Spectroscopic properties of high-temperature sintered SrS:0.05%Ce³⁺ under high hydrostatic pressure

Abstract

Luminescence properties of SrS:Ce pellets sintered at 1700 °C were investigated under high pressure. Two different Ce3+-related emissions were confirmed to appear in the blue-green and red parts of the spectrum and were shown to shift significantly and linearly to longer wavelengths with increasing pressure. Changes in decay times of both emissions were also thoroughly analyzed. The results confirmed that Ce3+ ion pairing/clustering occurring due to their enhanced mobility at high temperatures is responsible for the appearance of the recently reported red Ce3+ emission in sintered SrS:Ce pellets.

Abnormal co-doping effect on the red persistent luminescence SrS:Eu2+,RE3+ materials

“…As a result, the only effect by co-doping should be the creation of charge compensation defects, and since all the rare earth co-dopants present similar ionic radii, the defects should be similar. The RE 3+ co-dopants might be present as clusters in distorted sites, as observed by Mahlik et al for Ce 3+ -doped SrS materials 37 . The thermoluminescence glow curves (Fig.…”

“…The spectra of SrS:Eu 2+ ,Ce 3+ material are dominated by Eu 2+ bands and low contribution of Ce 3+ transitions. Even if Ce 3+ can also emit in red region, there is no clear difference in the Eu 2+ 620 nm band with Ce-co-doping 37,38 . Since the excitation bands of Ce 3+ and Eu 2+ are overlapped, the energy transfer from cerium to europium is highly probable.…”

Tailoring the Luminescent Properties of SrS:Ce3+ by Sr-Deficiency and Na+ Doping

“…As shown in Figure a, the SrS:(Ce 3+ ) x phosphors exhibit two overlapping signals at λ ≈ 495 nm and a minor shoulder centered at λ ≈ 530 nm under excitation at λ ≈ 276 nm. It is due to the typical Ce 3+ emission from the 5d 1 excited energy level to the 4f 1 ground energy level. , The corresponding PLE spectrum (Figure b) monitored at λ ≈ 536 nm possesses a broad band in the region of λ ≈ 250–500 nm, accompanied by a weak band at λ ≈ 280 nm and an intense band at λ ≈ 430 nm. The former band (280 nm) can be attributed to the effective host band–band transition, whereas the latter (430 nm) is related to the transitions to the 2 T 2g and 2 E g states of the 5d electronic manifold of octahedrally coordinated Ce 3+ , replacing the Sr 2+ ion in the SrS lattice. , We conclude that SrS doped with Ce 3+ can be sufficiently excited by both ultraviolet and blue light and shows its potential for LED fabrication.…”

Correlating doping with the stability and color rendition of red phosphors

“…18,26 The weak band (λ ~ 280 nm) is attributed to the effective band-band transition in the SrS lattice. 27 No trace of Eu 3+ emission is found for intervalence charge transfer (IVCT) which could quench the Eu 3+ emission pairs with Eu 2+ ions. 28 Figure 2d displays the diffuse reflection spectra of SrS:(Eu 2+ ) n , which show a broad absorption band (400-600 nm) in accordance with the PLE spectra as afore mentioned.…”

“…18,26 The weak band (l B 280 nm) is attributed to the effective bandband transition in the SrS lattice. 27 No trace of Eu 3+ emission is found for intervalence charge transfer (IVCT), which could quench the Eu 3+ emission pairs with Eu 2+ ions. 28 Fig.…”