ACS Nano
·
2021
·
IF 15.881
Xunuo Lou,Shuang Li,Xiang Chen,Qingtang Zhang,Houquan Deng,Jian Zhang,Di Li,Xuemei Zhang,Yongsheng Zhang,Haibo Zeng,Guodong Tang
Polycrystalline SnSe materials with ZT values comparable to those of SnSe crystals are greatly desired due to facile processing, machinability, and scale-up application. Here manipulating interatomic force by harnessing lattice strains was proposed for achieving significantly reduced lattice thermal conductivity in polycrystalline SnSe. Large static lattice strain created by lattice dislocations and stacking faults causes an effective shortening in phonon relaxation time, resulting in ultralow lattice thermal conductivity. A combination of band convergence and resonance levels induced by Ga incorporation contribute to a sharp increase of Seebeck coefficient and power factor. These lead to a high thermoelectric performance ZT ∼ 2.2, which is a record high ZT reported so far for solution-processed SnSe polycrystals. Besides the high peak ZT, a high average ZT of 0.72 and outstanding thermoelectric conversion efficiency of 12.4% were achieved by adopting nontoxic element doping, highlighting great potential for power generation application at intermediate temperatures. Engineering lattice strain to achieve ultralow lattice thermal conductivity with the aid of band convergence and resonance levels provides a great opportunity for designing prospective thermoelectrics.
研究领域:
材料科学
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热电材料
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能源转换
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Advanced Electronic Materials
·
2022
·Vol. 8
·期 11
·2200577
·
IF 7.633
Nan Xin,Guihua Tang,Yifei Li,Hao Shen,Yinan Nie,Min Zhang,Xin Zhao
Single crystal tin selenide (SnSe) has a recorded high thermoelectric figure of merit (ZT) value of 2.6 at 923 K, but it is easy to form mechanical cracks and difficult to apply in thermoelectric conversion devices. Polycrystalline SnSe has better mechanical properties but inferior ZT values, which needs further optimization for applications. This work aims at enhancing the thermoelectric performance of polycrystalline SnSe through synergistic optimization of sliver (Ag) and aluminum (Al) co-doping with the hydrogen reduction. The effects of Ag and Al doping on electronic transport properties are systematically investigated by density functional theory calculation and experimental measurement. Compared with pristine SnSe, Ag doping can effectively increase the hole concentration to 1.58 × 10 19 cm −3 and improve the conductivity. Results also indicate that using Al dopant may slightly decrease the hole concentration but reduce the thermal excitation temperature, and introduce point defects reducing the lattice thermal conductivity through scattering phonons. In addition, the hydrogen reduction of sample powders before synthesis can effectively remove Sn oxides and reduce lattice thermal conductivity. At last, a state-of-the-art maximum ZT value of 1.69 at 823 K is obtained in Ag 0.01 Al 0.01 Sn 0.98 Se. This study provides a theoretical basis and technical guidance for designing high-performance polycrystalline SnSe.
研究领域:
材料科学
·
凝聚态物理
✓ 已验证
产品关联
DOI
高影响因子
Chinese Physics B
·
2018
·Vol. 27
·期 4
·047211
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IF 1.321
Chengyan Liu,Lei Miao,Xiaoyang Wang,Shaohai Wu,Yanyan Zheng,Ziyang Deng,Yulian Chen,Guiwen Wang,Xiaoyuan Zhou
Thermoelectric selenides have attracted more and more attentions recently. Herein, p-type SnSe polycrystalline bulk materials with good thermoelectric properties are presented. By using the SnSe2 nanostructures synthesized via a wet-chemistry route as the precursor, polycrystalline SnSe bulk materials were successfully obtained by a combined heat-treating process under reducing atmosphere and following spark plasma sintering procedure. As a reference, the SnSe nanostructures synthesized via a wet-chemistry route were also fabricated into polycrystalline bulk materials through the same process. The thermoelectric properties of the SnSe polycrystalline transformed from SnSe2 nanostructures indicate that the increasing of heattreating temperature could effectively decrease the electrical resistivity, whereas the decrease in Seebeck coefficient is nearly invisible. As a result, the maximum power factor is enhanced from 5.06\times {10}^{-4}\,{\rm{W}}/{\rm{m}}\cdot {{\rm{K}}}^{2} to 8.08\times {10}^{-4}\,{\rm{W}}/{\rm{m}}\cdot {{\rm{K}}}^{2} at 612 °C. On the other hand, the reference sample, which was obtained by using SnSe nanostructures as the precursor, displays very poor power factor of only 1.30\times {10}^{-4}\,{\rm{W}}/{\rm{m}}\cdot {{\rm{K}}}^{2} at 537 °C. The x-ray diffraction (XRD), scanning electron microscope (SEM), x-ray fluorescence (XRF), and Hall effect characterizations suggest that the anisotropic crystal growth and existing Sn vacancy might be responsible for the enhanced electrical transport in the polycrystalline SnSe prepared by using SnSe2 precursor. On the other hand, the impact of heat-treating temperature on thermal conductivity is not obvious. Owing to the boosting of power factor, a high zT value of 1.07 at 612 °C is achieved. This study provides a new method to synthesize polycrystalline SnSe and pave a way to improve the thermoelectric properties of polycrystalline bulk materials with similar layered structure.
研究领域:
材料科学
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热电学
✓ 已验证
产品关联
DOI
高影响因子
Small
·
2024
·Vol. 20
·期 32
·2312003
·
IF 13
Mohammad Nisar,Adeel Abbas,Junze Zhang,Fu Li,Zhuanghao Zheng,Guangxing Liang,Ping Fan,Yue-Xing Chen
Enhancing the thermoelectric performance of n-type polycrystalline SnSe is essential, addressing challenges posed by elevated thermal conductivity and compromised power factor inherent in its intrinsic p-type characteristics. This investigation utilized solid-state reactions and spark plasma sintering techniques for the synthesis of n-type SnSe. A significant improvement in the figure of merit (ZT) is achieved through strategic reduction in Se concentration and optimization of crystal orientation. The co-doping with Br and Ge further improves the material; Br amplifies carrier concentration, enhancing electrical conductivity, while Ge introduces effective phonon scattering centers. In the Br/Ge co-doped SnSe sample, thermal conductivity dropped to 0.38 Wm⁻¹K⁻¹, yielding a remarkable power factor of 662 µW mK − 2 at 773 K, culminating in a ZT of 1.34. This signifies a noteworthy 605% improvement over the pristine sample, underscoring the pivotal role of Ge doping in enhancing n-type material thermoelectric properties. The enhancement is attributed to Br doping introducing additional electronic states near the valence band, and Ge doping modifying the band structure, fostering resonant states near the conduction band. The Br/Ge co-doping further transforms the band structure, influencing electrical conductivity, Seebeck coefficient, and thermal conductivity, advancing the understanding and application of n-type SnSe materials for superior thermoelectric performance.
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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凝聚态物理
✓ 已验证
DOI
高影响因子
Nature Communications
·
2024
·Vol. 15
·期 1
·1-13
·
IF 14.7
Gong Yaru,Dou Wei,Lu Bochen,Zhang Xuemei,Zhu He,Ying Pan,Zhang Qingtang,Liu Yuqi,Li Yanan,Huang Xinqi,Iqbal Muhammad Faisal,Zhang Shihua,Li Di,Zhang Yongsheng,Wu Haijun,Tang Guodong
N -type polycrystalline SnSe is considered as a highly promising candidates for thermoelectric applications due to facile processing, machinability, and scalability. However, existing efforts do not enable a peak ZT value exceeding 2.0 in n -type polycrystalline SnSe. Here, we realized a significant ZT enhancement by leveraging the synergistic effects of divacancy defect and introducing resonance level into the conduction band. The resonance level and increased density of states resulting from tungsten boost the Seebeck coefficient. The combination of the enhanced electrical conductivity (achieved by increasing carrier concentration through WCl 6 doping and Se vacancies) and large Seebeck coefficient lead to a high power factor. Microstructural analyses reveal that the co-existence of divacancy defects (Se vacancies and Sn vacancies) and endotaxial W- and Cl-rich nanoprecipitates scatter phonons effectively, resulting in ultralow lattice conductivity. Ultimately, a record-high peak ZT of 2.2 at 773 K is achieved in n -type SnSe 0.92 + 0.03WCl 6 .
研究领域:
材料科学
·
热电学
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固体物理学
✓ 已验证
DOI
高影响因子
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
·
2016
·Vol. 18
·期 46
·31821-31827
·
IF 4.449
Dan Feng,Zhen-Hua Ge,Di Wu,Yue-Xing Chen,Tingting Wu,Ju Li,Jiaqing He
We present in this manuscript that enhanced thermoelectric performance can be achieved in polycrystalline SnSe prepared by hydrothermal reaction and spark plasma sintering (SPS). X-ray diffraction (XRD) patterns revealed strong orientation along the [l 0 0] direction in bulk samples, which was further confirmed by microstructural observation through transmission electron microscopy (TEM) and field emission scanning electron microscopy (FESEM). It was noticed that the texturing degree of bulk samples could be controlled by sintering temperature during the SPS process. The best electrical transport properties were found in the sample which sintered at 450 °C in the direction vertical to the pressing direction, where the highest texturing degree and mass density were achieved. Coupled with the relatively low thermal conductivity, an average ZT of ∼ 0.38, the highest ever reported in pristine polycrystalline SnSe was obtained. This work set up a forceful example that a texture-control approach can be utilized to enhance the thermoelectric performance effectively.
研究领域:
材料科学
·
热电学
✓ 已验证
DOI
PubMed
高影响因子
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