Wearable and flexible thin film thermoelectric module for multi-scale energy harvesting

Abstract

Developing a thermoelectric generator(TEG) with shape conformable geometry for sustaining low-thermal impedance and large temperature gradient (∆ ) is fundamental for wearable and multi-scale energy harvesting applications. Here we demonstrate a flexible architectural design, with efficient thin film thermoelectric generator as a solution for this problem. This approach not only decreases the thermal impedance but also multiplies the temperature gradient, thereby increasing the power conversion efficiency (PCE) as comparable to bulk TEG. Intact thin films of Tin telluride (p-type) and Lead Telluride (n-type) are deposited on flexible substrate through physical vapor deposition and a thermoelectric module possessing a maximum output power density of 8.4mW/cm 2 is fabricated. We have demonstrated the performance of p-SnTe/n-PbTe based TEG as a flexible wearable power source for electronic gadgets, as a thermal touch sensor for real-time switching and temperature monitoring for exoskeleton applications.

Heat source-free water-floating carbon nanotube thermoelectric generators

“…These applications require TEGs that are small, lightweight, and mechanically exible, without excessively high power caused by a large temperature gradient. Thinlm TEGs on a exible substrate are the most promising candidate to satisfy these requirements [12][13][14][15] . To date, bismuth telluride-based alloys have proved a popular choice for thin-lm TEGs owing to their impressive thermoelectric properties near room temperature [16][17][18][19] .…”

Polymer‐Based Low‐Temperature Thermoelectric Composites

“…Polarization effect 105 0.014 0.2 Sun et al [78] P3HT F4TCNQ vapor Improved crystallinity 60 10 32.7 Hynynen et al [79] P3HT F4TCNQ vapor 85 180 27 Lim et al [80] P3HT F4TCNQ Structural ordering 110 13 10 Lim et al [81] P3HT F4TCNQ HOMO edge adjustment 424 0.0085 Zou et al [82] P3HT FeCl 3 , I 2 doping…”

“…The use of thermoelectric (TE) materials (especially low‐T and flexible TE) can play a role in new and low energy consumption application such as portable sensors and wearable electronics. [ 10 ]…”

Thermoelectric Materials for Textile Applications

“…There has been a vast amount of research conducted in the field of thin film-based flexible TE devices (FTEs) due to the fact that compared to bulk TE devices, FTEs provide the advantage of providing a conformable structure that can make intimate contact with a curved heat source (such as skin) [51][52][53][54], lower temperature processing than bulk TE materials [55][56][57][58], as well as the fact that FTEs are lightweight and less bulky than their rigid counterparts [19,20,59] [57], Wan et al also developed hybrid organic-inorganic TiS 2 superlattices with power factor as high as their inorganic counterparts at 904 µW/mK 2 [63]. While it is beyond the scope of this review to cover the vast literature on thin film FTEs, a number of excellent reviews which discuss both materials and configurations of thin-film FTE structures are recommended to readers (Figure 2) [10,35,[64][65][66][67].…”

“…There has been a vast amount of research conducted in the field of thin film-based flexible TE devices (FTEs) due to the fact that compared to bulk TE devices, FTEs provide the advantage of providing a conformable structure that can make intimate contact with a curved heat source (such as skin) [ 51 , 52 , 53 , 54 ], lower temperature processing than bulk TE materials [ 55 , 56 , 57 , 58 ], as well as the fact that FTEs are lightweight and less bulky than their rigid counterparts [ 19 , 20 , 59 ]. Various materials have been explored for creating FTEs such as Fan et al developed thin film FTEs with n-type Al doped ZnO and p-type Zn-Sb to create a flexible device with a maximum power output of 246.3 µW [ 60 ], Parashchuk et al developed p-type BiSbTe thin films on a flexible polyimide substrate with a figure of merit as high as 2.4 × 10 3 /K [ 61 ], Karthikeyan et al used n-type PbTe and p-type SnTe to develop thin film FTEs for wearable energy harvesting with a power density of 8.4 mW/cm 2 [ 51 ], Jiang et al fabricated n-type Ag 2 Se films on a porous nylon membrane with a power density of 22 W/m 2 [ 62 ], Tian et al developed flexible organic-inorganic hybrid n-type TiS 2 /hexylamine treated superlattice structure with a power density of 2.5 W/m 2 [ 57 ], Wan et al also developed hybrid organic-inorganic TiS 2 superlattices with power factor as high as their inorganic counterparts at 904 µW/mK 2 [ 63 ]. While it is beyond the scope of this review to cover the vast literature on thin film FTEs, a number of excellent reviews which discuss both materials and configurations of thin-film FTE structures are recommended to readers ( Figure 2 ) [ 10 , 35 , 64 , 65 , 66 , 67 ].…”