Flexible Ag nanoparticles-decorated Ag2Te nanowire film for broad-band and self-powered Photothermoelectric detection

Photothermoelectric (PTE) detectors, characterized by self-powered operation and broadband response, represent a promising alternative to conventional photodetectors. However, achieving efficient photothermal conversion and thermoelectric response within a single material remains a key challenge. In this work, we successfully constructed a flexible Ag 2 Te@Ag composite film of Ag 2 Te nanowires (NWs) decorated with Ag nanoparticles (NPs), which exhibits a pronounced PTE effect. The Ag NPs act as plasmonic nanoheaters, significantly enhancing light absorption and local heat generation through localized surface plasmon resonance, while the porous Ag 2 Te NW network serves as an efficient thermoelectric scaffold with low lattice thermal conductivity and optical absorption cavity. As a result, this Ag 2 Te@Ag film achieves a remarkable temperature difference of 73.4 K and a corresponding photovoltage of 1.41 mV under 450 nm laser irradiation, with a maximum responsivity of 17.17 mV W −1 across the 380–1550 nm range. The device operates in a fully self-powered mode, exhibiting fast response, excellent output linearity, and outstanding mechanical flexibility with negligible degradation of properties after 200 bending cycles. This work provides a viable strategy for developing high-performance, flexible PTE detectors for wearable optoelectronics and energy harvesting.