Conjugate electrospinning-constructed special-shaped Janus nanobelt with improved upconversion luminescence and regulable magnetism Bi-functionality

Abstract

Developing multifunctional nanomaterials through the design and construction of advanced nanostructures that are highly compatible with various substances is a crucial approach. In this work, special-shaped Janus nanobelt with both up-conversion luminescence (UCL) and magnetism is firstly designed and fabricated via a conjugate electrospinning coupled with a di-crucible fluorination. [YF3: Yb3+, Ho3+@SiO2] belt-in-belt nanobelt//CoFe2O4 nanobelt conjugate electrospinning-constructed special-shaped Janus nanobelt (shorted as C-SJNB) was designed and successfully prepared for a case study. C-SJNB is composed of two mutually independent micro-zones, which are YF3: Yb3+, Ho3+@SiO2 belt-in-belt nanobelt (BNB) called as luminescent micro-zone, and CoFe2O4 magnetic nanobelt acted as magnetic micro-zone. In the C-SJNB structure, the design ensures that the luminescent substance does not directly contact with the magnetic substance, thereby reducing the adverse effects of the dark-brown magnetic CoFe2O4 on the luminescent performance. C-SJNBs with structural advantages exhibit 7 times the UCL intensity compared to counterpart luminescent-magnetic YF3: Yb3+, Ho3+/SiO2/CoFe2O4 hybrid nanobelts (HNBs) prepared by uniaxial electrospinning. Further, compared with [YF3: Yb3+, Ho3+@SiO2]//CoFe2O4 parallel electrospinning-constructed special-shaped Janus nanobelt (shorted as P-SJNB), C-SJNB possesses a higher quality of micro-morphology, and avoids the degradation of luminescence performance caused by the mixing of magnetic and luminescent substances at the interface. The UCL intensity and magnetism of C-SJNBs can be adjusted by changing the content of CoFe2O4. When the CoFe2O4 content increases from 0.5 mmol to 4 mmol, the saturation magnetization of C-SJNBs increases from 4.42 to 13.94 emu·g−1. The newly established technology eliminates the needs for complex electrospinning and post-processing procedures. The formation mechanism of C-SJNBs has been established, providing technical support for synthesizing other Janus nanobelts with a belt-in-belt structure on one side. These advanced Janus nanobelts are ideal for developing poly-functional nanomaterials and have important applications in dual-mode imaging, display devices, batteries, drug loading and delivery.