A flexible thermoelectric film based on Bi2Te3 for wearable applications

In recent years, with the development of the Internet of Things (IoT) and wearable technology, the research and exploration of thermoelectric materials have been greatly promoted. However, traditional thermoelectric materials are rigid and brittle. Thermoelectric devices made of these materials usually cannot be closely attached to the heat and cold sources that provide temperature differences, thus limiting the application of thermoelectric materials. Therefore, manufacturing new high-performance flexible thermoelectric devices is still a huge challenge. In this work, polyimide/copper (PI/Cu) substrate was deposited by electron deposition technology. The flexible thermoelectric thin film device was fabricated by bonding [Formula: see text]-type and [Formula: see text]-type bismuth telluride (Bi2Te[Formula: see text] slurries onto the PI/Cu substrate. Then, the PDMS film was coated on the device to make the device waterproof and oxidation resistant. The output voltage and maximum power of this device, at the temperature of 80 K, reach 97.5 mV and 60 uW, respectively. After 200 cycles of cyclic bending experiments, 90% high conductivity retention can be maintained. It demonstrates that the new flexible thermoelectric thin film has good flexibility and excellent stability. This work provides a simple method for the preparation of flexible thermoelectric thin films and opens up a new way for its application in the sensing equipment and wearable device of the IoT.