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Type: article × Publisher: Cambridge : RSC Publ. × Subject: Monolayers ×

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Now showing 1 - 3 of 3
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    Influence of 4f filling on electronic and magnetic properties of rare earth-Au surface compounds
    (Cambridge : RSC Publ., 2020) Fernandez, L.; Blanco-Rey, M.; Castrillo-Bodero, R.; Ilyn, M.; Ali, K.; Turco, E.; Corso, M.; Ormaza, M.; Gargiani, P.; Valbuena, M.A.; Mugarza, A.; Moras, P.; Sheverdyaeva, P.M.; Kundu, Asish K.; Jugovac, M.; Laubschat, C.; Ortega, J.E.; Schiller, F.
    One-atom-thick rare-earth/noble metal (RE-NM) compounds are attractive materials to investigate two-dimensional magnetism, since they are easy to synthesize into a common RE-NM2 structure with high crystal perfection. Here we perform a comparative study of the GdAu2, HoAu2, and YbAu2 monolayer compounds grown on Au(111). We find the same atomic lattice quality and moiré superlattice periodicity in the three cases, but different electronic properties and magnetism. The YbAu2 monolayer reveals the characteristic electronic signatures of a mixed-valence configuration in the Yb atom. In contrast, GdAu2 and HoAu2 show the trivalent character of the rare-earth and ferromagnetic transitions below 22 K. Yet, the GdAu2 monolayer has an in-plane magnetic easy-axis, versus the out-of-plane one in HoAu2. The electronic bands of the two trivalent compounds are very similar, while the divalent YbAu2 monolayer exhibits different band features. In the latter, a strong 4f-5d hybridization is manifested in neatly resolved avoided crossings near the Fermi level. First principles theory points to a residual presence of empty 4f states, explaining the fluctuating valence of Yb in the YbAu2 monolayer. © The Royal Society of Chemistry.
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    The interaction of chondroitin sulfate with a lipid monolayer observed by using nonlinear vibrational spectroscopy
    (Cambridge : RSC Publ., 2021) Szekeres, Gergo Peter; Krekic, Szilvia; Miller, Rebecca L.; Mero, Mark; Pagel, Kevin; Heiner, Zsuzsanna
    The first vibrational sum-frequency generation (VSFG) spectra of chondroitin sulfate (CS) interacting with dipalmitoyl phosphatidylcholine (DPPC) at air–liquid interface are reported here, collected at a laser repetition rate of 100 kHz. By studying the VSFG spectra in the regions of 1050–1450 cm−1, 2750–3180 cm−1, and 3200–3825 cm−1, it was concluded that in the presence of Ca2+ ions, the head groups together with the head-group-bound water molecules in the DPPC monolayer are strongly influenced by the interaction with CS, while the organization of the phospholipid tails remains mostly unchanged. The interactions were observed at a CS concentration below 200 nM, which exemplifies the potential of VSFG in studying biomolecular interactions at low physiological concentrations. The VSFG spectra recorded in the O–H stretching region at chiral polarization combination imply that CS molecules are organized into ordered macromolecular superstructures with a chiral secondary structure.
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    Modulating the luminance of organic light-emitting diodes: Via optical stimulation of a photochromic molecular monolayer at transparent oxide electrode
    (Cambridge : RSC Publ., 2020) Ligorio, Giovanni; Cotella, Giovanni F.; Bonasera, Aurelio; Zorn Morales, Nicolas; Carnicella, Giuseppe; Kobin, Björn; Wang, Qiankun; Koch, Norbert; Hecht, Stefan; List-Kratochvil, Emil J.W.; Cacialli, Franco
    Self-assembled monolayers (SAMs) deposited on bottom electrodes are commonly used to tune charge carrier injection or blocking in optoelectronic devices. Beside the enhancement of device performance, the fabrication of multifunctional devices in which the output can be modulated by multiple external stimuli remains a challenging target. In this work, we report the functionalization of an indium tin oxide (ITO) electrode with a SAM of a diarylethene derivative designed for optically control the electronic properties. Following the demonstration of dense SAM formation and its photochromic activity, as a proof-of-principle, an organic light-emitting diode (OLED) embedding the light-responsive SAM-covered electrode was fabricated and characterized. Optically addressing the two-terminal device by irradiation with ultraviolet light doubles the electroluminescence. The original value can be restored reversibly by irradiation with visible light. This expanded functionality is based on the photoinduced modulation of the electronic structure of the diarylethene isomers, which impact the charge carriers' confinement within the emissive layer. This approach could be successfully exploited in the field of opto-communication technology, for example to fabricate opto-electronic logic circuits. © 2020 The Royal Society of Chemistry.