Article
Crystallography
Faheem Ahmed, Mohammed Benali Kanoun, Chawki Awada, Christian Jonin, Pierre-Francois Brevet
Summary: Pure and silver-loaded TiO2 nanocrystals were prepared by a soft chemical route with varying concentrations of Ag, and the influence of Ag nanoparticles on the functional properties of TiO2 was studied. Results showed that the introduction of Ag led to changes in crystalline quality, optical properties, and bandgap of TiO2, introducing new localized gap states and potentially shifting the absorption edge through visible light.
Article
Chemistry, Multidisciplinary
Muhammad Asif, Ayash Alrashdi, Mohammed M. Fadhali, A. Afaq, Abu Bakar
Summary: In this study, the thermoelectric parameters of RuCrX (X = Si, Ge, Sn) half-Heusler alloys were investigated using the pseudopotential approach and Boltzmann transport theory. The results showed that these alloys have a stable C1b-type crystal structure, and their important thermoelectric properties were discussed.
Article
Chemistry, Physical
C. Tayran, M. Cakmak
Summary: In this study, we investigated the atomic and electronic structures of SnSe2 layers on the Sn/Si(111)-(root 3 x root 3)R30 degrees surface and studied the hydrogenation of this surface using density functional theory (DFT). We found that the hydrogenated surface alters the surface states associated with the SnSe2 layer and results in a decrease in the work function.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2022)
Article
Physics, Multidisciplinary
R. Garreis, A. Knothe, C. Tong, M. Eich, C. Gold, K. Watanabe, T. Taniguchi, V Fal'ko, T. Ihn, K. Ensslin, A. Kurzmann
Summary: Transport measurements through a few-electron circular quantum dot in bilayer graphene show bunching of conductance resonances in groups of four, eight, and twelve, which are related to the spin and valley degeneracies. As the electron numbers increase, the single-particle ground state evolves into a threefold degenerate minivalley ground state, confirmed by measurements in a magnetic field. The importance of Hund's second rule for spin filling of quantum dot levels is emphasized, highlighting the effects of exchange interactions.
PHYSICAL REVIEW LETTERS
(2021)
Article
Chemistry, Multidisciplinary
Olivier Mentre, Miguel A. Juarez-Rosete, Sebastien Saitzek, Cintli Aguilar-Maldonado, Marie Colmont, Angel M. Arevalo-Lopez
Summary: BiVO3F, a unique example of bismuth vanadyl oxyhalide with paramagnetic V4+ centers, features 1D magnetic units with rare alternation of edge-sharing O-O and F-F bridges in its crystal structure. Despite similarities with BiVO4, BiVO3F shows relatively modest photoactivity due to fast electron-hole recombination facilitated by electronic pairing.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2021)
Article
Chemistry, Inorganic & Nuclear
Xian Wei, Qi Zhang, Zhongjie Cui, Dan Yang, Shiliang Mei, Wanlu Zhang, Haijiao Xie, Kehan Yu, Ruiqian Guo, Wei Wei
Summary: Understanding the electronic structure of doped InP quantum dots is crucial for optimizing the material for specific applications. This study combines experimental and computational approaches to investigate the doping mechanism and surface passivation of InP QDs. The results provide insights into the microscopic details of doped InP and offer the potential for precise control of guest ion stoichiometry for optimized electrical devices.
INORGANIC CHEMISTRY
(2023)
Article
Engineering, Electrical & Electronic
Narasimhulu Thoti, Yiming Li, Wen-Li Sung
Summary: This study investigates the WKF of strained Si0.6Ge0.4 TFET with nanosheet geometry, showing that fewer WKFs are identified with higher MGN. The average energy reduction affects electron transport, with a higher reduction observed with high MGN and a lower reduction with low MGN. The variability in V-th increases with progressively diminished MGN, and marginal variations in SS, I-ON, and I-OFF are observed due to the dependability of WKF over the subthreshold region of operation.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2022)
Article
Chemistry, Inorganic & Nuclear
Yuning Yang, Shiru Wei, Zhijin Zhao, Jing Chen, Jianchen Wang, Hanshi Hu, Stefan G. Minasian, Taoxiang Sun
Summary: The crystal structure of NpO2Br4 (2-) was obtained for the first time, and the Np-O bonding covalency was found to be slightly reduced while the Np-X bonding covalency was enhanced in the NpO2X4 (2-) series. These findings are significant for studying the bonding nature of actinide complexes.
INORGANIC CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Tengfei Jiang, Jie Sun, Jiancai Leng
Summary: In this study, novel two-dimensional Mo2S2C2 and Mo2S2Si2 structures were theoretically designed and their stability, electronic, and mechanical properties were investigated. The results showed that both Mo2S2C2 and Mo2S2Si2 exhibited good dynamic and thermal stability, as well as excellent mechanical flexibility. They could also form p-type contact heterostructures with MoS2 and potentially be used as electrodes for MoS2-based devices.
JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS
(2023)
Article
Crystallography
Penglin Fang, Wenyue Tang, Yaoguo Shen, Jinquan Hong, Yongming Li, Junrong Jia
Summary: By using the homovalent cation substitution strategy, a new sulfate compound, Cs2Ca3(SO4)(4), was successfully synthesized. The compound exhibits a unique crystal structure and a large energy band gap. The role of cations in tuning structural symmetry and birefringence was also analyzed through comparisons with similar compounds.
Article
Chemistry, Physical
I. S. Fathima, Raihan Ahammed, Pradip Nandi, Ashima Rawat, Abir De Sarkar
Summary: Berry curvature, the effective magnetic field in k space, can be controlled through mechanical strain to achieve better control over valley polarization. SnS monolayer shows interesting electronic properties and enhanced Berry curvature under achievable compressive strain, which may extend the lifetime of valley polarized excitons.
APPLIED SURFACE SCIENCE
(2023)
Article
Chemistry, Physical
Yabei Xu, Hongyu Wang, Xiaoya Chang, Andres Fuentes, Rodrigo Demarco, Dongping Chen
Summary: The introduction of functional groups at high coverage levels can significantly influence the band structures of polycyclic aromatic hydrocarbon (PAH) clusters. The HOMO-LUMO gaps are highly sensitive to the type and distribution of functional groups. This study proposes an in-house method to build PAH clusters with surface functionalization of -OH, -COOH, and -CHO groups using the DFT method. It is found that the -CHO groups have the greatest impact in reducing the gap value, though exceptions exist due to the spatial distribution of functional groups. PAH clusters with oxygenated functions still exhibit characteristics of an indirect band gap material. The coupling effect of PAH stacking and PAH size on band structures is also discussed.
JOURNAL OF PHYSICAL CHEMISTRY A
(2022)
Article
Chemistry, Physical
Habibul Arfin, Radha Rathod, Ajinkya Sundarnath Shingote, K. R. Priolkar, Pralay K. Santra, Angshuman Nag
Summary: The environmentally benign Cs2NaInCl6 double perovskite has a wide band gap of about 5.1 eV, making it photocatively and photostable in the UV, visible, and SWIR regions. By doping lanthanide ions like Er3+ and Yb3+ into the octahedrally coordinated In3+ lattice site, SWIR radiation at 1540 nm and 994 nm can be emitted. However, the optical excitation of lanthanides is Laporte forbidden, and the host requires excitation energy >5.1 eV. To overcome this limitation, Te4+ was codoped with Er3+ or Yb3+ to transfer energy and emit SWIR radiation. Temperature-dependent measurements revealed the mechanism of energy transfer processes. A pc-LED emitting SWIR radiation was successfully fabricated.
CHEMISTRY OF MATERIALS
(2023)
Article
Physics, Condensed Matter
H. Mrezguia, L. Giovanelli, Y. Ksari, A. Akremi, J-M Themlin
Summary: Utilizing inverse photoemission spectroscopy (IPES), the electronic band structure of an ordered 2D Si layer on the root 3 x root 3-Ag/Si(111) surface was studied, revealing a metal-insulator transition on the interface when about 1 ML of Si is deposited on the root 3-Ag substrate maintained at around 200 degrees C. The newly formed state U-0 above the Fermi level is discussed in relation to various Si 2D structures including silicene.
JOURNAL OF PHYSICS-CONDENSED MATTER
(2021)
Article
Chemistry, Physical
Nefise Ozcelik, Tuncay Tunc, Raziye Catak Celik, Mahmut Erzengin, Haci Ozisik
Summary: A newly synthesized hydrazone derivative was characterized using various methods including XRD for crystal structure determination and antioxidant activity testing. The results showed potential radical scavenging ability of the synthesized compound.
JOURNAL OF MOLECULAR STRUCTURE
(2021)
Article
Physics, Applied
Pavel Galar, Jiri Stuchlik, Martin Muller, Jan Kocka, Katerina Kusova
Summary: In this study, highly spherical SiC nanocrystals (50-150 nm) were successfully synthesized using nonthermal plasma, a method not widely employed for SiC synthesis. The Si nanocrystals act as growth seeds for SiC in a two-stage reactor, resulting in SiC nanoparticles with yellow-orange photoluminescence visible to the naked eye.
PLASMA PROCESSES AND POLYMERS
(2022)
Article
Chemistry, Multidisciplinary
Kalyan Biswas, Lin Yang, Ji Ma, Ana Sanchez-Grande, Qifan Chen, Koen Lauwaet, Jose M. Gallego, Rodolfo Miranda, David ecija, Pavel Jelinek, Xinliang Feng, Jose I. Urgel
Summary: The synthesis of nanographenes with open-shell ground states has attracted increasing attention due to their interesting physicochemical properties and potential applications in carbon-based magnetism. This study reports the on-surface synthesis of three open-shell nanographenes with non-benzenoid structures and investigates their properties using various techniques. The results provide access to new types of open-shell nanographenes that were previously difficult to synthesize.
Article
Chemistry, Multidisciplinary
Euihwan Do, Jae Whan Park, Oleksandr Stetsovych, Pavel Jelinek, Han Woong Yeom
Summary: In this study, the low-temperature structural distortion of a one-dimensional electronic system formed on Au-decorated vicinal silicon surfaces is unambiguously identified using high-resolution atomic force microscopy and scanning tunneling microscopy. The buckling of the step-edge Si chains, forming trimer unit cells, is found to be the most important structural element of this surface. This observation supports the recent model of rehybridized dangling bonds and contradicts the previously proposed antiferromagnetic spin ordering.
Article
Physics, Multidisciplinary
Hanyan Fang, Aurelio Gallardo, Dikshant Dulal, Zhizhan Qiu, Jie Su, Mykola Telychko, Harshitra Mahalingam, Pin Lyu, Yixuan Han, Yi Zheng, Yongqing Cai, Aleksandr Rodin, Pavel Jelinek, Jiong Lu
Summary: Researchers have discovered a new electronic self-passivation scheme, known as single vacancy (SV), in monoelemental black phosphorus. By converting SV into negatively charged SV??? through thermal annealing or STM tip manipulation, the dangling bonds are passivated and the in-gap states are quenched. The formation of SV??? enhances passivation due to its weak dipolelike perturbation. As a result, SV??? acts as a more benign and weaker scattering center, potentially leading to improved charge mobility in black phosphorus and its analogs.
PHYSICAL REVIEW LETTERS
(2022)
Article
Chemistry, Multidisciplinary
Benjamin Mallada, Qifan Chen, Taras Chutora, Ana Sanchez-Grande, Borja Cirera, Jose Santos, Nazario Martin, David Ecija, Pavel Jelinek, Bruno de la Torre
Summary: This study reveals that deliberately introducing atomic-scale defects into a specific anthracene-ethynylene pi-conjugated polymer can modify its inherent electronic and magnetic properties, affecting the material's performance. The results demonstrate a higher likelihood of forming low-dimensional defects at specific sites in polymers, offering new possibilities for engineering macroscopic defects in surface-synthesized conjugated polymers.
CHEMISTRY-A EUROPEAN JOURNAL
(2022)
Article
Chemistry, Multidisciplinary
Kalyan Biswas, Maxence Urbani, Ana Sanchez-Grande, Diego Soler-Polo, Koen Lauwaet, Adam Matej, Pingo Mutombo, Libor Veis, Jiri Brabec, Katarzyna Pernal, Jose M. Gallego, Rodolfo Miranda, David Ecija, Pavel Jelinek, Tomas Torres, Jose I. Urgel
Summary: Introduces a combined strategy for the synthesis of one-dimensional porphyrinoid-based polymers with open-shell character via surface-catalyzed reaction, which has prospects in the synthesis of innovative functional nanomaterials for carbon-based spintronics.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Chemistry, Multidisciplinary
Jesus Mendieta-Moreno, Benjamin Mallada, Bruno de la Torre, Timothee Cadart, Martin Kotora, Pavel Jelinek
Summary: In this work, the synthesis of a novel PAH molecule with an unusual C-C bond cleavage and complex molecular scaffold rearrangement is reported. It is found that the complex chemical transformation is steered by the concerted motion of individual Au-0 gold atoms on a supporting Au(111) surface. This observation highlights the importance of single-atom catalysis and catalytic activity of single Au-0 atoms in facilitating covalent carbon bond cleavage in on-surface synthesis.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Multidisciplinary
Benjamin Lowe, Jack Hellerstedt, Adam Matej, Pingo Mutombo, Dhaneesh Kumar, Martin Ondracek, Pavel Jelinek, Agustin Schiffrin
Summary: This study investigates the interaction between 9,10-dicyanoanthracene molecules and gold adatoms on a silver surface, and reveals a mechanism for selective cleavage of C-H bonds and formation of organometallic compounds at room temperature. By harnessing the catalytic activity of single metal atoms, this research provides promising routes for future synthesis of functional organic and organometallic materials.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Chemistry, Multidisciplinary
Kalyan Biswas, Diego Soler, Shantanu Mishra, Qiang Chen, Xuelin Yao, Ana Sanchez-Grande, Kristjan Eimre, Pingo Mutombo, Cristina Martin-Fuentes, Koen Lauwaet, Jose M. Gallego, Pascal Ruffieux, Carlo A. Pignedoli, Klaus Mullen, Rodolfo Miranda, Jose I. Urgel, Akimitsu Narita, Roman Fasel, Pavel Jelinek, David Ecij
Summary: This study explores three families of nanographenes (A, B, and C) and finds that open-shell nanographenes exhibit the strongest magnetic exchange coupling, especially near the transition from closed-shell to open-shell states. Experimental results confirm the predictions, and two specific nanographenes show record values of magnetic exchange coupling measured on the Au(111) surface, close to 200 meV. This research provides insights for designing carbon nanomaterials with robust magnetic ground states.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
Eduardo Corral Rascon, Alexander Riss, Adam Matej, Alissa Wiengarten, Pingo Mutombo, Diego Soler, Pavel Jelinek, Willi Auwaerter
Summary: The study presents a surface chemistry route for synthesizing square-type porphyrin tetramers with a central COT ring, coexisting with other oligomers. It demonstrates the access to surface-supported, unsubstituted porphyrin tetramers that are not easily achievable by conventional synthesis means. The molecular structures and electronic structure, including the antiaromaticity induced by the COT moiety, are elucidated through atomic-level characterization and density functional theory modeling.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Chemistry, Multidisciplinary
Federico Frezza, Frederik Schiller, Ales Cahlik, Jose Enrique Ortega, Johannes V. Barth, Andres Arnau, Maria Blanco-Rey, Pavel Jelinek, Martina Corso, Ignacio Piquero-Zulaica
Summary: In this study, quinoidal ligands were reacted with single cobalt atoms on an Au(788) surface in ultra-high vacuum, resulting in the formation of cobalt-quinoid chains. The electronic structure of these chains was investigated using angle-resolved photoemission spectroscopy, and their narrow bandgap structure was revealed using low-temperature scanning tunneling microscopy/spectroscopy. Theoretical calculations confirmed that the observed electronic bands originated from the efficient hybridization of cobalt and molecular orbitals. This work provides a foundation for the systematic search of similar one-dimensional π-d hybridized metal-organic chains with tunable electronic and magnetic properties.
News Item
Chemistry, Multidisciplinary
P. Jelinek
Summary: An organic quantum magnet has been created by synthesizing short chains of porphyrin derivatives on a surface and manipulating atoms using a scanning probe microscope tip.
Article
Chemistry, Multidisciplinary
Tao Wang, Paula Angulo-Portugal, Alejandro Berdonces-Layunta, Andrej Jancarik, Andre Gourdon, Jan Holec, Manish Kumar, Diego Soler, Pavel Jelinek, David Casanova, Martina Corso, Dimas G. de Oteyza, Jan Patrick Calupitan
Summary: The coupling of a sterically demanded pentacene derivative on Au(111) into fused dimers connected by non-benzenoid rings was studied using high-resolution scanning tunneling microscopy/spectroscopy and density functional theory. The diradical character of the products was tuned by modifying the coupling section, with the antiaromaticity of cyclobutadiene and its position within the structure playing a significant role. Understanding these structure-property relationships is crucial for designing new complex and functional molecular structures.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Physics, Multidisciplinary
F. Matejka, P. Galar, J. Khun, V Scholtz, K. Kusova
Summary: Plasma activated water (PAW), traditionally used for decontamination and disinfection, can also be beneficial for tailoring the surface chemistry of semiconductor nanostructures when containing a high concentration of nitrogen-related species (HiN:PAW). The pathways leading to the production of HiN:PAW are investigated by monitoring the composition of PAW and the concentration of selected species in the discharge under various conditions. The presence of a barrier area in the discharge reactor is identified as a key factor for the production of HiN:PAW.
Article
Chemistry, Physical
Tomas Popelar, Pavel Galar, Filip Matejka, Giacomo Morselli, Paola Ceroni, Katerina Kusova
Summary: Silicon quantum dots (SiQDs) have potential for light emission, but the efficiency is hindered by dark quantum dots. We experimentally determine the dependence of radiative lifetimes on emission photon energy and use this to quantify the internal photoluminescence quantum yield. This approach can be applied by other researchers to study nonradiative processes and dark quantum dots. Additionally, we observe that the decay of SiQDs' photoluminescence can be non-single-exponential, possibly due to natural variation in radiative lifetimes. Average lifetimes are emphasized as an important quantity for characterizing photoluminescence decays in the absence of a widely accepted physical model.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)