Pub Date : 2025-04-22DOI: 10.1016/j.mtphys.2025.101733
Qintuo Zhang, Zhen Fan, Xiaofan Zhang, Nan Chen, Kaiwei Guo, Qi Zhao, Yi Wang, Chengpeng Pan, Shuai Qi, Xuan Zhou, Guannan Li, Yang Liu, Congcong Liu, Yibao Liu, Jingkun Xu, Huaizhou Zhao, Hangtian Zhu
Grain boundaries, as critical structural defects in materials, play a pivotal role in thermoelectric research. Mg3(Bi, Sb)2-based materials, which are prominent n-type thermoelectric materials, are significantly affected by the second phase at grain boundaries. This study investigates the influence of ZrSb1-x on the thermoelectric properties of Mg3(Bi, Sb)2, with particular focus on its impact on the chemical environment at grain boundaries. The ZrSb2 exacerbates the loss of Mg, resulting in a transition of the material from n-type to p-type conductivity. In contrast, the ZrSb3/5 mitigates the formation of Bi-rich precipitate, reduces the interfacial potential barriers, and enhances grain growth. A sample containing 5% ZrSb3/5 achieved a room temperature zT of 0.9, and the formation of <10 1> twins was observed. Furthermore, a thermoelectric device composed of this material, paired with commercial p-type Bi2Te3, demonstrated a maximum temperature difference of 67 K and a peak cooling power density of 1.2 W/cm2. The mathematical relationship between the device's COP under any operating condition and its fundamental parameters (Qc,max, ΔTmax and Imax) was derived.
{"title":"Enhancing Mg3(Bi, Sb)2 Thermoelectric Performance via ZrSb1-x Modified Grain-Boundary","authors":"Qintuo Zhang, Zhen Fan, Xiaofan Zhang, Nan Chen, Kaiwei Guo, Qi Zhao, Yi Wang, Chengpeng Pan, Shuai Qi, Xuan Zhou, Guannan Li, Yang Liu, Congcong Liu, Yibao Liu, Jingkun Xu, Huaizhou Zhao, Hangtian Zhu","doi":"10.1016/j.mtphys.2025.101733","DOIUrl":"https://doi.org/10.1016/j.mtphys.2025.101733","url":null,"abstract":"Grain boundaries, as critical structural defects in materials, play a pivotal role in thermoelectric research. Mg<sub>3</sub>(Bi, Sb)<sub>2</sub>-based materials, which are prominent n-type thermoelectric materials, are significantly affected by the second phase at grain boundaries. This study investigates the influence of ZrSb<sub>1-x</sub> on the thermoelectric properties of Mg<sub>3</sub>(Bi, Sb)<sub>2</sub>, with particular focus on its impact on the chemical environment at grain boundaries. The ZrSb<sub>2</sub> exacerbates the loss of Mg, resulting in a transition of the material from n-type to p-type conductivity. In contrast, the ZrSb<sub>3/5</sub> mitigates the formation of Bi-rich precipitate, reduces the interfacial potential barriers, and enhances grain growth. A sample containing 5% ZrSb<sub>3/5</sub> achieved a room temperature <em>zT</em> of 0.9, and the formation of <10 <span><span style=\"\"></span><span data-mathml='<math xmlns=\"http://www.w3.org/1998/Math/MathML\" />' role=\"presentation\" style=\"font-size: 90%; display: inline-block; position: relative;\" tabindex=\"0\"><svg aria-hidden=\"true\" focusable=\"false\" height=\"0.24ex\" role=\"img\" style=\"vertical-align: -0.12ex;\" viewbox=\"0 -51.7 0 103.4\" width=\"0\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"><g fill=\"currentColor\" stroke=\"currentColor\" stroke-width=\"0\" transform=\"matrix(1 0 0 -1 0 0)\"></g></svg><span role=\"presentation\"><math xmlns=\"http://www.w3.org/1998/Math/MathML\"></math></span></span><script type=\"math/mml\"><math></math></script></span> 1> twins was observed. Furthermore, a thermoelectric device composed of this material, paired with commercial p-type Bi<sub>2</sub>Te<sub>3</sub>, demonstrated a maximum temperature difference of 67 K and a peak cooling power density of 1.2 W/cm<sup>2</sup>. The mathematical relationship between the device's COP under any operating condition and its fundamental parameters (<em>Q</em><sub>c,max</sub>, Δ<em>T</em><sub>max</sub> and <em>I</em><sub>max</sub>) was derived.","PeriodicalId":18253,"journal":{"name":"Materials Today Physics","volume":"1 1","pages":""},"PeriodicalIF":11.5,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143857706","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}
Pub Date : 2025-04-22DOI: 10.1016/j.mtphys.2025.101735
Xian Zhang, Haojiang Du, Wei Liu, Zunke Liu, Hongkai Zhou, Ruoyi Wang, Hongyu Zhang, Huan Pu, Mingdun Liao, Zhiqin Ying, Xi Yang, Zhenhai Yang, Yuheng Zeng, Jichun Ye
The mainstream industrial-grade boron emitters for n-type tunnel oxide passivating contact (TOPCon) solar cells (SCs) are typically fabricated using low-pressure (LP) boron diffusion technology. Although this approach has achieved great success in the photovoltaic (PV) industry, LP-based boron emitters still face significant challenges in meeting the current demands for high-efficiency c-Si SCs while ensuring safe production. Plasma-enhanced chemical vapor deposition (PECVD)-based boron diffusion technology holds the potential to address these issues, which, however, usually suffers from poor passivation quality, limiting its broader application in the PV industry. In this work, we propose a flexible and controllable method using PECVD to deposit a double-layer boron silicate glass (BSG), combined with high-temperature annealing, for the fabrication of boron emitters. Our results indicate that the PECVD-based boron emitters exhibit a higher surface boron concentration and a shallower boron diffusion depth, which enhance hole transport compared to LP-based boron emitters. Consequently, the PECVD-based boron emitters achieve superior passivation and contact properties, with a high implied open-circuit voltage of 715 mV, a low single-sided saturation current density of 8.8 fA/cm2, and a low contact resistivity of less than 0.5 mΩ·cm2. Additionally, proof-of-concept TOPCon SCs incorporating such PECVD-based boron emitters are fabricated, achieving a remarkable efficiency of 24.30%, surpassing that of LP-based TOPCon SCs (23.51%). This study introduces a flexible PECVD-based boron diffusion technology for TOPCon SCs, demonstrating significantly improved passivation and contact properties and highlighting its potential applications in the PV industry.
{"title":"Enhanced Passivation and Contact Properties of Boron Emitters through PECVD-Deposited Double Boron Silicate Glass Layers for High-Efficiency Tunnel Oxide Passivating Contact Solar Cells","authors":"Xian Zhang, Haojiang Du, Wei Liu, Zunke Liu, Hongkai Zhou, Ruoyi Wang, Hongyu Zhang, Huan Pu, Mingdun Liao, Zhiqin Ying, Xi Yang, Zhenhai Yang, Yuheng Zeng, Jichun Ye","doi":"10.1016/j.mtphys.2025.101735","DOIUrl":"https://doi.org/10.1016/j.mtphys.2025.101735","url":null,"abstract":"The mainstream industrial-grade boron emitters for <em>n</em>-type tunnel oxide passivating contact (TOPCon) solar cells (SCs) are typically fabricated using low-pressure (LP) boron diffusion technology. Although this approach has achieved great success in the photovoltaic (PV) industry, LP-based boron emitters still face significant challenges in meeting the current demands for high-efficiency c-Si SCs while ensuring safe production. Plasma-enhanced chemical vapor deposition (PECVD)-based boron diffusion technology holds the potential to address these issues, which, however, usually suffers from poor passivation quality, limiting its broader application in the PV industry. In this work, we propose a flexible and controllable method using PECVD to deposit a double-layer boron silicate glass (BSG), combined with high-temperature annealing, for the fabrication of boron emitters. Our results indicate that the PECVD-based boron emitters exhibit a higher surface boron concentration and a shallower boron diffusion depth, which enhance hole transport compared to LP-based boron emitters. Consequently, the PECVD-based boron emitters achieve superior passivation and contact properties, with a high implied open-circuit voltage of 715 mV, a low single-sided saturation current density of 8.8 fA/cm<sup>2</sup>, and a low contact resistivity of less than 0.5 mΩ·cm<sup>2</sup>. Additionally, proof-of-concept TOPCon SCs incorporating such PECVD-based boron emitters are fabricated, achieving a remarkable efficiency of 24.30%, surpassing that of LP-based TOPCon SCs (23.51%). This study introduces a flexible PECVD-based boron diffusion technology for TOPCon SCs, demonstrating significantly improved passivation and contact properties and highlighting its potential applications in the PV industry.","PeriodicalId":18253,"journal":{"name":"Materials Today Physics","volume":"41 1","pages":""},"PeriodicalIF":11.5,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143857698","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}
Pub Date : 2025-04-22DOI: 10.1016/j.mtphys.2025.101734
Samira Nikmanesh, Seshasai Srinivasan, Rosa Safaiee
This study employs dispersion-corrected DFT-D2 calculations to investigate Li adsorption on pristine and Ti-decorated SiC2, evaluating their potential as anode materials for Li-ion batteries. Key analyses, including adsorption energy, density of states (DOS), Bader charge, diffusion barrier, and open-circuit voltage (OCV), reveal that the incorporation of titanium (Ti) into SiC2 significantly enhances the electrochemical performance, stability, and lithium atom diffusion characteristics of the material. Ti increases the adsorption energy, Eads, from -1.422 eV for SiC2 to -1.641 eV for Ti-decorated SiC2, strengthening the bond between lithium ions and the substrate. This stronger interaction improves capacity retention and cycling stability by reducing lithium desorption during cycling. While this increase in adsorption energy may slightly impede lithium diffusion, it contributes to greater structural stability and durability under high-rate charging and discharging conditions. Additionally, OCV is enhanced from 0.340 V in SiC2 to 0.392 V in Ti-decorated SiC2, improving the overall energy output. The lattice constants exhibit a minimal change of only 0.21%, indicating that lithium intercalation and deintercalation during battery charge and discharge cycles have an insignificant impact on volume variation. With a capacity of 965.25 mAh/g, Ti-decorated SiC2 achieves a more favorable balance of stability, rate capability, and energy efficiency compared to undoped SiC2, making it a promising material for practical, long-term applications in lithium-ion batteries.
{"title":"Ti-Decorated SiC2 as a High-Performance Anode Material for Li-ion Batteries: A DFT-D2 Approach","authors":"Samira Nikmanesh, Seshasai Srinivasan, Rosa Safaiee","doi":"10.1016/j.mtphys.2025.101734","DOIUrl":"https://doi.org/10.1016/j.mtphys.2025.101734","url":null,"abstract":"This study employs dispersion-corrected DFT-D2 calculations to investigate Li adsorption on pristine and Ti-decorated SiC<sub>2</sub>, evaluating their potential as anode materials for Li-ion batteries. Key analyses, including adsorption energy, density of states (DOS), Bader charge, diffusion barrier, and open-circuit voltage (OCV), reveal that the incorporation of titanium (Ti) into SiC<sub>2</sub> significantly enhances the electrochemical performance, stability, and lithium atom diffusion characteristics of the material. Ti increases the adsorption energy, Eads, from -1.422 eV for SiC<sub>2</sub> to -1.641 eV for Ti-decorated SiC<sub>2</sub>, strengthening the bond between lithium ions and the substrate. This stronger interaction improves capacity retention and cycling stability by reducing lithium desorption during cycling. While this increase in adsorption energy may slightly impede lithium diffusion, it contributes to greater structural stability and durability under high-rate charging and discharging conditions. Additionally, OCV is enhanced from 0.340 V in SiC<sub>2</sub> to 0.392 V in Ti-decorated SiC<sub>2</sub>, improving the overall energy output. The lattice constants exhibit a minimal change of only 0.21%, indicating that lithium intercalation and deintercalation during battery charge and discharge cycles have an insignificant impact on volume variation. With a capacity of 965.25 mAh/g, Ti-decorated SiC<sub>2</sub> achieves a more favorable balance of stability, rate capability, and energy efficiency compared to undoped SiC<sub>2</sub>, making it a promising material for practical, long-term applications in lithium-ion batteries.","PeriodicalId":18253,"journal":{"name":"Materials Today Physics","volume":"37 1","pages":""},"PeriodicalIF":11.5,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143857627","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}
Pub Date : 2025-04-20DOI: 10.1016/j.mtphys.2025.101721
Ziqi Guo, Ioanna Katsamba, Daniel Carne, Dudong Feng, Kellan Moss, Emily Barber, Ziqi Fang, Andrea Felicelli, Xiulin Ruan
A thin layer, lightweight, and ultra-white hexagonal boron nitride (h-BN) nanoporous paint has been developed recently. However, the underlying atomic and nanostructural physics of the paint’s radiative cooling performance remains quite elusive. In this work, a multiscale, multiphysics computational framework is employed to gain atomic level insights of the high radiative cooling performance. Leveraging first-principles calculations to study the electronic transitions and phonon dynamics, the refractive index and extinction coefficient are predicted across solar and mid-infrared (mid-IR) spectra, which are then used to calculate the optical properties of a single nanoparticle either by Mie Theory or computationally solving Maxwell’s Equations. Subsequently, the photon Monte Carlo simulation is used to predict the photon transport in nanoplatelet-matrix nanocomposites, by including the anisotropic optical properties of nanoplatelets for the first time. The predicted solar reflectance and sky window emissivity of the nanocomposites agree well with the experiments. By comparing with BaSO4-based paint, we attribute the high solar reflectance of h-BN paint at a lower thickness to its higher refractive index and nanoplatelet morphology, and attribute the relatively lower sky window emissivity to its lower extinction coefficient in mid-IR. Surprisingly, aligning the nanoplatelets horizontally does not significantly improve the solar reflectance at coating thickness due to diminishing returns. Finally, we compile many radiative cooling pigments and order the following few in decreasing refractive index: h-BN, BaSO4, CaCO3, SiO2. Our work advances the understanding of atomic-scale features in designing radiative cooling materials.
{"title":"Electronic and phononic characteristics of high-performance radiative cooling pigments h-BN: A comparative study to BaSO4","authors":"Ziqi Guo, Ioanna Katsamba, Daniel Carne, Dudong Feng, Kellan Moss, Emily Barber, Ziqi Fang, Andrea Felicelli, Xiulin Ruan","doi":"10.1016/j.mtphys.2025.101721","DOIUrl":"https://doi.org/10.1016/j.mtphys.2025.101721","url":null,"abstract":"A thin layer, lightweight, and ultra-white hexagonal boron nitride (h-BN) nanoporous paint has been developed recently. However, the underlying atomic and nanostructural physics of the paint’s radiative cooling performance remains quite elusive. In this work, a multiscale, multiphysics computational framework is employed to gain atomic level insights of the high radiative cooling performance. Leveraging first-principles calculations to study the electronic transitions and phonon dynamics, the refractive index and extinction coefficient are predicted across solar and mid-infrared (mid-IR) spectra, which are then used to calculate the optical properties of a single nanoparticle either by Mie Theory or computationally solving Maxwell’s Equations. Subsequently, the photon Monte Carlo simulation is used to predict the photon transport in nanoplatelet-matrix nanocomposites, by including the anisotropic optical properties of nanoplatelets for the first time. The predicted solar reflectance and sky window emissivity of the nanocomposites agree well with the experiments. By comparing with BaSO<sub>4</sub>-based paint, we attribute the high solar reflectance of h-BN paint at a lower thickness to its higher refractive index and nanoplatelet morphology, and attribute the relatively lower sky window emissivity to its lower extinction coefficient in mid-IR. Surprisingly, aligning the nanoplatelets horizontally does not significantly improve the solar reflectance at <span><span><math><mrow is=\"true\"><mn is=\"true\">150</mn><mspace is=\"true\" width=\"1em\"></mspace><mi is=\"true\" mathvariant=\"normal\">μ</mi><mi is=\"true\" mathvariant=\"normal\">m</mi></mrow></math></span><script type=\"math/mml\"><math><mrow is=\"true\"><mn is=\"true\">150</mn><mspace width=\"1em\" is=\"true\"></mspace><mi mathvariant=\"normal\" is=\"true\">μ</mi><mi mathvariant=\"normal\" is=\"true\">m</mi></mrow></math></script></span> coating thickness due to diminishing returns. Finally, we compile many radiative cooling pigments and order the following few in decreasing refractive index: h-BN, BaSO<sub>4</sub>, CaCO<sub>3</sub>, SiO<sub>2</sub>. Our work advances the understanding of atomic-scale features in designing radiative cooling materials.","PeriodicalId":18253,"journal":{"name":"Materials Today Physics","volume":"55 1","pages":""},"PeriodicalIF":11.5,"publicationDate":"2025-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143853150","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}
Pub Date : 2025-04-17DOI: 10.1016/j.mtphys.2025.101720
Min Zhao , Junyu Huang , Yu He , Tingfeng Li , Cuiping Xu , Peiqi Ji , Ziyi Xu , Xiaolei Li , Yiyu Tan , Aimei Zhang , Hong-Ling Cai , X.S. Wu
Electrocaloric (EC) refrigeration in nanocomposites provides sustainable heating and cooling through its excellent entropy change when applied or withdraw an electric field. Nonetheless, it's difficult to achieve a large EC performance under low electric fields since ferroelectrics have relatively low thermal conductivity and small diabatic temperature change. In this work, we design an EC nanocomposite by incorporating 12 %[0.68(BaZr0.2Ti0.8O3)-0.32(Ba0.7Ca0.3TiO3)] (BCZT) nanoparticles with significant ferroelectric properties and 7 %Boron Nitride nanosheets (BNNSs) with notable electrical insulation and ultra-high thermal conductivity into relaxor ferroelectric terpolymer P(VDF-TrFE-CFE), aiming to improve ECE performance and increase cooling power density of the nanocomposite. We attain an adiabatic temperature change (ΔT) of 8.85K, isothermal entropy change (ΔS) of 30.10J·kg−1·K−1 and isothermal cooling energy density (Q) of up to 5.10 × 107 J·m−3 under a low electric field of 80 MV/m by direct method, which is an order of magnitude larger than those of other EC materials reported so far. The introduced interfacial coupling effect between ceramic and terpolymer plays a very important role to ECE, which modulates their polarization, microscale electric-dipoles changes, and energy conversion behavior, simultaneously improves the cooling power density of nanocomposite. Furthermore, the heat transfer performance of nanocomposite is simulated using Finite-element method (FEM) to investigate their heat transfer properties based on the solid-state heat transfer theory. The phase-field simulation has demonstrated the nanocomposite still possesses impressive ferroelectric properties under the influence of elastic compressive strain based on time-dependent Landau-Ginzburg-Devonshire (TLGD) theory. This research is of significant importance for achieving precise thermal management of the next-generation microelectronic devices.
{"title":"Large electrocaloric refrigeration performance in ferroelectric polymer nanocomposite with complementary nano-structural fillers","authors":"Min Zhao , Junyu Huang , Yu He , Tingfeng Li , Cuiping Xu , Peiqi Ji , Ziyi Xu , Xiaolei Li , Yiyu Tan , Aimei Zhang , Hong-Ling Cai , X.S. Wu","doi":"10.1016/j.mtphys.2025.101720","DOIUrl":"10.1016/j.mtphys.2025.101720","url":null,"abstract":"<div><div>Electrocaloric (EC) refrigeration in nanocomposites provides sustainable heating and cooling through its excellent entropy change when applied or withdraw an electric field. Nonetheless, it's difficult to achieve a large EC performance under low electric fields since ferroelectrics have relatively low thermal conductivity and small diabatic temperature change. In this work, we design an EC nanocomposite by incorporating 12 %[0.68(BaZr<sub>0.2</sub>Ti<sub>0.8</sub>O<sub>3</sub>)-0.32(Ba<sub>0.7</sub>Ca<sub>0.3</sub>TiO<sub>3</sub>)] (BCZT) nanoparticles with significant ferroelectric properties and 7 %Boron Nitride nanosheets (BNNSs) with notable electrical insulation and ultra-high thermal conductivity into relaxor ferroelectric terpolymer P(VDF-TrFE-CFE), aiming to improve ECE performance and increase cooling power density of the nanocomposite. We attain an adiabatic temperature change (Δ<em>T</em>) of 8.85K, isothermal entropy change (Δ<em>S</em>) of 30.10J·kg<sup>−1</sup>·K<sup>−1</sup> and isothermal cooling energy density (<em>Q</em>) of up to 5.10 × 10<sup>7</sup> J·m<sup>−3</sup> under a low electric field of 80 MV/m by direct method, which is an order of magnitude larger than those of other EC materials reported so far. The introduced interfacial coupling effect between ceramic and terpolymer plays a very important role to ECE, which modulates their polarization, microscale electric-dipoles changes, and energy conversion behavior, simultaneously improves the cooling power density of nanocomposite. Furthermore, the heat transfer performance of nanocomposite is simulated using Finite-element method (FEM) to investigate their heat transfer properties based on the solid-state heat transfer theory. The phase-field simulation has demonstrated the nanocomposite still possesses impressive ferroelectric properties under the influence of elastic compressive strain based on time-dependent Landau-Ginzburg-Devonshire (TLGD) theory. This research is of significant importance for achieving precise thermal management of the next-generation microelectronic devices.</div></div>","PeriodicalId":18253,"journal":{"name":"Materials Today Physics","volume":"54 ","pages":"Article 101720"},"PeriodicalIF":10.0,"publicationDate":"2025-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143837943","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}
Pub Date : 2025-04-17DOI: 10.1016/j.mtphys.2025.101728
Min Hong , Yiyuan Yang , Jianhang Nie , Xiaohua Zhang , Wenjing Zhang , Cuicui Du , Jinhua Chen
Atomically dispersed Fe-N-C catalysts have currently received extremely widespread attention as one of encouraging candidates for Pt-based oxygen reduction reaction (ORR) catalysts owing to their high intrinsic activity and atomic utilization efficiency as well as the affluent reserve, but further optimizing the adsorption behaviors of the primitive FeNx sites in Fe-N-C for oxygen-related intermediates is significant for bifunctional oxygen catalytic performances to propel their applications for reversible Zn-air battery. Herein, Co9S8 nanoparticles incorporated into atomic Fe dispersed N-enriched porous graphene carbon aerogels (Co9S8/Fe-N-C) were fabricated via two rounds of hydrothermal treatment followed by high-temperature pyrolysis. DFT calculations and experimental investigation revealed that, in virtue of the strong interactions effect between Co9S8 nanoparticles and Fe-N-C, the regulated electronic structure of Co9S8/Fe-N-C and the introduced abundant sulfur vacancies induced the d-band center modulation of FeNx sites closer to the Fermi level, which can optimize the binding energy for oxygen-containing intermediates, thereby endowing the catalyst with enhanced bifunctional catalytic performance. Therefrom, the Co9S8/Fe-N-C catalyst presented efficient bifunctional ORR/OER activity with a narrower ΔE (0.68V), outstripping the Pt/C + RuO2 catalysts. Additionally, the Zn-air battery assembled with Co9S8/Fe-N-C delivered a large specific capacity (798 mAh gZn−1) with a power density of 103 mW cm−2 and a long-term stability over 140 h. This research presents an innovative perspective on theoretical design of highly efficient atomically dispersed Fe based catalysts for reversible Zn-air battery.
{"title":"D-band center modulation of atomic dispersed FeNx sites by incorporating Co9S8 nanoparticles towards augmented ORR/OER electrocatalysis in Zn-air batteries","authors":"Min Hong , Yiyuan Yang , Jianhang Nie , Xiaohua Zhang , Wenjing Zhang , Cuicui Du , Jinhua Chen","doi":"10.1016/j.mtphys.2025.101728","DOIUrl":"10.1016/j.mtphys.2025.101728","url":null,"abstract":"<div><div>Atomically dispersed Fe-N-C catalysts have currently received extremely widespread attention as one of encouraging candidates for Pt-based oxygen reduction reaction (ORR) catalysts owing to their high intrinsic activity and atomic utilization efficiency as well as the affluent reserve, but further optimizing the adsorption behaviors of the primitive FeN<sub>x</sub> sites in Fe-N-C for oxygen-related intermediates is significant for bifunctional oxygen catalytic performances to propel their applications for reversible Zn-air battery. Herein, Co<sub>9</sub>S<sub>8</sub> nanoparticles incorporated into atomic Fe dispersed N-enriched porous graphene carbon aerogels (Co<sub>9</sub>S<sub>8</sub>/Fe-N-C) were fabricated via two rounds of hydrothermal treatment followed by high-temperature pyrolysis. DFT calculations and experimental investigation revealed that, in virtue of the strong interactions effect between Co<sub>9</sub>S<sub>8</sub> nanoparticles and Fe-N-C, the regulated electronic structure of Co<sub>9</sub>S<sub>8</sub>/Fe-N-C and the introduced abundant sulfur vacancies induced the d-band center modulation of FeN<sub>x</sub> sites closer to the Fermi level, which can optimize the binding energy for oxygen-containing intermediates, thereby endowing the catalyst with enhanced bifunctional catalytic performance. Therefrom, the Co<sub>9</sub>S<sub>8</sub>/Fe-N-C catalyst presented efficient bifunctional ORR/OER activity with a narrower ΔE (0.68V), outstripping the Pt/C + RuO<sub>2</sub> catalysts. Additionally, the Zn-air battery assembled with Co<sub>9</sub>S<sub>8</sub>/Fe-N-C delivered a large specific capacity (798 mAh g<sub>Zn</sub><sup>−1</sup>) with a power density of 103 mW cm<sup>−2</sup> and a long-term stability over 140 h. This research presents an innovative perspective on theoretical design of highly efficient atomically dispersed Fe based catalysts for reversible Zn-air battery.</div></div>","PeriodicalId":18253,"journal":{"name":"Materials Today Physics","volume":"54 ","pages":"Article 101728"},"PeriodicalIF":10.0,"publicationDate":"2025-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143841460","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}
Pub Date : 2025-04-16DOI: 10.1016/j.mtphys.2025.101730
Tae Jin Jeong , Chan Wook Jang , Won Uk Jeong , Vu Thi Hoa , Sunglae Cho , Xiaolin Wang , R.G. Elliman , Sung Kim , Suk-Ho Choi
As a host of massless Weyl fermions, two-dimensional (2D) Weyl semimetals (WSMs) provide an ideal platform for studying exotic quantum phenomena in the emerging field of Dirac physics, including the circular photogalvanic effect (CPGE). Here, we report such behavior in a 2D WSM created in Bi0.96Sb0.04 thin films by a thickness-dependent topological phase transition caused by inversion symmetry breaking. Photocurrent maps and line profiles, and CPGE of lateral device structures are shown to depend on bias voltage and polarity, and to be well described by bias-dependent variations of the band profiles at the electrode/BiSb interfaces. Of particular note is the observation that the CPGE exhibits helicity-dependent behavior, indicating a counter-propagating distribution of opposite spins of the Weyl cones, which originates from reduced symmetry in the 2D film structure of WSMs despite normal incidence of the illumination. A strong thickness-dependent responsivity is also observed over a wide spectral range from ∼400 to ∼950 nm, and is attributed to the linear-dispersion of the Weyl cones. These results demonstrate manipulation of photocarrier generation, separation and transport processes in a simple 2D-WSM-based planar device using light polarization, bias voltage, and film thickness, and are promising for energy-harvesting devices.
{"title":"Circular photogalvanic effect in two-dimensional Weyl semimetals","authors":"Tae Jin Jeong , Chan Wook Jang , Won Uk Jeong , Vu Thi Hoa , Sunglae Cho , Xiaolin Wang , R.G. Elliman , Sung Kim , Suk-Ho Choi","doi":"10.1016/j.mtphys.2025.101730","DOIUrl":"10.1016/j.mtphys.2025.101730","url":null,"abstract":"<div><div>As a host of massless Weyl fermions, two-dimensional (2D) Weyl semimetals (WSMs) provide an ideal platform for studying exotic quantum phenomena in the emerging field of Dirac physics, including the circular photogalvanic effect (CPGE). Here, we report such behavior in a 2D WSM created in Bi<sub>0.96</sub>Sb<sub>0.04</sub> thin films by a thickness-dependent topological phase transition caused by inversion symmetry breaking. Photocurrent maps and line profiles, and CPGE of lateral device structures are shown to depend on bias voltage and polarity, and to be well described by bias-dependent variations of the band profiles at the electrode/BiSb interfaces. Of particular note is the observation that the CPGE exhibits helicity-dependent behavior, indicating a counter-propagating distribution of opposite spins of the Weyl cones, which originates from reduced symmetry in the 2D film structure of WSMs despite normal incidence of the illumination. A strong thickness-dependent responsivity is also observed over a wide spectral range from ∼400 to ∼950 nm, and is attributed to the linear-dispersion of the Weyl cones. These results demonstrate manipulation of photocarrier generation, separation and transport processes in a simple 2D-WSM-based planar device using light polarization, bias voltage, and film thickness, and are promising for energy-harvesting devices.</div></div>","PeriodicalId":18253,"journal":{"name":"Materials Today Physics","volume":"54 ","pages":"Article 101730"},"PeriodicalIF":10.0,"publicationDate":"2025-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143837273","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}
Pub Date : 2025-04-14DOI: 10.1016/j.mtphys.2025.101729
Jiale Zhang , Yurui Han , Yuefei Wang , Shihao Fu , Yiping Miao , Rongpeng Fu , Weizhe Cui , Zhe Wu , Bingsheng Li , Aidong Shen , Yichun Liu
A high-performance β-Ga2O3/GaN ultraviolet photodetector with bias-tunable spectral response (the UVC band to the UVA-UVC band) is demonstrated. The device is fabricated via a new route of reverse substitution growth, combined with oxygen plasma treatment (OPT) to introduce a GaON nucleation layer for the β-Ga2O3 synthesis on the GaN surface. The effects of the nucleation layer on the subsequent transformation from GaN to β-Ga2O3 at high temperature under oxygen ambience were analyzed in detail. X-ray diffraction (XRD) confirmed that (−201) preferred oriented monoclinic phase β-Ga2O3 with narrow linewidths has been formed. Both oxygen vacancies (VO) on the surface and the root mean square (RMS) of the surface roughness of β-Ga2O3 treated with OPT are reduced, as confirmed by X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM), resulting in better interfacial contact with the electrodes. Meanwhile, the increase in internal VO enhanced the conductivity of the material, thereby improving the photoelectric response performance. The metal-semiconductor-metal (MSM) device achieved ultra-high detection capabilities (responsivity = 653 A/W, detectivity = 2.9 × 1015 Jones) and response spectrum switches between solar-blind narrow band and broad UVA-UVC band by varying the applied bias. The transient response time was on the millisecond scale. In the vertical-type β-Ga2O3/GaN photodiode, the responsivity and detectivity of the photodetector reached 2.1 A/W and 7.2 × 1013 Jones with a fast transient response time (rise time = 0.24 ms, decay time = 17.1 ms) under a bias voltage of −10 V.
{"title":"Enhanced performance UV photodetectors based on the β-Ga2o3/GaN photodiode of the reversed substitution growth with introduction nucleation layer of GaON by oxygen plasma treatment","authors":"Jiale Zhang , Yurui Han , Yuefei Wang , Shihao Fu , Yiping Miao , Rongpeng Fu , Weizhe Cui , Zhe Wu , Bingsheng Li , Aidong Shen , Yichun Liu","doi":"10.1016/j.mtphys.2025.101729","DOIUrl":"10.1016/j.mtphys.2025.101729","url":null,"abstract":"<div><div>A high-performance <em>β</em>-Ga<sub>2</sub>O<sub>3</sub>/GaN ultraviolet photodetector with bias-tunable spectral response (the UVC band to the UVA-UVC band) is demonstrated. The device is fabricated via a new route of reverse substitution growth, combined with oxygen plasma treatment (OPT) to introduce a GaON nucleation layer for the <em>β</em>-Ga<sub>2</sub>O<sub>3</sub> synthesis on the GaN surface. The effects of the nucleation layer on the subsequent transformation from GaN to <em>β</em>-Ga<sub>2</sub>O<sub>3</sub> at high temperature under oxygen ambience were analyzed in detail. X-ray diffraction (XRD) confirmed that (−201) preferred oriented monoclinic phase <em>β</em>-Ga<sub>2</sub>O<sub>3</sub> with narrow linewidths has been formed. Both oxygen vacancies (<em>V</em><sub>O</sub>) on the surface and the root mean square (RMS) of the surface roughness of <em>β</em>-Ga<sub>2</sub>O<sub>3</sub> treated with OPT are reduced, as confirmed by X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM), resulting in better interfacial contact with the electrodes. Meanwhile, the increase in internal <em>V</em><sub>O</sub> enhanced the conductivity of the material, thereby improving the photoelectric response performance. The metal-semiconductor-metal (MSM) device achieved ultra-high detection capabilities (responsivity = 653 A/W, detectivity = 2.9 × 10<sup>15</sup> Jones) and response spectrum switches between solar-blind narrow band and broad UVA-UVC band by varying the applied bias. The transient response time was on the millisecond scale. In the vertical-type <em>β</em>-Ga<sub>2</sub>O<sub>3</sub>/GaN photodiode, the responsivity and detectivity of the photodetector reached 2.1 A/W and 7.2 × 10<sup>13</sup> Jones with a fast transient response time (rise time = 0.24 ms, decay time = 17.1 ms) under a bias voltage of −10 V.</div></div>","PeriodicalId":18253,"journal":{"name":"Materials Today Physics","volume":"54 ","pages":"Article 101729"},"PeriodicalIF":10.0,"publicationDate":"2025-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143831877","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}
Pub Date : 2025-04-14DOI: 10.1016/j.mtphys.2025.101727
Xueyan Li, Xiyuan Liu, Jiaqi Yang, Yinuo Zhang, Yi Pan
Magnetic skyrmions are topologically stable swirling spin textures, usually with nanoscale diameters. It has attracted tremendous research interest due to the rich new physics of chiral interactions between the atomic spins, as well as the intriguing potential application in non-volatile data storage and spin-logic devices. In recent years, the skyrmion physics and materials have been enriched significantly due to the rise of two-dimensional (2D) van der Waals (vdW) magnets. In this paper, we review the recent research advances of magnetic skyrmions in the van der Waals magnetic material systems. Firstly, we classify the physical mechanisms that induce the magnetic skyrmions in 2D materials and their heterostructures. Then, we discuss the specific properties of three representative material systems, Fe3GeTe2, Fe3GaTe2, and CrTex. In the third section, we introduce the theoretical strategy and experimental method for skyrmion manipulation in 2D-magnet-based devices. Finally, we summarize the main progress, as well as the challenges and perspectives of future research, particularly the scanning-probe-assisted in situ device investigation method.
{"title":"Creation and manipulation of magnetic skyrmions in 2D van der Waals magnets","authors":"Xueyan Li, Xiyuan Liu, Jiaqi Yang, Yinuo Zhang, Yi Pan","doi":"10.1016/j.mtphys.2025.101727","DOIUrl":"10.1016/j.mtphys.2025.101727","url":null,"abstract":"<div><div>Magnetic skyrmions are topologically stable swirling spin textures, usually with nanoscale diameters. It has attracted tremendous research interest due to the rich new physics of chiral interactions between the atomic spins, as well as the intriguing potential application in non-volatile data storage and spin-logic devices. In recent years, the skyrmion physics and materials have been enriched significantly due to the rise of two-dimensional (2D) van der Waals (vdW) magnets. In this paper, we review the recent research advances of magnetic skyrmions in the van der Waals magnetic material systems. Firstly, we classify the physical mechanisms that induce the magnetic skyrmions in 2D materials and their heterostructures. Then, we discuss the specific properties of three representative material systems, Fe<sub>3</sub>GeTe<sub>2</sub>, Fe<sub>3</sub>GaTe<sub>2</sub>, and CrTe<sub>x</sub>. In the third section, we introduce the theoretical strategy and experimental method for skyrmion manipulation in 2D-magnet-based devices. Finally, we summarize the main progress, as well as the challenges and perspectives of future research, particularly the scanning-probe-assisted in situ device investigation method.</div></div>","PeriodicalId":18253,"journal":{"name":"Materials Today Physics","volume":"54 ","pages":"Article 101727"},"PeriodicalIF":10.0,"publicationDate":"2025-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143827316","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}
Pub Date : 2025-04-12DOI: 10.1016/j.mtphys.2025.101713
Dario Narducci, Federico Giulio, Antonio Mazzacua
Thermoelectric generators are devices capable to convert heat into electric power with no moving part. However, and despite a tremendous research effort on materials, their conversion efficiency is still limited, especially in the low temperature range where most of the discarded heat is available. We show that the exact solution of the time-dependent Domenicali’s equation predicts that, when the temperature difference across the thermoelectric legs is modulated in time, efficiency at maximum power () improves by up to 50% compared to the stationary case — with a power output equivalent to that attainable by doubling the material figure of merit. Building on this evidence, we additionally show how, even for sources delivering heat at a constant rate, simple heat flux pre-processing leads to a comparable improvement. Since the operational mode we propose is material-agnostic and does not require changes of the device layout, it could find prompt application.
{"title":"Dynamic thermoelectric generation enables 50% increase of efficiency at maximum power","authors":"Dario Narducci, Federico Giulio, Antonio Mazzacua","doi":"10.1016/j.mtphys.2025.101713","DOIUrl":"10.1016/j.mtphys.2025.101713","url":null,"abstract":"<div><div>Thermoelectric generators are devices capable to convert heat into electric power with no moving part. However, and despite a tremendous research effort on materials, their conversion efficiency is still limited, especially in the low temperature range where most of the discarded heat is available. We show that the exact solution of the time-dependent Domenicali’s equation predicts that, when the temperature difference across the thermoelectric legs is modulated in time, efficiency at maximum power (<span><math><msub><mrow><mi>η</mi></mrow><mrow><mtext>MP</mtext></mrow></msub></math></span>) improves by up to 50% compared to the stationary case — with a power output equivalent to that attainable by doubling the material figure of merit. Building on this evidence, we additionally show how, even for sources delivering heat at a constant rate, simple heat flux pre-processing leads to a comparable <span><math><msub><mrow><mi>η</mi></mrow><mrow><mtext>MP</mtext></mrow></msub></math></span> improvement. Since the operational mode we propose is material-agnostic and does not require changes of the device layout, it could find prompt application.</div></div>","PeriodicalId":18253,"journal":{"name":"Materials Today Physics","volume":"54 ","pages":"Article 101713"},"PeriodicalIF":10.0,"publicationDate":"2025-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143823075","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}
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