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Journal of Physical Chemistry. C, Nanomaterials and Interfaces

Davide Bartesaghi, Adam H Slavney, María C Gélvez-Rueda, Bridget A Connor, Ferdinand C Grozema, Hemamala I Karunadasa, Tom J Savenije
Double perovskites, comprising two different cations, are potential nontoxic alternatives to lead halide perovskites. Here, we characterized thin films and crystals of Cs2 AgBiBr6 by time-resolved microwave conductance (TRMC), which probes formation and decay of mobile charges upon pulsed irradiation. Optical excitation of films results in the formation of charges with a yield times mobility product, φΣμ > 1 cm2 /Vs. On excitation of millimeter-sized crystals, the TRMC signals show, apart from a fast decay, a long-lived tail...
March 8, 2018: Journal of Physical Chemistry. C, Nanomaterials and Interfaces
Michael A Beuwer, Bas van Hoof, Peter Zijlstra
The high sensitivity of localized surface plasmon resonance sensors to the local refractive index allows for the detection of single-molecule binding events. Though binding events of single objects can be detected by their induced plasmon shift, the broad distribution of observed shifts remains poorly understood. Here, we perform a single-particle study wherein single nanospheres bind to a gold nanorod, and relate the observed plasmon shift to the binding location using correlative microscopy. To achieve this we combine atomic force microscopy to determine the binding location, and single-particle spectroscopy to determine the corresponding plasmon shift...
March 1, 2018: Journal of Physical Chemistry. C, Nanomaterials and Interfaces
Daniel Rettenwander, Reinhard Wagner, Andreas Reyer, Maximilian Bonta, Lei Cheng, Marca M Doeff, Andreas Limbeck, Martin Wilkening, Georg Amthauer
The interface stability versus Li represents a major challenge in the development of next-generation all-solid-state batteries (ASSB), which take advantage of the inherently safe ceramic electrolytes. Cubic Li7 La3 Zr2 O12 garnets represent the most promising electrolytes for this technology. The high interfacial impedance versus Li is, however, still a bottleneck toward future devices. Herein, we studied the electrochemical performance of Fe3+ -stabilized Li7 La3 Zr2 O12 (LLZO:Fe) versus Li metal and found a very high total conductivity of 1...
February 22, 2018: Journal of Physical Chemistry. C, Nanomaterials and Interfaces
Zhenhua Yang, Maria Moffa, Ying Liu, Hongfei Li, Luana Persano, Andrea Camposeo, Rosalba Saija, Maria Antonia Iatì, Onofrio M Maragò, Dario Pisignano, Chang-Yong Nam, Eyal Zussman, Miriam Rafailovich
Hybrid conjugated polymer/fullerene filaments based on MEH-PPV/PVP/PCBM were prepared by electrospinning, and their properties were assessed by scanning electron, atomic and lateral-force, tunneling, and confocal microscopies, as well as by attenuated-total-reflection Fourier transform infrared spectroscopy, photoluminescence quantum yield, and spatially resolved fluorescence. Highlighted features include the ribbon shape of the realized fibers and the persistence of a network serving as a template for heterogeneous active layers in solar cell devices...
February 8, 2018: Journal of Physical Chemistry. C, Nanomaterials and Interfaces
Alexander E J Hoffman, Louis Vanduyfhuys, Irena Nevjestić, Jelle Wieme, Sven M J Rogge, Hannes Depauw, Pascal Van Der Voort, Henk Vrielinck, Veronique Van Speybroeck
In this work, mid-infrared (mid-IR), far-IR, and Raman spectra are presented for the distinct (meta)stable phases of the flexible metal-organic framework MIL-53(Al). Static density functional theory (DFT) simulations are performed, allowing for the identification of all IR-active modes, which is unprecedented in the low-frequency region. A unique vibrational fingerprint is revealed, resulting from aluminum-oxide backbone stretching modes, which can be used to clearly distinguish the IR spectra of the closed- and large-pore phases...
February 8, 2018: Journal of Physical Chemistry. C, Nanomaterials and Interfaces
Adam Taylor, René Verhoef, Michael Beuwer, Yuyang Wang, Peter Zijlstra
We demonstrate the all-optical reconstruction of gold nanoparticle geometry using super-resolution microscopy. We employ DNA-PAINT to get exquisite control over the (un)binding kinetics by the number of complementary bases and salt concentration, leading to localization accuracies of ∼5 nm. We employ a dye with an emission spectrum strongly blue-shifted from the plasmon resonance to minimize mislocalization due to plasmon-fluorophore coupling. We correlate the all-optical reconstructions with atomic force microscopy images and find that reconstructed dimensions deviate by no more than ∼10%...
February 1, 2018: Journal of Physical Chemistry. C, Nanomaterials and Interfaces
Florian Kraushofer, Zdenek Jakub, Magdalena Bichler, Jan Hulva, Peter Drmota, Michael Weinold, Michael Schmid, Martin Setvin, Ulrike Diebold, Peter Blaha, Gareth S Parkinson
The α-Fe2 O3 (11̅02) surface (also known as the hematite r-cut or (012) surface) was studied using low-energy electron diffraction (LEED), X-ray photoelectron spectroscopy (XPS), ultraviolet photoelectron spectroscopy (UPS), scanning tunneling microscopy (STM), noncontact atomic force microscopy (nc-AFM), and ab initio density functional theory (DFT)+ U calculations. Two surface structures are stable under ultrahigh vacuum (UHV) conditions; a stoichiometric (1 × 1) surface can be prepared by annealing at 450 °C in ≈10-6 mbar O2 , and a reduced (2 × 1) reconstruction is formed by UHV annealing at 540 °C...
January 25, 2018: Journal of Physical Chemistry. C, Nanomaterials and Interfaces
Nelson Y Dzade, Nora H de Leeuw
Layered transition-metal chalcogenides have emerged as a fascinating new class of materials for catalysis. Here, we present periodic density functional theory (DFT) calculations of the adsorption of thiophene and the direct desulfurization reaction pathways on the (001), (011), and (111) surfaces of layered FeS. The fundamental aspects of the thiophene adsorption, including the initial adsorption geometries, adsorption energies, structural parameters, and electronic properties, are presented. From the calculated adsorption energies, we show that the flat adsorption geometries, wherein the thiophene molecule forms multiple π-bonds with the FeS surfaces, are energetically more favorable than the upright adsorption geometries, with the strength of adsorption decreasing in the order FeS(111) > FeS(011) > FeS(001)...
January 11, 2018: Journal of Physical Chemistry. C, Nanomaterials and Interfaces
Saskia Streubel, Felix Schulze-Zachau, Eric Weißenborn, Björn Braunschweig
Mixed layers of 6-hydroxy-5-[(4-sulfophenyl)azo]-2-naphthalenesulfonate (Sunset Yellow, SSY) and cetyltrimethylammonium bromide (C16TAB) at the air-water interface were studied using vibrational sum-frequency generation (SFG) and dynamic surface tension measurements. In the bulk, addition of C16TAB to SSY aqueous solution causes substantial changes in UV/vis absorption spectra, which originate from strong electrostatic interactions between the anionic SSY azo dye with the cationic C16TAB surfactant. These interactions are a driving force for the formation of SSY/C16TAB ion pairs...
December 21, 2017: Journal of Physical Chemistry. C, Nanomaterials and Interfaces
Jan Balajka, Ulrich Aschauer, Stijn F L Mertens, Annabella Selloni, Michael Schmid, Ulrike Diebold
The rutile TiO2(011) surface exhibits a (2 × 1) reconstruction when prepared by standard techniques in ultrahigh vacuum (UHV). Here we report that a restructuring occurs upon exposing the surface to liquid water at room temperature. The experiment was performed in a dedicated UHV system, equipped for direct and clean transfer of samples between UHV and liquid environment. After exposure to liquid water, an overlayer with a (2 × 1) symmetry was observed containing two dissociated water molecules per unit cell...
November 30, 2017: Journal of Physical Chemistry. C, Nanomaterials and Interfaces
María C Gélvez-Rueda, Eline M Hutter, Duyen H Cao, Nicolas Renaud, Constantinos C Stoumpos, Joseph T Hupp, Tom J Savenije, Mercouri G Kanatzidis, Ferdinand C Grozema
The optoelectronic properties of hybrid perovskites can be easily tailored by varying their components. Specifically, mixing the common short organic cation (methylammonium (MA)) with a larger one (e.g., butyl ammonium (BA)) results in 2-dimensional perovskites with varying thicknesses of inorganic layers separated by the large organic cation. In both of these applications, a detailed understanding of the dissociation and recombination of electron-hole pairs is of prime importance. In this work, we give a clear experimental demonstration of the interconversion between bound excitons and free charges as a function of temperature by combining microwave conductivity techniques with photoluminescence measurements...
November 30, 2017: Journal of Physical Chemistry. C, Nanomaterials and Interfaces
Hongsheng Liu, Cristiana Di Valentin
Magnetite exhibits a famous phase transition, called Verwey transition, at the critical temperature T V of about 120 K. Although numerous efforts have been devoted to the understanding of this interesting transition, up to now, it is still under debate whether a charge ordering and a band gap exist in magnetite above T V . Here, we systematically investigate the charge ordering and the electronic properties of magnetite in its cubic phase using different methods based on density functional theory: DFT+U and hybrid functionals...
November 22, 2017: Journal of Physical Chemistry. C, Nanomaterials and Interfaces
Karen Markey, Martin Krüger, Tomasz Seidler, Helge Reinsch, Thierry Verbiest, Dirk E De Vos, Benoît Champagne, Norbert Stock, Monique A van der Veen
p -Nitroaniline presents the typical motif of a second-order nonlinear optically (NLO) active molecule. However, because of its crystallization in an antiparallel and hence centrosymmetric structure, the NLO activity is lost. In this contribution, the p -nitroaniline motif was built successfully into the MIL-53 metal-organic framework. More precisely, MIL-53 was synthesized with 2-amino-5-nitroterephthalate as organic linker, with Al3+ , Ga3+ , or In3+ as inorganic cation. The Al and Ga structures are polar, as confirmed by second-harmonic generation microscopy, yielding stable NLO materials...
November 16, 2017: Journal of Physical Chemistry. C, Nanomaterials and Interfaces
Steven Vandenbrande, Toon Verstraelen, Juan José Gutiérrez-Sevillano, Michel Waroquier, Veronique Van Speybroeck
The search for nanoporous materials that are highly performing for gas storage and separation is one of the contemporary challenges in material design. The computational tools to aid these experimental efforts are widely available, and adsorption isotherms are routinely computed for huge sets of (hypothetical) frameworks. Clearly the computational results depend on the interactions between the adsorbed species and the adsorbent, which are commonly described using force fields. In this paper, an extensive comparison and in-depth investigation of several force fields from literature is reported for the case of methane adsorption in the Zr-based Metal-Organic Frameworks UiO-66, UiO-67, DUT-52, NU-1000, and MOF-808...
November 16, 2017: Journal of Physical Chemistry. C, Nanomaterials and Interfaces
Ru-Pan Wang, Boyang Liu, Robert J Green, Mario Ulises Delgado-Jaime, Mahnaz Ghiasi, Thorsten Schmitt, Matti M van Schooneveld, Frank M F de Groot
We show that with 2p3d resonant inelastic X-ray scattering (RIXS) we can accurately determine the charge-transfer parameters of CoF2 , CoCl2 , CoBr2 , and CoS. The 160 meV resolution RIXS results are compared with charge-transfer multiplet calculations. The improved resolution and the direct observation of the crystal field and charge-transfer excitations allow the determination of more accurate parameters than could be derived from X-ray absorption and X-ray photoemission, both limited in resolution by their lifetime broadening...
November 16, 2017: Journal of Physical Chemistry. C, Nanomaterials and Interfaces
Andrew Mellor, David Humphrey, Chi M Yim, Chi L Pang, Hicham Idriss, Geoff Thornton
Au nanoparticles supported on reducible metal oxide surfaces are known to be active catalysts for a number of reactions including CO oxidation and hydrogen production. The exact choice of a metal oxide support has been shown to have a marked impact on activity, suggesting that interactions between Au and the support play a key role in catalysis. For TiO2, a model substrate for Au catalysis, it had been thought that bridging oxygen vacancies are involved in binding Au atoms to the (110) surface based on indirect evidence...
November 9, 2017: Journal of Physical Chemistry. C, Nanomaterials and Interfaces
O T Hofmann, H Glowatzki, C Bürker, G M Rangger, B Bröker, J Niederhausen, T Hosokai, I Salzmann, R-P Blum, R Rieger, A Vollmer, P Rajput, A Gerlach, K Müllen, F Schreiber, E Zojer, N Koch, S Duhm
The adsorption of molecular acceptors is a viable method for tuning the work function of metal electrodes. This, in turn, enables adjusting charge injection barriers between the electrode and organic semiconductors. Here, we demonstrate the potential of pyrene-tetraone (PyT) and its derivatives dibromopyrene-tetraone (Br-PyT) and dinitropyrene-tetraone (NO2-PyT) for modifying the electronic properties of Au(111) and Ag(111) surfaces. The systems are investigated by complementary theoretical and experimental approaches, including photoelectron spectroscopy, the X-ray standing wave technique, and density functional theory simulations...
November 9, 2017: Journal of Physical Chemistry. C, Nanomaterials and Interfaces
Lorena Martín-Olivera, Dmitry G Shchukin, Gilberto Teobaldi
Magnetic hardening and generation of room-temperature ferromagnetism at the interface between originally nonmagnetic transition metals and π-conjugated organics is understood to be promoted by interplay between interfacial charge transfer and relaxation-induced distortion of the metal lattice. The relative importance of the two contributions for magnetic hardening of the metal remains unquantified. Here, we disentangle their role via density functional theory simulation of several models of interfaces between Cu and polymers of different steric hindrance, π-conjugation, and electron-accepting properties: polyethylene, polyacetylene, polyethylene terephthalate, and polyurethane...
October 26, 2017: Journal of Physical Chemistry. C, Nanomaterials and Interfaces
Chong Liu, Ionut Tranca, Rutger A van Santen, Emiel J M Hensen, Evgeny A Pidko
Zeolites are widely applied as solid acid catalysts in various technological processes. In this work we have computationally investigated how catalytic reactivity scales with acidity for a range of zeolites with different topologies and chemical compositions. We found that straightforward correlations are limited to zeolites with the same topology. The adsorption energies of bases such as carbon monoxide (CO), acetonitrile (CH3CN), ammonia (NH3), trimethylamine (N(CH3)3), and pyridine (C5H5N) give the same trend of acid strength for FAU zeolites with varying composition...
October 26, 2017: Journal of Physical Chemistry. C, Nanomaterials and Interfaces
S Strazdaite, J Versluis, N Ottosson, Huib J Bakker
We use heterodyne-detected vibrational sum-frequency generation (HD-VSFG) to determine the orientation of the molecular plane of methylguanidinium ions at the surface of aqueous solutions. We measure the VSFG response of the symmetric and antisymmetric methyl stretch vibrations of the methylguanidinium ion with different polarization combinations. We find that for at least 50% of the methylguanidinium ions the molecular plane is at an angle >20° with respect to the surface plane. Hence, for only a minor fraction of the ions does the molecular plane have an orientation (near-)parallel to the surface plane, in contrast to the predictions of recent molecular dynamics simulation studies...
October 26, 2017: Journal of Physical Chemistry. C, Nanomaterials and Interfaces
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