Facile, Economic and Size-Tunable Synthesis of Metal Arsenide Nanocrystals

Abstract

Synthesis of colloidal nanocrystals (NC) of important arsenide nanomaterials (e.g., InAs, Cd 3 As 2 ) has been limited by the lack of convenient arsenic precursors. Here we address this constraint by identifying a convenient and commercially available As precursor, tris-dimethylaminoarsine (As(NMe 2 ) 3 ), which can be used to prepare high quality InAs NCs with controlled size distributions. Our approach employs a reaction between InCl 3 and As(NMe 2 ) 3 using diisobutylaluminum hydride (DIBAL-H) to convert As(NMe 2 ) 3 in situ into reactive intermediates AsH x (NMe 2 ) 3– x, where x = 1,2,3. NC size can be varied by changing DIBAL-H concentration and growth temperature, with colloidal solutions of InAs showing size dependent absorption and emission features tunable across wavelengths of 750 to 1450 nm. We also show that this approach works well for the colloidal synthesis of Cd 3 As 2 NCs. By circumventing the preparation of notoriously unstable and dangerous arsenic precursors (e.g., AsH 3 and As(SiMe 3 ) 3 ), this work improves the synthetic accessibility of arsenide-based NCs and, by extension, the potential of such NCs for use in infrared (IR) applications such as communications, fluorescent labeling and photon detection.