Properties of green SrAl₂O₄ phosphor in LDPE and PMMA polymers

Abstract

Different contents of SrAl 2 O 4 :Eu,Dy, one of the long afterglow phosphorescent materials with high brightness, were melt-mixed with low-density polyethylene (LDPE) and Polymethyl methacrylate (PMMA) polymers, respectively. The morphology and composition of the samples were observed by means of a scanning electron microscope (SEM) coupled with an energy dispersive spectrometer (EDS), X-ray diffractometer (XRD), and transmission electron microscope (TEM). Sharp and broad X-ray diffraction (XRD) peaks were observed for the LDPE and the PMMA composites respectively, reflecting configuration characteristics similar to those of the respective pure polymers. TEM micrographs show a transition from nanosized particles to cluster formation with increase in phosphor concentration. The green long-lasting phosphorescence of the composites was observed in the dark after removal of the excitation light. Photoluminescence (PL) was observed in the composites of both polymers for phosphor volume concentrations above 1.0% for PMMA and above 0.5% for LDPE. For each of these samples, a broad PL peak at about 505 nm wavelength was observed after excitation at 350 nm with a xenon lamp. For the LDPE composites, the DSC results show that the presence of the phosphor in the polymer has no major influence on either the melting temperature or enthalpy values of the polymer.

UV excited green luminescence of SrAl2O4:Eu2+, Dy3+ nanophosphor

“…The strong peak at *2900 and 2850 cm -1 , and is assigned as due to the N-H anti-symmetric band. The sample showed a weak peak at *1700 cm -1 , and is assigned as due to the C-O anti-symmetric band [19].The appearance of a very strong band at *1500-1400 and 1200 cm -1 is due to the symmetric stretching vibrations of the N-O group, which might have resulted from the nitrate of the raw material [Sr(NO 3 ) 2 .…”

“…The alkaline earth aluminate, SrAl 2 O 4 is one of the most important persistent luminescent materials (phosphor). Their high initial luminescent intensity and low-dimensional long afterglow property makes the strontium aluminate phosphors an ideal substance to be widely used in many fields such as luminescent paint, luminescent plastic, luminescent ceramic, etc., and may lead to future nanoscale display devices [1][2][3]. Their afterglow lifetime and intensity can be enhanced by co-doping with some of the rare earth ions [4][5][6].…”

Developments in Eu+2‐Doped Strontium Aluminate and Polymer/Strontium Aluminate Composite

“…These composites find applications in catalysis, sorption, optical devices, and magnetism. Bem 57 The composites showed the photoluminescence when the phosphor concentration was ࣙ1% in poly(methy1 methacrylate) (PMMA) and 0.5% for LDPE. (Fig.…”

“…The authors have suggested that this pattern can be due to the filler orientation in the direction of shear force as well as the configuration of the extrusion die. Bem et al investigated the composites of LDPE with different volume ratios of SrAl 2 O 4 :Eu 2+ ,Dy 3+ phosphor. The composite emitted blue phosphorescence in the dark and exhibited luminescence spectra at 485.5 and 415 nm, which corresponds to the 4f–5d transition of Eu 2+ .…”

“…The phosphor particles slightly reduced the crystallinity of LDPE, whereas the thermal stability is significantly improved due to the immobilization of the polymer chain, higher thermal conductivity, and heat capacity of the phosphor. Bem et al compared the luminescence characteristics of LDPE/SrAl 2 O 4 :Eu 2+ ,Dy 3+ and PMMA/SrAl 2 O 4 :Eu 2+ ,Dy 3+ composites . The composites showed the photoluminescence when the phosphor concentration was ≥1% in poly(methy1 methacrylate) (PMMA) and 0.5% for LDPE.…”