Luminescent characterization of CaAl2S4:Eu powder

Haecke, Jo E. Van; Smet, Philippe; Poelman, Dirk

doi:10.1016/j.jlumin.2006.10.001

Cited by 50 publications

(34 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The 5d excited state is lowered by the centroid shift and split by the crystal field into two or more components, depending on the local symmetry [36]. Each corresponding absorption band is rather broad (typically 4000 cm -1 ), due to the 4f 6 ( 7 F J ) electronic level structure [37]. Consequently, the excitation spectrum is rather featureless due to the partially overlapping excitation bands.…”

Section: Thermoluminescence Excitation Contour Plotsmentioning

confidence: 99%

Temperature and wavelength dependent trap filling in M2Si5N8:Eu (M=Ca, Sr, Ba) persistent phosphors

Smet¹,

Eeckhout²,

Bos³

et al. 2012

Journal of Luminescence

View full text Add to dashboard Cite

The evaluation of persistent phosphors is often focused on the processes right after the excitation, namely on the shape of the afterglow decay curve and the duration of the afterglow, in combination with thermoluminescence glow curve analysis. In this paper we study in detail the trap filling process in europium-doped alkaline earth silicon nitrides (Ca 2 Si 5 N 8 :Eu, Sr 2 Si 5 N 8 :Eu and Ba 2 Si 5 N 8 :Eu), i.e., how the persistent luminescence can be induced. Both the temperature at which the phosphors are excited and the spectral distribution of the excitation light on the ability to store energy in the phosphors' lattices are investigated. We show that for these phosphors this storage process is thermally activated upon excitation in the lower 5d excited states of Eu 2+ , with the lowest thermal barrier for europium doped Ca 2 Si 5 N 8 . Also, the influence of co-doping with thulium on the trap filling and afterglow behavior is studied. Finally there exists a clear relation between the luminescence quenching temperature and the trap filling efficiency. The latter relation can be utilized to select new efficient 5d-4f based afterglow phosphors. 2 Center for Nano-and Biophotonics (NB-Photonics), Ghent University, Belgium.

show abstract

Section: Thermoluminescence Excitation Contour Plotsmentioning

confidence: 99%

Temperature and wavelength dependent trap filling in M2Si5N8:Eu (M=Ca, Sr, Ba) persistent phosphors

Smet¹,

Eeckhout²,

Bos³

et al. 2012

Journal of Luminescence

View full text Add to dashboard Cite

show abstract

“…The alkaline earth orthovanadates have attracted more attention because of their potential applications in the solid-state lighting [1][2][3]. Solid-state lighting based on InGaN LEDs shows significant potential application for replacing conventional lighting sources such as incandescent and fluorescent lamps.…”

Section: Introductionmentioning

confidence: 99%

Photoluminescence properties of Ca9Y(VO4)7 and Ca9Y0.95Ln0.05(VO4)7 (Ln3+= Eu3+, Sm3+, Pr3+)

Cao

Quan

et al. 2009

Journal of Alloys and Compounds

View full text Add to dashboard Cite

“…We know that as the temperature rises, the vibrational energy of ions in the crystal lattice increases, which leads to a decrease in the crystal fi eld [11]. This is apparent to different extents in the short-wavelength shift of the photoluminescence as the temperature rises in the Ca x Ba 1-x Ga 2 S 4 :Eu solid solutions for different x.…”

mentioning

confidence: 99%

Photoluminescence of Ca x Ba1–x Ga2S4 Solid Solutions Activated by Eu2+ Ions

et al. 2015

View full text Add to dashboard Cite

We have studied the photoluminescence (PL) of Ca x Ba 1-x Ga 2 S 4 solid solutions (x = 0.1, 0.2, 0.3, 0.4, and 0.5) activated by ions of the rare-earth element Eu 2+ in the temperature range 10-300 K, due to 4f 6 5d → 4f 7 transitions in the Eu 2+ ions. The photoluminescence spectra of Ca x Ba 1-x Ga 2 S 4 :Eu are located in the blue-green -green regions, and their maxima are shifted from 506 nm for x = 0.1 to 531 nm for x = 0.5. We show that the long-wavelength shift as Ca content increases is due to the increasing crystal fi eld, in the presence of which the 5d orbitals of the europium ions are split and consequently the energy of the recombination transitions decreases. We observed high temperature stability of the position of the photoluminescence spectra and the integrated intensity (decreasing by 13% for all x) in the temperature range 10-300 K. We have established that an increase in the Ca content in Ca x Ba 1-x Ga 2 S 4 :Eu leads to a decrease in the thermal shift of the photoluminescence, and for x = 0.5 there is no shift.Introduction. Synthesis of high-effi ciency luminophores emitting in the visible region of the spectrum is a key problem to be solved in designing devices for visualization and illumination that are competitive with conventional systems. Promising luminescent media include ternary chalcogenide semiconductors, in particular barium thiogallate (BaGa 2 S 4 ), strontium thiogallate (SrGa 2 S 4 ), and calcium thiogallate (CaGa 2 S 4 ) activated by rare-earth ions Eu or Ce [1-5]. These compounds differ from the binary compounds (GaS, Ga 2 S 3 ) in their resistance to hydrolysis and their good ability to incorporate rare-earth ions into their crystal lattice [5]. The compounds BaGa 2 S 4 and CaGa 2 S 4 activated by Eu 2+ ions display intense emission in the blue-green (~500 nm) and yellow (~555 nm) regions of the spectrum, due to 4f 6 5d → 4f 7 electronic transitions in the europium ions [1]. They are characterized by high thermal stability of the spectrum and photoluminescence (PL) intensity, and exhibit extreme stability of the position and shape of the spectrum and linearity of the photoluminescence intensity over a broad range of pulsed optical excitation all the way up to 10 4 W/cm 2 [5]. The presence of intense bands in the violet-blue region in the photoluminescence excitation (PLE) spectra of BaGa 2 S 4 :Eu and CaGa 2 S 4 :Eu makes them promising for effi cient excitation by the emission from commercial GaN and InGaN light-emitting diodes (LEDs) and laser diodes (LDs). Recently there have been studies of the optical properties of mixed compounds MGa 2 S 4 -M ' Ga 2 S 4 (M, M ' = Ba, Sr, Ca (alkaline earth elements) activated by rare-earth ions, in which variation of the composition of the matrix leads to a shift of the spectrum in the visible region [6,7]. Such mixed compounds are novel and their photoluminescence has not been suffi ciently studied.With the aim of varying the emission wavelength within the blue-green-yellow regions of the spectrum (505-555 nm), we synthesized novel...

show abstract

Luminescent characterization of CaAl2S4:Eu powder

Cited by 50 publications

References 26 publications

Temperature and wavelength dependent trap filling in M2Si5N8:Eu (M=Ca, Sr, Ba) persistent phosphors

Temperature and wavelength dependent trap filling in M2Si5N8:Eu (M=Ca, Sr, Ba) persistent phosphors

Photoluminescence properties of Ca9Y(VO4)7 and Ca9Y0.95Ln0.05(VO4)7 (Ln3+= Eu3+, Sm3+, Pr3+)

Photoluminescence of Ca x Ba1–x Ga2S4 Solid Solutions Activated by Eu2+ Ions

Contact Info

Product

Resources

About