Boosted photothermoelectric effect in silver nanoparticles decorated carbon nanotube films for infrared detection and actuation

Photothermoelectric (PTE) effect provides a platform for utilization both photon and thermal energy, giving rise to high-performance photodetector and radiation energy harvester. Carbon nanotube (CNT)/metal heterojunction has been demonstrated to be capable of boosting power generation based on PTE effect, and yet the responsivity and detectivity are inferior to those based on conventional optoelectronic effect. Herein, CNT films decorated by Ag nanoparticles (NPs) forming Ag/CNT heterojunctions have been investigated, showing both excellent photothermal and power conversion capability under infrared (IR) illumination. Ultrahigh ΔT of 196.4 K, maximum output voltage of 15.74 mV and power of 9.94 μW have been achieved under IR laser illumination at power density of 7.65 W/cm2, which are superior to reported photodetectors based on PTE effect. CNT@Ag NPs film possesses competitive photodetection performance as well, with responsivity and detectivity of 107 mV/W and 947.68 MHz1/2/W, respectively. Furthermore, when integrated with polydimethylsiloxane, an IR laser actuated movement function mimicking caterpillar has been realized. Our study thus expands the diverse functions of CNT-based films utilizing PTE effect toward applications in IR detection, radiation energy harvesting and soft actuation.