Materials Today Physics最新文献

{"title":"3D-Ising-type magnetic interactions stabilized by the extremely large uniaxial magnetocrystalline anisotropy in layered ferromagnetic Cr2Te3","authors":"","doi":"10.1016/j.mtphys.2024.101522","DOIUrl":"10.1016/j.mtphys.2024.101522","url":null,"abstract":"<div><p>We investigate the magnetocrystalline anisotropy, critical behavior, and magnetocaloric effect in ferromagnetic-layered Cr₂Te₃. We have studied the critical behavior around the Curie temperature (<em>T</em>_<em>C</em>) using various techniques, including the modified Arrott plot (MAP), the Kouvel-Fisher method (KF), and critical isothermal analysis (CI). The derived critical exponents <em>β</em> = 0.353(4) and <em>γ</em> = 1.213(5) fall in between the three-dimensional (3D) Ising and 3D Heisenberg type models, suggesting complex magnetic interactions by not falling into any single universality class. On the other hand, the renormalization group theory, employing the experimentally obtained critical exponents, suggests 3D-Ising-type magnetic interactions decaying with distance as <em>J</em>(<em>r</em>) = <em>r</em>^−4.89. We also observe an extremely large uniaxial magnetocrystalline anisotropy energy (MAE) of <em>K</em>_<em>u</em> = 2065 kJ/m³, the highest ever found in any Cr_<em>x</em>Te_<em>y</em> based systems, originating from the noncollinear ferromagnetic ground state as predicted from the first-principles calculations. The self-consistent renormalization theory (SCR) suggests Cr₂Te₃ to be an out-of-plane itinerant ferromagnet. Further, a maximum entropy change of -<span><math><mi>Δ</mi><msubsup><mrow><mi>S</mi></mrow><mrow><mi>M</mi></mrow><mrow><mi>max</mi></mrow></msubsup><mo>≈</mo></math></span> 2.08 J/kg − <em>K</em> is estimated around <em>T</em>_<em>C</em> for the fields applied parallel to the <em>c</em>-axis.</p></div>","PeriodicalId":18253,"journal":{"name":"Materials Today Physics","volume":null,"pages":null},"PeriodicalIF":10.0,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141877798","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Generalization of interfacial thermal conductance based on interfacial phonon localization","authors":"","doi":"10.1016/j.mtphys.2024.101516","DOIUrl":"10.1016/j.mtphys.2024.101516","url":null,"abstract":"<div><p>Interfacial energy transport is of great engineering and scientific importance. Traditional theoretical treatment based on phonon reflection and transmission only provides qualitative understanding of the interfacial thermal conductance (<em>G</em>). In the interface region, the material has gradual (covalent) or abrupt (van de Waals) physical structure transition, each transition features interface-region atomic interactions that are different from those of both adjoining sides. This difference makes the interface-region phonons extremely localized. Here, by constructing an “equivalent interfacial medium” (EIM) that accounts for the extremely localized phonon region, <em>G</em> can be described by a universal physical model that is characterized by an “interface characteristic temperature” (<span><math><msub><mi>Θ</mi><mrow><mi>i</mi><mi>n</mi><mi>t</mi></mrow></msub></math></span>) and energy carrier transfer time. The EIM model fits widely reported <em>G</em> ∼ <em>T</em> (<em>T</em>: temperature) data with high accuracy and provides remarkable prediction of <em>G</em> at different temperatures based on 2–3 experimental data points. Under normalized temperature (<em>T</em>/<span><math><msub><mi>Θ</mi><mrow><mi>i</mi><mi>n</mi><mi>t</mi></mrow></msub></math></span><em>)</em> and interfacial thermal conductance (<em>G</em>/<em>G</em>_max), all literature data of <em>G</em> can be universally grouped to a single curve. The EIM model provides a solid correlation between <em>G</em> and interfacial structure and is expected to significantly advance the physical understanding and design of interfacial energy transport toward high-efficiency energy conversion, transport, and micro/nanoelectronics.</p></div>","PeriodicalId":18253,"journal":{"name":"Materials Today Physics","volume":null,"pages":null},"PeriodicalIF":10.0,"publicationDate":"2024-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141732350","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Nonreciprocal wide-angle and narrowband thermal emitter","authors":"","doi":"10.1016/j.mtphys.2024.101515","DOIUrl":"10.1016/j.mtphys.2024.101515","url":null,"abstract":"<div><p>Nonreciprocal thermal radiation allows the violation of Kirchhoff's law, as the spectral directional emissivity and absorptivity at the same angle can be different. Prior research has elucidated that certain optical resonance modes facilitate amplification of nonreciprocity at specific angles or wavelengths. However, achieving nonreciprocal thermal radiation with both wide-angle coverage and narrowband characteristics poses a fundamental yet challenging problem. In this work, we demonstrate a nonreciprocal thermal emitter that achieves both wide-angle and narrowband through a periodic structure composed of magneto-optical materials. With an external magnetic field (<em>B</em> = 3 T or 1 T), the pronounced nonreciprocity arising from the magneto-optical localized resonance mode at 6.52 μm or 7.18 μm facilitates a distinct difference between the emissivity and absorptivity across a wide angular range from near 0°–89°. The robustness of the wide-angle and narrowband nonreciprocal thermal radiation is demonstrated with ±5 % fluctuations in structural parameters. The performance of the nonreciprocity with azimuthal angle <em>ϕ</em> ranging from 0° to 360° is also investigated. This work holds promising potential for applications in thermal management, directional thermal camouflage, high-efficiency thermophotovoltaic systems, and more.</p></div>","PeriodicalId":18253,"journal":{"name":"Materials Today Physics","volume":null,"pages":null},"PeriodicalIF":10.0,"publicationDate":"2024-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141630406","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Self-assembly of Sr2P2O7@2D rGO nano/micro-architecture for highly durable and bendable solid-state supercapattery","authors":"","doi":"10.1016/j.mtphys.2024.101510","DOIUrl":"10.1016/j.mtphys.2024.101510","url":null,"abstract":"<div><p>Metal pyrophosphate-based materials for supercapattery have recently attracted significant research interest due to their high energy density, structural stability, and cyclability. Despite this, the low electric conductivity of such compounds severely limits the rate efficiency of supercapattery. To address this challenge, self-assembly of strontium pyrophosphate (Sr₂P₂O₇) on 2D reduced graphene oxide (rGO) was produced (Sr₂P₂O₇@2D rGO) with varying urea and rGO proportions employing a two-stage procedure: (i) layer-by-layer (LBL) deposition of rGO nanosheets, followed by (ii) a hydrothermal method to produce strontium pyrophosphate (SP) microflakes. The effective integration of conductive rGO with Sr₂P₂O₇ flakes has been verified by structural and morphological investigation, which indicates that rGO nanosheets offer a large number of active sites, high electrical conductivity, and a wide surface area. However, when compared to the other electrodes, the optimized SP/rGO-3 hybrid electrode possesses battery-like properties, with an outstanding specific capacity of 205 mAh/g (738C/g) in 1 M KOH at a current density of 2 A/g and maintains 99 % durability after 10000 cycles. These outcomes imply a synergistically enhanced surface redox charge storage mechanism through the inclusion of rGO (optimal) and the influence of SP nano/microarchitecture, resulting in an extended cycle lifespan and remarkable electrochemical characteristics. Furthermore, a hybrid solid-state (HSS) supercapattery developed by employing SP/rGO-3 as the cathode and rGO as the anode (SP/rGO-3//rGO) achieved a maximum specific (areal) capacity of 189C/g (52 mAh/g, 133 mF cm⁻²), (areal) energy density of 42.04 Wh/kg (47.3 mWh cm⁻²), and a power density of 2755.6 W/kg (3.1 mW cm⁻²). In addition, the HSS device demonstrates remarkable long-term cyclability, retaining 96 % capacity after 10000 cycles. The present research suggests that Sr₂P₂O₇@2D rGO composites have extraordinary electrochemical properties, highlighting their potential as nano/micro-structured electrodes for future energy storage devices.</p></div>","PeriodicalId":18253,"journal":{"name":"Materials Today Physics","volume":null,"pages":null},"PeriodicalIF":10.0,"publicationDate":"2024-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141623943","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fermi energy modulation by tellurium doping of thermoelectric copper(I) iodide","authors":"","doi":"10.1016/j.mtphys.2024.101513","DOIUrl":"10.1016/j.mtphys.2024.101513","url":null,"abstract":"<div><p>Copper(I) iodide (CuI) is the leading inorganic <span><math><mrow><mi>p</mi></mrow></math></span>-type transparent conductor, attracting major attention for its promising optoelectronic properties and facile growth methods, although, commercial uptake is limited due to its as-of-yet insufficient electrical conductivity. Doping CuI with the chalcogens (O, S, Se, Te) is a viable route to tune its electrical conductivity for applications such as in thin film transistors, hole transport layers in solar cells, and transparent thermoelectric generators. The heaviest chalcogen element, Te, is yet to be explored in heavily intrinsically <span><math><mrow><mi>p</mi></mrow></math></span>-type doped CuI at non-alloying concentrations, the subject of the present work. We report the effects of tellurium at the boundary between the doping and alloying regime (up to a maximum of 2.4 % Te) in CuI thin films and investigation the variation in the thermoelectric properties and electronic band structure of the material. Ion implanting tellurium into CuI led to a progressive reduction in the films' work functions from 4.9 eV to 4.5 eV while the ionization potential remained unchanged, measured through photoemission spectrometry. This signified a modulation of the Fermi energy relative to the valence band edge, having a major effect on the materials' electrical conductivity and Seebeck coefficient, the former decreasing by 3 orders of magnitude, while the latter increased by 80 %. We conducted density functional theory (DFT) calculations to elucidate the effect of tellurium doping on the band structure of CuI. Tellurium doping corroborated the shift of Fermi energy, the incorporation of impurity acceptor states deeper into the band gap, in addition to disordering the valence band maximum. This work shows that, the Fermi energy in heavily <span><math><mrow><mi>p</mi></mrow></math></span>-type doped CuI can be moved away from the valence band through Te doping in addition to introducing band disorder, useful for controlling the hosts’ transport properties.</p></div>","PeriodicalId":18253,"journal":{"name":"Materials Today Physics","volume":null,"pages":null},"PeriodicalIF":10.0,"publicationDate":"2024-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141703688","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Reducing oxygen vacancies of MoO3 by polyaniline functionalization for stable and efficient inorganic tri-brominated perovskite solar cells","authors":"","doi":"10.1016/j.mtphys.2024.101514","DOIUrl":"10.1016/j.mtphys.2024.101514","url":null,"abstract":"<div><p>The photovoltaic performance of perovskite solar cells (PSCs) is closely dependent on the efficient carrier extraction and transport at the interface. Here, a polyaniline (PANI) functionalized MoO₃ (PANI/MoO₃) hole transport material (HTM) is exploited to perfect the interface between the perovskite layer and carbon electrode in all-inorganic CsPbBr₃ PSCs. After functionalization with PANI, the p-type behavior and the hole mobility and conductivity of MoO₃ are improved by reducing the oxygen vacancies, which boosts the hole extraction and transport, energy level arrangement at the interface of CsPbBr₃ perovskite/(PANI/MoO₃) HTM. Meanwhile, the PANI/MoO₃ with rich C–N and N–H groups introduced by PANI passivates the ions trap states of perovskite films by the C–N⋯Pb²⁺ (Cs⁺) Lewis acid-base coordination and the N–H⋯Br⁻ hydrogen bonding, leading to an effective suppression of non-radiative recombination for improved carrier extraction. As a result, the PANI/MoO₃ HTMs-based CsPbBr₃ PSCs obtain a remarkably increased power conversion efficiency of 10.41 %, in comparison with the efficiency of the original device (6.55 %). In addition, the unencapsulated device with PANI/MoO₃ HTMs shows excellent long-term stability with 93.9 % maintenance of the initial efficiency after storing in air with 85 % relative humidity and at 85 °C for 30 days.</p></div>","PeriodicalId":18253,"journal":{"name":"Materials Today Physics","volume":null,"pages":null},"PeriodicalIF":10.0,"publicationDate":"2024-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141623974","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Enhanced visible light harvesting in dye-sensitized solar cells through incorporation of solution-processable silver plasmons and anthracite-derived graphene quantum dots","authors":"Akshatha A. Rao,&nbsp;Santhosh Narendhiran,&nbsp;Manoj Balachandran","doi":"10.1016/j.mtphys.2024.101512","DOIUrl":"https://doi.org/10.1016/j.mtphys.2024.101512","url":null,"abstract":"<div><p>The major setback for the enhanced performance of DSSC is the narrow absorption window and the interfacial exciton recombination. Therefore, in this work, the photovoltaic performance of dye-sensitized solar cells has been improved by the synergistic effect of anthracite-derived graphene quantum dots and silver plasmons. GQD and Ag coupled photoanodes were fabricated by a facile solution processable process under room temperature. The as-fabricated DSSC TiO₂/Ag/GQD (TAG) exhibited an enhanced power conversion efficiency of 10.5 % with a current density of 22.40 mAcm⁻² measured under solar irradiation of 100 mWcm⁻² with AM 1.5G. An enhancement surpassing 30.5 % was obtained for the champion cell when compared to the pristine TiO₂ based DSSC. Furthermore, this study emphasizes developing a cutting-edge approach for the high-quality use of fossil fuel-derived graphene quantum dots in energy conversion systems, thereby encouraging the green conversion of fossil fuels and broadening the potential of anthracite coal's utilization in energy conversion applications.</p></div>","PeriodicalId":18253,"journal":{"name":"Materials Today Physics","volume":null,"pages":null},"PeriodicalIF":10.0,"publicationDate":"2024-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141605918","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Janus film coupling radiative cooling and heating for all-day active/passive personal thermal management","authors":"Xin Meng,&nbsp;Qi Zhao,&nbsp;Zhaochuan Chen,&nbsp;Qiang Li,&nbsp;Xuemei Chen","doi":"10.1016/j.mtphys.2024.101511","DOIUrl":"https://doi.org/10.1016/j.mtphys.2024.101511","url":null,"abstract":"<div><p>Textiles with passive radiative cooling (PRC)/passive radiative heating (PRH) capabilities have been developed to address human thermal comfort in different climate scenarios. Although materials with single PRC/PRH function have been reported, they tended to exhibit only one function of either cooling or heating, which was restrictive in achieving efficient and controllable personal thermal management. Herein, we propose a dual-mode Janus film composed of a PVDF-HFP/ZrO₂ cooling layer and a Mxene/CNT heating layer for efficient all-day PRC/PRH. Owing to the natural high refractive index of ZrO₂ nanoparticles and the strong scattering of sunlight by the PVDF-HFP nanofibers, the cooling side exhibits a high solar reflectance of 97.1 %. With an infrared emittance of 93 % in atmospheric window, the cooling side achieves subambient cooling temperatures of 8.8 °C during daytime and 7 °C during nighttime. Meanwhile, the Mxene/CNT synergy enables the heating side to exhibit high solar absorbance and electrical conductivity, resulting in a significant PRH capability of up to 19 °C and an outstanding active Joule heating capability as a temperature compensation. The dual-mode Janus film is able to switch cooling/heating modes by simply flipping the interface to alter the sky-facing side, enabling efficient and continuous personal thermal management in complex and changeable environments.</p></div>","PeriodicalId":18253,"journal":{"name":"Materials Today Physics","volume":null,"pages":null},"PeriodicalIF":10.0,"publicationDate":"2024-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141605805","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Isotope interface engineering for thermal transport suppression in cryogenic graphene","authors":"Xin Wu ,&nbsp;Yunhui Wu ,&nbsp;Xin Huang ,&nbsp;Zheyong Fan ,&nbsp;Sebastian Volz ,&nbsp;Qiang Han ,&nbsp;Masahiro Nomura","doi":"10.1016/j.mtphys.2024.101500","DOIUrl":"10.1016/j.mtphys.2024.101500","url":null,"abstract":"<div><p>The development of emerging technologies, such as quantum computing and semiconductor electronics, emphasizes the growing significance of thermal management at cryogenic temperatures. Herein, by designing isotope interfaces based on the Golomb ruler, we achieved effective suppression of the phonon thermal transport of cryogenic graphene. The pronounced disordering of the Golomb ruler sequence results in the stronger suppression of thermal transport compared to other sequences with the same isotope doping ratio. We demonstrated that the Golomb ruler-based isotope interfaces have strong scattering and confinement effects on phonon transport via extensive molecular dynamics simulations combined with wave packet analysis, with a proper correction for the missing quantum statistics. This work provides a new stream for the design of thermal transport suppression under cryogenic conditions and is expected to expand to other fields.</p></div>","PeriodicalId":18253,"journal":{"name":"Materials Today Physics","volume":null,"pages":null},"PeriodicalIF":10.0,"publicationDate":"2024-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141597792","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental investigation and CALPHAD modeling of thermal conductivities of the Cu–Ag–Cr–Zr system","authors":"Biao Hu ,&nbsp;Chenggang Jin ,&nbsp;Jing Xie ,&nbsp;Yuling Liu ,&nbsp;Xinyue Lan ,&nbsp;Qingping Wang ,&nbsp;Shaoding Sheng","doi":"10.1016/j.mtphys.2024.101502","DOIUrl":"10.1016/j.mtphys.2024.101502","url":null,"abstract":"<div><p>Thermal conductivity is one of the important thermophysical properties for describing the ability of a material to transfer heat. The thermal conductivities and microstructures of Cu–Ag, Cu–Cr and Cu–Zr binary alloys were experimentally investigated. 11 equilibrated binary alloys were designed and prepared annealed at 600 °C for 60 days. Their phase equilibria and compositions were analyzed by scanning electron microscopy with energy dispersive X-ray spectrometry (SEM/EDS), and the thermal diffusivities at 20, 100, 200 and 300 °C and the densities at room temperature were measured by laser flash analysis (LFA) method and Archimedes method, respectively. The heat capacities of alloys at different temperatures were calculated through the thermodynamic database, and then the experimental thermal conductivities of each alloys were obtained by the specific conversion equation. Based on the experimental data from the literature and present work, the thermal conductivities of pure elements, the solid solution phases, the stoichiometric compounds and the two-phase regions were evaluated by the CALPHAD (CALculation of PHAse Diagrams) approach. A set of self-consistent thermal conductivity parameters for description of the Cu–Ag–Cr–Zr system was obtained. Comprehensive comparisons between the calculated and experimental results show that the experimental thermal conductivities were satisfactorily accounted for by the present modeling. The present research results can provide important thermal conductivity information for designing new copper alloys and enrich the thermophysical database of copper alloys.</p></div>","PeriodicalId":18253,"journal":{"name":"Materials Today Physics","volume":null,"pages":null},"PeriodicalIF":10.0,"publicationDate":"2024-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141597793","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}