Different ionic surfactants assisted solvothermal synthesis of zero-, three and one-dimensional nickel oxide nanostructures and their optical properties

Different dimensional NiO nanomaterials hold great potential for new advanced applications in optoelectronic devices. Here, we report the synthesis of different ionic surfactants such CTAB, SDS and PEG assisted high-quality zero, three and one dimensional spherical, hexagonal and rod-like NiO nanopowders under facile solvothermal conditions. The XRD patterns for all the samples presented a set of peaks characteristic of NiO in the cubic phase. The scanning electron microscopy results revealed that the different morphologies of the prepared product could be tailored by changing the different ionic surfactants. The growth mechanism of the different dimensional NiO nanostructures is proposed. The optical absorption studies reveal that the prepared NiO nanomaterials exhibit strong quantum confinement effect, as the optical energy band gap increased significantly compared to the bulk NiO. The reasons for the growth of different morphologies and their photoluminescence (PL) properties have been presented and discussed. It has been found that the different-dimensional (0, 3 and 1D) ordered NiO structures exhibit a high intensity PL band, which may be due to the high optical quality of the prepared NiO nanomaterials, which are promising candidates for luminescent, nano-phonic and optoelectronic applications. This method is applicable for the large scale production of cubic nickel oxide nanoparticles with favorable optical properties. It can also be used to fabricate various semiconductor oxides with advanced properties.