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Photoproduction of Loop Currents in Coronene Isomers Without Any Applied Magnetic Field
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The Ni3Al/Ni Interfacial Contribution to the Indentation Size Effect of Ni-Based Single-Crystal Superalloys
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Vibrational Spectroscopy of Perovskite Ferroelectrics
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Optical and Amplified Spontaneous Emission Properties of Cyanoacetic Acid Derivative in Various Polymers
Journal Description
Solids
Solids
is an international, peer-reviewed, open access journal on all areas of solid-state sciences published quarterly online by MDPI.
- Open Access— free for readers, with article processing charges (APC) paid by authors or their institutions.
- High Visibility: indexed within ESCI (Web of Science), Scopus, EBSCO, CAPlus / SciFinder, and other databases.
- Rapid Publication: manuscripts are peer-reviewed and a first decision is provided to authors approximately 27.5 days after submission; acceptance to publication is undertaken in 3.9 days (median values for papers published in this journal in the second half of 2024).
- Journal Rank: CiteScore - Q2 (Physics and Astronomy (miscellaneous))
- Recognition of Reviewers: APC discount vouchers, optional signed peer review, and reviewer names published annually in the journal.
Impact Factor:
2.4 (2023);
5-Year Impact Factor:
2.4 (2023)
Latest Articles
Pristine and Reassembled Nanosheets of Layered Perovskite-like Titanates HLnTiO4 and H2Ln2Ti3O10 (Ln = La, Nd) as Photocatalysts for Hydrogen Evolution
Solids 2025, 6(2), 16; https://doi.org/10.3390/solids6020016 (registering DOI) - 2 Apr 2025
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Layered Ruddlesden–Popper titanates HLnTiO4 and H2Ln2Ti3O10 (Ln = La, Nd) have been exfoliated into nanosheets in aqueous tetrabutylammonium hydroxide and systematically investigated as hydrogen evolution photocatalysts. The nanosheets were tested both in as-prepared pristine form
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Layered Ruddlesden–Popper titanates HLnTiO4 and H2Ln2Ti3O10 (Ln = La, Nd) have been exfoliated into nanosheets in aqueous tetrabutylammonium hydroxide and systematically investigated as hydrogen evolution photocatalysts. The nanosheets were tested both in as-prepared pristine form and after reassembly by two methods (simple filtration and precipitation by hydrochloric acid). The nanosheet-based samples demonstrated by up to 88 times greater photocatalytic performance in comparison with the bulk precursors and, after modification with a Pt cocatalyst, provided apparent quantum efficiency of hydrogen generation up to 14.2% in 1 mol.% aqueous methanol and 3.15% in pure water. It was established that the form in which the nanosheets are used strongly affects the hydrogen production efficiency: the latter typically decreases when moving from the pristine nanosheets to filtered ones and then to those restacked by hydrochloric acid, which is determined by the difference in their physical–chemical characteristics being influenced by the reassembly approach.
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Open AccessFeature PaperArticle
Insights into the Electrochemical Synthesis and Supercapacitive Behaviour of 3D Copper Oxide-Based Nanostructures
by
Gintautas Jonkus, Ramunas Levinas, Natalia Tsyntsaru and Henrikas Cesiulis
Solids 2025, 6(2), 15; https://doi.org/10.3390/solids6020015 - 1 Apr 2025
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In this study, nanostructured copper oxide-based films with crystallite size below 10 nm were electrochemically synthesized on copper foil and foam electrodes and investigated for their supercapacitive behaviour. The synthesis was carried out via cyclic voltammetry (CV) for up to 1000 cycles in
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In this study, nanostructured copper oxide-based films with crystallite size below 10 nm were electrochemically synthesized on copper foil and foam electrodes and investigated for their supercapacitive behaviour. The synthesis was carried out via cyclic voltammetry (CV) for up to 1000 cycles in an alkaline electrolyte. By tuning the upper vertex potential (−0.3 V to 0.65 V vs. Ag/AgCl), both phase composition (Cu2O, Cu(OH)2, CuO) and morphology (grains, nanoneedles, nanoplatelets) were precisely controlled, demonstrating the versatility of this approach. The kinetics of oxide/hydroxide film formation on foil and foam electrodes were analysed based on EIS data that were interpreted in the frame of equivalent electric circuits and their changes with potential. The capacitive properties of the synthesized films were evaluated using CV in the potential range of 0 V–0.65 V, and the optimized CuO film synthesized on Cu foam exhibited a high specific capacitance of 1380 mF cm⁻2. An energy density of 0.061 mWh cm−2 and power density of 1.28 mW cm−2 were obtained at 10 mA cm−2 discharge current. Charge–discharge cycling at 100 mV s−1 for 1000 cycles indicated an initial capacitance increase followed by stable retention, highlighting the structural integrity and electrochemical stability of the films obtained on 3D foam. These findings provide valuable insights into the controlled electrochemical synthesis of copper oxide nanostructures and their potential for high-performance capacitor applications.
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Open AccessArticle
The Influence of Endogenous Derivatives on the Self-Assembly of Carbonized Polymer Dots
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Yingxi Qin, Wenkai Zhang, Ziwei Liu, Mingyan Jia, Jie Chi, Yujia Liu, Yue Wang, Aimiao Qin, Yu Wang and Liang Feng
Solids 2025, 6(1), 14; https://doi.org/10.3390/solids6010014 - 20 Mar 2025
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Carbonized polymer dots (CPDs) have emerged as a fascinating class of functional nanomaterials with unique physicochemical properties. However, the mechanisms governing their formation and photoluminescence remain a subject of intense debate. In this study, we conducted a systematic comparison of the structural, morphological,
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Carbonized polymer dots (CPDs) have emerged as a fascinating class of functional nanomaterials with unique physicochemical properties. However, the mechanisms governing their formation and photoluminescence remain a subject of intense debate. In this study, we conducted a systematic comparison of the structural, morphological, and optical properties of CPDs synthesized using various methods, revealing the self-assembly characteristics of low-molecular-weight CPDs with relatively complex structures. Through comprehensive structural, morphological, and optical analyses, we found that CPDs with fewer endogenous derivatives exhibited pronounced concentration-dependent self-assembly, leading to larger particle sizes and enhanced fluorescence emission at higher concentrations. In contrast, CPDs with higher proportions of endogenous derivatives showed limited self-assembly due to complex supramolecular interactions between the derivatives and polymer chains. Remarkably, the removal of endogenous derivatives using a ternary solvent extraction method significantly enhanced the self-assembly and fluorescence of the CPDs. These findings highlight the critical role of endogenous derivatives in modulating the self-assembly and photophysical properties of CPDs, paving the way for future advancements in this field.
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Open AccessFeature PaperArticle
Liquid Phase Preparation of Organic Thin Films Consisting of Complex Molecules—The Example of the Metallacrown CuCu4
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Frederik Pütz, Richard Blättner, Yves Kurek, Lukas Bolz, Swen Ehnert, Robert Wendels, Dominic Stephan, Philip Schreyer, Robert Ranecki, Ellen Brennfleck, Anne Lüpke, Dominik Laible, Benedikt Baumann, Stefan Lach, Eva Rentschler and Christiane Ziegler
Solids 2025, 6(1), 13; https://doi.org/10.3390/solids6010013 - 10 Mar 2025
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Large organic molecules and metal complexes are promising candidates for organic electronics, optoelectronics, and spintronics, with interfaces to metals being critical. Clean preparation in ultra-high vacuum (UHV) is ideal, but many systems are fragile and cannot be thermally sublimed. This study details the
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Large organic molecules and metal complexes are promising candidates for organic electronics, optoelectronics, and spintronics, with interfaces to metals being critical. Clean preparation in ultra-high vacuum (UHV) is ideal, but many systems are fragile and cannot be thermally sublimed. This study details the preparation of thin films of the metallacrown Cu(II)[12-MCCu(II)N(Shi)-4] (short: CuCu4) from the liquid phase using electrospray injection (ESI) and, in particular, liquid injection (LI). Both methods produce films with intact CuCu4 complexes, but they differ in the amount of co-adsorbed solvent molecules. Enhancements using an argon stream perpendicular to the molecular beam significantly reduce these contaminants. An additional effect occurs due to the counterions (HNEt3)2 of CuCu4. They are co-deposited by LI, but not by ESI. The advantages and limitations of the LI method are discussed in detail. The CuCu4 films prepared by different methods were analyzed with infrared (IR) spectroscopy, ultraviolet and X-ray photoelectron spectroscopy (UPS, XPS), and scanning tunneling microscopy (STM). For thicker films, ex situ and in situ prepared CuCu4 films to exhibit similar properties, but for studying interface effects or ultrathin films, in situ preparation is necessary.
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Open AccessArticle
Orientation of Conjugated Polymers in Single Crystals: Is It Really Unusual for the Polydiacetylene Backbone to Be Aligned Almost Perpendicular to the Hydrogen Bond Network?
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Pierre Baillargeon, Mathieu Desnoyers-Barbeau, Marc-Olivier Pouliot, Émile Gaouette, Rose Champoux, Myriam Veillette, Félix-Antoine Lemieux, Valentina Rojas Riano, Simone Picard, Ophélie Théberge, Jakob Boulanger, Sabrina Cissé, Daniel Fortin and Tarik Rahem
Solids 2025, 6(1), 12; https://doi.org/10.3390/solids6010012 - 9 Mar 2025
Abstract
We report the topochemical solid-state polymerization of different series of symmetrical diacetylenes (DAs) and asymmetrical chlorodiacetylenes (ClDAs), whose members differ in their alkyl spacing lengths of one to four methylene units (n = 1, 2, 3, 4) between the diyne and carbamate
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We report the topochemical solid-state polymerization of different series of symmetrical diacetylenes (DAs) and asymmetrical chlorodiacetylenes (ClDAs), whose members differ in their alkyl spacing lengths of one to four methylene units (n = 1, 2, 3, 4) between the diyne and carbamate functionalities. Structure determination by single-crystal X-Ray diffraction (SCXRD) confirms that in each of these series, at least 50% of the analyses show monomers with a particular stacking pattern presenting two potential directions of polymerization simultaneously. An organization of a crystalline polydiacetylene (PDA) with an oblique chain orientation with respect to the network of cooperatives hydrogen bonds is rather rare in the literature (only two cases), and here we have obtained two more examples of this type of structural motif (supported by SCXRD analysis of the polymer). Orientation control is essential to optimize the performance of conjugated polymers, and a spacer length modification strategy presents a potential way to achieve this in the case of PDA.
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(This article belongs to the Special Issue Young Talents in Solid-State Sciences)
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Open AccessReview
Research Progress on Texture Regulation of Rare-Earth Magnesium Alloys
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Weiyan Liu, Boxin Wei, Rengeng Li, Xin Wang, Hao Wu and Wenbin Fang
Solids 2025, 6(1), 11; https://doi.org/10.3390/solids6010011 - 7 Mar 2025
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Magnesium and its rare-earth alloys are extensively studied for their lightweight properties and high specific strength, making them attractive for aerospace, automotive, and biomedical applications. However, their hexagonal close-packed structure leads to a strong basal texture, limiting plasticity and formability at room temperature.
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Magnesium and its rare-earth alloys are extensively studied for their lightweight properties and high specific strength, making them attractive for aerospace, automotive, and biomedical applications. However, their hexagonal close-packed structure leads to a strong basal texture, limiting plasticity and formability at room temperature. Considerable research has been devoted to texture control strategies, including alloying, thermomechanical processing, and recrystallization mechanisms, yet a comprehensive understanding of their effects remains an ongoing research focus. This review summarizes recent advances in texture regulation of rare-earth magnesium alloys, focusing on the role of RE elements (Gd, Y, Nd, Ce) and non-RE elements (Zn, Ca) in modifying basal texture and enhancing mechanical properties. The influence of key processing techniques, such as extrusion, rolling, equal channel angular pressing, and rotary shear extrusion, is discussed in relation to their effects on recrystallization behavior. Additionally, the mechanisms governing texture evolution, including continuous dynamic recrystallization, discontinuous dynamic recrystallization (DDRX), and particle-stimulated nucleation, are critically examined. By integrating recent findings, this review provides a systematic perspective on alloying strategies, processing conditions, and recrystallization pathways, offering valuable insights for the development of high-performance magnesium alloys with improved formability and mechanical properties.
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Open AccessArticle
Taguchi Robust Design of Phase Transfer Catalytic Hydrolysis of Polyethylene Terephthalate (PET) Waste in Mild Conditions: Application for the Preparation of Metal–Organic Frameworks
by
Asma Nouira, Imene Bekri-Abbes, Isabel Pestana Paixão Cansado and Paulo Alexandre Mira Mourão
Solids 2025, 6(1), 10; https://doi.org/10.3390/solids6010010 - 6 Mar 2025
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With the rapid increase in polyethylene terephthalate (PET) usage in recent years, recycling has become indispensable in mitigating environmental damage and safeguarding natural resources. In this context, this study presents a methodology for valorizing PET waste through phase transfer catalytic hydrolysis conducted at
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With the rapid increase in polyethylene terephthalate (PET) usage in recent years, recycling has become indispensable in mitigating environmental damage and safeguarding natural resources. In this context, this study presents a methodology for valorizing PET waste through phase transfer catalytic hydrolysis conducted at a low temperature (80 °C) and atmospheric pressure, with the goal of recovering the terephthalic acid (TPA) monomer. The recovered TPA monomer was subsequently utilized as a precursor for the synthesis of metal–organic frameworks (MOFs). Tributylhexadecyl phosphonium bromide (3Bu6DPB) was selected as the phase transfer catalyst due to its efficiency and sustainability. The process parameters, including the concentration of NaOH, the wt.% of catalyst to PET, and the concentration of PET in the solution, were varied to optimize the hydrolysis reaction. The Taguchi design methodology with an L9 (3^3) orthogonal array was employed to analyze the influence of these factors on the depolymerization time. The analysis of variance (ANOVA) results revealed that the concentration of NaOH was the most significant factor, contributing to 93.3% of the process efficiency, followed by the wt.% of the catalyst to PET (6.5%). The findings also demonstrated that the concentration of NaOH had the greatest impact (Δ = 4.27, rank = 1), while the concentration of PET had the smallest effect (Δ = 0.16, rank = 3). The optimal conditions for PET depolymerization were achieved in 75 min with 20 g/100 mL of NaOH, 12 wt.% of catalyst to PET, and 5 g/100 mL of PET. The recovered TPA monomer was further employed as an organic ligand to synthesize Fe(III)-TPA MOFs under mild conditions (80 °C for 24 h). The X-ray diffraction (XRD) analysis revealed the simultaneous formation of MOF-235(Fe) and MIL-101(Fe), two multifunctional materials with diverse properties and applications. This study highlights an efficient approach for producing low-cost MOFs while promoting urban waste recycling, contributing to an integrated strategy for PET recycling and resource valorization.
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(This article belongs to the Special Issue Advances in the Study and Application of Polymers)
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Optimizing Mechanical Properties and Environmental Benefits of CFBFA Composite Gravels Through Gypsum, Hydrated Lime Addition, and CO2 Carbonation Curing
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Nuo Xu, Yuqing He, Rentuoya Sa, Nana Wang, Yuandong Yang and Suxia Ma
Solids 2025, 6(1), 9; https://doi.org/10.3390/solids6010009 - 26 Feb 2025
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This study explores the potential of utilizing circulating fluidized bed boiler fly ash (CFBFA) in the production of composite gravels, with the aim of achieving performance comparable to natural gravel while promoting sustainability. CFBFA, activated by hydrated lime and gypsum, was investigated for
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This study explores the potential of utilizing circulating fluidized bed boiler fly ash (CFBFA) in the production of composite gravels, with the aim of achieving performance comparable to natural gravel while promoting sustainability. CFBFA, activated by hydrated lime and gypsum, was investigated for its pozzolanic reaction and carbonation curing under simulated coal-fired power plant flue gas conditions (80 °C, 0.4 MPa, 15% CO2, 85% N2). The study focused on optimizing the ratios of gypsum and hydrated lime in CFBFA-based cementitious materials, with the goal of enhancing their mechanical properties and understanding the underlying hydration and carbonation mechanisms. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to analyze the mineral composition and microstructure of the composite gravels. The results revealed that the optimal gypsum-to-hydrated lime ratio for CFBFA composite gravels is 2:1, achieving a compressive strength of 9.01 MPa after 28 days of carbonation curing. Carbonation curing accelerated hydration, improving the material’s strength, stability, and microstructure. Additionally, the production of CFBFA composite gravels demonstrated significant environmental benefits, reducing Cumulative Energy Demand (CED) by 86.52% and Global Warming Potential (GWP) by 87.81% compared to cement road base materials. This research underscores the potential of CFBFA as a sustainable construction material, with insights into improving its mechanical performance and expanding its large-scale use through carbonation curing with flue gas.
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Open AccessArticle
Comparative Assessment of Surface Lattice Resonance Characteristics in Plasmonic Titanium Nitride and Gold Nanodisk Arrays
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Beyza Nur Günaydın, Süleyman Çelik, Meral Yüce and Hasan Kurt
Solids 2025, 6(1), 8; https://doi.org/10.3390/solids6010008 - 12 Feb 2025
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Titanium nitride (TiN) is an advantageous material for plasmonic applications and is suitable for extreme conditions in which conventional plasmonic materials such as gold (Au) cannot be utilized. In this study, TiN and Au nanodisk arrays with different lattice spacing (Λ) were fabricated
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Titanium nitride (TiN) is an advantageous material for plasmonic applications and is suitable for extreme conditions in which conventional plasmonic materials such as gold (Au) cannot be utilized. In this study, TiN and Au nanodisk arrays with different lattice spacing (Λ) were fabricated using the electron beam lithography (EBL) method to increase the quality factor of TiN. At a period of 550 nm, the TiN nanodisk arrays demonstrate a higher sensitivity, 412.79 nm·RIU−1, with the plasmonic resonance wavelength shifting from 883 nm (n = 1.3335) to 915 nm (n = 1.4069) in the NIR region. The surface lattice resonance (SLR) properties of the produced TiN nanodisk arrays were investigated in detail with Au nanodisk arrays. The TiN nanodisk arrays caused sharp plasmon resonances by creating a localized plasmon vibration mode coupled with the diffractive grazing wave excited by the incident light. The transmission dips obtained at narrower full width at half maximum (FWHM) values caused at least an almost 10-fold improvement in the quality factor compared to localized surface plasmon resonance (LSPR) dips. This study is significant for assessing the surface plasmon resonance characteristics of TiN and Au nanodisk arrays across various periods and indices.
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Open AccessArticle
Experimental Evaluation of Temperature and Strain-Rate-Dependent Mechanical Properties of Austenitic Stainless Steel SS316LN and a New Methodology to Evaluate Parameters of Johnson–Cook and Ramberg–Osgood Material Models
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Sanjay Kumar Pandey and Mahendra Kumar Samal
Solids 2025, 6(1), 7; https://doi.org/10.3390/solids6010007 - 11 Feb 2025
Abstract
Austenitic stainless steel SS316LN is used as the material of construction of the vessel and core components of fast breeder reactors, which operate at an elevated temperature of 550 °C. For design and integrity analysis using the finite element method, material models, such
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Austenitic stainless steel SS316LN is used as the material of construction of the vessel and core components of fast breeder reactors, which operate at an elevated temperature of 550 °C. For design and integrity analysis using the finite element method, material models, such as Johnson–Cook and Ramberg–Osgood, are widely used. However, the temperature- and strain-rate-dependent plasticity and damage parameters of these models for this material are not available in the literature. Moreover, the method of evaluation of temperature and strain-rate-dependent plasticity parameters, in literature, has some major shortcomings, which have been addressed in this work. In addition, a new optimization-based procedure has been developed to evaluate all nine plasticity and damage parameters, which uses results of combined finite element analysis and experimental data. The procedure has been validated extensively by testing tensile specimens at different temperatures, by testing notched tensile specimens of different notch radii, and by carrying out high strain-rate tests using a split Hopkinson pressure bar test setup. The parameters of the Johnson–Cook material model, evaluated in this work, have been used in finite element analysis to simulate load-displacement behavior and fracture strains of various types of specimens, and the results have been compared with experimental data in order to check the accuracy of the parameters. The procedure developed in this work shall help the researchers to adopt such a technique for accurate estimation of both plasticity and damage parameters of different types of material models.
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(This article belongs to the Topic Multi-scale Modeling and Optimisation of Materials)
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Open AccessReview
[MxLy]n[MwXz]m Non-Perovskite Hybrid Halides of Coinage Metals Templated by Metal–Organic Cations: Structures and Photocatalytic Properties
by
Piotr W. Zabierowski
Solids 2025, 6(1), 6; https://doi.org/10.3390/solids6010006 - 8 Feb 2025
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This review provides an analysis of non-perovskite hybrid halides of coinage metals templated by metal–organic cations (CCDC November 2023). These materials display remarkable structural diversity, from zero-dimensional molecular complexes to intricate three-dimensional frameworks, allowing fine-tuning of their properties. A total of 208 crystal
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This review provides an analysis of non-perovskite hybrid halides of coinage metals templated by metal–organic cations (CCDC November 2023). These materials display remarkable structural diversity, from zero-dimensional molecular complexes to intricate three-dimensional frameworks, allowing fine-tuning of their properties. A total of 208 crystal structures, comprising haloargentates, mixed-metal haloargentates, and halocuprates, are categorized and examined. Their potential in photocatalysis is discussed. Special attention is given to the structural adaptability of these materials for the generation of functional interfaces. This review highlights key compounds and aims to inspire further research into optimizing hybrid halides for advanced technological applications.
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Open AccessArticle
Mechanochemical Synthesis of High-Entropy Layered Double Hydroxide MgCoNi/AlFeY
by
Olga Kokoshkina, Maksim Yapryntsev and Olga Lebedeva
Solids 2025, 6(1), 5; https://doi.org/10.3390/solids6010005 - 2 Feb 2025
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In the present study, the possibility of synthesizing high-entropy hexacationic layered double hydroxide MgCoNi/AlFeY via mechanochemical synthesis was demonstrated. In the synthesis, the activation rate, activation time, and NaOH amount were varied. The main synthesis stages were as follows: the mechanical activation of
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In the present study, the possibility of synthesizing high-entropy hexacationic layered double hydroxide MgCoNi/AlFeY via mechanochemical synthesis was demonstrated. In the synthesis, the activation rate, activation time, and NaOH amount were varied. The main synthesis stages were as follows: the mechanical activation of salts, NaOH addition, washing with distilled water before achieving neutral pH, and drying at 100 °C. The stage of aging in aqueous solution was omitted. During the synthesis, the activation conditions were varied, the activation time ranged from 1 to 120 min, the rotation speed of the ball mill was changed from 200 to 400 rpm, and the ratio values of sodium hydroxide weight to the mass of cations were specified as 1.0, 1.5, or 2.0. The samples were characterized by X-ray diffraction, transmission electron microscopy, scanning electron microscopy combined with an energy-dispersive analyzer, thermal analysis, Fourier transform infrared spectroscopy, and Raman spectroscopy. The following optimal synthesis conditions for obtaining single-phase sample were determined: an activation rate of 300 rpm, an activation time of 30 min, and an m(cation)-to-m(NaOH) ratio of 1:1.
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Open AccessArticle
About the Rare-Earth Metal(III) Bromide Oxoarsenates(III) RE5Br3[AsO3]4 with A- (RE = La and Ce) or B-Type Structure (RE = Pr, Nd, Sm–Tb) and RE3Br2[AsO3][As2O5] (RE = Y, Dy–Yb)
by
Ralf J. C. Locke, Florian Ledderboge, Felix C. Goerigk, Frank C. Zimmer and Thomas Schleid
Solids 2025, 6(1), 4; https://doi.org/10.3390/solids6010004 - 15 Jan 2025
Cited by 1
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The monoclinic rare-earth metal(III) bromide oxoarsenates(III) RE5Br3[AsO3]4 of the A-type (RE = La and Ce) crystallize in the space group C2/c with the lattice parameters a = 1834.67(9) pm, b = 553.41(3) pm,
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The monoclinic rare-earth metal(III) bromide oxoarsenates(III) RE5Br3[AsO3]4 of the A-type (RE = La and Ce) crystallize in the space group C2/c with the lattice parameters a = 1834.67(9) pm, b = 553.41(3) pm, c = 1732.16(9) pm and β = 107.380(3)° for La5Br3[AsO3]4 and a = 1827.82(9) pm, b = 550.67(3) pm, c = 1714.23(9) pm and β = 107.372(3)° for Ce5Br3[AsO3]4 with Z = 4, while, for the B-type (RE = Pr, Nd and Sm–Tb), they prefer the space group P2/c with lattice parameters from a = 881.23(5) pm, b = 547.32(3) pm, c = 1701.14(9) pm and β = 90.231(3)° for Pr5Br3[AsO3]4 to a = 875.71(5) pm, b = 535.90(3) pm, c = 1643.04(9) pm and β = 90.052(3)° for Tb5Br3[AsO3]4 with Z = 2. The closely related rare-earth metal(III) bromide oxoarsenates(III) RE3Br2[AsO3][As2O5] crystallize in the triclinic space group P with lattice parameters from a = 539.15(4) pm, b = 870.68(6) pm, c = 1092.34(8), α = 90.661(2)°, β = 94. 792(2)° and γ = 90.223(2)° for Dy3Br2[AsO3][As2O5] to a = 533.56(4) pm, b = 869.61(6) pm, c = 1076.70(8), α = 90.698(2)°, β = 94.785(2)° and γ = 90.053(2)° for Yb3Br2[AsO3][As2O5] with Z = 2. All three structures have the same building units with [REO8]13− and [REO4Br4]9− polyhedra as well as isolated ψ1-tetrahedral [AsO3]3− anions in common, with the exception that, in the latter two, ψ1-[AsO3]3− tetrahedra linked by a corner form a pyroanionic [As2O5]4− entity. A- and B-type differ in the stacking sequence of their {[(RE3)O (Br1) (Br2) ]6.5−} layers. While the former have an ABC sequence, the latter exhibit an AAA variant. In the triclinic structures, the (RE3)3+ sites are thinned out, while the As3+ sites are simultaneously enriched, resulting in the mentioned condensed units.
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Open AccessArticle
In-Situ Cure-Induced Strain Measurements Using Optical Fiber Bragg Gratings for Residual Stress Determinations in Thermosets
by
Lars P. Mikkelsen, Jesper K. Jørgensen, Ulrich A. Mortensen and Tom L. Andersen
Solids 2025, 6(1), 3; https://doi.org/10.3390/solids6010003 - 9 Jan 2025
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A small experimental setup for in-situ measurement of the load-transferring strains during the curing process of thermosets is proposed. Combining the output from an unconstrained and a kinematically constrained setup, it is possible to design a cure profile for the first time, lowering
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A small experimental setup for in-situ measurement of the load-transferring strains during the curing process of thermosets is proposed. Combining the output from an unconstrained and a kinematically constrained setup, it is possible to design a cure profile for the first time, lowering the residual stresses in the final product while keeping the cure time short based on the output from a few simple experiments. The stress relaxation during the curing process under a kinetically constrained condition is accounted for by comparing the final cure-induced strain during a kinetically unconstrained and constrained cure experiment. The constrained polymer is curing between two laminates where the constraining layer is removed after finalizing the cure profile, making it possible to measure the final cure-induced strain for that case as well. The temperature at which the load-transferring point is reached is found to be a key process parameter from which the final cure-induced strains can be predicted for the unconstrained case. From the corresponding constrained cure experiments, the final residual stresses can be measured.
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Open AccessArticle
Impact of Vanadium and Zirconium Contents on Properties of Novel Lightweight Ti3ZryNbVx Refractory High-Entropy Alloys
by
Noura Al-Zoubi, Amer Almahmoud and Abdalla Obeidat
Solids 2025, 6(1), 2; https://doi.org/10.3390/solids6010002 - 2 Jan 2025
Cited by 2
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This research explores the physical properties of refractory high-entropy alloys Ti3ZryNbVx (0.5 ≤ x ≤ 3.5; 1 ≤ y ≤ 2), utilizing the first-principles exact muffin-tin orbitals method, in addition to the coherent potential approximation. We examine the
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This research explores the physical properties of refractory high-entropy alloys Ti3ZryNbVx (0.5 ≤ x ≤ 3.5; 1 ≤ y ≤ 2), utilizing the first-principles exact muffin-tin orbitals method, in addition to the coherent potential approximation. We examine the atomic size difference (δ), the valence electron concentration (VEC) and the total energy of the body-centered cubic (bcc), the face-centered cubic (fcc) and the hexagonal close-packed (hcp) lattices, revealing a disordered solid solution with a bcc lattice as the stable phase of these alloys. The stability of the bcc Ti3ZryNbVx alloys increases with the addition of vanadium, and slightly decreases with increasing Zr concentration. All the investigated RHEAs have densities less than 6.2 g/cm3. Adding V to the Ti-Zr-Nb-V system reduces the volume and slightly enhances the density of the studied alloys. Our results show that increasing V content increases the tetragonal shear modulus C′, which assures that V enhances the mechanical stability of the bcc phase, and also increases the elastic moduli. Moreover, all the examined alloys are ductile. Vickers hardness and bond strength increase as V concentration increases. In contrast, decreasing Zr content reduces the density and increases the hardness and the bond strength of the present RHEAs, potentially resulting in systems with desirable mechanical properties and lower densities. These findings provide theoretical insights into the behavior of RHEAs, and emphasize the necessity for additional experimental investigations.
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Open AccessArticle
A Quaternary Solid Dispersion System for Improving the Solubility of Olaparib
by
Tae-Han Yun, Jeong-Gyun Lee, Kyu-Ho Bang, Jung-Hyun Cho and Kyeong-Soo Kim
Solids 2025, 6(1), 1; https://doi.org/10.3390/solids6010001 - 2 Jan 2025
Abstract
To improve the low solubility of poorly water soluble olaparib, in the following study, we prepared olaparib-loaded quaternary solid dispersions with hypromellose, Tween 20 or Labrasol, and colloidal silica. The solubility of olaparib with various types of surfactants was evaluated to select the
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To improve the low solubility of poorly water soluble olaparib, in the following study, we prepared olaparib-loaded quaternary solid dispersions with hypromellose, Tween 20 or Labrasol, and colloidal silica. The solubility of olaparib with various types of surfactants was evaluated to select the most suitable surfactant to effectively enhance its solubility, and subsequently, olaparib-loaded quaternary solid dispersions were prepared through spray drying. The physicochemical properties of the prepared olaparib-loaded quaternary solid dispersions were investigated using scanning electron microscopy, flowability, powder X-ray diffraction, and Fourier-transform infrared spectroscopy. The particle size of the olaparib-loaded quaternary solid dispersions was smaller and more spherical compared to the olaparib drug powder and maintained an amorphous state, and olaparib exhibited no intermolecular interactions with other excipients within the solid dispersion. Additionally, they exhibited enhanced flow properties compared to the olaparib drug powder. The results of subsequent kinetic solubility tests and dissolution tests demonstrated that the surfactant influenced the enhancement of the solubility and drug release of olaparib. Therefore, olaparib-loaded quaternary solid dispersions, characterized by enhanced solubility, will be beneficial for the oral delivery of poorly soluble olaparib.
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(This article belongs to the Special Issue Amorphous Materials: Fabrication, Properties, and Applications)
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Open AccessArticle
Assessment of the Additive Fabrication Quality of Sandwich Structures with Novel Triply Periodic Minimal Surface Cores
by
Alexandru Vasile, Dan Mihai Constantinescu, Iulian Constantin Coropețchi, Ștefan Sorohan and Dragoș Alexandru Apostol
Solids 2024, 5(4), 665-680; https://doi.org/10.3390/solids5040045 - 11 Dec 2024
Cited by 1
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Triply periodic minimal surface (TPMS) structures raised significant interest in several areas of research due to their unique properties and broad range of applications. The aim of the paper is to verify if such complex metamaterials can be fabricated effectively without defects that
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Triply periodic minimal surface (TPMS) structures raised significant interest in several areas of research due to their unique properties and broad range of applications. The aim of the paper is to verify if such complex metamaterials can be fabricated effectively without defects that could compromise their mechanical response. An implicit modeling approach was used to generate eight novel TPMS structures and one stochastic topology. Multiple specimens were fabricated from a photopolymeric resin using a stereolithography (SLA) technique, and an analysis of the manufactured samples was carried out in terms of surface quality, dimensional and mass deviations, and internal porosity of the material. Laser scanning showed no significant deviations from the designed geometry but highlighted errors during the post-processing stages of manufacturing. Surface analysis resulted in an average roughness of 2.47 µm, a value specific to well-controlled additive manufacturing (AM) techniques. A microscopic examination portrays common types of defects, while an ultrasonic non-destructive inspection method showed no indication of defects in the depth of the samples. Sectioning the samples through water jet cutting exposed interior surfaces with better homogeneity than the exterior ones and the absence of a layer-by-layer aspect. Overall, the samples displayed no major defects and good accuracy, with minor inconsistencies and methods of mitigating them having been presented.
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Open AccessArticle
The Effect of Nitrogen as a Co-Dopant in p-Type NiO:Nb Films on the Photovoltaic Performance of NiO/TiO2 Transparent Solar Cells
by
Chrysa Aivalioti, Maria Androulidaki, Katerina Tsagaraki, Emmanouil G. Manidakis, Charidimos Koliakoudakis, Nikolaos T. Pelekanos, Mircea Modreanu and Elias Aperathitis
Solids 2024, 5(4), 651-664; https://doi.org/10.3390/solids5040044 - 7 Dec 2024
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Doping engineering has been applied in niobium-doped NiO (NiO:Nb) by adding nitrogen (N) in its structure. The rf-sputtered films were made from a Ni-Nb composite target on unheated substrates at 300 W rf power and 5 mTorr total pressure. The plasma contained 50%
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Doping engineering has been applied in niobium-doped NiO (NiO:Nb) by adding nitrogen (N) in its structure. The rf-sputtered films were made from a Ni-Nb composite target on unheated substrates at 300 W rf power and 5 mTorr total pressure. The plasma contained 50% Ar and 50% O2 for the fabrication of the single-doped NiO:Nb film (AΝ film), and N2 gas for the incorporation of N in the Ni-O-Nb structure. The N2 in plasma was introduced by keeping constant the flow rates of O2 and N2 gasses (O2/N2 = 1) and reducing the amount of Ar gas, namely 94% Ar, 3% O2, and 3% N2 (film AN1); 50% Ar, 25% O2, and 25% N2 (film AN2); and 6% Ar, 47% O2, and 47% N2 (film AN3). All films had the single phase of cubic NiO and both Nb and N in the Ni-O structure were revealed by XPS experiments. The roughness of the films was increased with the increase in N in plasma. Post-deposition thermal treatment improved the crystallinity and reduced the structural disorder of the films. The AN2 film was found to be the most transparent of all films, exhibiting the widest band gap, 3.72 eV, and the narrowest Urbach tail states’ width, 313 meV. The AN and the AN2 films were employed to form NiO/TiO2 heterostructures. The NiO:Nb/TiO2 and NiO:(Nb,N)/TiO2 heterostructures exhibited a visible transmittance of around 42% and 75%, respectively, and both showed rectification properties. Upon illumination with UV light, the NiO:(Nb,N)/TiO2 diode exhibited enhanced photovoltaic performance when compared to the NiO:Nb/TiO2 solar cell: the short-circuit current densities were 0.2 mA/cm2 versus 1.4 μA/cm2 and the open-circuit voltages were 0.5 V versus 0.2 V. The output characteristics of the p-NiO:(Nb,N)/n-TiO2 UV photovoltaics can be further improved by proper engineering of the individual layers and device processing procedures.
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Photoproduction of Loop Currents in Coronene Isomers Without Any Applied Magnetic Field
by
Jun Ohara and Shoji Yamamoto
Solids 2024, 5(4), 640-650; https://doi.org/10.3390/solids5040043 - 6 Dec 2024
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Applying an extended Peierls–Hubbard model to electrons in a coronene isomer, we investigate their ground-state properties and photoinduced dynamics with particular interest in possible loop current states. Once we switch on a static magnetic field perpendicular to the coronene disk, diamagnetic (diatropic)
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Applying an extended Peierls–Hubbard model to electrons in a coronene isomer, we investigate their ground-state properties and photoinduced dynamics with particular interest in possible loop current states. Once we switch on a static magnetic field perpendicular to the coronene disk, diamagnetic (diatropic) and paramagnetic (paratropic) loop currents appear on the rim circuit and inner hub, respectively. Besides this well-known homocentric two-loop current state, heterocentric multiloop current states can be stabilized by virtue of possible electron–lattice coupling. These multiloop current states generally have a larger diamagnetic moment than the conventional two-loop one, and hence it follows that coronene, or possibly polycyclic conjugated hydrocarbons in general, may become more aromatic than otherwise with their electrons being coupled to phonons. When we photoirradiate a ground-state coronene isomer without applying a static magnetic field, loop currents are induced in keeping with the incident light polarization. Linearly and circularly polarized lights induce heterocentric two-loop and multiloop currents, respectively, without and together with two homocentric loop currents of the conventional type, respectively. The heterocentric two-loop currents occur in a mirror-symmetric manner, which reads as the emergence of a pair of antiparallel magnetic moments, whereas the heterocentric multiloop ones appear at random in both space and time, which reads as the emergence of disordered local magnetic moments.
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Open AccessArticle
Unexpected Polymerization of Carbamate-Bridged {Al3(μ3−O)}7+ Complex Units
by
Erik Schumann, Erica Brendler, Uwe Böhme and Florian Mertens
Solids 2024, 5(4), 626-639; https://doi.org/10.3390/solids5040042 - 4 Dec 2024
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The literature on aluminum coordination networks so far contains data on COO-bridged derivatives exclusively. This paper addresses the question whether or not aluminum complexes, especially carbamate-bridged {Al3( 3−O)}7+ units, can also form networks via the neutral ligand positions.
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The literature on aluminum coordination networks so far contains data on COO-bridged derivatives exclusively. This paper addresses the question whether or not aluminum complexes, especially carbamate-bridged {Al3( 3−O)}7+ units, can also form networks via the neutral ligand positions. Our findings show that a highly unexpected polymerization of the aluminum carbamates can occur during the isolation of the initially targeted compound. Although bidentate ligands bind to the neutral ligand coordination sites as expected, they do not act as linker molecules but cause an uncontrolled networking via the carbamate ligands. One- and two-dimensional solution and solid-state NMR experiments were primarily used to investigate the coordination behavior of the ligands and to elucidate the actual obtained product.
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