Flexible,\nHigh-Power Density, Wearable Thermoelectric\nNanogenerator and Self-Powered Temperature Sensor

Abstract

We\npropose a flexible and wearable thermoelectric nanogenerator\n(FTEG) made from Bi₂Te₃, which allows high voltage\nand output power density. The proposed FTEG works as a thermopile\nwith the end-to-end connection of 126 thermoelectric legs, and which\nis fabricated through magnetron sputtering Cu conductor on polyethylene\nterephthalate film. Bi, Te, Sb, and Se alloys are used to prepare\nthermoelectric materials by doping in a fixed proportion and zone\nmelting, and nickel plating on the surface mitigates the deterioration\nof thermoelectric properties caused by the diffusion of Cu atoms or\nCu⁺ ions. The thermoelectric figure of merit is stable\nand maintained above 0.7, up to 1.02. More flexibility is allowed\nby employing double sinusoidal serpentine connecting wires, and no\nsignificant property changes are observed even after being folded\n200 times. When the temperature difference reaches 50 K, the output\nvoltage of the FTEG will be no less than 520 mV, and the power density\nwill reach 11.14 mW·cm^–2. By integration of\na low-power, low-threshold voltage boost circuit on the back end of\nthe FTEG, the electronic watch with a liquid crystal display screen\ncan be easily powered to work properly. Furthermore, the FTEG is temperature-sensitive\nand, thus, can be used for temperature measurement with a resolution\nof 0.5 K. This work may have important prospects in flexible wearable\nphysical sensors and individualized medical care.