Multifold enhancement of the output power of flexible thermoelectric generators made from cotton fabrics coated with conducting polymer

Thermoelectric (TE) conversion of human body heat is highly desirable for powering microelectronic devices. However, most of the existing TE generators are not practical because they contain toxic substances, are difficult to process, are rigid and impermeable, or are unable to be produced on a large scale. Previously, we have demonstrated a flexible, air-permeable TE power generator fabricated from polyester fabric coated with a conducting polymer, poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate), and fine silver wires [Y. Du, et al., Sci. Rep., 2015, 5, 06411]. Here, we show a multifold enhancement of the output power of this type of flexible thermoelectric generator using poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) coated cotton fabric, and fine Constantan wires. A fabric device consisting of 5 TE units was found to generate a voltage output (V) of 18.7 mV and maximum output electrical power of 212.6 nW at a temperature difference (Delta T) of 74.3 K. The fabric generators can be rolled up and remain operational after being bent at different bending radii and in different directions. Furthermore, a TE generator has been shown to be stable even after 10 days of continuous operation at a Delta T up to similar to 78 K. This fabric-based TE generator is seen to be useful for the development of self-powered, wearable electronic devices.