Optical and electrical properties of Fe3O4@MoS2 nanocomposites and doped lead boron tellurite glass

Abstract

Transition metal oxide core–shell-nanostructured Fe3O4@MoS2 is attractive in photocatalytic, optoelectronics and optical applications. Magnetic Fe3O4@MoS2 core–shell nanocomposites were synthesized by a facile hydrothermal method. Transmission electron microscopy (TEM) results show that the 80-nm-diameter nanoparticles were composed of Fe3O4 core and MoS2 shell. The presence of characteristic of Fe–O and Mo–O vibrations in Fe3O4@MoS2 FT-IR spectra indicate the Fe3O4 has been composited with MoS2 successfully. The optical UV–Vis spectra of Fe3O4@MoS2 composites exhibited a strong peak at 250–300 nm due to the strong absorption of MoS2. The photoluminescence spectra of Fe3O4@MoS2 showed two peaks at 670 and 625 nm corresponding to A1 and B1 excitons of MoS2. Glass-containing nanoparticles have promising multifunctional advantages such as the simultaneous existence of magnetic, optical and photoluminescence. Glasses containing different Fe3O4@MoS2 contents were fabricated in this study by melt-quenching method. Glass network was disordered by the doping, and as the doping content increasing, the coordination numbers were changed and more non-bridging oxygen numbers were produced, these modifications on glass structure induced changes of glass properties. Compared to spectra of base glass, the UV–Vis absorption spectra of doped glasses showed a red-shift in cutoff wavelength and an absorption peak around 680 nm due to the excitation of Mo5+ (4d1) ions. The photoluminescence spectra of Fe3O4@MoS2-doped glasses present one intense peak centered around 570 nm due to the charge transfer of O2−→Mo6+ ions in MoO42− units, and the intensity of this emission peak increased with doping contents. The conductivity of base glass gets increased from 1.59 × 10−7 to 2.08 × 10−6 S cm−1 when the doping content reaches to 5%. Such improvement is mainly caused by the non-adiabatic small polaron hopping at 473 K and non-bridging oxygens production. Glass doped with 5% Fe3O4@MoS2 exhibited promising photoluminescence, optical cutoff wavelength (526 nm) and high electrical conductivity (2.08 × 10−6 S cm−1) due to the charge transfer of Fe and Mo ions and high polarization property of Fe3O4@MoS2.