jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: H. K. Ram
Source: Journal of Advances and Scholarly Researches in Allied Education (article, 2024-07-01)
Field: Materials Science — Materials Chemistry

A Study of Plasmonic Nanostructures for Enhanced Photovoltaic Performance in Quantum dot Solar Cells Quantum Dot (QD) Solar Cells have emerged as promising candidates for next-generation photovoltaic technologies due to their tunable bandgaps, solution processability, and potential for low-cost fabrication. However, their photovoltaic performance is often limited by factors such as low light absorption and charge carrier recombination. Plasmonic nanostructures, which exploit the resonant oscillation of conduction electrons in metallic nanoparticles, offer a viable strategy to enhance light absorption and improve charge carrier dynamics in QD solar cells. This paper reviews the integration of plasmonic nanostructures with QD solar cells, examining the mechanisms by which plasmonics can enhance photovoltaic performance. We discuss various types of plasmonic materials, their configurations within solar cell architectures, and the resultant improvements in efficiency. Additionally, the challenges and future prospects of plasmonic-enhanced QD solar cells are explored. Quantum dot ; Photovoltaic system ; Plasmon ; Optoelectronics ; Nanostructure ; Materials science ; Quantum dot solar cell ; Nanotechnology ; Solar cell ; Physics ; Polymer solar cell ; Engineering ; Electrical engineering Quantum Dots Synthesis And Properties ; Chalcogenide Semiconductor Thin Films
Authors: Carlos V. M. Inocêncio | Almudena Torres‐Pardo | David Montero | Lucien Roach | Pierre‐Olivier Autran | Capucine Sassoye | Cyril Aymonier | Áurea Varela | M. Parras | Christel Laberty‐Robert | David Portehault
Source: ChemRxiv (preprint, 2024-12-12)
Field: Materials Science — Materials Chemistry

Crystallization of manganese (V) oxides by hydroflux synthesis: Control of anisotropic growth and electrochemical stability Despite intriguing optical, magnetic, and redox properties, inorganic materials containing pentavalent manganese (Mn5+) are rare and could never be designed as shape-controlled crystals, which limits the ability to tune properties. Herein, we explore alkali hydroxide mixtures with controlled water content, namely hydrofluxes, to demonstrate phase, shape, and nanostructure control of Mn(V) oxides. We demonstrate speciation among KSrMnVO4, Sr5(MnVO4)3OH, and SrMnIVO3 with the water content, the strontium content, and the nature of the alkali cation of the hydroxide salt. We then provide evidence of the key role of water in enabling shape and nanostructure control, which we relate to the preferential interaction of water with specific crystal facets of the hydroxyapatite Sr5(MnVO4)3OH, and to the impact of water on precursor solubility in water-poor hydrofluxes. We then show that nanostructured Mn(V) hydroxyapatite possesses an acid-base redox stability window enabling electrochemical operation in strongly oxidative conditions. By correlating fundamental knowledge of hydrofluxes with crystallization mechanisms, this work sheds light on the possibilities offered by hydrofluxes for crystal shape, size and property control. Crystallization ; Electrochemistry ; Hydroxide ; Manganese ; Materials science ; Alkali metal ; Strontium ; Nanostructure ; Chemical engineering ; Redox ; Crystal growth ; Solubility ; Crystal (programming language) ; Metal hydroxide ; Inorganic chemistry ; Nanotechnology ; Chemistry ; Crystallography ; Electrode ; Physical chemistry ; Organic chemistry ; Metallurgy Catalytic Processes in Materials Science ; Iron oxide chemistry and applications ; Catalysis and Oxidation Reactions
Authors: Yong Rui Poh | Joel Yuen-Zhou
Source: ChemRxiv (preprint, 2024-02-07)
Field: Chemistry — Electrochemistry

Physico-chemical principles of AC electrosynthesis Electrolysis integrates renewable energy into chemical manufacturing and is key towards sustainable chemistry. Controlling the waveform beyond direct current addresses the long-standing obstacle of chemoselectivity, yet it also expands the parameter set to optimise, creating a demand for theoretical predictions. Here, we report the first analytical theory for predicting chemoselectivity in alternating current electrosynthesis. The mechanism is a selective reversal of the unwanted redox reaction during periods of opposite polarity. Notably, we find regimes within which a square waveform can not only bias but also reverse the chemoselectivity compared to direct current approaches, favouring overoxidation/overreduction. Sinusoidal waves exhibit the opposite effect. These trends are consistent with existing experimental works. Therefore, we find alternating current to be a promising avenue for achieving the ultimate control over reaction pathways. Chemoselectivity ; Electrosynthesis ; Waveform ; Electrolysis ; Computer science ; Current (fluid) ; Renewable energy ; Alternating current ; Chemistry ; Biochemical engineering ; Nanotechnology ; Materials science ; Electrical engineering ; Power (physics) ; Physics ; Engineering ; Electrochemistry ; Telecommunications ; Electrode ; Organic chemistry ; Catalysis Electrochemical Analysis and Applications ; Radical Photochemical Reactions ; Electrocatalysts for Energy Conversion
Authors: Geraudys Mora-Barzaga | E. N. Miranda | Eduardo M. Bringa
Source: Journal of Applied Physics (article, 2024-11-04)
Field: Materials Science — Materials Chemistry

Plasticity tuning of thermal conductivity between nanoparticles We study the effects of uniaxial pressure on the thermal conductivity between two nanoparticles using atomistic simulation. While the system is compressed, we analyze the evolution of contact area, the relative density, and the dislocation density. Lattice thermal conductivity is calculated by non-equilibrium molecular dynamics simulations at several stages of the compression. Despite the increment of dislocation defects, thermal conductivity increases with pressure due to the increase in relative density and contact radius. The behavior of the contact radius is compared with the Johnson–Kendall–Roberts (JKR) model. While there is good agreement at low strain, after significant plasticity, signaled by the emission of dislocations from the contact region, the discrepancy with JKR grows larger with the dislocation density. The results for thermal conductivity show good agreement with previous studies at zero strain, and a theoretical model is used to accurately explain its behavior vs strain-dependent contact radius. Both the Kapitza resistance and thermal resistance decrease with strain but with very different evolution. Simulations of a bulk sample under uniaxial strain were also carried out, allowing for a clear distinction between the role of compressive stress, which increases the conductivity, vs the role of dislocations, which decrease the conductivity. For the NP system, there is the additional role of contact area, which increases with stress and also modifies conductivity. An analytical model with a single free parameter allows for a description of all these effects and matches both our bulk and NP simulation results. Thermal conductivity ; Nanoparticle ; Materials science ; Plasticity ; Conductivity ; Electrical resistivity and conductivity ; Nanotechnology ; Composite material ; Chemistry ; Physics ; Physical chemistry Thermal properties of materials ; Carbon Nanotubes in Composites ; Composite Material Mechanics
Authors: Jiaxin Liao | Lin Chen | Luyang Zhang | Xunlei Chen | Cheng Xu | Tianyu Li | Jing Feng
Source: Coatings (article, 2024-08-31)
Field: Materials Science — Materials Chemistry

Regulations of Thermal Expansion Coefficients of Yb1−xAlxTaO4 for Environmental Barrier Coatings Applications Environmental barrier coatings (EBCs) are widely used to protect ceramic matrix composites (CMCs, SiCf/SiC, and Al2O3f/Al2O3), and they should have low thermal expansion coefficients (TECs) matching the CMCs and excellent mechanical properties to prolong their lifetime. Current EBC materials have disadvantages of phase transitions and insufficient mechanical properties, which affect their working temperatures and lifetime. It is necessary to develop new oxide EBCs. Ytterbium tantalate (YbTaO4) is a stable and novel EBC material, and we have improved the mechanical properties and TECs of Yb1−xAlxTaO4 (x = 0.05, 0.1, 0.2, 0.3, 0.4, 0.5) ceramics by replacing Yb with Al. XRD, SEM, and EDS are used to verify the crystal and microstructures, and nano-indentation is used to measure the modulus and hardness when changes in TECs are measured within a thermal expansion device. The results show that the phase structure of Yb1−xAlxTaO4 (x = 0.05, 0.1, 0.2, 0.3, 0.4, 0.5) is stable at 25–1400 °C within air atmosphere, and their high-temperature TECs (6.4–8.9 × 10−6 K−1, 1400 °C) are effectively regulated by introductions of different contents of Al, which enlarge their engineering applications for SiCf/SiC and Al2O3f/Al2O3 CMCs. The evolutions of TECs are analyzed from structural characteristics and phase compositions, and the increased TECs make Yb1−xAlxTaO4 potential EBCs for Al2O3 matrixes. Due to the high bonding strength of Al–O bonds, hardness, as well as Young’s modulus, are enhanced with the increasing Al content, with Yb1−xAlxTaO4 (x = 0.05, 0.1, 0.2, 0.3, 0.4, 0.5) having a nano-hardness of 3.7–12.8 GPa and a Young’s modulus of 100.9–236.6 GPa. The TECs of YbTaO4 are successfully regulated to expand their applications, and they match those of Al2O3 and SiC matrixes, as well as displaying improved mechanical properties. This work promotes applications of YbTaO4 as potential EBCs and provides a new way to regulate the TECs of tantalates. Thermal expansion ; Environmental science ; Materials science ; Engineering physics ; Engineering ; Composite material Nuclear materials and radiation effects ; Advanced ceramic materials synthesis ; Microwave Dielectric Ceramics Synthesis
Authors: Jan Berger | Stephanie Terruzzi | Hana Bunzen | Marcello Marelli | Luca Braglia | Roland A. Fischer | Valentina Colombo | Gregor Kieslich
Source: ChemRxiv (preprint, 2024-03-26)
Field: Chemistry — Inorganic Chemistry

CO2 and Temperature Induced Switching of a Flexible Metal-Organic Framework with Surface-Mounted Nanoparticles The stimuli responsiveness of a material defines its potential application. Within the class of metal-organic frameworks (MOFs) the subclass of flexible MOFs (flexMOFs) has attracted great attention, showing large structural flexibility as a response to external stimuli such as guest adsorption, temperature, and pressure. Derived hybrid composites like nanoparticle (NP) loaded flexible MOFs, which stand to potentially combine advantageous properties of both are yet largely unexplored. Here we report the synthesis of flexible MOFs with surface mounted nanoparticles, e. g. NP@Zn2(BME-bdc)2dabco composites (NP = Pt and SiO2 nanoparticles, BME-bdc2- = 2,5-bismethoxyethoxy-1,4-benzenedicarboxylate, dabco = 1,4-diazabicyclo[2.2.2]octane), studying the impact of nanoparticles on the stimulus-responsiveness of a flexible MOF. We show that CO2 physisorption triggered flexibility of the MOF is fully retained and reversible for all NP@flexMOF composites. Additionally, we observe that NPs stabilize the large pore state of the MOF, slightly increasing and shifting the switching pressure window. This effect is also observed during temperature-induced switching but Pt@flexMOF composites partially lose long-range order during the reversion to their narrow pore state, while attached SiO2 NPs allow for a fully reversible transition. These findings suggest that the total exerted material strain triggering the switching is heavily dependent on NP size and the applied stimulus and that guest-induced switchability can be fully realized in NP@flexMOF hybrid materials. Nanoparticle ; Materials science ; Surface (topology) ; Metal-organic framework ; Metal ; Nanotechnology ; Chemical engineering ; Composite material ; Metallurgy ; Chemistry ; Engineering ; Adsorption ; Organic chemistry ; Geometry Metal-Organic Frameworks: Synthesis and Applications ; Graphene research and applications ; Supramolecular Self-Assembly in Materials
Authors: Ye Cao | Hongxing Song | Xiaozhen Yan | Hao Wang | Yufeng Wang | Fengchao Wu | Leilei Zhang | Qiang Wu | Huayun Geng
Source: Physical Chemistry Chemical Physics (article, 2024-01-01)
Field: Materials Science — Materials Chemistry

Theoretical study of the structural and thermodynamic properties of U–He compounds under high pressure Uranium is considered as a very important nuclear energy material because of the huge amount of energy it releases. As the main product of the spontaneous decay of uranium, it is difficult for helium to react with uranium because of its chemical inertness. Therefore, bubbles will be formed inside uranium, which could greatly reduce the performance of uranium or cause safety problems. Additionally, nuclear materials are usually operated in an environment of high-temperature and high-pressure, so it is necessary to figure out the exact state of helium inside uranium under extreme conditions. Here, we explored the structural stability of the U-He system under high pressure and high temperature by using density functional theory calculations. Two metastable phases are found between 50 and 400 GPa: U<sub>4</sub>He with space group <i>Fmmm</i> and U<sub>6</sub>He with space group <i>P</i>1̄. Both are metallic and adopt layered structures. Electron localization function calculation combined with charge density difference analysis indicates that there are covalent bonds between U and U atoms in both <i>Fmmm</i>-U<sub>4</sub>He and <i>P</i>1̄-U<sub>6</sub>He. Regarding the elastic modulus of α-U, the addition of helium has certain influence on the mechanical properties of uranium. Besides, first-principles molecular dynamics simulations were carried out to study the dynamical behavior of <i>Fmmm</i>-U<sub>4</sub>He and <i>P</i>1̄-U<sub>6</sub>He at high-temperature. It was found that <i>Fmmm</i>-U<sub>4</sub>He and <i>P</i>1̄-U<sub>6</sub>He undergo one-dimensional superionic phase transitions at 150 GPa. Our study revealed the exotic structure of U-He compounds beyond the formation of bubbles under high-pressure and high-temperature, which might be relevant to the performance and safety issues of nuclear materials under extreme conditions. Uranium ; Metastability ; Helium ; High pressure ; Thermodynamics ; Chemistry ; Nuclear fuel ; Enriched uranium ; Equation of state ; Density functional theory ; Allotropy ; Nuclear engineering ; Materials science ; Physics ; Nuclear chemistry ; Metallurgy ; Computational chemistry ; Phase (matter) ; Phase diagram Nuclear Materials and Properties ; High-pressure geophysics and materials ; Rare-earth and actinide compounds
Authors: Yong Rui Poh | Joel Yuen-Zhou
Source: ChemRxiv (preprint, 2024-02-06)
Field: Chemistry — Electrochemistry

Physico-chemical principles of AC electrosynthesis Electrolysis integrates renewable energy into chemical manufacturing and is key towards sustainable chemistry. Controlling the waveform beyond direct current addresses the long-standing obstacle of chemoselectivity, yet it also expands the parameter set to optimise, creating a demand for theoretical predictions. Here, we report the first analytical theory for predicting chemoselectivity in alternating current electrosynthesis. The mechanism is a selective reversal of the unwanted redox reaction during periods of opposite polarity. Notably, we find regimes within which a square waveform can not only bias but also reverse the chemoselectivity compared to direct current approaches, favouring overoxidation/overreduction. Sinusoidal waves exhibit the opposite effect. These trends are consistent with existing experimental works. Therefore, we find alternating current to be a promising avenue for achieving the ultimate control over reaction pathways. Chemoselectivity ; Electrosynthesis ; Waveform ; Electrolysis ; Current (fluid) ; Renewable energy ; Alternating current ; Chemistry ; Computer science ; Biochemical engineering ; Nanotechnology ; Materials science ; Electrical engineering ; Engineering ; Electrochemistry ; Telecommunications ; Electrode ; Organic chemistry ; Catalysis Electrochemical Analysis and Applications ; Radical Photochemical Reactions ; Electrocatalysts for Energy Conversion
Authors: Chihan Meng | Jiachun Zhong | Zejun Pu | Wenhui Wu | Rongli Zhu | Yuhao Yang
Source: Research Square (preprint, 2024-04-29)
Field: Chemistry — Organic Chemistry

Probability Evaluation of the ternary polymerization and reactivity ratio of bio-based PA5T/56 Ternary operation ; Reactivity (psychology) ; Polymerization ; Copolymer ; Thermodynamics ; Monomer ; Polymer chemistry ; Chemistry ; Probabilistic logic ; Materials science ; Mathematics ; Organic chemistry ; Computer science ; Statistics ; Polymer ; Physics Advanced Polymer Synthesis and Characterization ; Injection Molding Process and Properties ; Manufacturing Process and Optimization
Authors: Kelvin Wong | Qi Runzhang | Ye Yang | Zhi Luo | Stefan Guldin | Keith T. Butler
Source: ChemRxiv (preprint, 2024-04-16)
Field: Materials Science — Materials Chemistry

Predicting Colloidal Interaction Parameters from Small Angle X-Ray Scattering Curves using Artificial Neural Networks and Markov Chain Monte Carlo Sampling Small Angle X-Ray Scattering (SAXS) is a characterization technique which allows for the study of colloidal interactions by fitting the structure factor of the SAXS profile for a selected model and closure relation. However, the applicability of this approach is constrained by the limited number of existing models which can be fitted analytically, as well as the narrow operating range for which the models are valid. In this work, we demonstrate a proof-of-concept for using an artificial neural network (ANN) trained on small-angle x-ray scattering (SAXS) curves obtained from Monte Carlo (MC) simulations to predict values of the effective macroion valency (Zeff) and the Debye length (κ) for a given SAXS profile. This ANN, which was trained on 200,000 simulated SAXS curves, was able to predict values of Zeff and κ for a test set containing 25,000 simulated SAXS curves with ±20% accuracy to the ground truth values. Subsequently, an ANN was used as a surrogate model in a Markov Chain Monte Carlo sampling algorithm to obtain maximum a posteriori (MAP), associated confidence intervals estimates and details of correlations of Zeff and κ for an experimentally obtained SAXS profile. Small-angle X-ray scattering ; Monte Carlo method ; Scattering ; Markov chain Monte Carlo ; Small-angle scattering ; Statistical physics ; Metropolis–Hastings algorithm ; Materials science ; Mathematics ; Physics ; Statistics ; Optics Material Dynamics and Properties ; Phase Equilibria and Thermodynamics ; Adsorption, diffusion, and thermodynamic properties of materials
Authors: Xiaozhi Fu | Oriol Gracia Carmona | György Abrusán | Xiang Jiao | Alexander Diaciuc | Mathias Gautel | Franca Fraternali | Aleksej Zelezniak
Source: bioRxiv (Cold Spring Harbor Laboratory) (preprint, 2024-09-11)
Field: Chemistry — Organic Chemistry

Single Distal Mutation Enhances Activity of known PETases via Stabilisation of PET-binding Abstract As a major source of plastic pollution, PET has attracted significant interest for biodegradation due to its potential in the circular economy. Finding effective enzymes still remains a challenge as screening methods are limited by either the low throughput or dependence on alternative non-PET substrates due to PET’s insolubility. Here, we report a highly active, stable and robust enzyme, Fast_2.9, identified while directly screening for PET-degrading activity in mesophilic conditions using droplet-based encapsulation of PET nanoparticles with the throughput above 1 kHz. We identified a distal S269T mutation that improves activity in the majority of all known PETases with up to 400 times over wildtype, and more than twice of known engineered PETases, as tested on untreated post-consumer plastics. Microsecond time scale molecular dynamics analyses indicate that this distant mutation possibly influences residues near the substrate-binding cleft via a common mechanism across PETases. Compared to the state-of-the-art FastPETase and LCC ICCG enzymes, the engineered Fast_2.9 enzyme requires up to 8 and 42 times lower enzyme concentrations to reach the same enzymatic activity, ultimately requiring significantly less enzyme. As such our engineered enzyme degrades multiple post-consumer PET substrates, including polyester textiles, within as least as just 2 days with up to nearly 100% terephthalic acid conversion using as little as 0.72 mg enzyme /g PET at 50℃. Our study presents a universal methodology for direct screening of insoluble substrates at ultra-high-throughput and highlights the techno-economic potential of Fast_2.9 for PET depolymerisation. Mutation ; Chemistry ; Biophysics ; Biology ; Biochemistry ; Gene Click Chemistry and Applications ; Radiopharmaceutical Chemistry and Applications ; Peptidase Inhibition and Analysis
Authors: Sanggeun Song | Donghee Kim | Jingyu Kang | Jonghwa Han | Byung Hyo Kim | Sangwoon Yoon | Sungjee Kim | Taeghwan Hyeon | Jungwon Park | Ji‐Hyun Kim | Jaeyoung Sung
Source: ChemRxiv (preprint, 2024-02-16)
Field: Chemistry — Organic Chemistry

Thermodynamic Origin of Nuclei Seed Formation and Monomer Supply Rate-Dependent Crystallization Dynamics Supersaturation and nucleus seed formation are universal processes that precede all phase transitions. Despite extensive research on nucleation, our understanding on supersaturation, nucleus seed formation and phase transition dynamics remains rudimentary. Here, we present exact statistical thermodynamic formula for the saturation degree, the most-probable size distribution of mesoscopic nuclei, and their phase transition, introducing the mesoscopic state defined by temperature, the total monomer concentration, and the largest cluster size (LCS). These results show that supersaturation emerges even at equilibrium for mesoscopic nuclei systems and decreases with the LCS. The size-distribution of nucleus seeds is either a unimodal or a monotonically decreasing function of size, depending on the system and temperature. There exists a critical supersaturation condition under which nucleus seeds undergo a phase transition, during which the most probable size exhibits an abrupt change. We also investigated nonequilibrium dynamics of supersaturation, nucleus seed formation, and phase transition, accounting for the monomer-supply-rate effects. Nucleus seeds attain either nonequilibrium-steady-state (NESS) or transient-oscillatory-state (TOS) depending on the monomer-supply-rate, before undergoing phase transition. In both NESS and TOS, nuclei assume a quasi-equilibrium size distribution; their population exhibits a universal power-law relaxation during the phase transition. This work can be extended to investigate diverse nucleation and phase transition phenomena prevalent across nature and industry. Crystallization ; Dynamics (music) ; Thermodynamics ; Chemical physics ; Monomer ; Materials science ; Statistical physics ; Chemistry ; Physics ; Polymer Chemical Thermodynamics and Molecular Structure ; Material Dynamics and Properties ; nanoparticles nucleation surface interactions