Tb3+/Eu3+ Complex-Doped Rigid Nanoparticles in Transparent Nanofibrous Membranes Exhibit High Quantum Yield Fluorescence.

Peng Lu,Yao Wang,Jianguo Tang,Sixian Lian,Laurence A Belfiore,Yanxin Wang,Linjun Huang,Matt J Kipper

doi:10.3390/nano10040694

Abstract

In this study, transparent membranes containing luminescent Tb3+ and Eu3+ complex-doped silica nanoparticles were prepared via electrospinning. We prepared the electrospun fibrous membranes containing Tb(acac)3phen- (acac = acetylacetone, phen = 1,10-phenanthroline) and/or Eu(tta)3phen- (tta = 2-thenoyltrifluoroacetone) doped silica (M-Si-Tb3+ and M-Si-Eu3+) and studied their photoluminescence properties. The fibrous membranes containing the rare earth complexes were prepared by electrospinning. The surface morphology and thermal properties of the fibrous membrane were studied by atomic force microscopy (AFM), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), respectively. Fluorescence spectroscopy was used to characterize the fluorescence properties of the membranes. During the electrospinning process, the PVDF transitions from the α phase to the β phase, which exhibits a more rigid structure. The introduction of rigid materials, like PVDF and silica, can improve the fluorescence properties of the hybrid materials by reducing the rate of nonradiative decay. So the emission spectra at 548 nm (Tb) and 612 nm (Eu) were enhanced, as compared to the emission from the pure complex. Furthermore, the fluorescence lifetimes ranged from 0.6 to 1.5 ms and the quantum yields ranged from 32% to 61%. The luminescent fibrous membranes have potential applications in the fields of display panels, innovative electronic and optoelectronic devices.

Highlights

Rare earth (RE) ions, especially lanthanide (Ln) ions, have excellent luminescence characteristics with extremely sharp emission bands, making them attractive for use in technological applications, such as optoelectronics devices [1,2,3,4,5] and sensors [6,7]
We propose a new fluorescent nanofiber membrane obtained by electrospinning doped with highly sensitive fluorescent complexes
An air-dried membrane sample was fixed on a specimen holder and 2.5 μm × 2.5 μm areas were scanned by tapping mode in air at room temperature

Summary

Introduction

Rare earth (RE) ions, especially lanthanide (Ln) ions, have excellent luminescence characteristics with extremely sharp emission bands, making them attractive for use in technological applications, such as optoelectronics devices [1,2,3,4,5] and sensors [6,7]. The direct absorption of Ln3+ ions is weak, so the Ln3+ emissive state is achieved through the excitation of a coordinated organic ligand and the subsequent energy transfer from its triplet state to the metal ions by a dipole-dipole exchange mechanism [9] These complexes cannot be used directly in some practical applications due to poor thermal stability and weak mechanical properties, which limit their durability and processability. Razaki described an innovative multilayered membrane based on Tm(III)-containing alternating layers of thin films and nanofibers made of poly(vinyl alcohol) and Tm(III)-doped SiO2-Al2O3 [14] They demonstrated enhancement of the Tm(III) luminescence, which they partially attributed to the confinement of the Tm(III) ions in the one-dimensional nanofiber environment. These hybrid nanofibers have potential applications in the fields of optical devices [22] and sensor systems [23]

Materials

Morphology of the Electrospun Fiber Polymer Membranes

Conclusions