Preparation and Thermoelectric Performance of Tellurium Nanowires-based Thin-Film Materials

doi:10.15541/jim20190550

Abstract

Abstract:

Flexible thermoelectric devices have received a great deal of interest due to their capability of direct convert human body heat into electrical energy. In this work, we synthesized the tellurium nanowires by using hydrothermal method. The effects of hydrothermal temperature and reducibility of the reaction solution (with or without ascorbic acid) on morphology and thermoelectric properties of tellurium nanowires were investigated. Compared to the nanowires prepared in strong reducing solution, those prepared in relatively weak reducing solution (without ascorbic acid) reveal a higher aspect ratio up to 200 and the as-assembled film exhibits better electrical conductivity up to 26 S·m^-1. It is also found that the wet-press method can enhance the micro-densification of the film, resulting in a tighter connection among the micro-nanowires. Therefore, the carrier mobility and carrier concentration of the tellurium nanowire film are significantly increased. As a result, its electrical conductivity is improved by 18.3 times, reached 476 S?m^-1. Simultaneously the optimal tellurium nanowire film exhibits good performances including Seebeck coefficient (282.9 μV?K^-1) and power factor (38 μW?m^-1?K^-2).

Key words: flexible thermoelectric, wet-press, tellurium nanowire

CLC Number:

TQ174

XU Haifeng,HOU Chengyi,ZHANG Qinghong,LI Yaogang,WANG Hongzhi. Preparation and Thermoelectric Performance of Tellurium Nanowires-based Thin-Film Materials[J]. Journal of Inorganic Materials, 2020, 35(9): 1034-1040.

Figures/Tables 9

Fig. 1 Schematic illustration for the preparation of the Te nanowire and flexible film

Fig. 2 FESEM images of Te nanowires obtained by the solution without ascorbic acid at (a) 140, (b)160, (c) 180 and (d) 200 ℃, and with ascorbic acid at (e) 140, (f) 160, (g) 180 and (h) 200 ℃

Fig. 3 XRD pattern of TN160 film

Fig. 4 (a) Low-magnification, (b) high-magnification TEM images and (c) Fourier transformation pattern of TN160

Fig. 5 (a) Seebeck coefficients, (b) electrical conductivities, (c) power factors of Te nanowire films prepared under different conditions; Surface FESEM images of (d) ATN160 and (g) TN160 films with insets showing corresponding cross-sectional FESEM images; Digital photos of film (1 cm×2 cm) resistance tests for (e) ATN160 and (f) TN160 films

Fig. 6 (a-d) Digital photos of film (1 cm×2 cm) resistance test and (e-h)FESEM surface images of TN160 film (a, e) without and with wet press at (b, f)10, (c, g) 20, (d, h) 30 MPa; (i, k) Cross-sectional and (j, l) high-magnification cross-sectional FESEM images of TN160 films (i, j) without and (k, l) with wet press at 30 MPa

Fig. 7 (a) Electrical conductivity, (b) Seebeck coefficient and (c) power factor of TN160 film before and after wet press

Fig. 8 Carrier concentration and carrier mobility of TN160 film with wet press at different pressures

Table 1 Flexibilities of TN160 film with wet press at 30 MPa

Curve radius/ cm	Electrical conductivity/ (S·m^-1)	Seebeck coefficient/ (μV·K^-1)	Power factor/ (μW·m^-1∙K^-2)
∞	476	282.9	38
2.0	472	282.0	37.5
1.6	465	282.3	37.1
1.2	458	282.0	36.4
0.8	448	281.9	35.6

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