Efficient InAs Nanorod Colloidal Quantum Dot Deep-SWIR Absorbers and Emitters

InAs colloidal quantum dots (CQDs) have emerged as promising lead- and mercury-free semiconductors for shortwave infrared (SWIR) technology due to their appropriate bulk bandgap tunable via quantum confinement and favorable charge-carrier transport properties. However, their application has been constrained by the scarcity of suitable arsenic precursors and the challenging synthesis conditions, limiting their bandgaps to <1400 nm in the near-infrared range. Conventional InAs CQD synthesis relies on highly reactive, hazardous arsenic precursors, complicating their controlled production and study. To address these limitations, we developed a novel synthesis strategy using readily available and less reactive precursors. This approach enabled the controlled growth of monodisperse InAs nanorod CQDs with tunable bandgaps up to ~1800 nm, significantly extending their absorption capability into the SWIR region. Through surface engineering, we enhanced the photoluminescence quantum yield (PLQY) of these SWIR-active InAs nanorod CQDs to as high as 60%. This marks the first efficient SWIR light emission from InAs CQDs. Moreover. utilizing these surface engineered InAs nanorod CQDs we demonstrated highly efficient SWIR-active photodetectors. Our work represents a significant advancement, expanding the potential applications of InAs CQDs across a broad spectrum of SWIR technologies.