Thermoelectric generators (TEGs) provide a unique solution for energy harvesting from waste heat, presenting a potential solution for green energy. However, traditional rigid and flexible TEGs cannot work on complex and dynamic surfaces. Here, we report a stretchable TEG (S-TEG) (over 50% stretchability of the entire device) that is geometrically suitable for various complex and dynamic surfaces of heat sources. The S-TEG consists of hot-pressed nanolayered p-(Sb2Te3) and n-(Bi2Te3)-type thermoelectric couple arrays and exploits the wavy serpentine interconnects to integrate all units. The internal resistance of a 10 × 10 array is 22 ohm, and the output power is ∼0.15 mW/cm2 at ΔT = 19 K on both developable and nondevelopable surfaces, which are much improved compared with those of existing S-TEGs. The energy harvesting of S-TEG from the dynamic surfaces of the human skin offers a potential energy solution for the wearable devices for health monitoring.

The manipulation of individual intrinsic point defects is crucial for boosting the thermoelectric performances of n-Bi2Te3-based thermoelectric films, but was not achieved in previous studies. In this work, we realize the independent manipulation of Te vacancies VTe and antisite defects of TeBi and BiTe in molecular beam epitaxially grown n-Bi2Te3 films, which is directly monitored by a scanning tunneling microscope. By virtue of introducing dominant TeBi antisites, the n-Bi2Te3 film can achieve the state-of-the-art thermoelectric power factor of 5.05 mW m–1 K–2, significantly superior to films containing VTe and BiTe as dominant defects. Angle-resolved photoemission spectroscopy and systematic transport studies have revealed two detrimental effects regarding VTe and BiTe, which have not been discovered before: (1) The presence of BiTe antisites leads to a reduction of the carrier effective mass in the conduction band; and (2) the intrinsic transformation of VTe to BiTe during the film growth results in a built-in electric field along the film thickness direction and thus is not beneficial for the carrier mobility. This research is instructive for further engineering defects and optimizing electronic transport properties of n-Bi2Te3 and other technologically important thermoelectric materials.

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Flexible thermoelectric generators (f-TEGs) have demonstrated great potential in wearable self-powered health monitoring devices. However, the existing wearable f-TEGs are neither flexible enough to bend and stretch while maintaining the device's integrity with a good TE performance nor directly compatible with clothes materials. Here, ultraflexible fabric-based thermoelectric generators (uf-TEGs) are proposed with conductive cloth electrodes and elastic fabric substrate. The patterned elastic fabric substrate fits the rigid cuboids well, together with serpentine structured cloth electrodes, rendering uf-TEG with excellent integrity and flexibility, thereby achieving a highly functional TE performance when strain reaches 30% or on arbitrarily shaped heat sources. The uf-TEGs show a large peak power of 64.10 𝝁W for a temperature difference of 33.24 K with a high voltage output of 111.49 mV, which is superior compared to previously reported fabric-based TEG devices, and it is still functional after the water immersion test. Besides the energy harvesting function, with both the temperature sensing ability and the touch perception, this uf-TEG is demonstrated as the electrical skin when mounted on a robot. Moreover, due to the wind-sensitive performance and self-power ability, the uf-TEGs are assembled on cloth as wearable health and motion monitoring devices.

Wearable devices have become very important for collecting health information and monitoring the condition of seriously ill patients. However, most recently developed wearable devices can only monitor limited signals within a very small range of values. A novel sensor is fabricated by modifying the surface of polyimide nanowires with silver nanoparticles. These nanowire sensors can sense both pressure and temperature changes and have antimicrobial properties. The fabricated sensor can detect a wide range of pressure variation from 5 KPa to 100 KPa. A theoretical model is developed to explain the sensing mechanism of the silver‐nanoparticle‐modified polyimide nanowires. The experimental and theoretical results for the nanowires are in good agreement. By attaching these sensors to human joints and fingers, real‐time information can be detected for human motion, such as walking or holding a hot cup of water. The excellent performance of this device shows that it has great potential for use in artificial skins for detecting temperature and human motion.

Engineering of low-dimensional metal–semiconductor nanocomposites is expected to decouple electrical and thermal property, leading to substantially higher thermoelectric property. In this study, we rationally design a unique 0D–2D Au–Sb2Te3 architecture with beneficial interface barrier and strengthened phonon scattering, resulting in synergistically optimized electrical and thermal properties. In-situ growth of Au nanoparticles ∼10 nm on Sb2Te3 nanoplates enables better manipulation of electron and phonon transport compared to traditional bulks. The energy barrier between Au and Sb2Te3 effectively filters low-energy holes, while the Au nanoparticles competently hinder the propagation of midto-long wavelength phonons. As a result, this unique 0D–2D Au–Sb2Te3 composite exhibits a concurrent increase in electrical conductivity and Seebeck coefficient, and a decrease in lattice thermal conductivity, which allows a double of ZT value (∼0.8 at 523 K) for 1 mol % Au–Sb2Te3 composites with respect to the pristine Sb2Te3 (∼0.39 at 523 K). This self-assembled heterostructure provides a direction to design other low-dimensional metal–semiconductor nanoassemblies for thermoelectric application.

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