Interfacial charge transfer processes in 2D and 3D semiconducting hybrid perovskites: azobenzene as photoswitchable ligand

• Nicole Fillafer,
• Tobias Seewald,
• Lukas Schmidt-Mende and
• Sebastian Polarz

Beilstein J. Nanotechnol. 2020, 11, 466–479, doi:10.3762/bjnano.11.38

• . The most likely explanation are steric factors. The photoisomerisation requires freedom to move for the molecular groups. The space within the layers is so limited that the activation barrier becomes too high and thus photoswitching cannot take place. Weaker π-stacking in 2D-AzoOC4 and 2D-AzoOC12

Integration of sharp silicon nitride tips into high-speed SU8 cantilevers in a batch fabrication process

• Nahid Hosseini,
• Matthias Neuenschwander,
• Oliver Peric,
• Santiago H. Andany,
• Jonathan D. Adams and
• Georg E. Fantner

Beilstein J. Nanotechnol. 2019, 10, 2357–2363, doi:10.3762/bjnano.10.226

• oxidation sharpening [29]. Studies report a 30% decrease of the oxide thickness along the sharp silicon ridges after wet oxidation at 900–950 °C [30]. This decrease is due to an increase of the activation barrier of the interfacial reactions induced by the stress build-up in these areas [31]. Due to the

The impact of crystal size and temperature on the adsorption-induced flexibility of the Zr-based metal–organic framework DUT-98

• Simon Krause,
• Volodymyr Bon,
• Hongchu Du,
• Rafal E. Dunin-Borkowski,
• Ulrich Stoeck,
• Irena Senkovska and
• Stefan Kaskel

Beilstein J. Nanotechnol. 2019, 10, 1737–1744, doi:10.3762/bjnano.10.169

• , smaller crystal sizes seem to stabilize the presence of a metastable op phase by impacting the activation barrier, presumably due to the contribution of the surface energy and other factors. This observation was previously made for DUT-8 for which the guest-free metastable op phase was also found to be

Amorphous Ni_xCo_yP-supported TiO₂ nanotube arrays as an efficient hydrogen evolution reaction electrocatalyst in acidic solution

• Yong Li,
• Peng Yang,
• Bin Wang and
• Zhongqing Liu

Beilstein J. Nanotechnol. 2019, 10, 62–70, doi:10.3762/bjnano.10.6

• bottleneck for HER is the high overpotential associated with the process that takes place at a significant rate due to the high activation barrier and the sluggish multiple-proton-coupled electron transfer [4][5][6]. Noble metal Pt-based catalysts are widely used for HER to circumvent the overpotential

Metal-free catalysis based on nitrogen-doped carbon nanomaterials: a photoelectron spectroscopy point of view

• Mattia Scardamaglia and
• Carla Bittencourt

Beilstein J. Nanotechnol. 2018, 9, 2015–2031, doi:10.3762/bjnano.9.191

• pyridinic nitrogen improves the onset potential for the ORR, by weakening the O–O bond [101][102][115][118]. However, from a theoretical point of view, it has been shown that the activation barrier is much higher for the O2 adsorption on both the pyridinic nitrogen site and the nearest carbon atom [60][110

• carbon nanotubes without additional metal catalysts. Although similar in structure, carbon nanotubes (in particular single-walled CNTs) and graphene have different catalytic properties that are mostly due to the curvature of the CNTs. It has been calculated that the reaction energy and the activation

• barrier of O2 molecules on CNTs depends on their curvature and whether the nanotubes are metallic or semiconducting [21]. However, in most of the examples reported in this review concerning CNTs, the CNTs are mostly multiwalled and the theory used in the cited works is usually based on graphene as model

Formation mechanisms of boron oxide films fabricated by large-area electron beam-induced deposition of trimethyl borate

• Aiden A. Martin and
• Philip J. Depond

Beilstein J. Nanotechnol. 2018, 9, 1282–1287, doi:10.3762/bjnano.9.120

• demonstrated for a wide range of materials is electron beam-induced deposition (EBID) [6]. It avoids instabilities related to thermal- and mass-transport by overcoming the activation barrier for material deposition via electron-induced dissociation of surface-adsorbed precursor molecules into atomic or

Comparative study of sculptured metallic thin films deposited by oblique angle deposition at different temperatures

• Susann Liedtke,
• Christoph Grüner,
• Jürgen W. Gerlach and
• Bernd Rauschenbach

Beilstein J. Nanotechnol. 2018, 9, 954–962, doi:10.3762/bjnano.9.89

• homologous temperature for tilted Ta, Mo and Al columns. While the plot for the Mo columns shows a small slope up to TH = 0.15, for larger TH there is a significant increase up to TH = 0.3. A reason is that below TH = 0.15 the Mo adatoms have not enough energy to overcome the diffusion activation barrier

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

• species PBINT-1 is exothermic by −0.207 eV. Comparing the pathways considered and the computed activation energies as shown in Figure 5, the third methyl elimination in presence of oxygen, and the subsequent formation of Pt-oxy species (Path-B, C, D), have a high activation barrier. The formed Pt and Pt

Electron-driven and thermal chemistry during water-assisted purification of platinum nanomaterials generated by electron beam induced deposition

• Ziyan Warneke,
• Markus Rohdenburg,
• Jonas Warneke,
• Janina Kopyra and
• Petra Swiderek

Beilstein J. Nanotechnol. 2018, 9, 77–90, doi:10.3762/bjnano.9.10

• reduction of one of the two double bonds would lead to the different isomers of methylcyclopentene. Also, it is known that single electron oxidation of dienes significantly reduces the activation barrier towards formation of the Diels–Alder dimer [37] so that this product is also anticipated under electron

The rational design of a Au(I) precursor for focused electron beam induced deposition

• Ali Marashdeh,
• Thiadrik Tiesma,
• Niels J. C. van Velzen,
• Sjoerd Harder,
• Remco W. A. Havenith,
• Jeff T. M. De Hosson and
• Willem F. van Dorp

Beilstein J. Nanotechnol. 2017, 8, 2753–2765, doi:10.3762/bjnano.8.274

• enough to be used as a precursor for chemical vapor or electron-induced deposition [12][51][52]. Concluding, the DFT calculations of the ground states of isolated molecules help to explain the stability of ClAuPF3, CF3AuCO and ClAuPMe3. MeAuPMe3 appears to be stabilized by a significant activation

• barrier for decomposition, as it is more stable in practice than the low value of ΔG of +11.6 kcal/mol suggests. As for ClAuCO, the calculations appear to overestimate its stability, as it decomposes faster than the ΔG value of +25.5 kcal/mol would lead us to expect. From this we conclude that for ClAuCO

Adsorption of iron tetraphenylporphyrin on (111) surfaces of coinage metals: a density functional theory study

• Hao Tang,
• Nathalie Tarrat,
• Véronique Langlais and
• Yongfeng Wang

Beilstein J. Nanotechnol. 2017, 8, 2484–2491, doi:10.3762/bjnano.8.248

• Coulomb repulsion. The deckchair conformation of the molecule favours intermolecular π–π-type interactions in a less densely packed monolayer than the saddle conformation. The activation barrier between the two stable magnetic states (high spin, S = 2 and intermediate spin, S = 1) of the molecule in

• spin switches. Keywords: activation barrier; density functional theory; iron tetraphenylporphyrin; spin switch; spin states; Introduction Porphyrins, phthalocyanines and their transition-metal (TM) complexes are largely investigated in surface science as reported in detail by Gottfried [1]. The

• S = 1 associated with a conformational change by passing from a saddle shape to a planar shape in the presence of the STM tip. To the best of our knowledge, the stability as well as the activation barrier between HS and IS FeTPP have not yet been investigated. In this paper, a brief analysis of the

Spin-chemistry concepts for spintronics scientists

• Konstantin L. Ivanov,
• Alexander Wagenpfahl,
• Carsten Deibel and
• Jörg Matysik

Beilstein J. Nanotechnol. 2017, 8, 1427–1445, doi:10.3762/bjnano.8.143

• the recombination reaction of the two radicals (R1• + R2• → R1–R2) typically occurs without any activation barrier. That statement, however, is only true if the radical pair (R1• + R2•) forms a singlet state, that is, the electronic spin wavefunction is antisymmetric. If the spin wavefunction is

Thickness-modulated tungsten–carbon superconducting nanostructures grown by focused ion beam induced deposition for vortex pinning up to high magnetic fields

• Ismael García Serrano,
• Javier Sesé,
• Isabel Guillamón,
• Hermann Suderow,
• Sebastián Vieira,
• Manuel Ricardo Ibarra and
• José María De Teresa

Beilstein J. Nanotechnol. 2016, 7, 1698–1708, doi:10.3762/bjnano.7.162

• formed potential well can be estimated assuming that around the matching field the resistance follows an activation behavior as a function of temperature: where T0 is an indicator of the activation barrier [17]. A few selected local minima have been fit to Equation 4, as shown for the sample with 60 nm

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

• successful approach to control crystal structures. Higher reaction temperature and longer reaction time are required to provide sufficient free energy to overcome the activation barrier of an α/ß phase transition [19][33]. In the XRD experiments, all crystal diffractions and amorphous halos of the OM–NaYF4

The role of low-energy electrons in focused electron beam induced deposition: four case studies of representative precursors

• Rachel M. Thorman,
• Ragesh Kumar T. P.,
• D. Howard Fairbrother and
• Oddur Ingólfsson

Beilstein J. Nanotechnol. 2015, 6, 1904–1926, doi:10.3762/bjnano.6.194

Continuum models of focused electron beam induced processing

• Milos Toth,
• Charlene Lobo,
• Vinzenz Friedli,
• Aleksandra Szkudlarek and
• Ivo Utke

Beilstein J. Nanotechnol. 2015, 6, 1518–1540, doi:10.3762/bjnano.6.157

• that can undergo physisorption and activated chemisorption can be described by the potential energy diagram shown in Figure 12 [68], comprised of a physisorbed state (denoted “p”) and a chemisorbed state (denoted “c”) separated by an activation barrier for conversion between these states. The

• respective physisorption and chemisorption potential wells have depths Ep and Ec, and the activation barrier has height Econv. Chemisorption is typically a dissociative process in which the activation barrier represents the energy needed to fragment the precursor molecule. For example, O2 chemisorbs onto

• monolayer limit 1/Ap. At the lower substrate temperatures of 300 and 200 K, kconv, kp and kc are reduced through Equation 41, Equation 42 and Equation 43, yielding the adsorption isotherms shown in Figure 13a. It is important to note that the rate of chemisorption is always limited by the activation barrier

Entropy effects in the collective dynamic behavior of alkyl monolayers tethered to Si(111)

• Christian Godet

Beilstein J. Nanotechnol. 2015, 6, 583–594, doi:10.3762/bjnano.6.60

• excitations available from the thermal bath (divided by a number of the order of 1). Hence, as |VDC| increases, increasingly large number of vibrational excitations (in the range of 10–50) is required to overcome the activation barrier for collective molecular reorientation. Coupling with vibrational modes

Chains of carbon atoms: A vision or a new nanomaterial?

• Florian Banhart

Beilstein J. Nanotechnol. 2015, 6, 559–569, doi:10.3762/bjnano.6.58

• stability in comparison with narrow graphene ribbons will be discussed below in the context of defects and irradiation. One of the most discussed properties of sp1-hybridized carbon is its chemical stability. Two parallel chains develop cross-links; this is an exothermic reaction with an activation barrier

Influence of grain size and composition, topology and excess free volume on the deformation behavior of Cu–Zr nanoglasses

• Daniel Şopu and
• Karsten Albe

Beilstein J. Nanotechnol. 2015, 6, 537–545, doi:10.3762/bjnano.6.56

• Cu64Zr36 NG the maximum stress is lower (about 4.0 GPa) compared to the BMG (about 4.7 GPa). The same trend is found for the maximum stress of NG1 Cu36Zr64 (about 2.6 GPa) compared to 3.0 GPa in case of the BMG with the same chemical composition. This can be explained by the lower activation barrier for

Adsorption and oxidation of formaldehyde on a polycrystalline Pt film electrode: An in situ IR spectroscopy search for adsorbed reaction intermediates

• Zenonas Jusys and
• R. Jürgen Behm

Beilstein J. Nanotechnol. 2014, 5, 747–759, doi:10.3762/bjnano.5.87

• C–H bond, as expected for a higher activation barrier. Mechanistic implications The results presented and discussed in the previous three sections lead us to the following conclusions on the interaction of formaldehyde with Pt: 1. An IR band compatible with an adsorbed formyl species, at ca. 1660 cm

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

• 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

The role of oxygen and water on molybdenum nanoclusters for electro catalytic ammonia production

• Jakob G. Howalt and
• Tejs Vegge

Beilstein J. Nanotechnol. 2014, 5, 111–120, doi:10.3762/bjnano.5.11

• exergonic and no apparent activation barrier is observed for the N–N cleavage at either the third or fourth protonation step. The onset potential presented here for electrochemical ammonia production is similar to those obtained in previous studies on both clean and nitrogen covered molybdenum nanoclusters

Some reflections on the understanding of the oxygen reduction reaction at Pt(111)

• Ana M. Gómez-Marín,
• Ruben Rizo and
• Juan M. Feliu

Beilstein J. Nanotechnol. 2013, 4, 956–967, doi:10.3762/bjnano.4.108

• the Pt(111), Pt(211), Pt(100) and Pt(110) surfaces (Figure 4). In all cases, the used adsorption free energies were calculated while assuming a low oxygen coverage [13][33][44][58]. As can be seen from Figure 4, in the absence of any activation barrier the limiting elementary step for the ORR would be

Adsorption of the ionic liquid [BMP][TFSA] on Au(111) and Ag(111): substrate effects on the structure formation investigated by STM

• Benedikt Uhl,
• Florian Buchner,
• Dorothea Alwast,
• Nadja Wagner and
• R. Jürgen Behm

Beilstein J. Nanotechnol. 2013, 4, 903–918, doi:10.3762/bjnano.4.102

• is mainly determined by two parameters, by the surface diffusion barrier, i.e., the activation barrier for the motion of individual adsorbed species between two adjacent adsorption sides, and the interactions between adjacent adsorbates (adsorbate–adsorbate interactions). The fact that the IL

Generation and agglomeration behaviour of size-selected sub-nm iron clusters as catalysts for the growth of carbon nanotubes

• Ravi Joshi,
• Benjamin Waldschmidt,
• Jörg Engstler,
• Rolf Schäfer and
• Jörg J. Schneider

Beilstein J. Nanotechnol. 2011, 2, 734–739, doi:10.3762/bjnano.2.80

• twinned 5 nm catalyst particles as well as even larger aggregates, which are occasionally found during the TEM observations (Figure 2b). Depending on the activation barrier of the diffusion process, a temperature increase of 150 °C can lead to a significant increase in the diffusion length of the clusters