Stretchable Thermoelectric-Based Self-Powered Dual-Parameter Sensors with Decoupled Temperature and Strain Sensing

Thermoelectric-based sensors with multifunctional sensing properties that can recognize different stimulations in a self-powered environment by converting low-grade heat into electrical energy have attracted increasing attention. However, the current thermoelectric-based multifunctional sensors are faced with issues such as limited preparation methods, complex structural designs, and hard decoupling, which greatly hinder their further development in the field of wearable electronics. Herein, we have fabricated novel free-standing self-powered temperature-strain sensors based on poly(3,4-ethylenedioxythiophene) polystyrenesulfonate (PEDOT:PSS)/carbon nanotube (CNT)/waterborne polyurethane (WPU) composite films through a simple drop-casting method. The composite films can maintain stable thermoelectric performance after washing 1000 times and withstand repeated bending and stretching. More importantly, based on the Seebeck effect arising from PEDOT:PSS/CNT composites, the assembled sensor successfully detects temperature changes and strain deformations under a self-powered condition. The decoupling of strain stimulation and temperature stimulation is mainly attributed to the good conductive network inside the composite film and the conductive bridge formed by PEDOT:PSS particles between CNTs when the composite film is stretched. Thus, the designed self-powered sensor with dual-parameter sensing prepared by a simple strategy has shown great potential in wearable electronics.