Photothermoelectric Synergistic Hydrovoltaic Effect: A Flexible Photothermoelectric Yarn Panel for Multiple Renewable-Energy Harvesting

The human body is in a complex environment affected by body heat, light, and sweat, requiring the development of a wearable multifunctional textile for human utilization. Meanwhile, the traditional thermoelectric yarn is limited by expensive and scarce inorganic thermoelectric materials, which restricts the development of thermoelectric textiles. Therefore, in this paper, photothermoelectric yarns (PPDA–PPy-PEDOT/CuI) using organic poly(3,4-ethylenedioxythiophene) (PEDOT) and inorganic thermoelectric material cuprous iodide (CuI) are used for the thermoelectric layer and poly(pyrrole) (PPy) for the light-absorbing layer. With the introduction of PPy, the temperature difference of the photothermoelectric yarn can be increased for a better voltage output. Subsequently synergizing the photothermoelectric effect with the hydrovoltaic effect to create higher electric potentials, a single wet photothermoelectric yarn obtained by preparation can be irradiated under an infrared lamp at a voltage of up to 0.47 V. Finally, the photothermoelectric yarn PPDA–PPy-PEDOT/CuI was assembled in a series and parallel to obtain a photothermoelectric yarn panel, which was able to output 41.19 mV under an infrared lamp, and the synergistic photothermoelectric and hydrovoltaic effects of the photothermoelectric panel were tested outdoors on human body, and we found that the voltage was able to reach approximately 0.16 V under sunlight. Therefore, the voltage values obtained from the photothermoelectric yarns in this study are competitive and provide a new research idea for the study of photothermoelectric yarns.