ABSTRACT
Micro-thermoelectric coolers are emerging as a promising solution for high-density cooling applications in confined spaces. Unlike thin-film micro-thermoelectric coolers with high cooling flux at the expense of cooling temperature difference due to very short thermoelectric legs, thick-film micro-thermoelectric coolers can achieve better comprehensive cooling performance. However, they still face significant challenges in both material preparation and device integration. Herein, we propose a design strategy which combines Bi2Te3-based thick film prepared by powder direct molding with micro-thermoelectric cooler integrated via phase-change batch transfer. Accurate thickness control and relatively high thermoelectric performance can be achieved for the thick film, and the high-density-integrated thick-film micro-thermoelectric cooler exhibits excellent performance with maximum cooling temperature difference of 40.6 K and maximum cooling flux of 56.5 W·cm-2 at room temperature. The micro-thermoelectric cooler also shows high temperature control accuracy (0.01 K) and reliability (over 30000 cooling cycles). Moreover, the device demonstrates remarkable capacity in power generation with normalized power density up to 214.0 µW · cm-2 · K-2. This study provides a general and scalable route for developing high-performance thick-film micro-thermoelectric cooler, benefiting widespread applications in thermal management of microsystems.
ABSTRACT
Thermoelectric (TE) effect based temperature sensor can accurately convert temperature signal into voltage without external power supply, which have great application prospects in self-powered temperature electronic skin (STES). But the fabrication of stretchable and distributed STES still remains a challenge. Here, a novel STES design strategy is proposed by combining flexible island-bridge structure with BiTe-based micro-thermoelectric generator (µ-TEG). Furthermore, a 4 × 4 vertical temperature sensor array with good stretchability and distributed sensing property has been fabricated for the first time. The interfacial chemical bonds located between the rigid islands (µ-TEG) and the flexible substrate (polydimethylsiloxane, PDMS) endow the STES with excellent stretchability, and its sensing performance remains unchanged under 30% strain (the maximum strain of human skin). Moreover, the STES sensing unit possesses high sensitivity (729 µV K-1 ), rapid response time (0.157 s), and high spatial resolution (2.75 × 2.75 mm2 ). As a proof of concept, this work demonstrates the application of the STES in the detection of mini-region heat sources in various scenarios including noncontact spatial temperature responsing, intelligent robotic thermosensing, and wearable temperature sensing. Such an inspiring design strategy is expected to provide guidance for the design and fabrication of wearable self-powered temperature sensors.
