Overcoming the Short-Wave Infrared Barrier in the Photoluminescence of Amino-As-Based InAs Quantum Dots

The synthesis of amino-As-based InAs quantum dots (QDs) with narrow excitonic absorption features and efficient photoluminescence (PL) beyond 1000 nm remains a considerable challenge. A key limitation lies in the use of conventional reducing agents, which typically release low-boiling byproducts. These volatile species cause temperature fluctuations, leading to unstable reaction conditions that are detrimental in seeded growth strategies. In this work, we demonstrate that trioctylamine-alane (TOA-AlH₃), a reducing agent with a high boiling point, enables the one-pot synthesis of InAs QDs with narrow excitonic absorption peaks extending up to 935 nm. Upon ZnSe shell growth, these QDs exhibit high PL quantum yields (QYs) of 75% and 60% at 905 and 1000 nm, respectively, which are record values for amino-As-based InAs@ZnSe systems. Moreover, TOA-AlH₃ is applied in a seeded growth approach to prepare larger InAs QDs, achieving narrow excitonic absorption up to 1350 nm. After ZnSe shelling, these samples exhibit PLQYs of 46%, 38%, 32%, and 23% at 1160, 1250, 1335, and 1430 nm, respectively. Importantly, TOA-AlH₃ is compatible with ZnCl₂, a necessary additive for reaching high PLQYs. These advancements establish a robust and scalable synthetic route to highly luminescent InAs QDs, paving the way for their integration into next-generation infrared optoelectronic applications.