Direct electrospinning construction of nanocables with electrical conductive-magnetic core and insulative-photoluminescent sheath

Abstract

Novel flexible luminescent-electrical-magnetic trifunctional nanocables have been successfully fabricated by specially designed coaxial spinnerets electrospinning technology. Europium complex Eu(TTA)₃(TPPO)₂ (TTA = 2-thenoyltrifluoroacetone, TPPO = triphenylphosphine oxide), PANI and Fe₃O₄ nanoparticles (NPs) were respectively incorporated into polyvinyl pyrrolidone (PVP) and electrospun into nanocables with Fe₃O₄/PANI/PVP as core and Eu(TTA)₃(TPPO)₂/PVP as the sheath. The morphology and properties of the final products were investigated in detail by X-ray diffractometry (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), fluorescence spectroscopy, Hall effect measurement system and vibrating sample magnetometer (VSM). SEM observation indicates that the diameter of the nanocables is 414 ± 13 nm. TEM analysis shows the core diameter is ca. 250 nm containing magnetic nanoparticles and polyaniline, and the sheath thickness is ca. 81 nm. Fluorescence emission peaks of Eu³⁺ ions in the [Fe₃O₄/PANI/PVP]@[Eu(TTA)₃(TPPO)₂/PVP] nanocables are observed and assigned to the energy levels transitions of ⁵D₀ → ⁷F₀ (579 nm), ⁵D₀ → ⁷F₁ (592 nm), ⁵D₀ → ⁷F₂ (614 nm), and the ⁵D₀ → ⁷F₂ hypersensitive transition at 614 nm is the dominant emission peak. The obtained nanocables possess better fluorescent intensity than their counterpart Fe₃O₄/PANI/Eu(TTA)₃(TPPO)₂/PVP composite nanofibers. The electrical conductivity of the core of nanocable reaches up to the order of 10⁻³ S cm⁻¹. The luminescent intensity, electrical conductivity and magnetic properties of the nanocables can be tunable by adjusting various amounts of rare earth complex, PANI and Fe₃O₄ NPs. The [Fe₃O₄/PANI/PVP]@[Eu(TTA)₃(TPPO)₂/PVP] flexible luminescent-electrical-magnetic trifunctional nanocables have potential applications in molecular electronics, biomedicine, microwave absorption and display device owing to their excellent multifunctionality.