Effect of indium precursor and ligand type on the structure, morphology and surface functionalization of InP nanocrystals prepared by gas-liquid approach

We report on a simplified procedure of InP/In2O3 core/shell nanocrystals preparation in which indium(III) carboxylates are used as indium precursors and at the same time as a source of capping ligands whereas phosphine (PH3), generated in situ in the reaction of HCl with zinc phosphide, (Zn3P2), is used as a source of phosphorus. This modified one-step, one-pot procedure, exploiting a smaller number of components in the reaction mixture, extends the range of obtainable nanocrystals' sizes below 3.0 nm while retaining their low polydispersity. Initial ligands can be readily exchanged at ambient conditions for aliphatic diamines such as hexane-1,6-diamine (HDA) or ethane-1,2-diamine (EDA), as evidenced by IR and NMR investigations. EDA-capped nanocrystals can be transferred to aqueous solution forming colloidal dispersions. This property is of significant importance in the view of their potential use in biolabeling. The prepared nanocrystals can also be surface functionalized with electroactive molecules such as N-(4-aminophenyl)-N'-(4-nitrophenyl)benzene-1,4-diamine (nitroderivative of aniline trimer) yielding an electrochemically interesting hybrid nanomaterials whose conductivity, magnetic and spectral properties can be controlled by the applied potential. (C) 2013 Elsevier B.V. All rights reserved.