Spectroscopic mapping and selective electronic tuning of molecular orbitals in phosphorescent organometallic complexes – a new strategy for OLED materials

• Pascal R. Ewen,
• Jan Sanning,
• Tobias Koch,
• Nikos L. Doltsinis,
• Cristian A. Strassert and
• Daniel Wegner

Beilstein J. Nanotechnol. 2014, 5, 2248–2258, doi:10.3762/bjnano.5.234

• states in both measurements? For this we have to consider the possibility of strong physisorption (or even chemisorption). While weak physisorption only leads to a broadening of the MO levels (as described above), a strong molecule–substrate hybridization (i.e., strong physisorption or chemisorption) can

Advances in NO₂ sensing with individual single-walled carbon nanotube transistors

• Kiran Chikkadi,
• Matthias Muoth,
• Cosmin Roman,
• Miroslav Haluska and
• Christofer Hierold

Beilstein J. Nanotechnol. 2014, 5, 2179–2191, doi:10.3762/bjnano.5.227

• ][39][40][41][42][43]. Although the first calculations [39][40] suggested a charge transfer upon physisorption, Santucci et al. [43] showed that this charge transfer disappeared when spin-polarized treatment was used in the calculations. Yim et al. [44] have suggested that a pairwise chemisorption of

• NO2 molecules is more favorable than the chemisorption of individual molecules, but the energy of interaction they report is far lower than the observed experimental results as well as theoretical calculations in other reports [41][45]. Another possibility is dissociative adsorption of NO2. Goldoni et

• energy for NO3 on the nanotube. However, it has since been pointed out that the methods used in this paper tend to overestimate the binding energy [41][45] and charge transfer. Dai et al. [41] found that chemisorption of two NO3 molecules, on the other hand, is found to be favorable, with an adsorption

Cathode lens spectromicroscopy: methodology and applications

• T. O. Menteş,
• G. Zamborlini,
• A. Sala and
• A. Locatelli

Beilstein J. Nanotechnol. 2014, 5, 1873–1886, doi:10.3762/bjnano.5.198

• phase shows a negligible DOS at the K point of the π-band. These results point to the disruption of the Dirac cones and the formation of a metal-like DOS. Surprisingly, the hybridization of the π-band with Ir states is due to the chemisorption of just 11% of the C atoms in the unit cell of the buckled

• chemisorption bonds such as those observed in the buckled graphene phase on Ir(100). In our work, the related variations in C–substrate bonding and the electronic structure of graphene were quantified in μ-XPS and μ-ARPES experiments, taking the pristine graphene/Ir(100) system as reference. Experimentally, Au

• further confirms that, after Au intercalation, graphene is entirely physisorbed and no chemisorption bonds are established between C and the substrate. The C 1s μ-XPS spectrum of the graphene/Ir(100) system exhibits two components. The dominant one, at about 283.95 eV binding energy, has been previously

Purification of ethanol for highly sensitive self-assembly experiments

• Kathrin Barbe,
• Martin Kind,
• Christian Pfeiffer and
• Andreas Terfort

Beilstein J. Nanotechnol. 2014, 5, 1254–1260, doi:10.3762/bjnano.5.139

• with the desired thiolates for surface sites. Here we present that gold nanoparticles deposited onto zeolite X can be used to remove these contaminants by chemisorption. This nanoparticle-impregnated zeolite does not only show high capacities for surface-active contaminants, such as thiols, but can be

• thiols and other surface-active impurities from ethanol was tested by varying the gold load at the zeolite as well as the gold-NP preparation temperature. Dodecanethiol was used as test substance for these chemisorption experiments because it binds effectively and fast to gold surfaces [3]. In a typical

• change of thin gold films upon chemisorption of molecular films. For a selected class of compounds, such as alkanethiols, a very good linear correlation between the increase of resistivity and the surface coverage Θ has been established [29][32]. As an initial test, several commercial qualities of

Growth and characterization of CNT–TiO₂ heterostructures

• Yucheng Zhang,
• Ivo Utke,
• Johann Michler,
• Gabriele Ilari,
• Marta D. Rossell and
• Rolf Erni

Beilstein J. Nanotechnol. 2014, 5, 946–955, doi:10.3762/bjnano.5.108

• can be found in the review by Leary [19]. Recently, we have adopted the atomic layer deposition (ALD) technique to deposit TiO2 on CVD-grown MW-CNTs. ALD relies on self-limiting surface reactions (dissociative chemisorption) of gases which are alternately introduced into and purged out of the reaction

• chamber. The surface reaction will establish a chemical bond of the precursor molecule with the substrate through the reaction of an organic ligand to a volatile compound. The remaining organic ligands still bound to the metal atom prevent further chemisorption. This self-limitation has two important

• , e.g., trimethylaluminium for Al2O3, titanium tetraisopropoxide for TiO2, diethylzinc for ZnO, or tetrakis(ethylmethylamido)hafnium for HfO2, need surfaces that are terminated with a functional group, which would allow for their dissociative chemisorption reaction. Hydroxy-(OH)-group terminated

Gas sensing with gold-decorated vertically aligned carbon nanotubes

• Prasantha R. Mudimela,
• Mattia Scardamaglia,
• Oriol González-León,
• Nicolas Reckinger,
• Rony Snyders,
• Eduard Llobet,
• Carla Bittencourt and
• Jean-François Colomer

Beilstein J. Nanotechnol. 2014, 5, 910–918, doi:10.3762/bjnano.5.104

• temperature. However, mild heating at 150 °C was needed to help desorb the species from the surface so the baseline resistance could be fully recovered. This is not surprising because a rather strong interaction (chemisorption) between oxygen plasma treated or gold nanoparticle decorated CNTs and NO2 has been

Injection of ligand-free gold and silver nanoparticles into murine embryos does not impact pre-implantation development

• Ulrike Taylor,
• Wiebke Garrels,
• Annette Barchanski,
• Svea Peterson,
• Laszlo Sajti,
• Andrea Lucas-Hahn,
• Lisa Gamrad,
• Ulrich Baulain,
• Sabine Klein,
• Wilfried A. Kues,
• Stephan Barcikowski and
• Detlef Rath

Beilstein J. Nanotechnol. 2014, 5, 677–688, doi:10.3762/bjnano.5.80

• (physisorption or chemisorption) strongly affects the toxicity of AuNP on human embryonic kidney cells [39]. Another factor which has been shown to influence embryotoxicity is the size of the nanoparticles. For both AuNP and AgNP an increase in toxicity has been shown in conjuction with a decrease in size [13

In vitro toxicity and bioimaging studies of gold nanorods formulations coated with biofunctional thiol-PEG molecules and Pluronic block copolymers

• Tianxun Gong,
• Douglas Goh,
• Malini Olivo and
• Ken-Tye Yong

Beilstein J. Nanotechnol. 2014, 5, 546–553, doi:10.3762/bjnano.5.64

• by means of the chemisorption process between the thiol moiety and the gold particle surface [24][25]. Pluronic is a commercially available triblock copolymer with a hydrophobic segment of poly(propylene oxide) (PPO) polymer sandwiched between two hydrophilic segments of PEO. In our previous study

Neutral and charged boron-doped fullerenes for CO₂ adsorption

• Suchitra W. de Silva,
• Aijun Du,
• Wijitha Senadeera and
• Yuantong Gu

Beilstein J. Nanotechnol. 2014, 5, 413–418, doi:10.3762/bjnano.5.49

• adsorption the calculated adsorption energy should have a negative value. To provide more accurate results for the chemisorption energy the counterpoise corrected energy [26][27] was also calculated. The transition state was located by using the synchronous transit-guided quasi-Newton (STQN) method [28][29

• to undergo significant structural deformations. A stable CO2 adsorption is observed at the HH B–C site. The chemisorption energy of −15.41 kcal/mol (−64.48 kJ/mol) (−13.48 kcal/mol with BSSE correction) agrees well with the ideal range of chemisorption energy (40–80 kJ/mol) for a good CO2 adsorbent

• frequency calculations on the optimized transition structure, which confirms that it is a first order saddle point and hence an actual transition structure. From this figure, the activation barrier for the chemisorption is estimated to be 13.25 kcal/mol (55.43 kJ/mol). The low barrier of the reaction

Modeling and optimization of atomic layer deposition processes on vertically aligned carbon nanotubes

• Nuri Yazdani,
• Vipin Chawla,
• Eve Edwards,
• Vanessa Wood,
• Hyung Gyu Park and
• Ivo Utke

Beilstein J. Nanotechnol. 2014, 5, 234–244, doi:10.3762/bjnano.5.25

• , and α(x,t) is a loss term that corresponds to the adsorption of precursor molecules onto available bonding sites and their subsequent chemical bond formation (chemisorption). The adsorption rate per unit volume, α, is modeled to be proportional to the number of precursor molecules striking the CNT

Change of the work function of platinum electrodes induced by halide adsorption

• Florian Gossenberger,
• Tanglaw Roman,
• Katrin Forster-Tonigold and
• Axel Groß

Beilstein J. Nanotechnol. 2014, 5, 152–161, doi:10.3762/bjnano.5.15

• nitrogen adsorbed on a tungsten (100) surface. They showed that the decrease of the work function depends strongly on the length of the chemisorption bond. If the adatom is located close to the surface, it is in the region of the overspill electron density of the metal. This leads to an area of electron

• shown to give reliable results in terms of atomization energy, chemisorption energies [24][25], work function changes [26], and good estimates of bulk properties of metals [27]. Hybrid functionals are not necessarily improvements to PBE; for example they do not yield a satisfactory description of the

• can be associated with a covalent character of the chemisorption bond. This rearrangement is particularly strong for the adsorption of iodine, and slightly weaker for bromine and chlorine. The character of the chemisorption bond between iodine and platinum was discussed in the past [10][17] and

Influence of the adsorption geometry of PTCDA on Ag(111) on the tip–molecule forces in non-contact atomic force microscopy

• Gernot Langewisch,
• Jens Falter,
• André Schirmeisen and
• Harald Fuchs

Beilstein J. Nanotechnol. 2014, 5, 98–104, doi:10.3762/bjnano.5.9

• , could in this case be explained by the different spectral weight of the energetically shifted LUMO state (the hybrid state resulting from the chemisorption) below the Fermi level and corresponding differences in the electron density of the two orientations. A higher electron density would lead to a

Magnetic anisotropy of graphene quantum dots decorated with a ruthenium adatom

• Igor Beljakov,
• Velimir Meded,
• Franz Symalla,
• Karin Fink,
• Sam Shallcross and
• Wolfgang Wenzel

Beilstein J. Nanotechnol. 2013, 4, 441–445, doi:10.3762/bjnano.4.51

• shall consider the nature of its bonding to the graphene flake. We find the calculated Ru–flake separation to be 1.75 Å, strongly indicating chemisorption, a fact supported by the significant reduction in the Ru moment from the atomic state (we find the moment to be always less than 2 μB while the

Photoresponse from single upright-standing ZnO nanorods explored by photoconductive AFM

• Igor Beinik,
• Markus Kratzer,
• Astrid Wachauer,
• Lin Wang,
• Yuri P. Piryatinski,
• Gerhard Brauer,
• Xin Yi Chen,
• Yuk Fan Hsu,
• Aleksandra B. Djurišić and
• Christian Teichert

Beilstein J. Nanotechnol. 2013, 4, 208–217, doi:10.3762/bjnano.4.21

• . The surface conductivity of ZnO is highly dependent on the presence of adsorbates [20][21][22][23]. Such surface defects serve as binding sites for chemisorption processes and may contribute to the scattering and trapping of carriers [24], which lower the intrinsic conductivity of the material

Nanostructure-directed chemical sensing: The IHSAB principle and the dynamics of acid/base-interface interaction

• James L. Gole and
• William Laminack

Beilstein J. Nanotechnol. 2013, 4, 20–31, doi:10.3762/bjnano.4.3

• this process induces. In combination, this provides a focused chemistry that tailors electron flow at the interface, differentiates electron transduction versus chemisorption, and can enhance light-harvesting efficiency. This approach is now developed to the extent that the dynamics of analyte

• tenets of HSAB interactions [14][15]. It includes the coupling of analyte/interface acid/base chemistry with select interfaces, leading to a balance and separation of surface electron transduction and chemisorption, and enables the ability of active nanostructure-based sites to utilize these differences

• transformation from acidic to basic sites. These studies also define a broadened interaction matrix as it extends from physisorption (sensing) applications to chemisorption and microreactor design. Recently, we have produced visible-light-absorbing TiO2−xNx photocatalyst nanoparticles in seconds at room

Pure hydrogen low-temperature plasma exposure of HOPG and graphene: Graphane formation?

• Baran Eren,
• Dorothée Hug,
• Laurent Marot,
• Rémy Pawlak,
• Marcin Kisiel,
• Roland Steiner,
• Dominik M. Zumbühl and
• Ernst Meyer

Beilstein J. Nanotechnol. 2012, 3, 852–859, doi:10.3762/bjnano.3.96

• of the graphene. The elegant yet simple solution to obtain such a chemisorption may be to use a pure hydrogen low-temperature plasma (LTP) with a typical average electron temperature (Te) of 2–5 eV, where the hydrogen would be easily dissociated (with the required energy being Te: 4.52 eV) and

• theoretical [15], and experimental works focused on the chemisorption of atomic hydrogen [16][17][18][19][20]. A new research focus is the investigation of hydrogen-containing plasmas with graphitic surfaces [5][21]. Particularly the work of Elias et al. is interesting, in which graphane growth was claimed

Current–voltage characteristics of single-molecule diarylethene junctions measured with adjustable gold electrodes in solution

• Bernd M. Briechle,
• Youngsang Kim,
• Philipp Ehrenreich,
• Artur Erbe,
• Dmytro Sysoiev,
• Thomas Huhn,
• Ulrich Groth and
• Elke Scheer

Beilstein J. Nanotechnol. 2012, 3, 798–808, doi:10.3762/bjnano.3.89

• curves is that the molecule is chemisorbed to one electrode only and physisorbed to the other one. While there is no strict distinction between physisorption and chemisorption, we use these terms for describing strong coupling including a bond formation (chemisorption), and van der Waals like coupling

• (physisorption). In the case of physisorption, one can expect that the current is mediated by tunneling. For thiol end-groups on gold, it has been shown that both chemisorption and physisorption is possible [42][43][44] depending on the surface morphology and the deposition method. For the amine end-group the

Spontaneous dissociation of Co₂(CO)₈ and autocatalytic growth of Co on SiO₂: A combined experimental and theoretical investigation

• Kaliappan Muthukumar,
• Harald O. Jeschke,
• Roser Valentí,
• Evgeniya Begun,
• Johannes Schwenk,
• Fabrizio Porrati and
• Michael Huth

Beilstein J. Nanotechnol. 2012, 3, 546–555, doi:10.3762/bjnano.3.63

• settings, using dispersion-corrected density functional theory, support this assumption. We observe physisorption of the precursor molecule on a fully hydroxylated SiO2 surface (untreated surface) and chemisorption on a partially hydroxylated SiO2 surface (pretreated surface) with a spontaneous

Directed deposition of silicon nanowires using neopentasilane as precursor and gold as catalyst

• Britta Kämpken,
• Verena Wulf,
• Norbert Auner,
• Marcel Winhold,
• Michael Huth,
• Daniel Rhinow and
• Andreas Terfort

Beilstein J. Nanotechnol. 2012, 3, 535–545, doi:10.3762/bjnano.3.62

• process of nanoparticles often requires other reagents, e.g., for micelle nanolithography or chemisorption at surface-attached organic monolayers [24][25]. These organic additives (stabilizer/monolayer) might disturb the growth process of the silicon NWs and lead to contaminations, thus they need to be

• coordinate to the Au nanoparticles. The chemisorption of the nanoparticles proceeded by simple immersion into the respective solution and resulted in surfaces that were evenly, but not closely decorated by the nanoparticles (Figure 8). The average distance between two nanoparticles could be estimated to be

Functionalised zinc oxide nanowire gas sensors: Enhanced NO₂ gas sensor response by chemical modification of nanowire surfaces

• Eric R. Waclawik,
• Jin Chang,
• Andrea Ponzoni,
• Isabella Concina,
• Dario Zappa,
• Elisabetta Comini,
• Nunzio Motta,
• Guido Faglia and
• Giorgio Sberveglieri

Beilstein J. Nanotechnol. 2012, 3, 368–377, doi:10.3762/bjnano.3.43

• semiconductor surface towards chemisorption or else to ensure heterogeneous catalysis of a high proportion of target gas molecules at the sensor surface. High-temperature operation also ensures the complete desorption of gaseous species following transduction. Maintaining a semiconductor gas sensor at a stable

• decreased number of “active” sites for chemisorption may arise through chemical functionalisation by an organic layer, the effect may be offset by increased rates of gas decomposition or reduced interference caused by moisture or other species present in a gas stream. It should be noted that since

• chemisorption involves electronic charge transfer, functionalisation of the surface of a metal-oxide semiconductor gas sensor with an organic monolayer will strongly influence the electronic properties of the surface. Transfer of electron density into the semiconductor will reduce the depletion layer, which is

Surface functionalization of aluminosilicate nanotubes with organic molecules

• Wei Ma,
• Weng On Yah,
• Hideyuki Otsuka and
• Atsushi Takahara

Beilstein J. Nanotechnol. 2012, 3, 82–100, doi:10.3762/bjnano.3.10

• groups of organic molecules and the aluminol (AlOH) surface of imogolite nanotubes. An aqueous modification process employing a water soluble ammonium salt of alkyl phosphate led to chemisorption of molecules on imogolite at the nanotube level. Polymer-chain-grafted imogolite nanotubes were prepared

• hybrid. Keywords: chemisorption; imogolite; inorganic nanotube; surface functionalization.; Review Surface functionalization of metal or metal-oxide surfaces has received considerable attention in recent years [1][2][3]. It presents an easy, accurate and precise approach for the fabrication of

• selectively assemble on the surfaces of metal oxides rather than on SiO2 surfaces in an aqueous medium, due to the sensitivity of Si–O–P bonds to hydrolysis [19][20][21]. In this review paper, the chemisorption and assembly of several phosphonic-acid-containing organic compounds on imogolite nanotubes, based

Self-assembled monolayers and titanium dioxide: From surface patterning to potential applications

• Yaron Paz

Beilstein J. Nanotechnol. 2011, 2, 845–861, doi:10.3762/bjnano.2.94

• monolayers may affect the photocatalytic properties of titania as well as be affected by these properties. Likewise, the superhydrophilicity of TiO2 known to be induced upon exposure to UV light [13] may affect the chemisorption process of SAMs. This gives rise to diverse phenomena, which can be utilized in

• the metallic micro-islands were denser than monolayers chemisorbed on TiO2 substrates that had no metallic islands. Results were explained in terms of charging effects [18]. That charging of the substrate may affect the chemisorption of organosiloxane monolayers can be deduced also from a comparison

• grafting density with respect to chemisorption by conventional methods (2.8–3.0 molecules per nm2 versus 4.3–4.8 molecules per nm2). It is worth mentioning that a study on organosilane monolayers formed on the surfaces of zirconia and titania (anatase and rutile), by a gas–phase process employing

STM visualisation of counterions and the effect of charges on self-assembled monolayers of macrocycles

• Tibor Kudernac,
• Natalia Shabelina,
• Wael Mamdouh,
• Sigurd Höger and
• Steven De Feyter

Beilstein J. Nanotechnol. 2011, 2, 674–680, doi:10.3762/bjnano.2.72

• principle, an additional functionality can be introduced in physisorbed molecular monolayers by co-adsorption of, for instance, thiols [8], combining physisorption and chemisorption. It can be envisioned that counterions of charged molecules that are adsorbed at the surface could be used not only to control

Sensing surface PEGylation with microcantilevers

• Natalija Backmann,
• Natascha Kappeler,
• Thomas Braun,
• François Huber,
• Hans-Peter Lang,
• Christoph Gerber and
• Roderick Y. H. Lim

Beilstein J. Nanotechnol. 2010, 1, 3–13, doi:10.3762/bjnano.1.2

• , time resolved manner [13][14]. By an asymmetrical chemisorption of molecules (i.e., on one side of the microcantilever), the sensors can detect processes in “static” mode by measuring the bending of a microcantilever due to stress formation during the adsorption process; or in “dynamic” mode where the

• shown in Figure 2A, the chemisorption of mPEG–SH chains generates a compressive force that bends the Au-coated microcantilevers downwards. This behavior is significantly different to that of the cantilever pre-functionalized with EG4–C11–SH where no adsorption-related bending is observed and confirms