Cobalt Ferrite Particles Produced by Sol-Gel Autocombustion and Embedded in Polysilane: An Innovative Route to Magnetically-Induced Fluorescence Composites

Abstract

Fluorescence detection is currently one of the commonly used techniques worldwide. Through this work, the preparation and optical properties of an interesting composite material are discussed. It is shown that encapsulating cobalt spinel ferrite (CoFe2O4), obtained by the sol-gel autocombustion method, into poly[diphenyl-co-methyl(H)]silane matrix leads to fluoromagnetic particles (PSCo) with intriguing optical properties. Transmission electron microscopy, combined with energy-dispersive X-ray analysis, showed 500 nm large spherical structures containing a core (around 400 nm in diameter) composed of magnetic ferrite particles, surrounded by a thin layer of semiconductive fluorescent polymer. The as-obtained material exhibited ferrimagnetic properties. The FTIR spectrum confirmed that the Si-H functionality of the polysilane was preserved. UV spectroscopy combined with molecular modeling studies indicated that the magnetic core had a strong influence on the intramolecular electron transitions characteristic of the σ-conjugated polysilane. Further analysis by steady-state fluorescence spectroscopy revealed that the internal magnetic field strongly enhances the polysilane emission. This property will be further investigated in the future in order to develop new detection devices.

Structural and Magnetic Characterization of Ni-Co Mixed Ferrite Nanopowders Synthesized via Coprecipitation and Sol-Gel Methods

“…Changes in the crystalline structure, as well as the disparity in size and magnetic moment of the Ni 2+ and Co 2+ cations, influence the physical properties of the ferrite, such as saturation magnetization and coercivity. There are several methods to synthesize ferrite nanoparticulate powders, including chemical methods such as coprecipitation 19,20 , sol-gel 21,22 , and autocombustion 23 . These methods are relatively simple and low-cost, utilizing metal precursors such as nitrates and chlorides.…”

Effect of the Substitution of Co by Ni on the Crystal Structure and Magnetic Properties of Cobalt Ferrite Nanoparticles

“…Therefore, it is important to make a good selection of the appropriate synthesis method according to the desired properties and applications. Various methods have been used for the synthesis of ferrite nanoparticles, such as: coprecipitation [14], sol-gel [15], autocombustion [16], hydrothermal synthesis [17], microemulsion [18], reverse micelles [19]. Chemical coprecipitation has proven to be a simple, fast, and low-cost synthesis method that allows obtaining nanoparticulate powders [20].…”