One-step solvothermal synthesis of Ni 2+ doped indium oxide nanocrystals and evidences of their in situ growth mechanism

Abstract

Ni 2+ doped In 2O 3 has the potential use in transparent spintronic devices as a kind of dilute magnetic semiconductor. In this paper, Ni 2+ doped In 2O 3 nanocrystals with cube shapes (about 18 nm) are directly synthesized by a simple one-step solvothermal method, free of any dispersants, surfactants, templates and postannealing treatment. The influences of reaction solvents, solvothermal time, reaction temperatures and alkaline concentrations on phase transitions and morphological evolutions are systematically investigated. The concrete formation mechanisms for the Ni 2+ doped In 2O 3 phase are suggested based on stepwise dehydrations of Ni 2+ doped In(OH) 3 precursors while the appearance of a metastable Ni 2+ doped InOOH intermediate phase plays an important role in this conversion and is also supported by thermodynamic data. The in situ growth mechanisms for the formation of regular nanocubes are proposed based on detailed evidences of morphological evolutions with reaction time. In addition, the infrared and magnetic properties of Ni 2+ doped In 2O 3 nanocrystals are also characterized. Our studies provide a time-saving and easy way to synthesize other transition-metal ion doped In 2O 3 nanomaterials by the one-step solvothermal route. Show more