Synthesis of near-infrared emissive InAs/InP/ZnSe from low toxicity precursors | Poster Board #163

Easily accessible synthetic strategies for obtaining near-infrared emissive nanomaterials are needed to advance new technologies, such as in-vivo imaging probes and luminescent solar concentrators. Synthesis methods for InAs core/shell/shell nanocrystals (NCs), however, have traditionally depended on pyrophoric, toxic, and highly reactive tris-trimethylsilyl (or tris-trimethylgermil) arsine and phosphine precursors. In contrast, the approach here utilizes less toxic and commercially available reagents, such as tris(dimethylamino)arsine for InAs and tris(dimethylamino)phosphine for InP synthesis. InAs/InP/ZnSe core/shell/shell nanocrystals made from these materials are typically poor luminophores and thus require further optimization to turn on and improve luminescence. This is due to a multitude of factors, including polydisperse size distributions, inhomogeneous shell encapsulation to remove InAs and InP surface defects, and poorly defined heterostructure interfaces. Here, we investigate the shelling dynamics of tris(dimethylamino)phosphine for the creation of an InP shell on InAs NCs made using tris(dimethylamino)arsine. Creating a uniform InP intermediate shell is crucial due to the significant lattice mismatch between InAs and ZnSe. This enables the construction of a core/shell/shell system where the InP shell minimizes the lattice mismatch between the InAs core and the outermost ZnSe shell, leading to enhanced photoluminescence quantum yield. Consequently, this approach facilitates the development of fully RoHS-compliant near-infrared luminescent heterostructures, promising safer synthesis methods.