Synergistic Plasmonic‐Thermoelectric Enhancement in Semiconducting Carbon Nanotubes for Infrared Light Detection

Infrared (IR) detection technologies are central to applications ranging from molecular fingerprinting to next‐generation wireless communication systems. However, developing uncooled, high‐sensitivity IR photodetectors remains challenging due to the low photon energy in this spectral range. This study reports a rational design strategy for enhancing the photothermoelectric (PTE) response by using semiconducting single‐walled carbon nanotubes (CNTs) with precisely tailored electronic and thermal transport properties. The PTE sensitivity is increased through structural sorting, controlled chemical doping, and passivation, relative to devices fabricated with unsorted CNTs. This enhancement arises from a synergistic interplay between plasmon‐enabled photothermal excitation and optimized thermoelectric transport properties, including an increased effective Seebeck coefficient and suppressed thermal conductivity, which together enable stronger temperature gradients upon IR irradiation. These findings establish a design principle for integrating light absorption, heat management, and charge transport in nanostructured materials, supporting the development of efficient, scalable, ambient‐operable IR sensing platforms.