Materials Today Physics
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2020
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IF 10.443
Juan Li,Shuai Zhang,Fei Jia,Shuqi Zheng,Xiaolei Shi,Daqiang Jiang,Siyu Wang,Guiwu Lu,Liming Wu,Zhi-Gang Chen
Approaching practical thermoelectric devices require high-performance and machinable thermoelectric materials . However, the currently available materials are usually brittle. In this work, Nd-doped Mg 3 Sb 2 -based compounds exhibit not only excellent thermoelectric performance but also superior machinability . Mg 3.2 Nd 0.03 Sb 1.5 Bi 0.5 exhibits a high power factor of 20.6 μW cm −1 K −2 at 725 K and a peak zT of 1.8, which mainly originates from the increased n of ~8 × 10 19 cm −3 by Nd/Mg substitutional defects. Defect calculations predict that other rare earth elements (Sm, Gd, Tb, Dy and Ho) have the same effect as Nd on Mg 3 Sb 2 and the predicted highest achievable electron concentrations at 700 K are ~10 20 cm −3 . The measured hardness, Young's modulus and fracture toughness of Mg 3.2 Nd 0.03 Sb 1.5 Bi 0.5 are 1.1 GPa, 49.8 GPa and 1.4 MPa m 1/2 , respectively. In addition, the sample can be easily machined into the dog-bone shape with external thread at both ends, indicating the excellent machinability of Mg 3 Sb 2 -based materials. This work suggests a bright future of Mg 3 Sb 2 -based thermoelectric materials for practical applications and device fabrication .
研究领域:
材料科学
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热电材料研究
✓ 已验证
产品关联
DOI
高影响因子
ACTA MATERIALIA
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2024
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IF 8.3
Wei Cao,Ziwei Chen,Maolin Yang,Hanxi Guan,Xing Cheng,Ming Zhang,Feng Lin,Yinguo Xiao,Min Ling,Chengdu Liang,Jun Chen
Point defect engineering has garnered widespread application for enhancing the dynamic behavior of anode materials and improving electrochemical performance. Herein, a hybrid point defect strategy is proposed in Ti-based oxide materials to achieve N doping induced oxygen vacancies (OVs) and subsequently accelerated electron mobility and perform better diffusion kinetics. This methodology culminates in the fabrication of self-supported nanotube arrays comprising N-doped OVs-rich TiO 2 (denoted as N-TNTs). Density functional theory (DFT) calculations and electrochemical characterizations validate that, hybrid point defects lead to high electron mobility and perform better diffusion kinetics, as well as higher Li + /Na + ions adsorption energy barrier and diffusion energy barrier, which in turn improves the rate performance and cycling stability. This research provides a forward-looking and feasible strategy for the application of point defect engineering in anode materials.
研究领域:
材料科学
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电化学
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
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2024
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IF 5.1
Haoran Su,Xinyi Li,Dongze Li,Di Gao,Mengxue Zhang,Yufan Shang,Yanping Liu,Huiling Geng,Xiang Liu,Ruijin Yu
Thermal stability holds particular significance for phosphors intended for LEDs . Abnormal thermal quenching was successfully reached by strategic point defect engineering by inserting Frenkel defects and nonequivalent substitution defects in novel Sm 3+ ions doped Na-rich distorted double perovskite Na 1.5 La 1.5 TeO 6 phosphors. Its integral intensity at 420 K (115.03 %) was far higher than that of room temperature . Besides, the phosphors exhibited a pronounced orange-red emission peak at 644 nm when excited at 404 nm, which was ascribed to the 4 G 5/2 - 6 H 9/2 transition of Sm 3+ ions. The concentration quenching phenomenon resulting from dipole-dipole interactions was observed in the phosphors, and the optimal concentration of dopant Sm 3+ was determined to be 1 mol%. After calculation, it was surprising that the color purity values of all phosphors were not less than 99.9 %. Additionally, the internal quantum efficiency (IQE) reached 65.30 %, and the activation energy ( E a ) of Na 1.5 La 1.5 TeO 6 :1 mol%Sm 3+ was 0.570 eV. Meanwhile, the emission spectrum of the produced orange-red light emitting diodes (LEDs) exhibited a close correspondence with the absorption curves of various plant pigments (chlorophyll b , allophycocyanin, phycocyanin, phytochrome red and far red (P R and P FR )). The prepared white light emitting diodes (WLEDs) possessed low correlated color temperature (CCT) of 4769 K and as high general color rendering index (CRI, R a ) value as 91. In summary, the phosphors presented promising options for plant-cultivating LEDs and high CRI WLEDs based on their superior optical and thermal properties .
研究领域:
材料科学
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光学工程
✓ 已验证
产品关联
DOI
高影响因子
Journal of Materials Chemistry C
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2025
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IF 5.1
Rong Li,Chong-yu Wang,Qiu-Yu Luo,Ze Li,Xing Yang,Wang-Qi Bao,Yi-Xin Zhang,Jing Feng,Zhenhua Ge
Lead-free SnSe2 materials have intrinsic low thermal conductivities and are promising thermoelectrics. However, their relatively low electrical conductivity limits the improvement of thermoelectric performance. This study successfully introduced halogen elements (X = F, Cl, Br, and I) into SnSe2 to increase carrier concentration for better thermoelectric performance. The defect formation energy calculation results showed the lowest value for SeCl, indicating that incorporating Cl into the SnSe2 matrix could achieve higher thermoelectric performance. Experimental results further verified this conclusion. At 323 K, the electrical conductivity for the SnSe1.94Cl0.06 sample was 86 S cm–1, 61 times higher than that of pristine SnSe2. Combined with the DFT calculation results, the decreased bandgap of the Cl-doped sample benefitted the transport of carriers. Due to the increased electrical conductivity, a peak power factor value of 457μW m–1 K–2 was achieved at 473 K. Meanwhile, the formed point defects decreased the lattice thermal conductivity to 0.38 W m–1K–1 at 773 K, 14% lower than that of the pristine SnSe2 sample. Consequently, the SnSe1.97Cl0.03 sample obtained a peak ZT value of 0.63 at 773 K, five times higher than that of pristine SnSe2. This strategy of thermoelectric performance optimization through the introduction of halogen elements can be applied to other thermoelectric material systems.
研究领域:
材料科学
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热电材料
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固体物理
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缺陷工程
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能量转换材料
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）