Enhanced Near-Infrared Organic Photodetectors Leveraging Core–Shell Nanotripods

Abstract

Near-infrared (NIR) photodetectors are essential for diverse applications, including medical diagnostics, optical communication, and bioimaging. Traditional photodetectors, typically made from silicon and III–V semiconductors, struggle with large-area devices on precured or flexible substrates due to complex manufacturing and high costs. Organic photodetectors (OPDs), however, offer cost-effectiveness, flexibility, and a customizable spectral response. In this study, we report our effort to enhance NIR absorption in OPDs by incorporating core–shell structured PdCu@Au@SiO₂ nanotripods (NTs) with a D_3h configuration, designed for localized surface plasmon resonance (LSPR) beyond 1000 nm. Integrating these NTs into the OPD active layer significantly boosts NIR absorption, achieving a responsivity of 0.46 A/W and a dynamic range of 145 dB at 1050 nm. NT-based OPDs show superior sensitivity over the control OPD and a silicon photodetector at wavelengths of over 1000 nm. This improvement is due to the synergistic effects of LSPR and omnidirectional scattering from the PdCu@Au@SiO₂ NTs, enhancing carrier generation and extraction. The improved performance highlights their potential for advanced applications such as long-range photoplethysmography and visual line-of-sight communication systems.