Ambient-Temperature-Independent Power Generation in Wearable Thermoelectric Generator with CNTs/MoS₂ Solar Absorber

The low-temperature difference (ΔT) of the body-heat-driven wearable thermoelectric generators (WTEG) is one of the major issues that set back the application of the device. Recently, we proposed a WS-TEG that achieves a high ΔT by introducing a solar absorber on the hot side of the device, which has inspired many subsequent studies. Here, we propose a systematic approach to further increase the ΔT by considering heat conduction and convection in WS-TEG. For the fabrication of WS-TEGs, TE legs are dispenser-printed with BiTe-based ink, and the CNT/MoS₂ solar absorber was spin-coated on a polyimide substrate. The ΔT was ramped up by incorporating a PDMS lid to prevent convective heat loss on the hot side and Cu foams as heat sinks to accelerate heat dissipation on the cold side. Upon exposure to sunlight, the wearable TEG exhibits a ΔT of 33.9 °C. In addition, unlike conventional WTEG, the ΔT of the WS-TEG is maintained almost independently of ambient temperature due to the stable and sustained absorption of sunlight. We believe that the suggested methodology is a pragmatic and viable solution to the ΔT issue, one of the biggest hurdles for wearable TEGs.