A pressed bulk pellet MoI3 photodetector with high photocurrent

Low-dimensional materials have attracted significant attention for their unique structural and electronic properties, making them promising for optoelectronic applications. Among these materials, molybdenum triiodide (MoI3) exhibits great potential in photodetection due to its suitable bandgap and optical absorption characteristics; however, large-sized MoI3 has not yet been effectively demonstrated. In this work, we propose a low-cost and environmentally friendly solvent-assisted method for synthesizing MoI3 powder via a solid-state reaction. The resulting MoI3 crystals predominantly self-assemble into urchin-like aggregates, forming a bulk morphology. The absorption spectrum displays a distinct peak at ∼950 nm (corresponding to a bandgap of 1.26 eV), indicating its suitability for photodetectors operating in the near-infrared and visible regions. Furthermore, a MoI3 pressed bulk pellet was fabricated via isostatic pressing and subsequently used to construct a photodetector with an Au/MoI3/Au photoconductive structure. The device exhibits reasonable photosensitivity, achieving a photocurrent of 2.1 × 10−8 A and an Ilight/Idark ratio of 1.8 under 650 nm illumination. This work highlights the potential of MoI3 for scalable and low-cost photodetection applications.