Short-wave infrared organic photodetectors based on n-type small molecular semiconductors

Abstract

Short-wave infrared (SWIR, 1–3 µm) light has become indispensable for applications including remote sensing, mineral identification, night vision, vital sign monitoring, and disaster response due to its exceptional ability to penetrate scattering media under harsh conditions. Serving as a disruptive alternative to conventional inorganic counterparts, short-wave infrared organic photodetectors (SWIR-OPDs) leverage inherent advantages such as light weight, mechanical flexibility, and large-area solution processability. Current material platforms for SWIR-OPDs primarily focus on narrow bandgap polymers and small molecules. Among these, n-type small-molecules are particularly promising for sensitive SWIR-OPDs, owing to their well-defined molecular structures, high crystallinity, tunable light spectral response and energy levels, and excellent electron transport properties. This review summarizes recent advances in SWIR-OPDs based on n-type small molecular semiconductors. Key topics cover the fundamentals of devices, design strategies for narrow bandgap molecules, representative n-type small molecules, device engineering and potential applications of SWIR-OPDs. Finally, current limitations are discussed alongside an outlook for future development.