High pressure responsive luminescence of flexible Eu^(3+) doped PVDF fibrous mats

Exploring lanthanide doped materials and their high-pressure optical properties is important from the perspective of designing pressure sensors, piezoelectric materials, scintillators, and optoelectronic devices, just to mention a few. Understanding the high-pressure optical properties of polymeric fibrous mats provides significant advantages in terms of flexibility, tunability, facile processability, and malleability. In this work, we have developed flexible polyvinylidene difluoride(PVDF) fibrous mats doped with an Eu^(3+) source of Eu(NO_(3))_(3)·5H_(2)O(EN-PF) or Eu_(2)(SO_(4))_(3)(ES-PF) by a Forcespinning■ method. Microstructural analysis of these two systems indicates that Eu(NO_(3))_(3)·5H_(2)O and Eu_(2)(SO_(4))_(3) are homogeneously distributed and dispersed into the PVDF matrix. Fiber formation promotes a β-phase PVDF. Eu^(3+) doping increases the β-phase. Its fraction is larger for the ES-PF mats. To understand their high-pressure optical properties, their photoluminescence spectra have been taken at various pressures up to 58 GPa in a diamond anvil cell. High-pressure luminescence illustrates a clear change in asymmetry ratio, peak intensity, peak breadth, color coordinate, and color temperature of Eu^(3+) ions from both EN-PF and ES-PF with a different extent of changes. Specifically, Eu^(3+) ions in the ES-PF mats switch from asymmetric to symmetric environment as pressure increases. Those in the EN-PF mats present symmetric environment for all tested pressures. Both of the Eu^(3+) doped PVDF systems present irreversible changes. Therefore,the EN-PF fibrous mats present an opportunity to make pressure induced red-orange-yellow tunable phosphors for multifunctional applications.

Recent advances,challenges,and opportunities of inorganic nanoscintillators

This review article highlights the exploration of inorganic nanoscintillators for various scientific and technological applications in the fields of radiation detection,bioimaging,and medical theranostics.Various aspects of nanoscintillators pertaining to their fundamental principles,mechanism,structure,applications are briefly discussed.The mechanisms of inorganic nanoscintillators are explained based on the fundamental principles,instrumentation involved,and associated physical and chemical phenomena,etc.Subsequently,the promise of nanoscintillators over the existing single-crystal scintillators and other types of scintillators is presented,enabling their development for multifunctional applications.The processes governing the scintillation mechanisms in nanodomains,such as surface,structure,quantum,and dielectric confinement,are explained to reveal the underlying nanoscale scintillation phenomena.Additionally,suitable examples are provided to explain these processes based on the published data.Furthermore,we attempt to explain the different types of inorganic nanoscintillators in terms of the powder nanoparticles,thin films,nanoceramics,and glasses to ensure that the effect of nanoscience in different nanoscintillator domains can be appreciated.The limitations of nanoscintillators arc also highlighted in this review article.The advantages of nanostructured scintillators,including their property-driven applications,are also explained.This review article presents the considerable application potential of nanostructured scintillators with respect to important aspects as well as their physical and application significance in a concise manner.