Multifunctional magneto-fluorescent NiZnFe@CdS core-shell nanostructures for multimodal applications

Abstract

Magneto-fluorescent nanostructures are promising materials for application in biological fields such as optically tracked targeted drug delivery systems etc, and in the field of electronics and spintronics. Here, a new set of magneto-fluorescent core-shell nanostructures were formed from the Ni-Zn-ferrite as magnetic core and CdS quantum dots as fluorescent semiconducting shell with exceptional physical and chemical properties of individual magnetic core and QDs shell. These magneto-fluorescent nanostructures were prepared to overcome the limitations present in the studied iron oxide based magneto-fluorescent or magneto-plasmon nanostructures in the field. These magneto-fluorescent nanostructures were prepared using two-step process, which includes sol-gel and wet chemical methods. Ni-Zn-ferrites@CdS nanostructures were synthesized for different loadings of ferrite with different sizes of CdS QDs, where 2-mercaptoethanol was used as the stabilizing agent for the controlled growth of CdS QDs size. Ni-Zn ferrites, CdS and core-shell Ni-Zn-ferrite@CdS nanoparticles were investigated for structural, optical and magnetic properties. X-ray studies reveal the structural properties of Ni-Zn ferrite, CdS QDs, and Ni-Zn-ferrite@CdS. The optical properties of prepared nanoparticles were characterized by UV–visible and photoluminescence spectroscopy at room temperature. High-resolution transmission electron microscopy was used to observe the core-shell structure. Vibrating sample magnetometer was used to study the magnetic behavior of the samples at room temperature.