Article
Chemistry, Physical
Ming-An Fu, Ren-Shu Wang, Hui Yang, Pei-Yuan Zhang, Chun-Fang Zhang, Xiao-Jia Chen, Yun Gao, Zhong-Bing Huang
Summary: Intercalating alkali metal into polyaromatic hydrocarbons can tune their physicochemical properties. In this study, weak ferromagnetism with a Curie temperature of 5.2 K was realized in potassium-intercalated 9-phenylanthracene, with an antiferromagnetic transition at around 35 K. The weak ferromagnetism is attributed to intramolecular ferromagnetic and intermolecular antiferromagnetic spin couplings in the crystal unit cell.
Article
Engineering, Environmental
Cong Chen, Minjie Shi, Yue Zhao, Cheng Yang, Liping Zhao, Chao Yan
Summary: The novel Al-intercalation engineering of MnO2 cathode for aqueous ZIBs significantly improves specific capacity and cycling retention, demonstrating great potential for applications in energy technologies and portable/wearable electronics.
CHEMICAL ENGINEERING JOURNAL
(2021)
Article
Chemistry, Multidisciplinary
P. A. D. Goncalves, F. Javier Garcia de Abajo
Summary: This study theoretically demonstrates that core-level photoemission from nanostructures can exhibit spectrally narrow plasmonic features with relatively high probabilities analogous to the direct peak. The morphology and dimensionality of the nanostructures have a dramatic effect on the plasmon-satellite probabilities, and universal scaling laws are found. Additionally, a pump-probe scheme is introduced to explore the ultrafast dynamics of the sampled nanostructure by optically exciting plasmons prior to photoemission.
Article
Chemistry, Physical
Daniele Paoloni, Alessandro Ruocco
Summary: By analyzing spot profiles of electron diffraction patterns, we found that copper-phthalocyanine (CuPc) films exhibit ordered growth on highly oriented pyrolytic graphite (HOPG) ranging from sub-monolayer to 3.3 nm. The weak physisorption of CuPc molecules at the interface contributes to the formation of ordered 2-D islands and ordered 3-D islands. Electron diffraction and electron energy loss spectroscopy (EELS) measurements reveal a novel long-range ordered structure of CuPc only observed at the CuPc/HOPG interface.
Article
Multidisciplinary Sciences
Sandhya Susarla, Pablo Garcia-Fernandez, Colin Ophus, Sujit Das, Pablo Aguado-Puente, Margaret McCarter, Peter Ercius, Lane W. Martin, Ramamoorthy Ramesh, Javier Junquera
Summary: This research utilizes a combination of techniques to probe the electronic structure within polar vortices in oxide superlattices at the atomic scale, finding that the peaks in Ti L-edge spectra systematically shift depending on the position of the Ti4+ cations. First-principles computations and simulations derived from first principles show good agreement with experimental results.
NATURE COMMUNICATIONS
(2021)
Article
Materials Science, Multidisciplinary
Tom Klaproth, Martin Knupfer, Anna Isaeva, Maria Roslova, Bernd Buechner, Andreas Koitzsch
Summary: This study investigates the interface of manganese(II) phtalocyanine (MnPc) with an alpha-RuCl3 single crystal using photoelectron spectroscopy. The results show that alpha-RuCl3 has similar electronic properties to common fluorinated acceptor molecules, but with the potential to absorb more electrons at interfaces. This makes it a promising strong acceptor material for organic molecules at interfaces.
Article
Physics, Multidisciplinary
Renwen Yu, Andrea Konecna, F. Javier Garcia de Abajo
Summary: This study investigates the impact of electron propagation direction on excitations of InAs films in structures with gyrotropic nonreciprocal material characteristics, utilizing electron energy-loss spectroscopy and cathodoluminescence. The results show that the optical field distribution of the sampled resonances can be modified by the magnetic field, resulting in direction-dependent coupling to the electron. This paves the way for using electron microscope spectroscopies to explore near-field characteristics of nonreciprocal systems with high spatial resolution.
PHYSICAL REVIEW LETTERS
(2021)
Review
Chemistry, Multidisciplinary
Marianna V. Kharlamova
Summary: This paper discusses the kinetics of growth and electronic properties of filled carbon nanotubes using spectroscopy for applications. It starts with the discussion of growth of carbon nanotubes inside metallocene-filled carbon nanotubes. Then, four spectroscopic techniques are used to investigate the filled carbon nanotubes. The results show that different substances lead to changes in electronic structure of the nanotubes and offer promising applications.
Article
Materials Science, Multidisciplinary
A. Singh, H. Y. Huang, Christopher Lane, J. H. Li, J. Okamoto, S. Komiya, Robert S. Markiewicz, Arun Bansil, T. K. Lee, A. Fujimori, C. T. Chen, D. J. Huang
Summary: The layered crystal structures of cuprates exhibit unique charge excitations different from three-dimensional metals. Acoustic plasmons have been observed in electron-doped cuprates, but their existence in hole-doped cuprates is still debated. In this study, resonant inelastic x-ray scattering measurements and calculations were conducted to investigate the charge excitations of hole-doped cuprate La2−xSrxCuO4. The results provide evidence for the acoustic plasmons of Zhang-Rice singlet and suggest that the metallic behavior is attributed to the movement of Zhang-Rice singlet rather than simple hopping of oxygen holes.
Article
Chemistry, Multidisciplinary
Kaja Schubert, Lucas Schwob, Simon Doerner, Marion Girod, Luke MacAleese, Cornelius L. Pieterse, Thomas Schlathoelter, Simone Techert, Sadia Bari
Summary: The photoionization and fragmentation of isolated metal protoporphyrin IX cations were investigated using VUV action spectroscopy. It was found that ionization leads to non-statistical fragmentation processes compared to photoexcitation, resulting in the formation of new fragments.
CHEMISTRY-A EUROPEAN JOURNAL
(2021)
Article
Materials Science, Multidisciplinary
David Kordahl, Duncan T. L. Alexander, Christian Dwyer
Summary: The majority of works in nanomaterial analysis focus on collective or single-particle excitations described by the electrostatic approximation, neglecting retardation and magnetic field effects. However, in some cases, this approximation is fundamentally inadequate when beam energy exceeds certain threshold values and sample dimensions are comparable to the wavelength of light in the material. In these situations, spatial variations in low-loss spectral maps from guided light modes may be observed.
Article
Chemistry, Multidisciplinary
Zukun Wang, Cheng Sun, Xuehui Xu, Yanping Liu, Zeng Chen, Yang Michael Yang, Haiming Zhu
Summary: By tracking the characteristic electroabsorption signal from separated charges, this study directly observes the electron-hole pair separation process in an organic/2D semiconductor heterostructure. The study shows that the charge delocalization in organic layers plays a key role in the separation process, while the in-plane delocalization of the 2D semiconductor has negligible contribution. This research is important for the future development of efficient organic/2D semiconductor optoelectronic devices.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Physics, Condensed Matter
Y. R. Wang, S. Wang, H. L. Tao, Y. Cui, S. M. Liu, M. He, B. Song, Z. H. Zhang
Summary: The electronic structure of LiOsO3 was investigated using first-principle calculations and electron energy loss spectroscopy (EELS). The hybridization of O 2p with Os 5d was found to be crucial for the coexistence of metal and ferroelectricity in LiOsO3. Simulation of energy loss near-edge structure (ELNES) showed good agreement between the fine structure of O K-edge and the experimental spectrum, with little effect from core hole effect and spin-orbital coupling on the spectra.
SOLID STATE COMMUNICATIONS
(2021)
Article
Multidisciplinary Sciences
Zhengran Ji, Mike Hu, Huolin L. Xin
Summary: Accurate decomposition of the mixed Mn oxidation states is highly important for characterizing the electronic structures, charge transfer and redox centers for electronic, and electrocatalytic and energy storage materials that contain Mn. In this study, a deep learning approach was adopted to develop a calibration-free and reference-free method for decomposing the oxidation state of Mn L2,3 edges for both EELS and XAS. The convolutional neural network achieved 85% accuracy on the validation dataset.
SCIENTIFIC REPORTS
(2023)
Article
Chemistry, Multidisciplinary
William Nicholson, Joseph L. Howard, Giuseppina Magri, Alex C. Seastram, Adam Khan, Robert R. A. Bolt, Louis C. Morrill, Emma Richards, Duncan L. Browne
Summary: Efforts to generate organomanganese reagents under ball-milling conditions have led to the serendipitous discovery that manganese metal can mediate the reductive dimerization of arylidene malonates. This unique reactivity can also be translated to solution, but pre-milling of the manganese is required for this transformation.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Nanoscience & Nanotechnology
Yuriy M. Azhniuk, Vasyl V. Lopushansky, Dmytro Solonenko, Volodymyr M. Kryshenik, Vasyl Y. Loya, Ivan M. Voynarovych, Alexander V. Gomonnai, Dietrich R. T. Zahn
Summary: The amorphous Cd-doped GeS2 films were found to form CdS nanocrystals under high laser power densities due to non-thermal photofluidity causing photoenhanced diffusion. Factors related to the variation of the CdS LO phonon peak with laser power density were discussed.
APPLIED NANOSCIENCE
(2022)
Article
Chemistry, Inorganic & Nuclear
Marcus Weber, Raul D. Rodriguez, Dietrich R. T. Zahn, Klaus Stoewe, Michael Mehring
Summary: delta-Bi2O3:M (M = S, Se, and Re) with an oxygendefective fluorite-type structure was prepared by a coprecipitation method, and their properties were investigated and compared.
INORGANIC CHEMISTRY
(2022)
Correction
Physics, Applied
E. Bortchagovsky, Yu. Demydenko, A. Bogoslovskaya, J. Tang, F. Dai, M. Fleischer, I. Milekhin, A. Sharma, G. Salvan, D. R. T. Zahn
JOURNAL OF APPLIED PHYSICS
(2022)
Review
Physics, Condensed Matter
Volodymyr Dzhagan, Alexander P. Litvinchuk, Mykhailo Ya Valakh, Dietrich R. T. Zahn
Summary: Ternary and quaternary metal-chalcogenides, such as CuInS2 and Cu2ZnSn(S,Se)(4), have gained significant attention for their applications in alternative energy conversion and light-emitting devices. These compounds offer more sustainable and affordable solutions compared to traditional semiconductors. However, their tolerance to non-stoichiometric compositions and polymorphism can lead to undesirable coexistence of different compounds and point defects, posing challenges for practical applications. Raman spectroscopy has emerged as a powerful tool for structural diagnostics and characterization of these compounds, especially in the context of nanostructures. This review aims to summarize the current knowledge on the phonon spectra and the capabilities of Raman and IR spectroscopies in characterizing these promising families of compounds.
JOURNAL OF PHYSICS-CONDENSED MATTER
(2023)
Article
Polymer Science
Doan Vu, Wen Liang Tan, Lu He, Alexander Ehm, Dietrich R. T. Zahn, Christopher R. McNeill
Summary: We report the discovery of a third crystalline polymorph of the electron-transporting conjugated polymer P(NDI2OD-T2), called form III, which exhibits an end-on texture. This new polymorph is characterized by the incorporation of two monomer units along the backbone-stacking direction, resulting in a doubling of the unit cell c axis. The formation of form III crystallites is achieved by melt annealing a thin film followed by slow cooling. Analysis using grazing-incidence wide-angle X-ray scattering (GIWAXS) and peak simulation confirms the unique packing of this polymorph. This discovery presents an exciting opportunity to study the structure/function relationships of this important semiconducting polymer.
Article
Chemistry, Multidisciplinary
Yevhenii Havryliuk, Volodymyr Dzhagan, Anatolii Karnaukhov, Oleksandr Selyshchev, Julia Hann, Dietrich R. T. Zahn
Summary: In this study, the composite films of Cu2ZnSnS4 (CZTS) nanocrystals (NCs) with PEDOT:PSS were investigated. The structural stability of both NCs and polymers in the composite films with different ratios was studied. It was found that CZTS NCs and PEDOT:PSS mutually influence each other in the composite. The thermoelectric properties of PEDOT:PSS/CZTS composite films were higher compared to the films consisting of bare materials and can be further improved with the addition of DMSO. However, the presence of NCs in the polymer deteriorates its structural stability when subjected to flash lamp annealing or laser treatment.
Article
Physics, Applied
Yang Pan, Lu He, Ilya Milekhin, Alexander G. Milekhin, Dietrich R. T. Zahn
Summary: In this study, the local photoluminescence quenching and enhancement in the quantum tunneling regime at MoSe2/hBN/plasmonic nanostructure interfaces were investigated using monolayer MoSe2/hBN heterostructure on Au nanotriangles as an example. By utilizing tip-enhanced photoluminescence spectroscopy, the nanostructures were resolved and imaged locally. Furthermore, the competing mechanisms of localized surface plasmon resonance, electron tunneling, and highly localized strain were studied to understand the local photoluminescence quenching and enhancement at the nanoscale.
APPLIED PHYSICS LETTERS
(2023)
Article
Chemistry, Physical
N. N. Kurus, I. A. Milekhin, N. A. Nebogatikova, I. Antonova, E. E. Rodyakina, A. G. Milekhin, A. Latyshev, D. R. T. Zahn
Summary: This study focuses on enhancing Raman scattering in multilayered graphene films through plasmonic interaction. By placing the films on a plasmonic substrate consisting of arrays of gold nanodisks, resonant Raman enhancement of the main vibrational modes of multilayered graphene was achieved. The results showed a 25-fold enhancement for nanodisks with a diameter of 103 nm. Moreover, stronger local enhancement (50-fold) was obtained using gap-mode tip-enhanced Raman scattering. The study also revealed the presence of nanofolds in the graphene film, which exhibited mechanical stresses up to 0.7% and lower frequency positions for certain vibrational modes.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)
Article
Engineering, Electrical & Electronic
A. Ievtushenko, V Dzhagan, O. Khyzhun, O. Baibara, O. Bykov, M. Zahornyi, V Yukhymchuk, M. Valakh, D. R. T. Zahn, K. Naumenko, P. Zaremba, S. Zagorodnya
Summary: Ag-containing ZnO nanostructures were synthesized on Ag coated Si substrates using atmospheric pressure metal-organic chemical vapour deposition. The relation between structural parameters and chemical composition with photoluminescence properties and electron-phonon coupling was investigated through XRD, XPS, and Raman spectroscopy. The position and width of the phonon Raman peaks and near bandgap PL band were found to be determined by the structural quality of the crystallites. The heat dissipation in the film, influenced by the nanostructure morphology and Ag content, played a crucial role in the behavior of phonon and PL bands.
SEMICONDUCTOR SCIENCE AND TECHNOLOGY
(2023)
Article
Chemistry, Multidisciplinary
Yevhenii Havryliuk, Volodymyr Dzhagan, Anatolii Karnaukhov, Oleksandr Selyshchev, Julia Hann, Dietrich R. T. Zahn
Summary: The problem of waste heat in solar panels has led to research on hybrid solar cells that combine photovoltaic and thermoelectric properties. One potential material for this is Cu2ZnSnS4 (CZTS). In this study, CZTS thin films were formed using green colloidal synthesis and subjected to thermal annealing or flash-lamp annealing. The optimal temperature range for obtaining conductive nanocrystalline films and determining reliable thermoelectric parameters was found to be 250-300 ?. The presence of the CuxS phase was found to be important for the electrical and thermoelectric properties of CZTS films obtained in this way.
Article
Chemistry, Multidisciplinary
Volodymyr Dzhagan, Nazar Mazur, Olga Kapush, Oleksandr Selyshchev, Anatolii Karnaukhov, Oleg A. Yeshchenko, Mykola I. Danylenko, Volodymyr Yukhymchuk, Dietrich R. T. Zahn
Summary: This study investigates the influence of the parameters of the shell and interface in semiconductor core/shell nanocrystals (NCs) on their optical properties and charge transfer, using Raman spectroscopy. The results show that the use of thioglycolic acid (TGA) during the synthesis leads to the formation of a CdS shell around the CdTe core in the NCs. The optical absorption and photoluminescence bands of these NCs are determined by the CdTe core, while the far-infrared absorption and resonant Raman scattering spectra are dominated by the vibrations related to the shell.
Review
Chemistry, Multidisciplinary
Oleksandr Stroyuk, Oleksandra Raievska, Dietrich R. T. Zahn, Christoph J. Brabec
Summary: The review summarizes recent reports on highly efficient photoluminescence originating from self-trapped exciton states in various materials, including chalcopyrite ternary quantum dots, polyheptazine carbon nitrides, and lead-free double halide perovskites. The review outlines the photoluminescence features of these self-trapped exciton emitters and discusses the challenges and promising directions for future research.
Article
Chemistry, Physical
Serhiy Kondratenko, Oleksandr I. Datsenko, Danylo Babich, Volodymyr Dzhagan, Yang Pan, Mahfujur Rahaman, Oleksandr Selyshchev, Dietrich R. T. Zahn
Summary: This study presents the fabrication of hybrid 2D-QD MoS2-AgInS2 photoconductive devices by pressing a MoS2 flake onto an AgInS2 QD film. The devices exhibit enhanced photoresponse under continuous and modulated optical excitations, attributed to the built-in electric field near the MoS2/AgInS2 interface. The study demonstrates the potential of these devices for photovoltaic and optoelectronic applications.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Chemistry, Physical
Lu He, Dietrich R. T. Zahn, Teresa I. I. Madeira
Summary: Titanium dioxide (TiO2) thin films have photocatalytic properties and can be used for recycling and maintenance. Factors affecting their performance include nanocrystalline size, surface morphology, and phase composition, which need to be better studied and correlated.
Article
Chemistry, Multidisciplinary
Ilya Milekhin, Kirill Anikin, Nina N. Kurus, Vladimir G. Mansurov, Timur V. Malin, Konstantin S. Zhuravlev, Alexander V. Latyshev, Alexander V. Latyshev, Dietrich R. T. Zahn
Summary: We carried out local phonon analysis on single AlN nanocrystals using two complementary imaging spectroscopic techniques: tip-enhanced Raman scattering (TERS) and nano-Fourier transform infrared (nano-FTIR) spectroscopy. The TERS spectra showed strong surface optical (SO) phonon modes, with their intensities having a weak polarization dependence. The electric field enhancement from the plasmon mode of the TERS tip altered the phonon response of the sample, causing the dominance of the SO mode over other phonon modes. TERS imaging allowed for the visualization of the spatial localization of the SO mode. We successfully observed the angle anisotropy of the SO phonon modes in AlN nanocrystals with nanoscale spatial resolution. The frequency position of the SO modes in nano-FTIR spectra was determined by the excitation geometry and the local nanostructure surface profile, as demonstrated by analytical calculations.
NANOSCALE ADVANCES
(2023)
