碲纳米线柔性薄膜的制备及其热电性能

doi:10.15541/jim20190550

摘要/Abstract

摘要：

柔性热电器件能够直接将人体热量转化为电能, 因而受到广泛的关注。本研究采用水热法合成了碲纳米线, 探究了水热温度和反应溶液的还原性强弱(添加抗坏血酸与否)对碲纳米线形貌及热电性能的影响。与强还原性反应液(添加抗坏血酸)中制备的碲纳米线相比, 弱还原性反应液(未添加抗坏血酸)中制备的碲纳米线具有较高的长径比, 最高可达200, 其组装的薄膜具有更高的电导率, 达到26 S·m^-1。进一步研究了成膜工艺对碲纳米线薄膜热电性能的影响, 发现湿压法可提升薄膜的微观致密度, 使薄膜中碲纳米线之间的微观连接更为紧密, 从而改善了薄膜的载流子迁移率和载流子浓度, 使薄膜的电导率提升了18.3倍, 达到476 S?m^-1, 塞贝克系数为282.9 μV?K^-1, 功率因子达到38 μW?m^-1?K^-2。

关键词: 柔性热电, 湿压, 碲纳米线

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

中图分类号:

TQ174

徐海丰,侯成义,张青红,李耀刚,王宏志. 碲纳米线柔性薄膜的制备及其热电性能[J]. 无机材料学报, 2020, 35(9): 1034-1040.

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.

图/表 9

图1 碲纳米线的制备及其柔性薄膜组装流程示意图

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

图2 未添加抗坏血酸的反应溶液在(a) 140、(b) 160、(c) 180、(d) 200 ℃制备的碲纳米线的FESEM照片; 添加抗坏血酸的反应溶液在(e) 140、(f) 160、(g) 180、(h) 200 ℃制备的碲纳米线的FESEM照片通过氧化碲、抗坏血酸、乙二醇、氢氧化钠、PVP制备碲纳米线, 其化学反应式如下:

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 ℃

图3 TN160薄膜的XRD图谱

Fig. 3 XRD pattern of TN160 film

图4 TN160的(a)低倍、(b)高倍TEM照片和(c)傅里叶变换图

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

图5 不同条件下制备的碲纳米线薄膜的(a)塞贝克系数、(b)电导率和(c)功率因子; (d) ATN160和(g) TN160薄膜的表面FESEM照片, 插图为对应薄膜的断面FESEM照片; (e) ATN160和(f)TN160薄膜(1 cm×2 cm)的电阻测试的数码照片

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

图6 (a, e)未湿压处理以及在(b, f)10、(c, g)20、(d, h)30 MPa湿压处理的TN160薄膜(1 cm×2 cm)的(a~d)电阻测试数码照片和(e~h)薄膜表面FESEM照片; (i, j)未湿压处理和在(k, l)30 MPa湿压处理的TN160薄膜的(i, k)断面和(j, l)局部放大FESEM照片

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

图7 湿压处理前后TN160薄膜的(a)电导率、(b)塞贝克系数和(c)功率因子

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

图8 湿压处理后TN160薄膜的载流子浓度和载流子迁移率

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

表1 30 MPa湿压处理的TN160薄膜柔性测试

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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