Article
Chemistry, Physical
George F. Harrington, Sunho Kim, Kazunari Sasaki, Harry L. Tuller, Steffen Grieshammer
Summary: This study investigates how ionic transport in functional oxides is influenced by strain, particularly focusing on rare-earth substituted ceria epitaxial films under biaxial strain. The research shows that the out-of-plane transport is more sensitive to strain than in-plane transport, and the size of rare-earth substitutionals significantly impacts the strain effect on ionic conductivity. By simulating conductivity using the kinetic Monte Carlo method based on density functional theory, the study reveals that both migration barriers and defect interactions contribute to the strain-modified transport.
JOURNAL OF MATERIALS CHEMISTRY A
(2021)
Article
Materials Science, Multidisciplinary
Abbas Saeed Hakeem, Majid Khan, Bilal Anjum Ahmed, Ahmed Al Ghanim, Faheemuddin Patel, Muhammad Ali Ehsan, Sadaqat Ali, Tahar Laoui, Sharafat Ali
Summary: Multiple sialon ceramics compositions were synthesized using nanosized metal oxides (MOs) as additives in the oxynitride network. The formation of alpha-sialon and its properties were investigated, with the samples showing high relative densities and Vickers hardness values, along with variations in fracture toughness and thermal conductivity based on the type of MO used.
INTERNATIONAL JOURNAL OF REFRACTORY METALS & HARD MATERIALS
(2021)
Review
Optics
Zong-Quan Zhou, Chao Liu, Chuan-Feng Li, Guang-Can Guo, Daniel Oblak, Mi Lei, Andrei Faraon, Margherita Mazzera, Hugues de Riedmatten
Summary: An optical quantum memory is a device that can store and release photonic quantum information. It is crucial for mitigating channel losses in large-scale quantum networks. Different physical systems such as atomic gases, single atoms in optical cavities, and rare-earth-ion doped solids have been used for realizing optical quantum memories. The focus is now on miniaturization and integration of quantum memories for practical applications in quantum networks, with solid state systems being a favored choice due to their stability and ease of fabrication.
LASER & PHOTONICS REVIEWS
(2023)
Article
Optics
Yulia A. Uspenskaya, Elena Edinach, Alexandr S. Gurin, Roman A. Babunts, Hike R. Asatryan, Nikolai G. Romanov, Pavel G. Baranov
Summary: The spin-dependent optical properties of garnet crystals and ceramics doped with cerium and co-doped with gadolinium and/or terbium were studied using optically detected magnetic resonance. The results showed that the photoluminescence excited by circularly polarized light can be used for selective monitoring of the spin sublevels of cerium ions. The study also revealed the coupling between the gadolinium and cerium spin systems, as well as the presence of non-Kramers terbium centers in yttrium aluminum garnet crystals.
JOURNAL OF LUMINESCENCE
(2022)
Article
Materials Science, Multidisciplinary
Miela J. Gross, Jackson J. Bauer, Supriya Ghosh, Subhajit Kundu, Kensuke Hayashi, Ethan R. Rosenberg, K. Andre Mkhoyan, Caroline A. Ross
Summary: The crystallization of rare earth iron garnet films on Si substrates provides a way to integrate these complex oxides into magnetic devices. The growth of dysprosium yttrium iron garnet films and the effect of Y:Dy ratio on magnetization and anisotropy were studied. In order to crystallize thinner films, tri-layer stacks were prepared and showed promising results.
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
(2022)
Article
Nanoscience & Nanotechnology
Xuewen Xia, Junqi Li, Chaoyi Chen, Yuan-Pei Lan, Xisong Mao, Fusheng Bai
Summary: The method of morphological tuning or additional cation doping is a potential and simple way to enhance the photocatalytic properties of ceria. In this study, La, Y, and Sm were doped into CeO2 NRs in various concentrations, with 10% doping showing the narrowest band gaps and higher photocatalytic performance. The enhanced photocatalytic activity of CeO2 was mainly attributed to the promotion of oxygen vacancy generation and impeding the recombination of photogenerated carriers by doped RE ions.
Article
Chemistry, Physical
Tijana Stamenkovic, Dejan Pjevic, Jugoslav Krstic, Maja Popovic, Vladimir Rajic, Vesna Lojpur
Summary: A series of SrGd2O4 samples doped with different concentrations of Sm3+ and Dy3+ were prepared through glycine-assisted combustion synthesis. X-ray Powder Diffraction investigation confirmed the presence of pure orthorhombic lattice SrGd2O4. Energy Dispersive X-ray Spectroscopy showed that the desired elements were incorporated in the structure. Field Emission Scanning Electron Microscopy revealed the morphology of the samples as porous aggregated particles consisting of approximately 50 nm-sized spherical particles. Mercury Intrusion Porosimetry demonstrated the presence of a real permanent 3D pore structure. X-ray Photoelectron Spectroscopy confirmed the successful incorporation of Dy3+ and Sm3+ ions. Down-conversion luminescence spectra showed typical emission transitions for Sm3+ and Dy3+ ions. The energy band gap of the doped samples was calculated to be 4.3 eV using UV-VIS Diffuse Reflectance Spectroscopy. UV-VIS Absorption Spectroscopy observed the photocatalytic degradation process, with approximately 50% of Rhodamine B being mineralized after 4 hours of simulated Sun exposure.
SURFACES AND INTERFACES
(2023)
Article
Biotechnology & Applied Microbiology
Astita Dubey, Soma Salamon, Supun B. Attanayake, Syaidah Ibrahim, Joachim Landers, Marianela Escobar Castillo, Heiko Wende, Hari Srikanth, Vladimir V. Shvartsman, Doru C. Lupascu
Summary: Ionic engineering is used to substitute rare-earth elements in BiFe0.95Mn0.05O3 NPs, resulting in morphological changes and improved piezoresponse and magnetic hyperthermia potential. The increment in magnetization has an impact on the hyperthermia results.
FRONTIERS IN BIOENGINEERING AND BIOTECHNOLOGY
(2022)
Article
Materials Science, Multidisciplinary
R. M. Rakhmatullin, V. V. Semashko, A. Lovchev, A. A. Rodionov, I. F. Gilmutdinov, A. G. Kiiamov
Summary: Room-temperature ferromagnetism found in powders of both undoped CaF2 and CaF2 doped with CeO2 suggests a key role of surface defects, as compared to bulk crystals exhibiting diamagnetic or paramagnetic behavior. The study may provide new insights into the phenomenon of room-temperature ferromagnetism in nonmagnetic nanoparticles.
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
(2022)
Article
Physics, Multidisciplinary
Dheeraj Ranaut, K. Mukherjee
Summary: Although the 4 f 6 systems were expected to have a non-magnetic (J = 0) ground state, all such systems have shown the presence of a non-zero effective moment at low temperatures. In the case of the rare earth orthovanadate EuVO4, which has a J = 0 ground state, our studies reveal three different regions with distinct magnetic susceptibility features. The high temperature susceptibility is linearly dependent on temperature due to the inter-mixing of ground and excited states, while the temperature independent plateau-like region is attributed to Van Vleck paramagnetism. At low temperatures, a Curie-Weiss-like behavior is observed, resulting from the magnetic Eu2+ ions and leading to a non-zero effective moment. Our analysis shows that increasing the external magnetic field reduces the separation (A) between the J = 0 and 1 states, resulting in an enhanced effective moment at higher fields.
Review
Engineering, Biomedical
Mengqin Gu, Wei Li, Li Jiang, Xiyu Li
Summary: Rare earth-doped hydroxyapatite nanoparticles display unique physicochemical and imaging properties, making them promising for biomedical applications.
ACTA BIOMATERIALIA
(2022)
Article
Chemistry, Physical
Tatyana B. Bekker, Alexey A. Ryadun, Alexey V. Davydov, Vladimir P. Solntsev, Veronika D. Grigorieva
Summary: Single crystals of undoped and rare-earth-doped Ba-12(BO3)(6)[BO3][LiF4] were grown from high-temperature solutions. The luminescence of these crystals at specific excitation wavelengths shows potential for converting LED emissions into white light.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Optics
Baobao Zhang, Xiaojun Guo, Zhenglong Zhang, Zhengkun Fu, Hairong Zheng
Summary: Luminescence thermometry is a unique temperature detection technology that offers remote and noncontact functions. Rare earth doped materials, known for their chemical stability and non-blinking properties, have been widely used in luminescent thermometers. With the rapid advancement of nanoscience and nanotechnology, rare earth doped nanoparticles have emerged as promising candidates for luminescence thermometry, providing high spatial resolution and a wide temperature detection range.
JOURNAL OF LUMINESCENCE
(2022)
Review
Energy & Fuels
Taiyu Bian, Tianhong Zhou, Yang Zhang
Summary: Rare-earth-doped ferroelectric oxides are materials with abundant physical functionalities and have great potential in applications such as optical sensing, lighting, and solar cells.
Review
Materials Science, Ceramics
Ziyu Liu, Akio Ikesue, Jiang Li
Summary: Sesquioxide ceramics and their solid solutions are considered ideal hosts for solid-state laser gain materials, especially for rare-earth ions. The review of the fabrication process and laser performance demonstrates their great potential in high power and ultrashort pulse laser applications.
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
(2021)
Article
Energy & Fuels
M. Kauk-Kuusik, K. Timmo, K. Muska, M. Pilvet, J. Krustok, M. Danilson, V Mikli, R. Josepson, M. Grossberg-Kuusk
Summary: The efficiency of CZTS solar cells can be improved by controlling the intermixing of Cd and Cu at the CZTS/CdS interface. Cd diffusion into the CZTS surface after CdS air-annealing forms an ultra-thin Cu2Zn (x) Cd1-x SnS4 layer, reducing interface recombination and enhancing the performance of the cell.
JOURNAL OF PHYSICS-ENERGY
(2022)
Article
Engineering, Aerospace
Katriin Kristmann, Taavi Raadik, Mare Altosaar, Maarja Grossberg-Kuusk, Juri Krustok, Maris Pilvet, Valdek Mikli, Marit Kauk-Kuusik, Advenit Makaya
Summary: This study proposes the use of monograin layer (MGL) solar cell technology for in-situ production of solar panels on the Moon. The synthesis-growth of suitable single phase pyrite monograin powder from local resources was achieved. The produced FeS2 MGLs were used as absorber layers in MGL solar cells.
Article
Materials Science, Multidisciplinary
H. Khanduri, Mukesh C. Dimri, S. A. Khan, Prashant Kumar, J. Link, R. Stern, Nanhe Kumar Gupta, R. P. Pant
Summary: This study investigates the effects of swift heavy ion irradiation on the structural, microstructural, and magnetic properties of Mn/Al bilayer thin films. The irradiated films demonstrated enhanced ferromagnetic properties and perpendicular magnetic anisotropy, making them promising materials for rare-earth-free permanent magnets and spintronic applications.
JOURNAL OF MATERIALS RESEARCH
(2022)
Article
Chemistry, Physical
Rokas Kondrotas, Ramunas Nedzinskas, Juri Krustok, Maarja Grossberg, Martynas Talaikis, Saulius Tumenas, Arturas Suchodolskis, Raimundas Zaltauskas, Raimundas Sereika
Summary: This study investigates the radiative carrier recombination mechanisms in Sb2Se3 single crystals and whether there are any fundamental limitations to achieving high open-circuit voltage (VOC). The results show that three distinct radiative recombination mechanisms are present and heavily influenced by impurities. The most intense photoluminescence emissions are located near the band edge. No evidence of emission from self-trapped excitons or band-tails is found, suggesting that there is no fundamental limitation to achieving high VOC.
ACS APPLIED ENERGY MATERIALS
(2022)
Article
Chemistry, Multidisciplinary
Tanya Berry, Nicodemos Varnava, Dominic H. Ryan, Veronica J. Stewart, Riho Rasta, Ivo Heinmaa, Nitesh Kumar, Walter Schnelle, Rishi Bhandia, Christopher M. Pasco, N. P. Armitage, Raivo Stern, Claudia Felser, David Vanderbilt, Tyrel M. McQueen
Summary: Electrons in solids adopt complex patterns of chemical bonding driven by energy gains and costs. We report a chemical pressure-driven transition in EuMn2P2 from proper Mn magnetic ordering to a Mn magnetic phase crossover, despite remaining an insulator at all temperatures. The absence of a Mn magnetic phase transition contrasts with other isoelectronic materials. Our results demonstrate the sensitivity of the band structure to magnetic order and imply the suppression of long-range Mn magnetic order by chemical pressure.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Materials Science, Multidisciplinary
I. Mengu, J. Krustok, R. Kaupmees, V. Mikli, M. Kauk-Kuusik, M. Grossberg-Kuusk
Summary: The photoluminescence (PL) spectra of Cu2ZnSnSe4 microcrystals with different degrees of disorder were studied by examining the temperature and excitation power dependencies. The crystals were cooled at varying rates after high-temperature annealing to alter the degree of disorder. Both samples exhibited an asymmetrical band in the PL spectra, located at 0.88 eV and 0.92 eV for disordered and ordered crystals, respectively. At low temperatures, both samples had similar origins of PL involving localized electron states. However, the ordered sample displayed deeper localized electron states, requiring higher temperatures to transition electrons to the band states. Changes in disorder affected the radiative recombination in CZTSe microcrystals.
MATERIALS CHEMISTRY AND PHYSICS
(2023)
Article
Materials Science, Multidisciplinary
Juri Krustok, Reelika Kaupmees, Nafiseh Abbasi, Katri Muska, Idil Mengu, Kristi Timmo
Summary: The temperature and laser power dependencies of the band-to-acceptor recombination in Cu2ZnSn(SxSe1-x)(4) (x = 0.7) microcrystals, which exhibit significant fluctuations in bandgap energy, were investigated. The fluctuations had an average depth of approximately 79 meV. A modified localized-state ensemble model was used to analyze the shape of the wide photoluminescence (PL) band. The temperature dependence of the PL band was found to be influenced by the redistribution of holes between potential wells in the valence band, while the shape of the band at different temperatures could be accurately fitted by introducing an effective carrier temperature.
PHYSICA STATUS SOLIDI-RAPID RESEARCH LETTERS
(2023)
Article
Energy & Fuels
M. Koltsov, S. V. Gopi, T. Raadik, J. Krustok, R. Josepson, R. Grzibovskis, A. Vembris, N. Spalatu
Summary: The emergence of new PV applications in society necessitates the design of new materials and devices based on green and earth-abundant elements. Bi2S3 semiconductor material has gained attention as a defect-tolerant, non-toxic, and highly stable material for earth-abundant thin film PV technologies. This study systematically investigates the impact of close-spaced sublimation (CSS) conditions on the growth of Bi2S3 absorbers on various substrates and provides new insights on possible defects and recombination mechanisms using low-temperature dependence photoluminescence (PL) analysis.
SOLAR ENERGY MATERIALS AND SOLAR CELLS
(2023)
Article
Energy & Fuels
Katri Muska, Kristi Timmo, Maris Pilvet, Reelika Kaupmees, Taavi Raadik, Valdek Mikli, Maarja Grossberg-Kuusk, Juri Krustok, Raavo Josepson, Sven Lange, Marit Kauk-Kuusik
Summary: This study investigated the effects of Li and K co-doping on the properties of Cu2ZnSnS4 (CZTS) monograin powders used in monograin layer (MGL) solar cells. CZTS powders were grown using different LiI-KI ratios in the synthesis-growth process. The Li concentration in the synthesized CZTS varied depending on the initial amount of LiI, while the amount of K remained constant. The addition of Li in CZTS resulted in the formation of a solid solution and an increase in the effective bandgap energy. Solar cells using Li and K co-doped CZTS powder showed the highest performance with a power conversion efficiency of 9.4%.
SOLAR ENERGY MATERIALS AND SOLAR CELLS
(2023)
Article
Biochemistry & Molecular Biology
Danh H. Vu, Amir Mahboubi, Andrew Root, Ivo Heinmaa, Mohammad J. Taherzadeh, Dan akesson
Summary: Retaining high cell density using an immersed membrane bioreactor (iMBR) in a (semi-) continuous process can enhance the production of polyhydroxyalkanoates (PHAs) using volatile fatty acids (VFAs) as a carbon source.
Article
Chemistry, Inorganic & Nuclear
Aleksandr Kulchu, Roman A. Khalaniya, Andrei V. Mironov, Olga N. Khrykina, Valeriy Yu. Verchenko, Raivo Stern, Andrei V. Shevelkov
Summary: Single crystals of RMn(x)Ga-3 and R4Mn1-xGa12-yGe(y) were grown from a Ga flux. The Ge doping leads to higher Mn content and the formation of a superstructure. R atoms order antiferromagnetically below 25K, while Mn atoms order ferromagnetically at 125-225K with Ge doping resulting in higher T(C) and partial ferromagnetic ordering of R atoms below T(C).
INORGANIC CHEMISTRY
(2023)
Article
Materials Science, Multidisciplinary
Benas Beklesovas, Vytautas Stankus, Brigita Abakeviciene, Joosep Link, Raivo Stern, Artyom Plyushch, Juras Banys, Jurgita Cyviene, Rolandas Gircys, Matas Basinskas, Evaldas Kalvaitis
Summary: Multiferroic materials, such as Pb2Fe2O5 (PFO), have attracted attention due to their multifunctional properties. Doping with aliovalent ions, like Cr3+, has been proposed as an effective method for enhancing the ferroelectric and magnetic properties of PFO. The study shows that Cr-doped PFO films exhibit improved polarization and magnetization, while their morphology changes with increasing chromium content.
ECS JOURNAL OF SOLID STATE SCIENCE AND TECHNOLOGY
(2023)
Article
Chemistry, Multidisciplinary
Peter Walke, Reelika Kaupmees, Maarja Grossberg-Kuusk, Juri Krustok
Summary: The growth of WS2 monolayers from a potassium-salt precursor leads to pronounced low-energy emission in the PL spectrum, which is attributed to defects in the layer. The emission can be controlled by altering the introduction of hydrogen.
Review
Chemistry, Physical
Marit Kauk-Kuusik, Kristi Timmo, Maris Pilvet, Katri Muska, Mati Danilson, Juri Krustok, Raavo Josepson, Valdek Mikli, Maarja Grossberg-Kuusk
Summary: Monograin powder technology is a possible approach to develop sustainable and flexible solar cells. The focus of this review is on the synthesis and properties of Cu2ZnSnS4 (CZTS) absorber materials. Despite its advantages, kesterite solar cells still have lower efficiency due to V-OC deficit. Various strategies such as post-annealing, alloying, and co-doping are explored to improve V-OC losses. Heterojunction modifications show the most effective improvement in CZTS-based solar cells.
JOURNAL OF MATERIALS CHEMISTRY A
(2023)
Article
Materials Science, Multidisciplinary
Kristi Timmo, Maris Pilvet, Katri Muska, Mare Altosaar, Valdek Mikli, Reelika Kaupmees, Raavo Josepson, Juri Krustok, Maarja Grossberg-Kuusk, Marit Kauk-Kuusik
Summary: This study investigates the influence of different alkali salts on the properties of CZTS powders and the characteristics of MGL solar cells. The results show that the morphology and composition of the crystals are affected by the nature of the flux materials. Different alkali salts result in different crystallinities and band gap energy values of the CZTS powders. The MGL solar cell based on CZTS powder grown in CsI exhibits the highest power conversion efficiency of 10.9%.
MATERIALS ADVANCES
(2023)
