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

Abstract

Synthesis of colloidal nanocrystals (NC) of important arsenide nanomaterials (e.g., InAs, Cd3As2) 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(NMe2)3), which can be used to prepare high quality InAs NCs with controlled size distributions. Our approach employs a reaction between InCl3 and As­(NMe2)3 using diisobutylaluminum hydride (DIBAL-H) to convert As­(NMe2)3 in situ into reactive intermediates AsH x (NMe2)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 Cd3As2 NCs. By circumventing the preparation of notoriously unstable and dangerous arsenic precursors (e.g., AsH3 and As­(SiMe3)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.

III–V colloidal nanocrystals: control of covalent surfaces

“…7b). 91 Through these results, control of the surface energy based on the electron counting model effectively stabilizes the specic facets of III-V QDs. Furthermore, we expect that QDs with desired facets will be controlled by this method.…”

Synthesis of NIR‐Emitting InAs‐Based Core/Shell Quantum Dots with the Use of Tripyrazolylarsane as Arsenic Precursor

“…Reacting a 0.5 m As(OLA) 3 stock solution with the In precursor according to a typical InAs hot injection synthesis without adding a reducing agent does not lead to the expected color change which is an indication for the particle formation. By contrast, following the procedure of Srivastava et al and Grigel et al initializes particle formation and growth. The simultaneous injection of both the arsenic precursor and the reducing agent DIBAL‐ H , yields InAs QDs.…”

“…Nevertheless, As(SiMe 3 ) 3 is the most commonly used arsenic precursor besides the less reactive tris(trimethylgermyl)arsane (As(GeMe 3 ) 3 ) or highly toxic arsine gas (AsH 3 ) . Recently, Srivastava et al and Grigel et al highlighted tris(dimethylamino)arsane (As(NMe 2 ) 3 ) as commercially available precursor for the facile synthesis of InAs QDs. Mechanistically, As(NMe 2 ) 3 undergoes a transamination reaction with the solvent and reagent oleylamine (OLA H ) to give trioleylarsane (As(OLA) 3 ) under the release of three equivalents of flammable dimethylamine.…”

“…Mechanistically, As(NMe 2 ) 3 undergoes a transamination reaction with the solvent and reagent oleylamine (OLA H ) to give trioleylarsane (As(OLA) 3 ) under the release of three equivalents of flammable dimethylamine. The reaction of As(OLA) 3 with indium(III) chloride (InCl 3 ) to InAs QDs does not proceed without the subsequent addition of a reducing agent for which typically diisobutylaluminum hydride (DIBAL‐ H ) and nowadays also trioleylphosphane (P(OLA) 3 ) or a N,N ‐dimethylethylamine complex (DMEA‐AlH 3 ) are used. In the case of DIBAL‐ H and DMEA‐AlH 3 , the As–N bonds are cleaved to give in situ (OLA) x AsH 3‐ x species which react with the indium precursor to InAs QDs .…”

“…In the case of DIBAL‐ H and DMEA‐AlH 3 , the As–N bonds are cleaved to give in situ (OLA) x AsH 3‐ x species which react with the indium precursor to InAs QDs . With the applied concentration of DIBAL‐ H the size of InAs QDs can be tuned according to the method by Srivastava et al By contrast, the approach by Grigel et al applies in situ generated P(OLA) 3 as reducing agent for the InAs QD synthesis ( Scheme ). This species is known to act both, as a remarkably efficient phosphorus precursor and reducing agent for the preparation of InP QDs .…”