Energy harvesting from human body heat using highly flexible thermoelectric generator based on Bi2Te3 particles and polymer composite

Energy harvesting technology is in high demand for self-powered devices. Flexible thermoelectric generators (f-TEGs) have attracted considerable attention for application in wearable electronics, which can be applied to healthcare and smart clothing. However, previous f-TEGs still have limitations such lack of novel research focus concerning its wearable applications and complicated and high-cost fabrication procedures. This study reports an f-TEG comprising Bi2Te3-based thermoelectric composite films on a flexible substrate to demonstrate thermoelectric energy conversion from the human body. To verify the thermoelectric energy harvesting efficiency of the energy harvester based on temperature gradients, an f-TEG was developed by placing p-type Bi0.5Sb1.5Te3 (BST) of 133 μWm−1K−2 and n-type Bi2Te2.7Se0.3 (BTS) of 124 μWm−1K−2 thermoelectric films. The fabricated f-TEG harvested an output voltage of 18.13 mV, current signal of 2.74 μA, and output power of ≈ 12.6 nW at ΔT = 25 K. The theoretical thermoelectric potential distribution of the f-TEG was confirmed by finite element analysis using multiphysics simulation. Furthermore, we investigated the biological output performance of the f-TEG on the human body, which showed the output performance of ≈ 0.38 μA and ≈ 2.3 mV. This study presents the possibility of harvesting thermal energy from human body heat, which will be useful for improving wearable device applications.