packing density than powder-processed thin films due to the presence of high density of grain-boundaries inside the thin films [9][10]. The density

Possibilities and limitations of advanced transmission electron microscopy for carbon-based nanomaterials

• Xiaoxing Ke,
• Carla Bittencourt and
• Gustaaf Van Tendeloo

Beilstein J. Nanotechnol. 2015, 6, 1541–1557, doi:10.3762/bjnano.6.158

• vacancies, dislocations, grain boundaries and strain can be revealed in great detail. The fundamental understanding of CNTs, particularly of graphene in the past decade, have largely benefited from the development in electron microscopy. Taking CNTs again as an example, the direct imaging of a zig-zag

• polycrystalline morphology with defects such as grain boundaries [62][63] and therefore suffers from a degradation of its physical properties. Characterization of the intrinsic defects and their further relation to the synthesis conditions, e.g., substrate lattice mismatch and annealing temperature is therefore

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

• good agreement with the speculation that polycrystallinity causes the presence of grain boundaries, which significantly influences the stability/susceptibility to the oxide. On the other hand, in the case of polycrystalline particles, their structure is also less dense and oxygen can penetrate more

• treated as single crystals, have been obtained. This can be seen in HRTEM studies [49]. Therefore, oxide penetration is hampered and becomes much slower. The stepwise decomposition of the Fe(acac)3 complex causes the presence of grain-like growth of each subsequent layer. This introduces many more grain

• boundaries and dislocations, and therefore, more room for oxide penetration, which significantly facilitates the oxidation process. Conclusion The performed experiments show that thermal stability of magnetite nanoparticles is dependent on the fabrication procedure. The temperature scans, combined with

The Kirkendall effect and nanoscience: hollow nanospheres and nanotubes

• Abdel-Aziz El Mel,
• Ryusuke Nakamura and
• Carla Bittencourt

Beilstein J. Nanotechnol. 2015, 6, 1348–1361, doi:10.3762/bjnano.6.139

• present within the formed bismuth oxide shell (such as grain boundaries) serve as diffusion channels which enhance the outward diffusion of bismuth. They have further demonstrated that before being oxidized, bismuth tends to condense into several nanodroplets on the outer layer of the nanoparticle (Figure

Characterization of nanostructured ZnO thin films deposited through vacuum evaporation

• Jose Alberto Alvarado,
• Arturo Maldonado,
• Héctor Juarez,
• Mauricio Pacio and
• Rene Perez

Beilstein J. Nanotechnol. 2015, 6, 971–975, doi:10.3762/bjnano.6.100

• of particles that do not have an ordering, and thus the grain boundaries from each nanoparticle are not activated. Therefore, the adherence to the substrate is poor, which is also seen in the transmittance results. Varying the duration for which the films are annealed results in a perceptible

• , and the extrapolation of the straight line to zero gives the value of the energy gap of the film. The energy value obtained for this film is about 3.22 eV, and can be due to the grain boundaries and the size of the nanoparticles. As seen in the HRSEM images, there are a lot of grain boundaries and

Mapping of elasticity and damping in an α + β titanium alloy through atomic force acoustic microscopy

• M. Kalyan Phani,
• Anish Kumar,
• T. Jayakumar,
• Walter Arnold and
• Konrad Samwer

Beilstein J. Nanotechnol. 2015, 6, 767–776, doi:10.3762/bjnano.6.79

• for studying their deformation behavior, crack nucleation and propagation, dislocation activity and interaction with grain boundaries and also even helps in understanding the bulk elastic properties of multiphase materials [1][2]. Over the last two decades many contact-resonance-based atomic force