Article
Materials Science, Multidisciplinary
Tristan Heider, Timm Gerber, Okan Koeksal, Markus Eschbach, Ewa Mlynczak, Patrick Loemker, Pika Gospodaric, Mathias Gehlmann, Moritz Ploetzing, Rossitza Pentcheva, Lukasz Plucinski, Claus M. Schneider, Martina Mueller
Summary: The electronic structure of the ferromagnetic semiconductor EuO has been investigated using spin- and angle-resolved photoemission spectroscopy (spin-ARPES) and density functional theory. EuO exhibits unique properties of hosting both weakly dispersive nearly fully polarized Eu 4 f bands and O 2p levels indirectly exchange-split by the interaction with Eu nearest neighbors. The study sheds light on the mechanisms of indirect exchange in the O 2p levels and predicts significant directional effects due to spin-orbit coupling in the Eu 4 f band manifold.
Article
Nanoscience & Nanotechnology
Joung Eun Yoo, Ju Young Sung, Jin Ha Hwang, Inhee Maeng, Seung-Jae Oh, Inho Lee, Ji Hoon Shim, Sung Dug Kim, Du-Seop Yoon, Seo Young Jang, Young Jae Kang, Sang Woon Lee
Summary: Metal thin films such as Cu and TiN exhibit a substantial increase in resistivity as they become thinner, while MAX-phase V2AlC films show a weaker dependence on thickness. This is due to the highly ordered crystalline quality and small electron mean free path of V2AlC films, making them a promising option to overcome scaling limitations in semiconductor devices.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Article
Materials Science, Multidisciplinary
Naoto Hasegawa, Kohei Yoshimatsu, Daisuke Shiga, Tatsuhiko Kanda, Satoru Miyazaki, Miho Kitamura, Koji Horiba, Hiroshi Kumigashira
Summary: Ti2O3 exhibits a unique metal-insulator transition accompanied by lattice deformation. Electron-electron correlation plays an important role in its electronic structure and transition process. The electronic band structure of insulating Ti2O3 films with slight hole doping is obtained using ARPES.
Article
Chemistry, Physical
Luca Craciunescu, Sara Wirsing, Sebastian Hammer, Katharina Broch, Andreas Dreuw, Felipe Fantuzzi, Vipilan Sivanesan, Petra Tegeder, Bernd Engels
Summary: Theoretical studies using clusters as model systems have been successful in explaining photophysical phenomena in organic semiconductor thin films, but have not been able to accurately simulate absorption spectra. This work demonstrates the accurate prediction of spectra using time-dependent density functional theory and optimal tuned functionals when the employed cluster reflects the symmetry of the crystal structure. For pentacene thin films, the computed electronic spectra show an impressive accuracy compared to experimental data, allowing for accurate peak assignments and mechanistic studies.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2022)
Article
Physics, Multidisciplinary
Szilard Sajti
Summary: This paper discusses the application of off-specular scattering methods in the investigation of lateral inhomogeneities in single and multilayer systems, such as domain structures and rough interfaces. The domain-domain correlation functions were introduced, but some questions regarding them were left unanswered. This work aims to address these issues, which are crucial for fitting and interpreting experimental data effectively.
PHYSICA A-STATISTICAL MECHANICS AND ITS APPLICATIONS
(2023)
Article
Spectroscopy
Vladimir Ivanovski, Ireneusz Piwonski, Dariusz Guziejewski, Thomas G. Mayerhoefer
Summary: In this study, a new method is proposed to evaluate the quality and structure of siloxane coatings. By analyzing the ratio-reflectance spectra and reflectance-absorbance spectra, relevant information can be obtained, and certain characteristics of the reflectance-absorbance spectra are found to be associated with film morphology and bridging oxygen number.
SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
(2022)
Article
Physics, Applied
Dario Narducci, Laura Zulian, Bruno Lorenzi, Federico Giulio, Elia Villa
Summary: Boron-hyperdoped nanocrystalline thin films without hydrogen embedded during deposition show an increased power factor of up to 33mW K-2 m（-1）at 300K, making nanocrystalline silicon a realistic competitor to Bi2Te3 for low-temperature heat harvesting due to its greater geo-availability and lower cost.
APPLIED PHYSICS LETTERS
(2021)
Review
Materials Science, Coatings & Films
Mikhail R. Baklanov, Konstantin P. Mogilnikov, Alexey S. Vishnevskiy
Summary: The review article provides an overview of important techniques for evaluating the porosity of thin films. These methods include ellipsometric porosimetry (EP), positron annihilation spectroscopy (PAS/PALS), and grazing incidence small-angle x-ray scattering (GISAXS). The article highlights the challenges and limitations of each method and demonstrates their unique insights into pore structure. The cross-evaluation of different methods enhances understanding of complex pore structures and emphasizes the importance of appropriate data modeling and interpretation.
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A
(2023)
Article
Materials Science, Coatings & Films
Lakshman Srinivasan, Cyril Jadaud, Francois Silva, Jean-Charles Vanel, Jean-Luc Maurice, Erik Johnson, Pere Roca i Cabarrocas, Karim Ouaras
Summary: We successfully grew polycrystalline GaN thin films on Si (100) substrates at room temperature using radiofrequency reactive magnetron sputtering, with Ar and N-2 as the main sputtering and N-atom precursor gas sources, respectively. The effect of working pressure on the thin film's crystalline quality was studied, and it was found that pressures below 50 mTorr result in amorphous films, while pressures above 50 mTorr result in polycrystalline films. The films grown at 50 mTorr exhibited the best crystallinity with a dominant wurtzite hexagonal structure, and a uniform elemental distribution of Ga and N throughout the growth profile.
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A
(2023)
Article
Materials Science, Multidisciplinary
C. Yuan, M. Park, Y. Zheng, J. Shi, R. Dargis, S. Graham, A. Ansari
Summary: This study investigates phonon scattering processes and thermal conductivity in Al1-xScxN alloys grown by molecular beam epitaxy. The results show a decreasing trend in thermal conductivity with increasing scandium content, with an increase in thermal conductivity with temperature below 200 K and a plateau at higher temperatures. Application of an analytical model helps estimate the effects of scattering mechanisms on thermal conductivity behavior.
MATERIALS TODAY PHYSICS
(2021)
Article
Engineering, Electrical & Electronic
Ipsita Jena, Udai P. Singh
Summary: This study focuses on the influence of copper incorporation in cadmium telluride (CdTe) films. CdTe absorber layers were grown using thermal evaporation technique, while cadmium sulfide (CdS) buffer layers were deposited using chemical bath deposition method. The copper-incorporated CdTe films were characterized using various methods such as X-ray diffraction (XRD), Atomic force microscopy (AFM), scanning electron microscopy (SEM), UV-Vis spectroscopy, Raman spectroscopy, and Hall Effect measurements. The results showed that the properties of the CdTe films varied with the amount of copper incorporation, such as the crystal structure, grain size, surface roughness, Raman spectra, optical properties, and electrical properties. It was concluded that with controlled copper incorporation, these CdTe thin films have the potential to be used as absorber layers for solar cells.
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
(2023)
Article
Chemistry, Multidisciplinary
Aishanee Sur, Joe D. Simmons, Andrew A. Ezazi, Kyle J. Korman, Subham Sarkar, Ethan T. Iverson, Eric D. Bloch, David C. Powers
Summary: The study demonstrates the versatile platform of optically transparent, porous salt thin films for solid-state photochemistry and in operando spectroscopy. Photolysis efficiently reduces Mn-(III) sites to Mn-(II) sites.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Physics, Applied
Mohammad M. Taheri, Triet M. Truong, Siming Li, William N. Shafarman, Brian E. McCandless, Jason B. Baxter
Summary: Understanding the nature of recombination and its dependence on defects and interfaces is crucial for improving open-circuit voltage and power conversion efficiency in photovoltaic devices. The use of time-resolved terahertz spectroscopy and TRPL combined with numerical modeling allows for the quantification of carrier dynamics and recombination mechanisms, demonstrating the potential for developing thin-film PV technology with enhanced performance.
JOURNAL OF APPLIED PHYSICS
(2021)
Article
Chemistry, Physical
Ismail Karakurt, Gunay Basar, Paul Leiderer, Seyma Parlatan, Nihan Arapoglu
Summary: We studied the anomalous lateral diffusion process in thin tungsten trioxide films using optical methods. The diffusion starts at imperfections within the film shortly after H+ ion intercalation begins and progresses parallel to the film surface. We measured the mean square displacement of the diffusion front and calculated the instantaneous diffusion coefficient using its time-dependence. The observed large diffusion coefficients and depth dependence of film expansion can be explained by interfacial jobsharing diffusion of electrons and protons. Raman measurements revealed an additional strong band at 855 cm-1 after the lateral diffusion, indicating the irreversible nature of this process.
SURFACES AND INTERFACES
(2023)
Article
Physics, Applied
Qiyu Chen, Qing Hao
Summary: Polycrystalline thin films, commonly found in devices and energy-related applications, often exhibit columnar grains and rough grain boundaries. The lack of a simple analytical model to treat phonon scattering at these boundaries and interfaces hinders the understanding of in-plane thermal transport crucial for heat spreading in thin-film devices. In this paper, an effective medium formulation is extended to columnar-grained thin films, and the model predictions are validated with phonon Monte Carlo simulations and experimental data on polycrystalline ZnO thin films.
JOURNAL OF APPLIED PHYSICS
(2023)
Article
Crystallography
Cara Buchholz, Lara F. Reichart, Furio Surfaro, Ralph Maier, Fajun Zhang, Alexander Gerlach, Frank Schreiber
Summary: By using human serum albumin (HSA) and trivalent salt cerium chloride (CeCl3) to control the effective interactions, we induce crystallization and relate the crystallization kinetics to different regions of the phase diagram. The nucleation density, nucleation rate, and crystal size reach maximum values slightly above the specific salt concentration c* for aggregation. Comparing with data of the reduced second virial coefficient, it is found that B-2/B-2(HS) alone is insufficient to explain the observed trends. Thus, further aspects impacting the crystallization behavior are discussed, and the kinetic regimes are linked and distinguished based on their relative distance to phase boundaries, namely c* and liquid-liquid phase separation (LLPS) border.
JOURNAL OF CRYSTAL GROWTH
(2023)
Article
Chemistry, Multidisciplinary
Ralph Maier, Rodrigo Cuevas Arenas, Fajun Zhang, Ana Garcia-Saez, Frank Schreiber
Summary: This study investigates the use of polymer-bounded nanodiscs to study the lipid model system. The size of nanodiscs formed with styrene maleic acid (SMA) is smaller compared to diisobutylene maleic acid (DIBMA). Increasing polymer concentration leads to a decrease in nanodisc size. The stability of nanodiscs formed with SMA is less affected by temperature compared to those formed with DIBMA in phosphate buffer. These findings contribute to the development of protocols for studying membrane proteins in similar membrane mimics.
Article
Materials Science, Multidisciplinary
Tobias Antrack, Martin Kroll, Lena Merten, Miguel Albaladejo-Siguan, Alexander Hinderhofer, Oleg Konovalov, Maciej Jankowski, Johannes Benduhn, Frank Schreiber, Yana Vaynzof, Karl Leo
Summary: The impact of the environment on the formation of island-like layers in CsPbBr3/LiBr thermally deposited bilayers is investigated. It is found that the island-like layers only form in humid environments, leading to a 350-fold enhancement in photoluminescence quantum yield. Time-resolved grazing-incidence wide-angle X-ray scattering experiments reveal that LiBr alters the crystal orientation of the perovskite prior to the formation of island-like layers.
ADVANCED OPTICAL MATERIALS
(2023)
Review
Chemistry, Multidisciplinary
Alexander Hinderhofer, Alessandro Greco, Vladimir Starostin, Valentin Munteanu, Linus Pithan, Alexander Gerlach, Frank Schreiber
Summary: This paragraph discusses the status, opportunities, challenges, and limitations of machine learning applied to X-ray and neutron scattering techniques, focusing on surface scattering. Typical strategies and potential pitfalls are outlined. The applications to reflectometry and grazing-incidence scattering are critically discussed. Comment is also given on the availability of training and test data for machine learning applications, such as neural networks, and a large reflectivity data set is provided as reference data for the community.
JOURNAL OF APPLIED CRYSTALLOGRAPHY
(2023)
Article
Chemistry, Physical
Nadine Russegger, Hongwon Kim, Jakub Hagara, Oleg Vladimirov, Timo Eberle, Ivan Zaluzhnyy, Alexander Gerlach, Alexander Hinderhofer, Wolfgang Bruetting, Frank Schreiber
Summary: We conducted a comprehensive investigation on cocrystal formation and charge transfer effects in weakly interacting organic semiconductor mixtures. By choosing diindenoperylene (DIP) as a donor molecule and several perylene diimide derivatives (PDI) as acceptor molecules, we identified the optimized side groups for the acceptors that show efficient mixing behavior and molecular charge transfer effects with the donor DIP. The result showed that the mixing behavior and charge transfer effects depend heavily on the structure of the acceptors, which can be easily chemically tuned.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)
Article
Chemistry, Physical
Julian Hausch, Nico Hofeditz, Jona Bredehoeft, Sebastian Hammer, Jens Pflaum, Katharina Broch, Marina Gerhard, Frank Schreiber
Summary: In the solid state, the coherent distribution of an electronic excitation, known as excited-state delocalization, plays a crucial role in photophysical processes like singlet fission. However, studying the influence of excited-state delocalization on singlet fission has been challenging due to the lack of a simple measurement method and the difficulty of tracking changes in the optically dark triplet-pair state, which is an important intermediate in singlet fission. By varying the growth conditions, researchers have demonstrated that emission from the triplet-pair state can be detected in films with low growth rates, indicating a higher excited-state delocalization.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)
Article
Instruments & Instrumentation
Ekaterina Kneschaurek, Alexander Hinderhofer, Bernd Hofferberth, Niels Scheffczyk, Linus Pithan, Paul Zimmermann, Lena Merten, Florian Bertram, Frank Schreiber
Summary: We present a compact sample environment for studying the kinetics of thin film crystallization on synchrotron beamlines, which includes atmospheric control, automated deposition, spin-coating, and annealing stages. The setup allows real-time investigation of thin film growth using grazing-incidence X-ray diffraction techniques. Sensors are used to detect humidity and oxygen levels. The spinning stage has low vertical oscillation amplitude and can be used for antisolvent application or gas quenching. Differential reflectance spectroscopy is implemented for analyzing thin film thickness and optical properties. The system can be controlled remotely by the control software at synchrotron beamlines.
REVIEW OF SCIENTIFIC INSTRUMENTS
(2023)
Article
Chemistry, Multidisciplinary
Oscar Telschow, Niels Scheffczyk, Alexander Hinderhofer, Lena Merten, Ekaterina Kneschaurek, Florian Bertram, Qi Zhou, Markus Loeffler, Frank Schreiber, Fabian Paulus, Yana Vaynzof
Summary: Metal halide perovskites, a type of crystalline semiconductors, are of great interest for optoelectronics. This study investigates the formation of highly oriented triple cation perovskite films using different alcohols as solvents. A short-lived highly oriented crystalline intermediate is found and used as a template for the formation of highly oriented perovskite layers. The photovoltaic devices fabricated from the highly oriented films show superior performance and stability compared to those with a random polycrystalline structure.
Article
Chemistry, Physical
Manoj Singh, Jatin Nama, Tufan Paul, Nisha Hiralal Makani, Aditi Sahoo, Sudhanshu Sharma, Rupak Banerjee
Summary: We report on ambient processed, lead-free nanocrystalline perovskites, which are halide-tunable and exhibit photocatalytic CO2 reduction. The conversion yield of CO2 to CO can be controlled by regulating the Cl-to-Br ratio. The addition of a negative potential significantly enhances the conversion yield, with the Cs3Bi2Br3Cl6 variant achieving a maximum yield of about 105 mu mol/g.
ACS APPLIED ENERGY MATERIALS
(2023)
Article
Nanoscience & Nanotechnology
Simranjit Singh, Vishakha Takhar, Shivanand H. Nannuri, Sajan D. George, Rupak Banerjee, Superb K. Misra
Summary: The synergistic effect of synthesized MoS2 nanosheets and NaYF4:Yb,Tm,Nd upconversion nanoparticles (UCNP) on effective dye degradation is demonstrated. The optical properties show that the emission spectra of UCNP overlap with the absorption spectra of MoS2. The combination of UCNP and syn-MoS2 achieves 96% degradation of methylene blue, compared to 56.4% for syn-MoS2 alone and 42% for b-MoS2. Concentration-dependent dye degradation studies reveal a maximum removal efficiency of 99.6% with 150 mg L-1 of syn-MoS2 and 200 mg L-1 of UCNP within 2 hours.
ACS APPLIED NANO MATERIALS
(2023)
Article
Medicine, Research & Experimental
Ilaria Mosca, Keivin Pounot, Christian Beck, Louise Colin, Olga Matsarskaia, Christoph Grapentin, Tilo Seydel, Frank Schreiber
Summary: Monoclonal antibodies (mAbs) are widely used for therapeutic purposes due to their high specificity and versatility. In this study, the self-diffusion of different mAbs was investigated using quasi-elastic neutron scattering (QENS) and small-angle neutron scattering (SANS) techniques. The results provide insights into the hydrodynamic properties, protein-protein interactions (PPIs), and internal dynamics of mAbs. This comprehensive understanding is crucial for formulating highly concentrated antibody solutions with optimal therapeutic effects.
MOLECULAR PHARMACEUTICS
(2023)
Article
Instruments & Instrumentation
Linus Pithan, Vladimir Starostin, David Marecek, Lukas Petersdorf, Constantin Voelter, Valentin Munteanu, Maciej Jankowski, Oleg Konovalov, Alexander Gerlach, Alexander Hinderhofer, Bridget Murphy, Stefan Kowarik, Frank Schreiber
Summary: Recently, there has been a growing interest in applying machine-learning techniques to automated analysis of X-ray scattering experiments. This study describes the incorporation of a combined one-dimensional convolutional neural network and multilayer perceptron for extracting physical thin-film parameters and taking prior knowledge into account. Experimental results demonstrate the accuracy and stability of this method.
JOURNAL OF SYNCHROTRON RADIATION
(2023)
Article
Chemistry, Multidisciplinary
Christoph P. Theurer, Florian Laible, Jia Tang, Katharina Broch, Monika Fleischer, Frank Schreiber
Summary: Utilizing strong light-matter coupling can modify the energy landscapes of excited states of organic semiconductors. This can be achieved by implementing them in optical microcavities, without the need for chemical modification. In this study, the strong coupling of Davydov transitions in polycrystalline pentacene thin films to surface lattice resonances supported by open cavities made of silver nanoparticle arrays was demonstrated. These thin films, together with the open architecture, are more suitable for device applications.
