
==== Front
Sci Rep
Sci Rep
Scientific Reports
2045-2322
Nature Publishing Group UK London

39300244
72950
10.1038/s41598-024-72950-7
Article
The impact of varying EDTA dosage on the flower-like morphology and thermoelectric properties of Ce-doped Bi2Te₃
Wu Fang fwu082@126.com

https://ror.org/04kfz4b98 0000 0004 1761 5108 College of Computer and Artificial Intelligence, Henan Finance University, Zhengzhou, 450046 China
19 9 2024
19 9 2024
2024
14 2185524 7 2024
12 9 2024
© The Author(s) 2024
2024
https://creativecommons.org/licenses/by-nc-nd/4.0/ Open Access This article is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License, which permits any non-commercial use, sharing, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if you modified the licensed material. You do not have permission under this licence to share adapted material derived from this article or parts of it. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by-nc-nd/4.0/.
Thermoelectric materials have significant applications in energy utilization and environmental protection. The effect of different EDTA (ethylenediaminetetraacetic acid) dosages on the flower-like morphology and thermoelectric properties of Ce-doped Bi2Te3 nanoparticles were investigated. The Ce-doped Bi2Te3 nanoparticles were sucessfully prepared via the hydrothermal method, and the influence of EDTA dosage on the morphology, structure, and thermoelectric properties of the materials was analyzed. The experimental results showed that an appropriate amount of EDTA can promote the formation of a flower-like morphology in Ce-doped Bi2Te3 nanomaterials and enhance their thermoelectric properties. The ZT values of the x = 0.15 sample made by the better flower-like morphology of nanopowders are all around 1, which reach 1.15 at 398 K. This work demonstrates the synergistic effects of combining nanostructure engineering and chemical doping strategies for thermoelectric performance enhancement.

Keywords

EDTA
Ce-doped Bi2Te3
Flower-like morphology
Thermoelectric properties
Hydrothermal method
Subject terms

Materials science
Nanoscience and technology
the Science and Technology Development Program of Henan Province of China142102210043 Wu Fang issue-copyright-statement© Springer Nature Limited 2024
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pmcIntroduction

Thermoelectric materials, as functional materials capable of converting heat energy into electrical energy and vice versa, have significant applications in energy utilization and environmental protection1–3. The properties of the thermoelectric materials is decided by the figure of merit ZT which is defined by \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ZT = S^{2} T/\kappa \rho$$\end{document}. As the equation indicated, a high ZT value requires a large Seebeck coefficient S, low electrical resistivity ρ and low thermal conductivity k4–6. Bi2Te, as a typical thermoelectric material, has attracted widespread attention due to its excellent thermoelectric properties. As reported, the morphology of the synthesized nanoparticles by hydrothermal method has significant effect on the ZT values of the thermoelectric materias, and the flower-like morphology is beneficial to improve the ZT values7–9. Pillai et al. 7 utilized a cold-pressed method to prepare the nanostructured rGO/GO-bismuth telluride samples to retain the initial morphology of the host nanomaterials, revealing that larger diameter bismuth telluride nanomaterials exhibited higher Seebeck coefficients and lower thermal conductivity (0.26 W/m–K) compared to smaller diameter and nanowire-based bismuth telluride thermoelectric materials. Kim et al.8 reported that nanocrystalline Bi2Te3 nanotubes synthesized using the solution phase method offered improved ZT values compared to bulk Bi2Te3 near room temperature due to enhanced Seebeck coefficients and suppressed thermal conductivity. Kimura et al.9 reported enhanced thermoelectric properties of n-type Bi2(SexTe1-x)3 nanoplates synthesized using solvothermal methods by tuning selenium composition. EDTA, a commonly used surfactant, plays a crucial role in regulating the morphology and properties of nanomaterials during the preparation process10.

Although the thermal conductivity of Bi2Te3-based materials has been significantly reduced through powder processing, it remains challenging to compete with newly emerged TE materials that exhibit intrinsically high phonon anharmonicity or liquid-like sublattices. Further reductions in thermal conductivity could potentially enhance the TE performance of Bi2Te3-based materials11. It is well-known that Ce can form resonance electron states near the Fermi level, strongly influencing electronic transport properties, particularly thermopower12. Therefore, studying the impact of varying EDTA dosages on the flower-like morphology and thermoelectric properties of Ce-doped Bi2Te3 is of great significance. This work successfully prepared Ce-doped Bi2Te3 nanoparticles via the hydrothermal method and analyzed the effect of EDTA dosage on the morphology, structure, and thermoelectric properties of the materials. The results demonstrate the synergistic effects of combining nanostructure engineering and chemical doping strategies for enhancing thermoelectric performance.

Experimental section

Material preparation

The methods of the material preparation and performance testing are same as our previous reports12. Analytical-grade chemicals including 1.7 mmol BiCl3, 0.3 mmol Ce(NO3)3(6H2O) and 3 mmol 5 N pure Te powder were used as the precursors for the synthesis of the Ce0.3Bi1.7Te3 nanopowders. The precursors were placed in a Teflon-lined autoclave filled with distilled water. Sodium hydroxide (NaOH) was added as PH-value controller, and a certain amount of EDTA was added as surfactant. Then, the Teflon-lined autoclave was placed on a magnetic stirrer and agitated for 30 min. Subsequently, 0.35 g of NaBH4 was introduced into the solution as the organic complex reagent. The autoclave was then sealed and maintained at 443 K for 24 h. The resulting powders were filtered and thoroughly washed several times using distilled water, dehydrated ethyl alcohol, and acetone to eliminate impurities. Following this, the powders were dried in a vacuum oven at 373 K for 6 h. Afterwards, they were hot-pressed into bulk pellets with diameters of either 12.5 mm or 15 mm and a thickness of approximately 2 mm at a temperature of 773 K under a pressure of 60 MPa in a vacuum environment.

Performance testing

The phase composition of the powders was analyzed using X-ray diffraction (XRD) with Cu-Kα radiation (Rigaku D/MAX-2550p diffractometer, Japan). The data were collected within a 2θ range of 10–80°, with a step size of 0.02° and a scanning speed of 4°/min. The morphologies of both the powders and the bulk pellets were observed using a field emission scanning electron microscope (SEM) (JSM-6700F, Japan). The densities of the bulk pellets were determined by the Archimedes method. The electrical resistivity \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\rho$$\end{document} and Seebeck coefficient \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$S$$\end{document} of rectangle bars cut from the ϕ15 mm pellets were measured at several temperature points using an LSR-3/800 Seebeck coefficient/Electric Resistance Measuring System (LINSEIS, Germany) under He atmosphere. The measuring error of the electrical resistivity ρ and Seebeck coefficient S is about 5%. The thermal conductivity \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\kappa$$\end{document} of the ϕ12.5 mm pellets was measured using a thermal diffusivity system (FLASHLINETM 3000, ANTER, USA) using Pyroceram as the reference sample (Provided by ANTER) at several temperature points. To avoid the fluctuation in the thermal conductivity measurement several times measurement were perform. The measuring error of the thermal conductivity is about 10%14. The power factors p were calculated by the equation p = S2/ρ. The figures of merit, ZT, was calculated by the measured data \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$S,\rho$$\end{document} and \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\kappa$$\end{document}. So the errors are 10% for power factor and 11% for ZT.

Results and discussion

As in ref15 when the amounts of EDTA is more than 0.2 g, the synthesized Ce0.3Bi1.7Te3 nanoparticles exists obvious impure phase in current synthesized conditions, so in this work the amounts of EDTA used is less than 0.2 g. Figure 1 presents the x-ray diffraction patterns of Ce-doped Ce0.3Bi1.7Te3 nanoparticles synthesized using varying amounts of EDTA (x = 0.125 g, 0.15 g, 0.175 g, respectively). It can be seen that all the nanopowders show \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$R\mathop 3\limits^{ - } m$$\end{document} rhombohedral structure as for the Bi2Te3 alloy, and there are no obvious impurity phases as compared to the standard JCPDS card of Bi2Te3 (15-0863 card). It indicates that in current synthesized conditions pure phase of the Ce0.3Bi1.7Te3 can be formed for the Ce doping element. And the amount of EDTA used does not affect the phase composition of the synthesized nanopowders.Fig. 1 XRD patterns of the Ce0.3Bi1.7Te3 nanopowdres prepared with different EDTA amount x, which are 0.125 g, 0.15 g, 0.175 g, respectively.

Figure 2 depicts the morphologies of Ce0.3Bi1.7Te3 nanopowders prepared with different EDTA dosages. It can be seen from the figure, all samples exhibit a well-defined flower-like morphology consisting of larger sheets with thicknesses less than 100 nm. Notably, the nanosheets forming the flower-like structures in the x = 0.125 g and x = 0.15 g samples are significantly smaller compared to those in the x = 0.175 g sample. This suggests that EDTA promotes the growth of larger nanosheets. Bi2Te3 crystal has a layered hexagonal structure with Te and Bi atom layers arranged in the order of –Te(1)–Bi–Te(2)–Bi–Te(1)– along the c-axis. In natural growth process Bi2Te3 crystal grows much faster along a-axis and b-axis than that along c-axis, thus flake morphology is easy formed. However, this natural growth process can be changed greatly by adding some surfactants15. During the growth process, EDTA acts as a chelating agent, binding with Bi3+ ions to form large molecular complexes, thereby facilitating the growth of Bi2Te3 nanosheets. It is indicated that EDTA is helpful to the growth along the a-axis and b-axis of the Bi2Te3 crystal which is consistent with our previous reports10,12. In this work Te powders were used as Te source which makes it possible for neighboring nanosheets to laterally connect each other and consequently form large flower-like clusters as mentioned by our previous reports15.Fig. 2 SEM images of of Ce0.3Bi1.7Te3 nanopowders with different EDTA dosage. (a) x = 0.125 g; (b) x = 0.15 g; (c) x = 0.175 g.

Figure 3 shows the microstructure of Ce0.3Bi1.7Te3 bulk samples obtained by hot pressing the flower-like nanopowders with varying EDTA dosages. The densities of the samples are 7.3 g/cm3, 7.2 g/cm3, and 7.5 g/cm3 for x = 0.125 g, 0.15 g, and 0.175 g, respectively, which are close to the theoretical density of Bi2Te3 (7.7 g/cm3). Upon hot pressing the flower-like morphologies are no longer visible, but the sheet-shaped crystals still exist with thicknesses less than 100 nm which is beneficial to enhanced thermoelectric (TE) properties. Moreover, the sheet sizes increase significantly along directions parallel to the sheet surfaces due to the high temperature during hot pressing. For the x = 0.125 g and 0.15 g samples, the microstructure of the hot-pressed bulk pellets comprises a mixture of small grains embedded in the larger sheets, which can scatter phonons effectively but not scatter carriers much thus improving the TE properties of Bi2Te3-based alloys as reported10,12. In contrast, the x = 0.175 g sample exhibits a primarily large sheet microstructure, which is caused by the larger nanosheets observed in the corresponding nanopowder as shown in Fig. 2c.Fig. 3 SEM images of hot pressed Ce0.3Bi1.7Te3 bulk samples with different EDTA dosage. (a) x = 0.125 g; (b) x = 0.15 g; (c) x = 0.175 g.

Figure 4 displays the electrical resistivity of Ce0.3Bi1.7Te3 bulk samples with different EDTA dosages as a function of temperature. All samples exhibit an increase in resistivity with temperature, indicating a degenerate semiconductor behavior. Notably, the resistivities of the x = 0.15 g and x = 0.175 g samples are lower than that of the x = 0.125 g sample. This may be attributed to the larger sheets in the x = 0.15 g and 0.175 g samples, which facilitate carrier transport and enhance carrier mobility13. The electrical resistivity is generally expressed as16:1 \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\rho = \frac{1}{\mu ne}$$\end{document}

where μ is the carrier mobility, n is the carrier concentration, and e is the charge of an electron. As indicated by Eq. 1, a higher carrier mobility results in a lower electrical resistivity.Fig. 4 Electrical resistivity of the Ce0.3Bi1.7Te3 bulk samples with different EDTA dosage versus temperature.

Figure 5 presents the Seebeck coefficients of the samples versus temperature. All samples exhibit n-type conduction evidenced by negative Seebeck coefficients within the measured temperature range, which indicate that Ce substitution for Bi acts as a donor dopant. The Seebeck coefficients of the samples all show a nonmonotonic variation, which initially increase with temperature, and after reaching a maximum then decrease with further temperature increase. This decrease in Seebeck coefficient at higher temperatures can be attributed to the rapid increase in minority carrier concentration17. While the electrical resistivity of the x = 0.15 g and x = 0.175 g samples is lower than that of the x = 0.125 g sample (Fig. 4), their Seebeck coefficients (absolute values) are also lower (Fig. 5). This is consistent with the common knowledge that lower electrical resistivity leads to lower Seebeck coefficients. However, the electrical resistivity of the x = 0.15 sample is little smaller than that of the x = 0.175 sample, as depicted in Fig. 4. Fig. 5 reveals that the Seebeck coefficient (in absolute value) of the x = 0.15 samples is much lower than that of the x = 0.175 sample, while the electrial reisitivity of the x = 0.15 samples is similar with that of the x = 0.175 sample. The possible reason can be attributed to the interplay between electron concentrations and scattering mechanisms, which are influenced by the microstructure of the samples. The Seebeck coefficient in degenerate semiconductors can be formulated as18:2 \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$S = \frac{{2k_{B}^{2} Tm^{*} }}{{3e\hbar^{2} }}\left( {\frac{\pi }{3n}} \right)^{2/3} \left( {\frac{3}{2} + \gamma } \right)$$\end{document}

Fig. 5 Seebeck coefficient of Ce0.3Bi1.7Te3 bulk samples with different EDTA dosage versus temperature.

Here, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$k_{B}$$\end{document} represents the Boltzmann constant, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$T$$\end{document} is the temperature in Kelvin, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\hbar$$\end{document} is the reduced Planck constant, n denotes the carrier concentration, and \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\gamma$$\end{document} is the scattering factor. As commonly observed from Eq. 2, a larger scattering factor leads to an increased Seebeck coefficient, whereas a higher carrier concentration n, corresponds to a lower Seebeck coefficient S18. As seen in Fig. 3, the size of the large sheets in the x = 0.15 sample is comparable to that of the x = 0.175 sample. However, the microstructure of the x = 0.15 sample contains tiny grains embedded within the large sheets, leading to more grain boundaries and subsequently more scattering. Nevertheless, for the Seebeck coefficient, the influence of increased carrier concentration outweighs the effect of scattering, which can evident that the microstructure corresponding to the flower-like morphology do not scatter carriers much. Therefore, despite having a slightly smaller electrical resistivithy, the Seebeck coefficient of the x = 0.15 sample is much lower than that of the x = 0.175 sample.

Figure 6 illustrates the power factor (S2/ρ) of the samples as a function of temperature. It is evident from Fig. 6 that, the power factor of the x = 0.175 sample is consistently higher than that of the x = 0.15 and x = 0.125 samples in the tested temperature range. This is attributed to its lower electrical resistivity and relatively higher Seebeck coefficient, as shown in Figs. 4 and 5. Notably, the power factor of the x = 0.15 sample surpasses that of the x = 0.125 sample above 448 K and is comparable to the x = 0.175 sample at 523 K. This indicates that the optimized flower-like morphology achieved through the use of the appropriate EDTA amount is beneficial for enhancing the power factor.Fig. 6 Power factor of Ce0.3Bi1.7Te3bulk samples with different EDTA dosage versus temperature.

Figure 7 displays the thermal conductivities of the samples versus temperature. The thermal conductivities of all samples are approximately 1 W/mK and much lower for the x = 0.15 sample, which is lower than that of commercially zone-melted Bi2Te3 ingots19. The possible reason are as follows: firstly, Ce-doping can introduce a number of point defects in the crystals which can effectively enhance phonon scattering and hence reduce the thermal conductivity. In addition, the thickness of the sheets in their microstructures is less than 100 nm which is helpful to decrease thermal conductivity as mentioned above. Additionally, the thermal conductivity of the x = 0.15 sample is lower than the other two samples. This may also be linked to the differences in microstructure of the samples. For the x = 0.15 bulk sample, the microstructure comprises tiny grains embedded in larger sheet which is superior as compared with the other two, as depicted in Fig. 3. The larger sheets can facilitate carrier transport, contributing to the electrical resistivity. And while the tiny grains can effectively scatter phonons, further reducing thermal conductivity as compared with the other two samples. Taking into account the results of the electrical resistivity and thermal conductivity, the microstructure corresponding to flower-like morphology of the x = 0.15 nanopowders is superior as compared with the other two samples, which tcan scatter phonons effectively simultaneously not scatter carriers much. It can also concluded that the amounts of the EDTA is a key factor to form the optimized microstructure.Fig. 7 Thermal conductivities of of Ce0.3Bi1.7Te3 bulk samples with different EDTA dosage versus temperature.

Figure 8 presents the ZT values of the bulk samples. The ZT values of the x = 0.15 sample, featuring the improved flower-like morphology of nanopowders, are approximately 1, reaching 1.15 at 398 K. As n-type thermoelectric materials, the ZT value of the x = 0.15 sample is relatively high, given that the ZT value of n-type Bi2Te3-based alloys has not been significantly improved beyond 120. It is noted that the ZT values of the x = 0.15 sample are all around 1 in the testing temperature and reached 1.15 at 398 K which is higher than that of other related reports21–26, as shown in Table 1. This demonstrates that the flower-like morphology of nanopowders is effective in enhancing the thermoelectric properties of Ce0.3Bi1.7Te3 bulk materials. Importantly, the appropriate amount of EDTA is crucial for forming this optimal flower-like morphology, which can reduce thermal conductivity much and simultaneously keep electrical resistivity at a relatively low extent.Fig. 8 The figures of merit (ZT) of of Ce0.3Bi1.7Te3 bulk samples with different EDTA dosage versus temperature.

Table 1 The thermoelectric fgure-of-merit of the n-type Bi2Te3 alloys.

References	Year	Composition	ZTmax (K)	
12	2013	Ce0.3 Bi1.7Te3	0.93 at 386	
21	2005	Ce-Bi2Se0.3Te3	0.22 at 450	
22	2014	CeBiTe3	0.29 at 450	
23	2023	n-type Bi2Te3	0.2 at 500	
24	2020	Bi1.9Gd0.1Te3	0.75 at 420	
25	2020	Bi2Se0.6Te2.4	1.0 at 380–500	
26	2021	Bi2Se0.3Te2.7	1.05 at 423	
This work		Ce0.3 Bi1.7Te3	1.15 at 398	

Conclusion

In this paper, Ce-doped Bi2Te3 nanomaterials with a flower-like morphology were successfully synthesized via the hydrothermal method. The influence of varying EDTA dosages on their flower-like morphology were investigated. The phase composition of the powders was analyzed by XRD. And the morphology of the samples were observed by SEM. The results reveal that an optimal amount of EDTA significantly facilitates the development of the flower-like morphology in Ce-doped Bi2Te3 nanomaterials. and The effect of varying EDTA dosages on thermoelectric properties was thoroughly investigated. Notably, the appropriate amount of EDTA emerges as a crucial factor in achieving a superior flower-like morphology, which can reduce thermal conductivity much and simultaneously keep electrical resistivity at a relatively low extent. Consequently, the ZT values of the x = 0.15 sample, featuring the optimized flower-like morphology, attained all around 1, peaking at 1.15 at 398 K which is higher than that of the zone melt ingots27. This study demonstrates the synergistic potential of combining nanostructure engineering with chemical doping strategies for enhancing thermoelectric performance.

Acknowledgements

This work was supported partly by the Science and Technology Development Program of Henan Province of China (Grant No. 142102210043), and the Research and Practice Project of Research Teaching Reform of Henan Province in 2023.

Author contributions

Fang Wu wrote the main manuscript text and prepared figures. All authors reviewed the manuscript.

Data availability

All data generated or analysed during this study are included in this published article.

Declarations

Competing interests

The authors declare no competing interests.

Publisher’s note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
==== Refs
References

1. Mao J Chen G Ren ZF Thermoelectric cooling materials Nat. Mater. 2021 20 454 461 10.1038/s41563-020-00852-w 33288897
Mao, J., Chen, G. & Ren, Z. F. Thermoelectric cooling materials. Nat. Mater. 20, 454–461 (2021).33288897
2. Yasaman S Seyed AS A comprehensive review on the effects of doping process on the thermoelectric properties of Bi2Te3 based alloys J. Alloy. Compd. 2022 904 163918 10.1016/j.jallcom.2022.163918
Yasaman, S. & Seyed, A. S. A comprehensive review on the effects of doping process on the thermoelectric properties of Bi2Te3 based alloys. J. Alloy. Compd. 904, 163918 (2022).
3. Hu CL Xia KY Fu CG Zhao XB Zhu TJ Carrier grain boundary scattering in thermoelectric materials Energy Environ. Sci. 2022 15 1406 1422 10.1039/D1EE03802H
Hu, C. L., Xia, K. Y., Fu, C. G., Zhao, X. B. & Zhu, T. J. Carrier grain boundary scattering in thermoelectric materials. Energy Environ. Sci. 15, 1406–1422 (2022).
4. Ma Z Wei JT Song PS Zhang ML Yang LL Ma J Liu W Yang FH Wang XD Review of experimental approaches for improving ZT of thermoelectric materials Mat. Sci. Semicon. Proce. 2021 121 105303 10.1016/j.mssp.2020.105303
Ma, Z. et al. Review of experimental approaches for improving ZT of thermoelectric materials. Mat. Sci. Semicon. Proce. 121, 105303 (2021).
5. Fang T Li X Hu CL Zhang Q Yang J Zhang WQ Zhao XB Singh DJ Zhu TJ Complex band structures and lattice dynamics of Bi2Te3-based compounds and solid solutions Adv. Funct. Mater. 2019 29 1900677 10.1002/adfm.201900677
Fang, T. et al. Complex band structures and lattice dynamics of Bi2Te3-based compounds and solid solutions. Adv. Funct. Mater. 29, 1900677 (2019).
6. Abid N Khan AM Shujait S Chaudhary K Ikram M Imran M Haider J Khan M Khan Q Maqbool M Synthesis of nanomaterials using various top-down and bottom-up approaches, influencing factors, advantages, and disadvantages: A review Adv. Colloid. Interface. 2022 300 102597 10.1016/j.cis.2021.102597
Abid, N. et al. Synthesis of nanomaterials using various top-down and bottom-up approaches, influencing factors, advantages, and disadvantages: A review. Adv. Colloid. Interface. 300, 102597 (2022).
7. Pillala NN Dommisa DB Dash RK Infuence of nanowires and nanotubes on the therma conductivity of graphene–Bi2Te3 based nanostructured materials Appl. Nanosci. 2022 12 2551 2561 10.1007/s13204-022-02563-x
Pillala, N. N., Dommisa, D. B. & Dash, R. K. Infuence of nanowires and nanotubes on the therma conductivity of graphene–Bi2Te3 based nanostructured materials. Appl. Nanosci. 12, 2551–2561 (2022).
8. Kim DS Du RZ Yu SY Yin YW Dong SN Li Q Mohney SE Li XG Tadigadapa S Enhanced thermoelectric efficiency in nanocrystalline bismuth telluride nanotubes Nanotechnology 2020 31 365703 10.1088/1361-6528/ab97d2 32470964
Kim, D. S. et al. Enhanced thermoelectric efficiency in nanocrystalline bismuth telluride nanotubes. Nanotechnology 31, 365703 (2020).32470964
9. Kimura Y Mori R Yonezawa S Yabuki H Namiki H Ota Y Takashiri M Solvothermal synthesis of n-type Bi2(Sexte1−x)3 nanoplates for highperformance thermoelectric thin flms on fexible substrates Sci. Rep-UK 2020 10 6315 10.1038/s41598-020-63374-0
Kimura, Y. et al. Solvothermal synthesis of n-type Bi2(Sexte1−x)3 nanoplates for highperformance thermoelectric thin flms on fexible substrates. Sci. Rep-UK 10, 6315 (2020).
10. Wu F Wang W Thermoelectric properties of n type Bi2Se0.3Te2.7 based alloys with nanofowers morphology Appl. Phys. A-Mater. 2022 128 675 10.1007/s00339-022-05838-w
Wu, F. & Wang, W. Thermoelectric properties of n type Bi2Se0.3Te2.7 based alloys with nanofowers morphology. Appl. Phys. A-Mater. 128, 675 (2022).
11. Zhuang HL Hu HH Pei J Su B Li JW Jiang YL Han ZR Li JF High ZT in p-type thermoelectric (Bi, Sb)2Te3 with built-in nanopores Energy Environ. Sci. 2022 15 2039 2048 10.1039/D2EE00119E
Zhuang, H. L. et al. High ZT in p-type thermoelectric (Bi, Sb)2Te3 with built-in nanopores. Energy Environ. Sci. 15, 2039–2048 (2022).
12. Wu F Shi WY Hu X Preparation and thermoelectric properties of flower-like nanoparticles of Ce-Doped Bi2Te3 Electron. Electron. Mater. Lett. 2015 11 127 132 10.1007/s13391-014-4139-x
Wu, F., Shi, W. Y. & Hu, X. Preparation and thermoelectric properties of flower-like nanoparticles of Ce-Doped Bi2Te3. Electron. Electron. Mater. Lett. 11, 127–132 (2015).
13. Zhang XZ Wang ZY Hou Y Liu Y Hu LW Xie WH Shi J Wei JH Xiong R High-performance Bi0.4Sb1.6Te3 alloy prepared by a low-cost method for wearable real-time power supply and local cooling Chem. Eng. J. 2024 481 148530 10.1016/j.cej.2024.148530
Zhang, X. Z. et al. High-performance Bi0.4Sb1.6Te3 alloy prepared by a low-cost method for wearable real-time power supply and local cooling. Chem. Eng. J. 481, 148530 (2024).
14. Borup KA de Boor J Wang H Drymiotis F Gascoin F Shi X Chen LD Fedorov MI Muller E Iversena BB Snyder GJ Measuring thermoelectric transport properties of materials Energy Environ. Sci. 2015 8 423 435 10.1039/C4EE01320D
Borup, K. A. et al. Measuring thermoelectric transport properties of materials. Energy Environ. Sci. 8, 423–435 (2015).
15. Wu F Song HZ Gao F Shi WY Jia JF Hu X Effects of different morphologies of Bi2Te3 nanopowders on thermoelectric properties J. Electron. Mater. 2013 42 1140 1145 10.1007/s11664-013-2541-z
Wu, F. et al. Effects of different morphologies of Bi2Te3 nanopowders on thermoelectric properties. J. Electron. Mater. 42, 1140–1145 (2013).
16. Yelgel ÖC Srivastava GPJ Thermoelectric properties of p-type (Bi2Te3)x (Sb2Te3)1–x single crystals doped with 3 wt% Te Appl. Phys. 2013 113 073709 10.1063/1.4792653
Yelgel, Ö. C. & Srivastava, G. P. J. Thermoelectric properties of p-type (Bi2Te3)x (Sb2Te3)1–x single crystals doped with 3 wt% Te. Appl. Phys. 113, 073709 (2013).
17. Yang JJ Wu F Zhu Z Yao L Song HZ Hu X Thermoelectrical properties of lutetium-doped Bi2Te3 bulk samples prepared from flower-like nanopowders J. Alloy. Compd. 2015 619 401 405 10.1016/j.jallcom.2014.09.024
Yang, J. J. et al. Thermoelectrical properties of lutetium-doped Bi2Te3 bulk samples prepared from flower-like nanopowders. J. Alloy. Compd. 619, 401–405 (2015).
18. Dou YC Qin XY Li D Li LL Zou TH Wang QQ Enhanced thermopower and thermoelectric performance through energy filtering of carriers in (Bi2Te3)0.2(Sb2Te3)0.8 bulk alloy embedded with amorphous SiO2 nanoparticles J. Appl. Phys. 2013 114 044906 10.1063/1.4817074
Dou, Y. C. et al. Enhanced thermopower and thermoelectric performance through energy filtering of carriers in (Bi2Te3)0.2(Sb2Te3)0.8 bulk alloy embedded with amorphous SiO2 nanoparticles. J. Appl. Phys. 114, 044906 (2013).
19. Poudel B Hao Q Ma Y Lan YC Minnich A Yu B Yan X Wang DZ Muto A Vashaee D Chen XY Liu JM Dresselhaus MS Chen G Ren ZF High-Thermoelectric performance of nanostructured bismuth antimony telluride bulk alloys Science 2008 320 634 638 10.1126/science.1156446 18356488
Poudel, B. et al. High-Thermoelectric performance of nanostructured bismuth antimony telluride bulk alloys. Science 320, 634–638 (2008).18356488
20. Kawajiri Y Tanusilp ST Kumagai M Ishimaru M Ohishi Y Tanaka J Kurosaki K Enhancement of thermoelectric properties of n-Type Bi2Te3-xSex by energy filtering effect ACS Appl. Energy Mater. 2021 4 11819 11826 10.1021/acsaem.1c02560
Kawajiri, Y. et al. Enhancement of thermoelectric properties of n-Type Bi2Te3-xSex by energy filtering effect. ACS Appl. Energy Mater. 4, 11819–11826 (2021).
21. Ji XH Zhao XB Zhang YH Lu BH Ni HL Synthesis and properties of rare earth containing Bi2Te3 based thermoelectric alloys J. Alloy. Compd. 2005 387 282 286 10.1016/j.jallcom.2004.06.047
Ji, X. H., Zhao, X. B., Zhang, Y. H., Lu, B. H. & Ni, H. L. Synthesis and properties of rare earth containing Bi2Te3 based thermoelectric alloys. J. Alloy. Compd. 387, 282–286 (2005).
22. Quang TV Kim M Effect on the electronic, magnetic and thermoelectric properties of BiTe by the cerium substitution IEEE T. Magn. 2014 50 1000904 10.1109/TMAG.2013.2279854
Quang, T. V. & Kim, M. Effect on the electronic, magnetic and thermoelectric properties of BiTe by the cerium substitution. IEEE T. Magn. 50, 1000904 (2014).
23. Irfan S Din MAU Manzoor MQ Chen DL Effect of Co-Doping on thermoelectric properties of n-Type Bi2Te3 nanostructures fabricated using a low-temperature Sol-Gel method Nanomaterials 2021 11 2719 10.3390/nano11102719 34685160
Irfan, S., Din, M. A. U., Manzoor, M. Q. & Chen, D. L. Effect of Co-Doping on thermoelectric properties of n-Type Bi2Te3 nanostructures fabricated using a low-temperature Sol-Gel method. Nanomaterials 11, 2719 (2021).34685160
24. Ivanov O Yaprintsev M Vasil’ev A Comparative analysis of the thermoelectric properties of the non-textured and textured Bi1.9Gd0.1Te3 compounds J. Solid State Che. 2020 290 121559 10.1016/j.jssc.2020.121559
Ivanov, O., Yaprintsev, M. & Vasil’ev, A. Comparative analysis of the thermoelectric properties of the non-textured and textured Bi1.9Gd0.1Te3 compounds. J. Solid State Che. 290, 121559 (2020).
25. Meroz O Elkabets N Gelbstein Y Enhanced thermoelectric properties of nType Bi2Te3-xSex alloys following melt-spinning ACS Appl. Energy Mater. 2020 3 2090 2095 10.1021/acsaem.9b02133
Meroz, O., Elkabets, N. & Gelbstein, Y. Enhanced thermoelectric properties of nType Bi2Te3-xSex alloys following melt-spinning. ACS Appl. Energy Mater. 3, 2090–2095 (2020).
26. Lee JK Son JH Park SD Particle size dependent anisotropic thermoelectric properties of N-type Bi2(Te, Se)3 alloys on hot deformation J. Alloy. Compd. 2021 858 157727 10.1016/j.jallcom.2020.157727
Lee, J. K., Son, J. H. & Park, S. D. Particle size dependent anisotropic thermoelectric properties of N-type Bi2(Te, Se)3 alloys on hot deformation. J. Alloy. Compd. 858, 157727 (2021).
27. Li J Wang Y Yan Y Wang C Li L Pressure effect on the electronic structure and thermoelectric properties of alpha-MgAgSb Comput. Mater. Sci. 2018 155 450 456 10.1016/j.commatsci.2018.08.003
Li, J., Wang, Y., Yan, Y., Wang, C. & Li, L. Pressure effect on the electronic structure and thermoelectric properties of alpha-MgAgSb. Comput. Mater. Sci. 155, 450–456 (2018).
