Recombination processes and emission spectrum of terbium in oxysulfides

Amiryan, A. M.; Gurvieh, A. M.; Katomina, R. V.; Petrova, I. Yu.; Soshchin, N. P.; Tombak, Mati

doi:10.1007/bf00625902

Cited by 10 publications

(8 citation statements)

References 8 publications

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“…SrSO 4 , which is a typical insulator with a band gap of around 7.6 eV, 22 is often utilized as the host material of rare-earth dopants to develop efficient luminescent materials. Due to the large band gap of SrSO 4 , the photon energy of our ultraviolet laser (3.82 eV) is not high enough to pump carriers from its valence band to conduction band.…”

Section: Results and Discussionmentioning

confidence: 99%

“…Apparently, our calculated band gap value of SrSO 4 is underestimated when compared to the experimental band gap value of 7.6 eV for SrSO 4 . 22 The density functional calculations are often known to underestimate the band gap value of materials. For example, Zhai et al reported that SrSO 4 is an insulator with an indirect band gap of 6.14 eV using the GGA approach in the density functional calculations.…”

Section: Results and Discussionmentioning

confidence: 99%

“…The band gap of SrSO 4 is assumed to be 7.6 eV. 22 As shown in Figure 9 , one of the defect energy levels of oxygen vacancy is located at E V + 2.50 eV, while the other defect energy level of oxygen vacancy, which is located at E V + 0.31 eV, is not shown in Figure 9 for the purpose of clarity. Similarly, the defect energy level of strontium vacancy is located at E V + 0.175 eV.…”

Section: Results and Discussionmentioning

confidence: 99%

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Blue Photoluminescence and Cyan-Colored Afterglow of Undoped SrSO₄ Nanoplates

Zhai

Zhang

et al. 2021

ACS Omega

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Undoped SrSO 4 nanoplates were synthesized via the composite hydroxide-mediated approach. The products were characterized by means of X-ray diffractometry, scanning electron microscopy, X-ray energy-dispersive spectroscopy, X-ray photoelectron spectroscopy, photoluminescence (PL) spectroscopy, electron spin resonance technique, afterglow spectroscopy, and thermoluminescence dosimetry. The steady-state PL spectrum of undoped SrSO 4 nanoplates can be deconvoluted into two distinct Gaussian bands centered at 2.97 eV (417.2 nm) and 2.56 eV (484.4 nm), respectively. The nature of the defect emissions is confirmed through the emission-wavelength-dependent PL decays as well as the excitation-wavelength-dependent PL decays. A cyan-colored afterglow from undoped SrSO 4 nanoplates can be observed with naked eyes in the dark, and the afterglow spectrum of the undoped SrSO 4 nanoplates exhibits a peak at about 492 nm (2.52 eV). The duration of the afterglow is measured to be 16 s. The thermoluminescence glow curve of the undoped SrSO 4 nanoplates shows a peak at about 40.1 °C. The trapping parameters are determined with the peak shape method, the calculated value of the trap depth is 0.918 eV, and the frequency factor is 1.2 × 10 14 s –1 . Using density functional calculations, the band structures and densities of states of oxygen-deficient SrSO 4 and strontium-deficient SrSO 4 are presented. The mechanisms of the cyan-colored afterglow are discussed for undoped SrSO 4 , and the oxygen vacancies in SrSO 4 are proposed to be the luminescence center of the afterglow.

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Section: Results and Discussionmentioning

confidence: 99%

Section: Results and Discussionmentioning

confidence: 99%

Section: Results and Discussionmentioning

confidence: 99%

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Blue Photoluminescence and Cyan-Colored Afterglow of Undoped SrSO₄ Nanoplates

Zhai

Zhang

et al. 2021

ACS Omega

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“…Though there were significant absorption in the near-UV region and the excitation at 352 nm has highest intensity, we have chosen λex=38 nm as it is more suitable near UV excitation for white LED and therefore La 2 O 2 S: Tb had potential to be used as near-UV LED phosphors [36]. The emission spectrum of La 2 O 2 S: Tb is determined by the transitions of electrons from an upper ( 5 D 3 ) and a lower ( 5 D 4 ) excited level to the level of the multiplet term 7 F J (J = 0, 1, 2, 3, 4, 5, 6) levels of the 4 f 8 configuration [37,38]. The emission of terbium doped phosphor is mainly in the green due to transitions 5 D 4 → 7 F J and the blue emission contributes to the emission from the higher level transitions 5 D 3 → 7 F J .…”

Section: Ii) Pl Emission Of Dy 3+ In La 2 O 2 Smentioning

confidence: 99%

Synthesis and Luminescence Properties of La2O2S:RE3+ (RE3+ = Ce3+, Dy3+, Eu3+ and Tb3+) Submicron Size Phosphors for Lamp Industry

Shinde,

Dhoble*

2020

IJITEE

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RE3+(RE3+ = Ce3+, Dy3+, Eu3+ and Tb3+) doped La2O2S phosphors was synthesized by solid state flux fusion method and their down conversion spectral properties were studied as a function different RE3+ concentrations and reported in this paper. The solid state flux fusion results in well crystallized hexagonal shaped phosphor particles. The samples were characterized by XRD, SEM, FT-IR photoluminescence (PL) and CIE colour co-ordinates techniques. The lanthanum oxysulphide (La2O2S) phosphor doped with Ce3+ shows broad band emission with peak at 390 nm and 415 nm when excited at 340 nm excitation. La2O2S:Dy3+ shows efficient blue and yellow band emissions at 480 nm and 572 nm. La2O2S:Eu3+ phosphor shows an orange and red emission at 590 nm and 615 nm. Whereas La2O2S:Tb3+ phosphor shows weak blue emission at 488 nm and strong green 545 nm. The excitation spectra used for the La2O2S:RE3+ (where RE3+ = Ce3+, Dy3+, Eu3+ and Tb3+) phosphors is in the near UV region extending from 350 to 400 nm, which is characteristics of near UV excited LED. The effect of the RE3+ (RE3+= Ce3+, Dy3+ , Eu3+ and Tb3+) concentration on the luminescence properties of La2O2S:RE3+ phosphors were also studied. The investigated prepared La2O2S phosphors may be suitable for a near UV excited W-LED. Keywords: Oxysulphide, SEM, FT-IR, PL, SSL, CIE.

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“…A more accurate approach of the excited states is the self-consistent quasiparticle GW (sc-QPGW) calculation [30] which includes the corrections for the electrostatic interactions between electrons and holes. After conducting sc-QPGW calculations [30], the band gaps were updated to 8.73 eV for α-SiO 2 (measured value was 8.90 eV [47]) and 7.27 eV for BaSO 4 (experimental value was 7.60 eV [49]), which were also depicted in their band structure as shown in Figs. 1 (a) and (c), respectively.…”

mentioning

confidence: 99%

Atomistic metrics of BaSO$_4$ as an ultra-efficient radiative cooling material: a first-principles prediction

Tong¹,

Peoples²,

Li³

et al. 2021

Preprint

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Radiative cooling has recently revived due to its significant potential as an environmentally friendly cooling technology. However, the design of particle-matrix cooling nanocomposites was generally carried out via tedious trial-and-error approaches, and the atomistic physics for efficient radiative cooling was not well understood. In this work, we identify the atomistic metrics of Barium Sulfate (BaSO4) nanocomposite, which is an ultra-efficient radiative cooling material, using a predictive first-principles approach coupled with Monte Carlo simulations. Our results show that BaSO4-acrylic nanocomposites not only attain high total solar reflectance of 92.5% (0.28 -4.0 µm), but also simultaneously demonstrate high normal emittance of 96.0% in the sky window region (8 -13 µm), outperforming the commonly used α-quartz (α-SiO2). We identify two pertinent characters of ultra-efficient radiative cooling paints: i) a balanced band gap and refractive index, which enables strong scattering while negating absorption in the solar spectrum, and ii) a sufficient number of infrared-active optical resonance phonon modes resulting in abundant Reststrahlen bands and high emissivity in the sky window. The first principles approach and the resulted physical insights in this work pave the way for further search of ultra-efficient radiative cooling materials.

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Recombination processes and emission spectrum of terbium in oxysulfides

Cited by 10 publications

References 8 publications

Blue Photoluminescence and Cyan-Colored Afterglow of Undoped SrSO₄ Nanoplates

Blue Photoluminescence and Cyan-Colored Afterglow of Undoped SrSO₄ Nanoplates

Synthesis and Luminescence Properties of La2O2S:RE3+ (RE3+ = Ce3+, Dy3+, Eu3+ and Tb3+) Submicron Size Phosphors for Lamp Industry

Atomistic metrics of BaSO$_4$ as an ultra-efficient radiative cooling material: a first-principles prediction

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Recombination processes and emission spectrum of terbium in oxysulfides

Cited by 10 publications

References 8 publications

Blue Photoluminescence and Cyan-Colored Afterglow of Undoped SrSO4 Nanoplates

Blue Photoluminescence and Cyan-Colored Afterglow of Undoped SrSO4 Nanoplates

Synthesis and Luminescence Properties of La2O2S:RE3+ (RE3+ = Ce3+, Dy3+, Eu3+ and Tb3+) Submicron Size Phosphors for Lamp Industry

Atomistic metrics of BaSO$_4$ as an ultra-efficient radiative cooling material: a first-principles prediction

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Blue Photoluminescence and Cyan-Colored Afterglow of Undoped SrSO₄ Nanoplates

Blue Photoluminescence and Cyan-Colored Afterglow of Undoped SrSO₄ Nanoplates