Synthesis and luminescence properties of YF3:Eu3+ hollow nanofibers via the combination of electrospinning with fluorination technique

RE-Based Inorganic-Crystal Nanofibers Produced by Electrospinning for Photonic Applications

Electrospinning is an effective and inexpensive technique to grow polymer materials in nanofiber shape with exceptionally high surface-area-to-volume ratio. Although it has been known for about a century, it has gained much interest in the new millennium thanks to its low cost and versatility, which has permitted to obtain a large variety of multifunctional compositions with a rich collection of new possible applications. Rare-earth doped materials possess many remarkable features that have been exploited, for example, for diode pumped bulk solid-state lasers in the visible and near infrared regions, or for biomedical applications when grown in nanometric form. In the last few decades, electrospinning preparation of rare-earth-doped crystal nanofibers has been developed and many different materials have been successfully grown. Crystal host, crystal quality and nanosized shape can deeply influence the optical properties of embedded rare earth ions; therefore, a large number of papers has recently been devoted to the growth and characterization of rare earth doped nanofibers with the electrospinning technique and an up-to-date review of this rapidly developing topic is missing; This review paper is devoted to the presentation of the main results obtained in this field up to now with particular insight into the optical characterization of the various materials grown with this technique.

Ionic Transportation and Dielectric Properties of YF₃:Eu3+ Nanocrystals

The ionic transportation and dielectric properties of YF₃:Eu³⁺ nanocrystals are investigated by AC impedance spectroscopy. The ion diffusion coefficient and conductivity increase along with the doping concentration and reach their highest values at 4% of Eu³⁺. The difference of ionic radius between Eu³⁺ and Y³⁺ leads to the structural disorder and lattice strain, which deduces the increase of the ion diffusion coefficient and conductivity before 4% Eu³⁺ doping; then the interaction of the neighboring doping ions is dominated, which results in the difficulty of ion migration and decreases of the ion diffusion coefficient and conductivity. The strong dispersion of the permittivity in the low frequency region indicates that the charge carrier transport mechanism is the ion hopping in the system. The low-frequency hopping dispersion is affected by an interfacial polarization, which exhibits a Maxwell-Wagner relaxation process, and its loss peak shifts to higher frequency with the ionic conductivity increasing.

Understanding the remarkable luminescence enhancement via SiO2 coating on TiO2:Eu3+ nanofibers

Red luminescence is enhanced by coating an SiO₂ layer on TiO₂:Eu³⁺ nanofibers, and the luminescence enhancement mechanism is discussed.

Novel construction technique, structure and photocatalysis of Y2O2CN2 nanofibers and nanobelts

Pure trigonal phase Y₂O₂CN₂ nanofibers and nanobelts have been successfully prepared by electrospinning in conjunction with cyanamidation technology. Y₂O₂CN₂ nanofibers and nanobelts possess excellent and stable photocatalytic performance.

Regulated morphology/phase structure and enhanced fluorescence in YF3:Eu3+,Bi3+via a facile method

Using a facile method to regulate morphology/phase structure and significantly enhance the fluorescence in YF₃:Eu³⁺,Bi³⁺.

New strategy to achieve La2O2CN2:Eu3+ novel luminescent one-dimensional nanostructures

For the first time, La₂O₂CN₂:Eu³⁺ nanofibers and nanobelts were successfully prepared and exhibit excellent luminescence properties.

Lanthanide-doped hollow nanomaterials as theranostic agents

The field of theranostics has sprung up to achieve personalized medicine. The theranostics fuses diagnostic and therapeutic functions, empowering early diagnosis, targeted drug delivery, and real-time monitoring of treatment effect into one step. One particularly attractive class of nanomaterials for theranostic application is lanthanide-doped hollow nanomaterials (LDHNs). Because of the existence of lanthanide ions, LDHNs show outstanding fluorescent and paramagnetic properties, enabling them to be used as multimodal bioimaging agents. Synchronously, the huge interior cavities of LDHNs are able to be applied as efficacious tools for storage and delivery of therapeutic agents. The LDHNs can be divided into two types based on difference of component: single-phase lanthanide-doped hollow nanomaterials and lanthanide-doped hollow nanocomposites. We describe the synthesis of first kind of nanomaterials by use of hard template, soft template, template-free, and self-sacrificing template method. For lanthanide-doped hollow nanocomposites, we divide the preparation strategies into three kinds (one-step, two-step, and multistep method) according to the synthetic procedures. Furthermore, we also illustrate the potential bioapplications of these LDHNs, including biodetection, imaging (fluorescent imaging and magnetic resonance imaging), drug/gene delivery, and other therapeutic applications.