Article
Chemistry, Physical
Hajer Chouaibi, Beatriz Rivas-Murias, Mourad Smari, Jalel Massoudi, Essebti Dhahri, Veronica Salgueirino
Summary: Perovskite nanocrystals, including cobalt perovskites, are gaining attention for their magnetic, transport, and catalytic properties. Nd0.75Sr0.25CoO3 nanocrystals were synthesized using the citrate sol-gel method and characterized through various techniques to understand their behavior.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Materials Science, Multidisciplinary
Premshila Kumari, Avritti Srivastava, Ruchi K. Sharma, Anjali Saini, Deepak Sharma, Jai S. Tawale, Sanjay K. Srivastava
Summary: This study reports the bulk synthesis of high quality ZnO nanoparticles using a facile wet chemical colloidal method, and investigates the effect of air annealing on their properties. New findings and explanations were presented regarding the structural, morphological, compositional, and optical aspects of the ZnO nanoparticles.
MATERIALS TODAY COMMUNICATIONS
(2022)
Article
Materials Science, Multidisciplinary
Seyed Mohammad Ali Hosseini-Saber, Ruslan Muydinov, Najme Ahmadi, Josefa Ibaceta-Jana, Zainab Kazemi, Stefan Seeger, Heiko Gundlach, Ulrich Gernert, Bernd Szyszka, Hans Joachim Eichler
Summary: SiOx layers with thicknesses of 300-1000 nm are produced by sputtering silicon onto glass and quartz substrates. Silicon is oxidized during deposition, leading to the formation of silicon nanocrystals in SiOx matrix after flash heating. The photoluminescence of the layers indicates potential applications, such as Si-LEDs or silicon lasers.
PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE
(2021)
Article
Chemistry, Physical
Taegeon Lee, Jeong-Hun Choi, Ji-Hoon Ahn, Young-Gui Yoon, Heesuk Rho
Summary: Understanding the charge doping and thermal heating effects in atomically thin transition metal dichalcogenides is important for designing efficient low-dimensional optoelectronics. This study investigates interlayer charge transfer doping and thermal heating effects in monolayer MoS2, revealing two distinct types of charge transfer phenomena and increased electron density in MoS2 with the presence of Bi2Te3. The results provide valuable insights into the interlayer charge transfer mechanism in various two-dimensional hetemstructures.
APPLIED SURFACE SCIENCE
(2022)
Article
Chemistry, Multidisciplinary
Reza J. Kashtiban, Maria G. Burdanova, Andrij Vasylenko, Jamie Wynn, Paulo V. C. Medeiros, Quentin Ramasse, Andrew J. Morris, David Quigley, James Lloyd-Hughes, Jeremy Sloan
Summary: The formation of one-dimensional CsI chains and helical chains within carbon nanotubes of different diameters has been demonstrated, showing varying effects on the encapsulating tubes' structure and electronic properties. Analysis using density-functional theory and Bader analysis was conducted to understand the observed changes.
Article
Chemistry, Physical
Miles Martinati, Wim Wenseleers, Lei Shi, Saied Md Pratik, Philip Rohringer, Weili Cui, Thomas Pichler, Veaceslav Coropceanu, Jean-Luc Bredas, Sofie Cambre
Summary: In this study, the excited states of ultralong carbon chains encapsulated inside double-walled carbon nanotubes were investigated using wavelength-dependent resonant Raman spectroscopy. The study identified vibronic series of two different electronic states.
Article
Spectroscopy
Trevor J. Wolfe, Nicholas A. Kruse, Mohamed M. Radwan, Amira S. Wanas, Kalee N. Sigworth, Mahmoud A. Elsohly, Nathan I. Hammer
Summary: This study presents the Raman spectra of 11 cannabinoids and compares them to simulated spectra. The results show higher peak separation in the experimental spectra and deviations in the -OH stretching region, indicating that this region is a good indicator for decarboxylation reactions in these cannabinoids.
SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
(2023)
Article
Chemistry, Physical
Amaresh Das, Durga Basak
Summary: This study presents a comprehensive investigation on the interplay between nitrogen and various defects in ZnO nanorods, revealing that nitrogen implantation induces structural damages and forms nitrogen-related defect complexes. Post-implantation annealing in O2 and Ar environments plays a key role in stabilizing nitrogen dopants in ZnO nanorods.
APPLIED SURFACE SCIENCE
(2021)
Article
Spectroscopy
Shuai Lian, Xun Gao, Chao Song, Hui Li, Anmin Chen, Jingquan Lin
Summary: In this study, the Raman activity spectra, frontier molecular orbitals, and molecular electrostatic potentials of CBD, THC, and their respective gold complexes were investigated. The results show that CBD is more reactive than THC, with CBD/THC-Au complexes displaying stronger chemical activities and greater charge transfer effects. The most electronegative sites of CBD and THC were identified as the adsorption sites on the gold surface.
SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
(2022)
Article
Nanoscience & Nanotechnology
Yun Xiao, Haibin Wang, Fumiyasu Awai, Naoyuki Shibayama, Takaya Kubo, Hiroshi Segawa
Summary: Oxygen vacancies and zinc interstitial sites are the main factors affecting the performance of solar cells, hindering carrier collection in the cells.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Nanoscience & Nanotechnology
Yun Xiao, Haibin Wang, Fumiyasu Awai, Naoyuki Shibayama, Takaya Kubo, Hiroshi Segawa
Summary: This study fabricated eco-friendly solar cells using interdigitated layers consisting of ZnO nanowires and infrared absorbing AgBiS2 nanocrystals. The quality of ZnO nanowires and its defects affecting solar cell performance were investigated. Oxygen vacancies and Zn interstitial sites were identified as the main recombination sites, hindering carrier collection in the solar cells. By reducing the concentration of these defects, the structural order and electron-phonon interaction in ZnO nanowires were improved. Furthermore, the study emphasized the significance of reducing defects in ZnO for improving not only colloidal quantum dot solar cells but also other emerging solar cell technologies.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Chemistry, Multidisciplinary
Hiroo Suzuki, Yijun Liu, Masaaki Misawa, Chiyu Nakano, Yingzhe Wang, Ryo Nakano, Kentaro Ishimura, Kenji Tsuruta, Yasuhiko Hayashi
Summary: This study investigates the intermediate state and characteristic Raman modes of Janus MoSeS during plasma processing. The intermediate partially substituted Janus (PSJ) structure is revealed through atomic composition analysis and atomic scale structural observations. The discontinuous transitions in the photoluminescence spectrum cannot be explained by theoretical calculations. These findings contribute to the understanding of the formation process and electronic-state modulation of Janus TMDCs.
Article
Chemistry, Multidisciplinary
Sergey A. Grudinkin, Nikolay A. Feoktistov, Kirill V. Bogdanov, Mikhail A. Baranov, Valery G. Golubev, Alexander V. Baranov
Summary: The study investigates the impact of reactive ion etching in oxygen plasma on the structure and luminescence properties of nanodiamonds, revealing that etching can improve the luminescence background and narrow the diamond Raman band.
Article
Spectroscopy
Supriya Ghosh, Debkumar Rana, Bapi Pradhan, Patrice Donfack, Johan Hofkens, Arnulf Materny
Summary: Metal halide-based perovskite semiconductors have excellent optoelectronic properties, with mixed compositions leading to structural changes and influencing electronic properties. By using Raman spectroscopy and density functional theory (DFT), we systematically investigated the vibrational features of lead bromide-based perovskites, finding a clear correlation between Raman band wavenumbers and the choice of cations.
JOURNAL OF RAMAN SPECTROSCOPY
(2021)
Article
Chemistry, Physical
V. N. Kazuchits, N. M. Kazuchits, M. S. Rusetskiy, O. Korolik, A. Konovalova, O. Ignatenko
Summary: The paper investigates the effects of RHPHT annealing on synthetic Ib-type diamond plates at high temperatures and pressures. The process resulted in inhomogeneous plastic deformation of diamond plates, generating vacancies and nitrogen defects. Higher temperatures during RHPHT annealing led to the formation of more complex nitrogen aggregates. The number of defects was significantly greater after RHPHT annealing compared to quasi-stationary HPHT annealing.
Article
Chemistry, Physical
M. Azizar Rahman, Sajid Ali, Matthew R. Phillips, Cuong Ton-That
Summary: In this study, the luminescence wavelength within individual GaZnO microrods was tailored via defect engineering, demonstrating the possibility of multi-wavelength emission within individual microrods. The variation in morphology and Ga dopant content of GaZnO microrods results in a red shift in the emission wavelength.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Chemistry, Physical
Zilan Wang, Zhigang Wang, M. Azizar Rahman, Cuong Ton-That, Francis C. C. Ling
Summary: The green luminescence of ZnO is an important research topic for defect-controlling engineering, and can be precisely controlled by surface modification techniques. Surface treatment also has a clear impact on defects, which is beneficial for improving the performance of ZnO devices.
JOURNAL OF PHYSICAL CHEMISTRY C
(2022)
Article
Physics, Applied
Ying-Li Shi, Dong Huang, Francis Chi-Chung Ling, Qi-Sheng Tian, Liang-Sheng Liao, Matthew R. Phillips, Cuong Ton-That
Summary: Pulsed laser deposition was used to fabricate as-grown amorphous and post-growth annealed crystalline beta-Ga2O3 films. The films annealed at temperatures above 600 degrees C exhibited a pure monolithic phase with a large bandgap. The thermally activated donor ionization and dielectric relaxation were investigated in these films, revealing the presence of donor levels and small polaron tunneling relaxation in the as-grown amorphous Ga2O3 film but not in the monolithic beta-Ga2O3 film.
APPLIED PHYSICS LETTERS
(2022)
Article
Nanoscience & Nanotechnology
Moritz Quincke, Tibor Lehnert, Itai Keren, Narine Moses Badlyan, Fabian Port, Manuel Goncalves, Michael J. Mohn, Janina Maultzsch, Hadar Steinberg, Ute Kaiser
Summary: Understanding the positions, densities, and atomic structures of crystallographic defects is crucial for the electronic and optical applications of two-dimensional materials and their vertical heterostructures. By combining device measurements with atomically resolved transmission electron microscopy (TEM) experiments, researchers have developed a generic sample platform that allows imaging of freestanding 2D materials in TEM, followed by experiments on the same sample area placed on an arbitrary substrate or embedded into a heterostructure device. The platform enables the creation and manipulation of atomic defects using the electron beam.
ACS APPLIED NANO MATERIALS
(2022)
Article
Chemistry, Inorganic & Nuclear
Franz Kamutzki, Maged F. Bekheet, Soren Selve, Felix Kampmann, Konrad Siemensmeyer, Delf Kober, Roland Gillen, Markus Wagner, Janina Maultzsch, Aleksander Gurlo, Dorian A. H. Hanaor
Summary: A novel sodium gadolinium pyroxene (NaGdSi2O6) was successfully synthesized and its crystal structure was determined. The sodium gadolinium pyroxene showed weak antiferromagnetic coupling, but no long-range magnetic order was observed above 2 K.
JOURNAL OF SOLID STATE CHEMISTRY
(2023)
Article
Chemistry, Physical
Pascal Buettner, Florian Scheler, Dirk Doehler, Maissa K. S. Barr, Michael Bosch, Marcel Rey, Tadahiro Yokosawa, Sandra Hinz, Janina Maultzsch, Erdmann Spiecker, Nicolas Vogel, Ignacio Minguez-Bacho, Julien Bachmann
Summary: This study addresses the issue of morphological rearrangement of Sb2S3 during thermal crystallization by introducing a sacrificial capping layer of ZnO and oxidative treatment of the Sb2S3 surface. The concentric p-i-n heterojunction solar cells fabricated using this approach show a high refractive index contrast and achieve >5% overall solar energy conversion efficiency with a simple light absorber phase of only 35 nm thickness.
Article
Materials Science, Multidisciplinary
Saskia Fiedler, Cuong Ton-That, Matthew R. R. Phillips
Summary: Low-temperature hydrothermal growth is a popular method for fabricating ZnO nanorods (NRs) with enhanced functionality. This study examines the influence of growth time, temperature, and seed layer on the dimensions and angular distribution of ZnO NRs. The results show that growth time and temperature do not have a controllable impact on NR diameter and length, while the deposition method and size of pre-growth deposited ZnO seeds affect diameter and NR angular alignment. The advantages of using crisscross-aligned NRs over planar ZnO for enhancing ZnO excitonic emission are demonstrated.
JOURNAL OF MATERIALS RESEARCH
(2023)
Article
Chemistry, Physical
Fatima Matar, Ying-Li Shi, Francis Chi-Chung Ling, Amar Salih, Curtis P. Irvine, Sujeewa De Silva, Matthew R. Phillips, Cuong Ton-That
Summary: This study fabricates monoclinic phase (BixGa1-x)2O3 ternary alloys on c-plane sapphire via magnetron co-sputtering and investigates their electrical properties. It is found that alloying Ga2O3 with Bi2O3 decreases the bandgap and lowers the self-trapping energy for holes. The conductivity of (Bi0.04Ga0.96)2O3 film is lower than that of undoped Ga2O3, likely due to the compensation of shallow donors by acceptors activated by Bi2O3-induced upward shift of the valence band edge.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Materials Science, Multidisciplinary
Raja Elrahoumi, Liangchen Zhu, Estelle Wagner, William Maudez, Giacomo Benvenuti, Matthew R. Phillips, Cuong Ton-That
Summary: In this work, the formation of oxygen vacancies (VO) and Ti3+ ions induced by n-type doping of TiO2 with Nb is demonstrated using a combinatorial investigation approach. The results show that the introduction of Nb donors can increase the luminescence intensity and enhance the photocatalytic efficiency of TiO2. Additionally, two different post-growth treatment approaches are shown to further increase the near-surface VO density without affecting the valence state of Ti, providing opportunities for defect engineering to optimize the photocatalytic properties of TiO2.
MATERIALS CHEMISTRY AND PHYSICS
(2023)
Article
Energy & Fuels
Amar K. Salih, Matthew R. Phillips, Cuong Ton-That
Summary: This study presents a simple method to produce highly efficient ZnO photoanodes for solar-driven water splitting. The fabrication process involves post-growth oxidation of a metallic Zn layer, resulting in a nanostructured ZnO film with a high concentration of surface oxygen vacancies. The ZnO photoanodes exhibit exceptional photocurrent density due to the ionized VO defects, making it one of the best-performing ZnO-based photoelectrodes reported so far. This research demonstrates a promising approach for large-scale production of efficient ZnO-based photoanodes.
SOLAR ENERGY MATERIALS AND SOLAR CELLS
(2023)
Article
Nanoscience & Nanotechnology
Md. Azizar Rahman, S. M. Naimul Mamun, Abul Kashem Mohammad Akther Hossain, Cuong Ton-That
Summary: In this work, an efficient p-n homojunction LED is fabricated based on the secondary growth of Ga-doped ZnO (GZO) nanorods onto a p-type Li-doped ZnO (LZO) thin film. The optimized GZO nanorods and LZO films exhibit low turn-on voltage and bright-yellow-orange electroluminescence. The optimized LED based on the GZO nanorods is 16 times more efficient in EL than the equivalent device made from ZnO nanorods.
ACS APPLIED NANO MATERIALS
(2023)
