Yanxia Liu

Superhigh-Throughput Needleless Electrospinning Using a Rotary Cone as Spinneret

Lanzhou Univ, Minist Educ, Key Lab Magnetism & Magnet Mat, Lanzhou 730000, Gansu, Peoples R China

Oxygen defects-modulated green photoluminescence of Tb-doped ZrO2 nanofibers

The photoluminescence properties of Tb-doped ZrO2 nanofibers synthesized by electrospinning technique were investigated. The intensity of the green light emission could be controlled by oxygen vacancy concentration, which could be enhanced by argon gas annealing or diminished by oxygen annealing. An energy transfer mechanism is proposed that the oxygen vacancies in the host acted as effective sensitizers for the adjacent Tb ions. The oxygen vacancies transferred excitation energy to the adjacent Tb ions sites and thus greatly enhanced the green emission. These results are of great importance for the future optoelectronic applications of Tb-doped ZrO2 nanofibers.

Direct preparation of carbon nanotubes and nanobelts from polymer

Carbon nanotubes and carbon nanobelts were obtained via single-needle electrospinning on a basis of water-in-oil (W/O) emulsion technique, respectively. The morphology of electrospun products can be controlled by controlling the temperature of the collector during the electrospinning process. The mechanism of fabricating PAN nanotubes and nanobelts by emulsion electrospinning is discussed in detail. Transmission electron microscopy and scanning electron microscope results show that the carbon nanotubes (the inner diameter of 25-50 nm and the outer diameter of 50-100 nm) have a wall thickness of 10-50 nm, and the width and thickness of the nanobelts range from 100 to 300 nm, and 1 to 5 nm, respectively. A slight difference of bonding configuration of the carbon nanofibers, carbon nanotubes and carbon nanobelts is attributed partly to their different topological structures. The novel method is versatile and could be extended to the fabrication of various types of nanotubes and nanobelts.

Synthesis and White-Light Emission of ZnO/HfO2: Eu Nanocables

ZnO/HfO2:Eu nanocables were prepared by radio frequency sputtering with electrospun ZnO nanofibers as cores. The well-crystallized ZnO/HfO2:Eu nanocables showed a uniform intact core–shell structure, which consisted of a hexagonal ZnO core and a monoclinic HfO2 shell. The photoluminescence properties of the samples were characterized. A white-light band emission consisted of blue, green, and red emissions was observed in the nanocables. The blue and green emissions can be attributed to the zinc vacancy and oxygen vacancy defects in ZnO/HfO2:Eu nanocables, and the yellow–red emissions are derived from the inner 4f-shell transitions of corresponding Eu3+ ions in HfO2:Eu shells. Enhanced white-light emission was observed in the nanocables. The enhancement of the emission is ascribed to the structural changes after coaxial synthesis.