Recombination luminescence in CaSO4

Salikhodzha, Zh.M.; Nurakhmetov, Т.N.; Аkilbekov, A.; Zhunusbekov, A.M.; Kainarbay, A.Zh.; Sadykova, B.M.; Zhangylysov, K.B.

doi:10.1016/j.radmeas.2019.04.010

Cited by 11 publications

(7 citation statements)

References 19 publications

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“…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%

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: Introductionmentioning

confidence: 99%

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

Nurakhmetov,

Alibay,

Tolekov

et al. 2023

chemija

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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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“…Экспериментальные результаты и их обсуждение. Как показано в наших предыдущих работах [9,10,12] Во время возбуждения фотонами с разной энергией от 5,5 эВ до 12,4 эВ, электроны с валентной зоны переходят в зону проводимости. В зависимости от энергии возбуждающего фотона в валентной зоне в трех кристаллографических направлениях создаются дырки ( SO − 4 -радикалы) с разной орбитальной энергией: центры типа А и типа В (при переходе 1 и 2).…”

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“…Mn 2+ -являются захватчиками свободных электронов. Увеличение в 2-3 раза интенсивности излучения при 3,8 эВ показывает, что это связано с рекомбинацией электронов с локализованными дырками.В последующих наших работах[9,10] были экспериментально обнаружено, что коротковолновая полоса излучения оказалась очень сложной и состоит из нескольких полос излучения в спектральном интервале 3, 64 ÷ 5, 5 эВ. Все эти полосы возникают при рекомбинации электронов с неэквивалентно расположенными локализованными дырками SO − 4 .…”

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“…Жанылысов, Б.Н. Юсупбекова,... работах[9,10,12] мы предполагали, что появление нескольких полос излучений должно быть связано с рекомбинацией электронов с неэквивалентно расположенными дырками SO − 4 в трех кристаллографических направлениях в кристаллической решетке. Возможно[13,14], существование неэквивалентно расположенных дырок или радикалов SO − 4 исходит из структурной особенности кристалла CaSO 4 .…”

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