Post ionized defect engineering of the screen-printed Bi2Te2.7Se0.3 thick film for high performance flexible thermoelectric generator
Post ionized defect engineering of the screen-printed Bi2Te2.7Se0.3 thick film for high performance flexible thermoelectric generator
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DOI：
10.1016/j.nanoen.2016.11.034
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发表时间：
2017-01-01
期刊：
影响因子：
17.6
通讯作者：
Cho, Byung Jin
中科院分区：
文献类型：
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作者：
Kim, Sun Jin;Choi, Hyeongdo;Cho, Byung Jin
利用丝网印刷技术制造的柔性热电发电机(f-teg)已被引入作为可穿戴式和柔性电子系统的半永久电源。然而，由于丝网印刷热电(TE)薄膜的ZT较低，f-TEG模块的输出功率密度仍然受到限制。在此，我们报告了一种有效地控制电离缺陷并提高丝网印刷三元TE膜的ZT值的后电离缺陷工程工艺。研究发现，在成型气氛(4%H-2+96%Ar)中的后退火可使丝网印刷n型BiTeSe薄膜中纳米和微米级的BiTeSe氧化物颗粒减少，从而形成富铋的状态，并产生铋反位缺陷。在常温下，丝网印刷n型BiTeSe厚膜的最大ZT达到0.90，几乎与块体Bi2Te2.7Se0.3相当，是未经氢气气氛退火的相同丝网印刷薄膜的2倍。为了验证这种方法的适用性，用丝网印刷技术制作了72个TE对(p型Bi0.5Sb1.5Te3，形成气退火n型Bi2Te2.7Se0.3)的f-TEG器件。该器件在Delta T=25.6℃时产生了6.32 mW cm(-2)的高输出功率。这些结果证明了利用电离缺陷工程制造高性能和大规模的f-TEG的可行性。
Flexible thermoelectric generators (f-TEGs), fabricated by the screen printing technique, have been introduced as a semi-permanent power source for wearable and flexible electronic systems. However, the output power density of the f-TEG module is still limited due to the low ZT of the screen-printed thermoelectric (TE) film. We herein report a post ionized defect engineering process that effectively controls ionized defects and improves the ZT value of a screen-printed ternary TE film. It was found that post annealing in a forming gas ambient (4% H-2+96% Ar) can reduce the nano- and micro-bismuth oxide particles in screen-printed n-type BiTeSe films, resulting in a bismuth rich condition and creation of bismuth antisite defects. We achieved a maximum ZT of 0.90 with the-screen-printed n-type BiTeSe thick film at-room temperature, which is-almost comparable to that of the bulk Bi2Te2.7Se0.3 and is a 2-fold increase over the same screen-printed film without the hydrogen ambient annealing. To demonstrate the applicability of this approach, a f-TEG device with 72 TE pairs (p-type Bi0.5Sb1.5Te3, forming gas annealed n-type Bi2Te2.7Se0.3) was fabricated by the screen printing technique. The device generated a high output power of 6.32 mW cm(-2) at Delta T=25.6 degrees C. These results demonstrate the feasibility of high performance and large-scale f-TEG fabrication using ionized-defect engineering.