Intrinsic luminescence in alkali metal sulfates

Nurakhmetov, Т.N.; Кутербеков, К. А.; Daurenbekov, D.H.; Salikhodzha, Zh.M.; Kainarbay, A.Zh.

doi:10.1016/j.jlumin.2015.10.068

Cited by 12 publications

(7 citation statements)

References 12 publications

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“…The samples were excited by 6.2 eV-5.64 eV. Emission observed in a region of 3.7-3.8 eV at 300 K is associated with the recombination of an electron with a non-equivalently located hole above the valence band [7][8][9][10]. Emission bands determined in regions of 3.1-3.17 eV, 2.6-2.7 eV and 2.3-2.4 eV (only at 80 K) are associated with electron-hole trapping centres [10].…”

Section: Resultsmentioning

confidence: 99%

“…Lithium containing mixed alkali metal sulphates activated by rare earth ions are used as phosphors and highly sensitive thermoluminescent dosimeters [1][2][3][4]. Emissions observed in sulphates of alkali and alkaline earth metals are associated with the recombination of electrons with localised holes [5][6][7][8][9][10]. The spectral position of emission in such processes mainly depends on the crystallographic arrangement of localised holes (as SO 4 radicals).…”

Section: Introductionmentioning

confidence: 99%

“…Experimental and theoretical calculations [11] have shown that the orbital energy of an unpaired electron in the ground state of the SO 4 radical differs in different crystallographic directions of anisotropic crystals. Therefore, during the recombination of an electron from the conduction band or the local state of the electron trapping centre with holes SO 4 emission should appear in a certain spectral range [5][6][7][8][9][10].…”

Section: Introductionmentioning

confidence: 99%

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Intrinsic emissions and formation of electron-hole trapping centres in excited Li2SO4

Nurakhmetov,

Alibay,

Tolekov

et al. 2023

chemija

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Vacuum ultraviolet and thermal activation spectroscopies were used to study the nature of intrinsic emission and the mechanisms of the formation of electron and hole trapping centres in irradiated Li2SO4 powders and crystals. The obtained results along with excitation spectra showed that recombination emission at 3.8–4.2 eV and 4.5–5.5 eV occurs when an electron passes from the second and third sub-bands of the valence band formed from the 2p state of oxygen to the conduction band. It has been determined that Li2SO4 electron and hole trapping centres are created when electrons are trapped in the SO42– anionic sites. The holes are localised in the form of SO4 – radicals. The spectral position and intensity of individual emission bands are dependent on the crystallographic arrangement of localised holes.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Intrinsic emissions and formation of electron-hole trapping centres in excited Li2SO4

Nurakhmetov,

Alibay,

Tolekov

et al. 2023

chemija

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“…This research work presents original experimental results on the ignition of intensity of exciton-like luminescence in a KCl matrix during the recombination formation of electron-hole pairs in a sodium field, stimulated by thermoelastic quenching and uniaxial (<100>, <110>) deformation.Recombination occurs due to mobile unrelaxed holes, in contrast to the recombination of electrons with self-trapped holes detected in alkali metal sulfates [24,25].…”

Section: Introductionmentioning

confidence: 99%

Exciton-like luminescence of KCl matrix under thermoelastic, local and uniaxial deformation

Shunkeyev

Tilep

Lushchik

et al. 2022

Eurasian j. phys. funct. mater.

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The radiative relaxation of exciton-like formations in KCl-Na single crystal has been studied by experimental methods of luminescent spectroscopy. The amplifying effect of the radiation intensity with a maximum at 2.8 eV up to 500 times as compared to pure KCl has been detected in KCl-Na. The luminescence efficiency of an exciton-like formation increases with rise in: sodium ions concentration ( 10 ÷ 1000 ppm), thermal exposure ( 500 • C ÷ 600 • C ) and the degree of uniaxial deformation along <100> and <110> crystallographic directions. Previously, such a scale of the luminescence enhancement effect has not been registered in KCl matrix at room temperature. At high sodium concentrations (1000 ppm) in KCl-Na crystals, the additional intense emission with a maximum at 3.1 eV has also been revealed, which is typical for pair sodium ions. It is interpreted that the exciton-like formation in the sodium field with the maximum quantum yield of luminescence is formed by recombination assembly of electron-hole pairs due to the mobility of unrelaxed holes.

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“…Only a few studies have been carried out showing the luminescence properties of SrSO 4 by doping it with rare-earth elements. [13,14,21,22] Similarly, few reports are available in the literature on intrinsic recombination luminescence in various alkali metal sulphates [23][24][25][26][27] and calcium sulphate [28,29] providing results on defect-based luminescence having a Stokes shift. Recently, Bao-gai Zhai et al have also shown intrinsic PL and cyan-coloured afterglow in undoped SrSO 4 nanoplates on UV excitation due to the presence of defects, mainly due to oxygen vacancies.…”

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confidence: 99%

Infrared‐to‐visible conversion in strontium sulphate through a defect‐based infrared stimulated visible emission phenomenon

et al. 2023

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Strontium sulphate (SrSO4) is a defect‐based photoluminescence material, generally used in thermoluminescence applications, and has been studied for infrared (IR) stimulated visible emission. The SrSO4 particles were synthesized using a precipitation method. The orthorhombic phase of SrSO4 was confirmed from the X‐ray diffraction pattern and the formation of micron‐sized particles was authenticated from field emission scanning electron micrographs. The elemental composition of oxygen and strontium was determined using energy‐dispersive X‐ray analysis measurement that confirmed the presence of VO•• and VSr′′ intrinsic defects in the material. Photoluminescence investigations showed the presence of various defect bands in the band gap giving rise to intrinsic luminescence in SrSO4. The emission in the visible region was attributed to the defect band arising due to 0.25emVO••. Photoluminescence lifetime measurement confirmed the presence of stable defect states with a lifetime in microseconds. The SrSO4 sample was tested using IR lasers and a red–orange emission spot was observed from the powder sample when excited with IR lasers. The underlying principle for IR‐to‐visible conversion in the material is a defect‐mediated phenomenon that has been described through the energy level diagram of the material.

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Intrinsic luminescence in alkali metal sulfates

Cited by 12 publications

References 12 publications

Intrinsic emissions and formation of electron-hole trapping centres in excited Li2SO4

Intrinsic emissions and formation of electron-hole trapping centres in excited Li2SO4

Exciton-like luminescence of KCl matrix under thermoelastic, local and uniaxial deformation

Infrared‐to‐visible conversion in strontium sulphate through a defect‐based infrared stimulated visible emission phenomenon

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