Review of nanostructured devices for thermoelectric applications

• Giovanni Pennelli

Beilstein J. Nanotechnol. 2014, 5, 1268–1284, doi:10.3762/bjnano.5.141

• measured in nanostructured bismuth antimony telluride alloys, because phonon scattering at nanocrystal boundaries gives a reduced thermal conductivity [26]. Hovewer, TEGs based on bismuth telluride compounds have a small operating temperature range, because the Z factor rapidly decreases well below 2 × 10

An insight into the mechanism of charge-transfer of hybrid polymer:ternary/quaternary chalcopyrite colloidal nanocrystals

• Parul Chawla,
• Son Singh and
• Shailesh Narain Sharma

Beilstein J. Nanotechnol. 2014, 5, 1235–1244, doi:10.3762/bjnano.5.137

• semiconductors and their optical energy gap engineering, which is tunable within the solar spectrum, renders CISe and related materials a very promising PV material in the near future. However, to the best of our knowledge, investigations of CISe and related nanocrystal-polymer based solar cells are scarce. A

• the above observations was provided by investigating the photoluminescence intensities of each of the prepared hybrid nanocomposites of CISe, CIGSe and CZTSe. Emission intensity studies for each of the nanocrystal inks: P3HT were investigated by photoluminescence spectroscopy to study trends of

Nanoporous composites prepared by a combination of SBA-15 with Mg–Al mixed oxides. Water vapor sorption properties

• Amaury Pérez-Verdejo,
• Alvaro Sampieri,
• Heriberto Pfeiffer,
• Mayra Ruiz-Reyes,
• Juana-Deisy Santamaría and
• Geolar Fetter

Beilstein J. Nanotechnol. 2014, 5, 1226–1234, doi:10.3762/bjnano.5.136

• with Si–CH3 and then functionalized with Mg and Al nitrate salts, has promoted the nanocrystal growth of Mg–Al hydrotalcite on the pore walls of the SBA-15 [9]. This composite presented a high catalytic activity in the acetone condensation at 273 K. Moreover, a basic composite has been prepared from

Functionalized nanostructures for enhanced photocatalytic performance under solar light

• Liejin Guo,
• Dengwei Jing,
• Maochang Liu,
• Yubin Chen,
• Shaohua Shen,
• Jinwen Shi and
• Kai Zhang

Beilstein J. Nanotechnol. 2014, 5, 994–1004, doi:10.3762/bjnano.5.113

• Pt/TiO2 nanocrystal photocatalysts exhibited enhanced photocatalytic hydrogen production under visible light irradiation [18]. Lee et al. also reported that CdS and CdSe nanocrystals dispersed on the internal surface of mesoporous TiO2 films could lead to the promoted photocatalytic hydrogen

• hydrogen production. These factors are significantly beneficial for their further application in the field of solar energy conversion. Crystal facets engineering As we know, the surface of a given semiconductor nanocrystal usually consists of certain crystal facets that occupy specific coordination numbers

• nanocrystal with controllable aspect ratios and a high percentage of long-range ordered twin planes. As shown in Figure 10, the densely distributed rotational twin planes are found to be parallel to each other and perpendicular to the <111> direction. More interestingly, zinc-blende (ZB) and wurtzite (WZ

Optimizing the synthesis of CdS/ZnS core/shell semiconductor nanocrystals for bioimaging applications

• Li-wei Liu,
• Si-yi Hu,
• Ying Pan,
• Jia-qi Zhang,
• Yue-shu Feng and
• Xi-he Zhang

Beilstein J. Nanotechnol. 2014, 5, 919–926, doi:10.3762/bjnano.5.105

• studies, a cell viability (MTS) assay was carried out for F127-CdS/ZnS QDs. As shown in Figure 10, we tested the cell viability of Panc-1 cells, treating them with various concentrations of ternary nanocrystal formulations for 48 h. The cell viability remained at 84% even at a concentration as high as 500

• imaged by using confocal microscopy. Figure 11 shows robust cellular uptakes of the ternary nanocrystal samples. The red singnal is from F127-CdS/ZnS QDs, and background fluorescence and autofluorescence from the cells have been successfully suppressed. We can see that there is no damage to the cells

Optical and structural characterization of oleic acid-stabilized CdTe nanocrystals for solution thin film processing

• Claudio Davet Gutiérrez-Lazos,
• Mauricio Ortega-López,
• Manuel A. Pérez-Guzmán,
• A. Mauricio Espinoza-Rivas,
• Francisco Solís-Pomar,
• Rebeca Ortega-Amaya,
• L. Gerardo Silva-Vidaurri,
• Virginia C. Castro-Peña and
• Eduardo Pérez-Tijerina

Beilstein J. Nanotechnol. 2014, 5, 881–886, doi:10.3762/bjnano.5.100

• shows a CdTe deposition with and without UV illumination. We further note that the nanocrystal luminescence under ambient conditions is preserved. X-ray diffraction analysis The structural properties of the prepared samples were evaluated by XRD and Raman spectroscopy, using CdTe thin films deposited on

• Vinculadas al Fortalecimiento de la Calidad del Posgrado Nacional 2013 (2)”. Also, authors are very thankful to Dr. Jaime Santoyo Salazar at the TEM facilities, Álvaro Guzmán Campuzano for his technical assistance in the nanocrystal synthesis, and M. Sc. Alejandra García Sotelo for the Raman measurements.

Shape-selected nanocrystals for in situ spectro-electrochemistry studies on structurally well defined surfaces under controlled electrolyte transport: A combined in situ ATR-FTIR/online DEMS investigation of CO electrooxidation on Pt

• Sylvain Brimaud,
• Zenonas Jusys and
• R. Jürgen Behm

Beilstein J. Nanotechnol. 2014, 5, 735–746, doi:10.3762/bjnano.5.86

• surface structures were prepared and structurally characterized by transmission electron microscopy (TEM) and electrochemical methods. The potential for in situ spectro-electrocatalytic studies is illustrated for COad oxidation on Pt nanocrystal surfaces, where we could separate contributions from two

• hydrogen sorption peaks are convincing indicators for both a well ordered Pt nanocrystal surface structure and the cleanness of the experimental setup and procedures. The hydrogen-region voltammograms obtained for such samples are approximated as weighted sum of the respective features of extended low

• determined this way accounts for about 50% of the electrochemically active surface area, as determined by Hupd, with different ratios between (111) and (100) surface orientation depending on the nanocrystal shapes. The charge displaced during CO adsorption at 0.10 V is about 150 µC cm−2 for all three samples

Nanostructure sensitization of transition metal oxides for visible-light photocatalysis

• Hongjun Chen and
• Lianzhou Wang

Beilstein J. Nanotechnol. 2014, 5, 696–710, doi:10.3762/bjnano.5.82

• nanosized CdS and TiO2 nanocrystal. The formation of Ti3+ was observed in the electron paramagnetic resonance (EPR) spectrum, which confirms an effective transfer of photogenerated electrons from the CB of CdS to the CB of TiO2. The same group also successfully extended this method for the oxidation of

• nanocrystal by micro-emulsion under ultrasound [57]. Co-axial arrays of CdS/TiO2 core/shell structures were also reported to be fabricated by an anodic aluminium oxide template [58]. This type of configuration can not only protect the quantum dots from photocorrosion, but also increases the contact interface

One-step synthesis of high quality kesterite Cu₂ZnSnS₄ nanocrystals – a hydrothermal approach

• Vincent Tiing Tiong,
• John Bell and
• Hongxia Wang

Beilstein J. Nanotechnol. 2014, 5, 438–446, doi:10.3762/bjnano.5.51

• -like nanocrystals with size ranging from 10–30 nm. The HRTEM image of the material (inset of Figure 6b) shows the lattice fringe of a nanocrystal with an interplanar spacing of 1.87 Å, which is in good agreement with the (886) plane of monoclinic structure of Cu7S4. Besides that, the lattice fringe of

• nanocrystal with an interplanar spacing of 1.97 Å which can be ascribed to (220) plane of cubic structure of Cu1.8S was also found as illustrated in the inset of Figure 6c. These finding are consisting with the above shown XRD pattern. Figure 6d and 6e show that when the hydrothermal reaction is proceeded for

Photoactivation of luminescence in CdS nanocrystals

• Valentyn Smyntyna,
• Bogdan Semenenko,
• Valentyna Skobeeva and
• Nikolay Malushin

Beilstein J. Nanotechnol. 2014, 5, 355–359, doi:10.3762/bjnano.5.40

• isolated in a polymer matrix is a significant chemical activity of the surface. It is important to experimentally investigate the nanosystems with interphase boundaries between the nanocrystal and matrix and study the processes that occur at this interface. There are particularly important questions about

• that is caused by recombination processes in the bulk of the nanocrystals [20]. Note that for the distribution of nanocrystal sizes in our samples it is not always possible to distinguish between these two recombination mechanisms. In order to determine the luminescence mechanism of the short

• band gap of NC. The energy separation between the band gap of the nanocrystal and the energy of the band maximum equals to 0.11 eV. It follows that the mechanism of recombination is the recombination of electrons that are captured by the small recombination centers with a depth of E = 0.11 eV and holes

Study of mesoporous CdS-quantum-dot-sensitized TiO₂ films by using X-ray photoelectron spectroscopy and AFM

• Mohamed N. Ghazzal,
• Robert Wojcieszak,
• Gijo Raj and
• Eric M. Gaigneaux

Beilstein J. Nanotechnol. 2014, 5, 68–76, doi:10.3762/bjnano.5.6

• of the deposition cycles (5, 7 and 15 deposition cycles). Two kinds of crystals were observed for five deposition cycles (5×CdS/TiO2) (Figure 2a): separately dispersed CdS nanocrystal behind the very small CdS particles regrouped in aggregates. The formation of the aggregates could result from the

Ni nanocrystals on HOPG(0001): A scanning tunnelling microscope study

• Michael Marz,
• Keisuke Sagisaka and
• Daisuke Fujita

Beilstein J. Nanotechnol. 2013, 4, 406–417, doi:10.3762/bjnano.4.48

• attractive force between tip and cluster overcomes the adhesive force of the Ni nanocrystal on the HOPG surface. For this purpose, the tip was first stabilized above the center of the targeted cluster, and then the current setpoint was increased to a value up to 10 nA while the z-feedback was kept enabled

Size variation of infrared vibrational spectra from molecules to hydrogenated diamond nanocrystals: a density functional theory study

• Mudar A. Abdulsattar

Beilstein J. Nanotechnol. 2013, 4, 262–268, doi:10.3762/bjnano.4.28

• assigned different origins for some of the well observed lines, such as the experimental 500 and 1130–1332 cm−1 diamond nanocrystal lines [2][3][6]. In the present work we shall try to explain and calculate some of these lines. In addition, we shall discuss C–H vibrations and their mixing with C–C

• functional theory at level of the generalized gradient approximation of Perdew, Burke and Ernzerhof (PBE) is used in the present work to determine stable optimized positions of atoms in the nanocrystal [10]. Double-zeta 3-21G basis functions are chosen to perform the above calculations so that all

• vibrational analysis is performed with the same level of theory, which is feasible within our computer system in terms of memory and time. The chosen diamond nanocrystal is of 1 nm length. It has the stoichiometry C64H84. After optimizing geometrical positions, vibrational frequencies are determined by

Photoelectrochemical and Raman characterization of In₂O₃ mesoporous films sensitized by CdS nanoparticles

• Mikalai V. Malashchonak,
• Sergey K. Poznyak,
• Eugene A. Streltsov,
• Anatoly I. Kulak,
• Olga V. Korolik and
• Alexander V. Mazanik

Beilstein J. Nanotechnol. 2013, 4, 255–261, doi:10.3762/bjnano.4.27

• these peaks in the Raman spectra can testify to the fact that the samples studied contain not only In2O3 and CdS, but also some additional phases formed during the SILAR process. High values of the FWHM of the LO phonon peak can point to both a significant degree of CdS nanocrystal disorder and size

• heterogeneity (Figure 6). As can be seen from Figure 6, the CdS phonon energy decreases with increasing the number of SILAR cycles (i.e., the nanocrystal size). This effect can be explained in the following way: according to wavevector-relaxation [17] and continuum [18][19] models, the decrease of the size of

Diamond nanophotonics

• Katja Beha,
• Helmut Fedder,
• Marco Wolfer,
• Merle C. Becker,
• Petr Siyushev,
• Mohammad Jamali,
• Anton Batalov,
• Christopher Hinz,
• Jakob Hees,
• Lutz Kirste,
• Harald Obloh,
• Etienne Gheeraert,
• Boris Naydenov,
• Ingmar Jakobi,
• Florian Dolde,
• Sébastien Pezzagna,
• Daniel Twittchen,
• Matthew Markham,
• Daniel Dregely,
• Harald Giessen,
• Jan Meijer,
• Fedor Jelezko,
• Christoph E. Nebel,
• Rudolf Bratschitsch,
• Alfred Leitenstorfer and
• Jörg Wrachtrup

Beilstein J. Nanotechnol. 2012, 3, 895–908, doi:10.3762/bjnano.3.100

• materials, especially from SiO2 layers, and second, background emission from the diamond nanocrystal itself. By optimization of the sputter parameters, we recently achieved a reduction in photoluminescence of sputtered SiO2 layers by a factor of nine at a wavelength of 637 nm (ZPL of NV− centers, Figure 9b

The oriented and patterned growth of fluorescent metal–organic frameworks onto functionalized surfaces

• Jinliang Zhuang,
• Jasmin Friedel and
• Andreas Terfort

Beilstein J. Nanotechnol. 2012, 3, 570–578, doi:10.3762/bjnano.3.66

• was then varied to explore the possibility of nanocrystal fabrication. Thus various concentrations and ratios of the precursors were used to evaluate the influence on the crystal size and appearance. Figure 2 depicts [Zn2(adc)2(dabco)] crystals obtained under three different conditions. When an

• room temperature. Within a few minutes, the mixture turned to a suspension. The precipitate was collected by centrifugation and washed with methanol twice. Finally, the precipitate was dried under vacuum. Yield: 0.13 g. By changing the concentration of the precursor solutions, the other nanocrystal

Forming nanoparticles of water-soluble ionic molecules and embedding them into polymer and glass substrates

• Stella Kiel,
• Olga Grinberg,
• Nina Perkas,
• Jerome Charmet,
• Herbert Kepner and
• Aharon Gedanken

Beilstein J. Nanotechnol. 2012, 3, 267–276, doi:10.3762/bjnano.3.30

• , exploiting the difference in wettability between the regions of the patterned polymeric substrate [3]. Suh et al. [3] fabricated single nanocrystal arrays of various sizes on sub-microwells of poly (ethylene glycol) copolymer, using selective wetting of the hydrophilic regions of the exposed substrate

• demonstrated regions with a regular NaCl nanocrystal structure, by AFM. These structures varied from rows of single square nanocrystals to rows of long rectangular crystals with average sizes of 300 nm in width, 60 nm in height and up to several micrometers long. The structural changes were explained as being

Investigation on structural, thermal, optical and sensing properties of meta-stable hexagonal MoO₃ nanocrystals of one dimensional structure

• Angamuthuraj Chithambararaj and
• Arumugam Chandra Bose

Beilstein J. Nanotechnol. 2011, 2, 585–592, doi:10.3762/bjnano.2.62

• and centrifuged with distilled water several times. The obtained powder was dried at 70 °C in vacuum for 6 h. Thus, by a chemical precipitation technique, the h-MoO3 nanocrystal was synthesized by acid decomposition of ammonium molybdate according to the following reaction equation, (NH4)6Mo7O24·4 H2O

Precursor concentration and temperature controlled formation of polyvinyl alcohol-capped CdSe-quantum dots

• Chetan P. Shah,
• Madhabchandra Rath,
• Manmohan Kumar and
• Parma N. Bajaj

Beilstein J. Nanotechnol. 2010, 1, 119–127, doi:10.3762/bjnano.1.14

• did not prove possible to obtain the β-value from the XRD pattern. Further, the particle size was also calculated, using the Williamson–Hall equation [32]. By plotting the value of β cos θ against 4 sin θ, the lattice strain of the nanocrystal ε can be obtained from the slope, and the crystallite size

Fabrication and spectroscopic studies on highly luminescent CdSe/CdS nanorod polymer composites

• Jana Bomm,
• Andreas Büchtemann,
• Angela Fiore,
• Liberato Manna,
• James H. Nelson,
• Diana Hill and
• Wilfried G. J. H. M. van Sark

Beilstein J. Nanotechnol. 2010, 1, 94–100, doi:10.3762/bjnano.1.11

• free drop-casting process. Core/shell NRs were chosen as they exhibit higher stability against photooxidation and chemical attack by radicals [2][9]. The band-gap within a type-I core/shell nanocrystal gradually increases from the inside to the outside [2][10]. In our first method, where radicals are

Aerosol assisted fabrication of two dimensional ZnO island arrays and honeycomb patterns with identical lattice structures

• Mitsuhiro Numata and
• Yoshihiro Koide

Beilstein J. Nanotechnol. 2010, 1, 71–74, doi:10.3762/bjnano.1.9

• honeycomb patterns consisting of ZnO nanocrystal clusters were fabricated on predefined TiO2 seed patterns prepared by vacuum free, aerosol assisted wet-chemical synthesis. The TiO2 seed patterns were prepared by applying an aerosol of a water soluble titanium complex on hexagonally close-packed polystyrene

• identical spatial pitch but different fill fractions of periodic ZnO nanocrystal clusters on a 1.5 cm × 1.5 cm n-type (100) silicon wafer. In a newly developed m-CVD technique, an aqueous solution of a water soluble titanium complex (TiO2 precursor) [24][25] was delivered as aerosol on a polystyrene bead

• structure is considered advantageous in achieving the large aspect ratio necessary to observe the photonic bandgap via surface reflection measurements [9]. Figure 1 summarizes the ZnO nanocrystal array fabrication under the PSL/m-CVD procedures. First, a polystyrene beads (median diameter = 1.50 μm