Colloidal Synthesis of Ultra-Large InAs Quantum Dots

Quantum dots (QDs) offer great potential for various applications, particularly in the infrared spectral range, including telecommunication, security, sensing, photovoltaics and bioimaging. Unlike the well-studied II-VI and IV-VI semiconductor QD systems, the colloidal synthesis of infrared-active, RoHS-compliant III-V semiconductor QDs like indium arsenide (InAs) remains less explored. Growing larger InAs QDs is challenging due to a lack of control over the precursor reactivity because of the high covalent character of In-As bonding, and due to a non-classical growth mechanism. Herein, we report on the first colloidally synthesized ultra-large InAs QDs, achieving record-breaking sizes up to 40.5 nm on average and optical activity in the range even beyond ~ 2600 nm. Besides, we present synthesis routes for InAs clusters, which were used as precursors for two different growth approaches of ultra-large InAs QDs. All nanostructures were prepared from `green` commercially available precursors.