A Narrow-Bandgap Conjugated-Polymer/MoS₂ Hybrid Photodetector for Room Temperature Shortwave Infrared Detection up to 2000 nm

Abstract

Two-dimensional materials coupled with light-absorbing materials (such as quantum dots) can exhibit extremely high photogain through photogating, where trapped photoinduced carriers at interfaces delay recombination and enhance current response, enabling room-temperature long-wavelength photodetection. Here, we present a high-performance SWIR photodetector based on few-layer MoS₂ with a narrow-optical bandgap (0.68 eV) organic conjugated polymer (Poly [α, α′-vinylene-meso-(2-ethylhexyl thiophene-2-carboxylate) boron difluoride dipyrromethene, (PTBD). The strong interfacial band alignment facilitates efficient charge transfer and induces a pronounced photogating effect, resulting in a high photoconductive gain >10⁵. Under vacuum conditions at room temperature, this device demonstartes broadband SWIR detection from 0.7 µm to 2 µm, delivering a high photoresponsivity of 2.4 × 10⁵  A/W and detectivity of 9.9 × 10¹¹ Jones at 1550 nm. These results highlight a promising platform for the future development of scalable and cost-effective uncooled broadband SWIR detection using 2D-organic polymer hybrid systems.