LUMINESCENCE AND THE FORMATION OF ELECTRON-HOLE TRAPPING CENTERS IN CaSO₄–Bi PHOSPHOR

The mechanisms of creation of a new combined electron-emissive state at 2.95 eV, 3.1 eV, 2.6–2.7 eV and 2.25–2.4 eV, which is a pre-decay state for energy transfer from the matrix to the emitters, were investigated in the CaSO₄ −Bi  phosphor. Combined electron-emissive states are formed from intrinsic SO₄³⁻ − SO₄⁻ and impurity Bi²⁺ −SO₄⁻ electronhole trapping centers according to studying via spectroscopic and thermal activation methods. In turn, the intrinsic and impurity electron-hole trapping centers are created during excitation of the anionic complex SO₄²⁻ as a result of charge transfer from the matrix to impurities (О²⁻ −Bi³⁺ ) and neighboring anions (О²⁻ − SO₄²⁻ ). It is shown that the energy accumulated in the intrinsic matrix during external irradiation in the form of a combined electron radiative state of SO₄³⁻ and Bi²⁺ decays as a result of the recombination process and is transferred to impurities.

1. Blasse, G., and A. Bril. Investigations on Bi3+‐activated phosphors // The Journal of Chemical Physics. – 1968. Vol. 48.1. – P. 217–222.

2. Lushchik, Ch, et al. Nature of the luminescence centers in ionic crystals // Czechoslovak Journal of Physics B. – 1970. – Vol. 20.5. – P. 585–604.

3. Boulon, G. Processus de photoluminescence dans les oxydes et les orthovanadates de terres rares polycristallins activés par l'ion Bi3+ // Journal de Physique. – 1971. – Vol. 32.4. – P. 333–347.

4. Di Bartolo, Baldassare, and Guzin Armagan. Spectroscopy of solid-state laser-type materials // Springer Science & Business Media – 2012. – Vol. 30.

5. Blasse, George. Luminescence of inorganic solids: from isolated centres to concentrated systems // Progress in Solid State Chemistry. – 1988. – Vol. 18.2. – P. 79–171.

6. Boutinaud, Philippe. Revisiting the spectroscopy of the Bi3+ ion in oxide compounds // Inorganic Chemistry. – 2013. – Vol. 52.10. – P. 6028–6038.

7. Zazubovich, S., et al. Nanocomposite, Ceramic, and Thin Film Scintillators – 2016. – P. 227–305.

8. Awater, Roy HP, and Pieter Dorenbos. The Bi3+ 6s and 6p electron binding energies in relation to the chemical environment of inorganic compounds // Journal of luminescence. – 2017. Vol. 184. – P. 221–231.

9. Krasnikov, Aleksei, et al. Photostimulated Defect Creation Processes in the Undoped and Bi3+‐Doped Ca3Ga2Ge3O12 Garnets // Physica status solidi (b). – 2012. – Vol. 258.10. – P. 2100080.

10. Baran, M., et al. Bi3+-doped garnets as possible ultraviolet persistent phosphors // Optical Materials. – 2013. – Vol. 137. – P. 113584.

11. Babin, V., et al. Origin of Bi3+‐related luminescence centres in Lu3Al5O12: Bi and Y3Al5O12: Bi single crystalline films and the structure of their relaxed excited states // Physica status solidi (b). – 2012. – Vol. 249.5. – P. 1039– 1045.

12. Babin, V., et al. Peculiarities of excited state structure and photoluminescence in Bi3+-doped Lu3Al5O12 single-crystalline films // Journal of Physics: Condensed Matter. – 2009. – Vol. 21.41. – P. 415502.

13. Gorbenko, V., et al. Photoluminescence and excited state structure of Bi3+-related centers in Lu2SiO5: Bi single crystalline films // Journal of luminescence. – 2013. – Vol. 134. – P. 469–476.

14. Babin, V., et al. Origin of Bi3+‐related luminescence centres in Lu3Al5O12: Bi and Y3Al5O12: Bi single crystalline films and the structure of their relaxed excited states // Physica status solidi (b). – 2012. – Vol. 249.5. – P. 1039– 1045.

15. Gorbenko V. et al. Photoluminescence and excited state structure of Bi3+-related centers in Lu2SiO5: Bi single crystalline films // Journal of luminescence. – 2013. – Vol. 134. – P. 469–476.

16. Awater, Roy HP, Louise C. Niemeijer-Berghuijs, and Pieter Dorenbos. Luminescence and charge carrier trapping in YPO4: Bi // Optical Materials. – 2017. – Vol. 66. – P. 351–355.

17. Cao, Renping, et al. Synthesis and luminescence properties of CaSnO3: Bi3+ blue phosphor and the emission improvement by Li+ ion //Luminescence. – 2017. – Vol. 32.6. – P. 908–912.

18. Yousif, A., et al. Luminescence and electron degradation properties of Bi doped CaO phosphor // Applied Surface Science. – 2015. – Vol. 356. – P. 1064–1069.

19. Puchalska, M., E. Zych, and P. Bolek. Luminescences of Bi3+ and Bi2+ ions in Bi-doped CaAl4O7 phosphor powders obtained via modified Pechini citrate process // Journal of Alloys and Compounds. – 2019. – Vol. 806. – P. 798–805.

20. Cao, Renping, et al. Yellow-to-orange emission from Bi2+doped RF 2 (R= Ca and Sr) phosphors // Optics express. – 2013. – Vol. 21.13. – P. 15728–15733.

21. Cao, Renping, Mingying Peng, and Jianrong Qiu. Photoluminescence of Bi2+-doped BaSO4 as a red phosphor for white LEDs // Optics express. – 2012. – Vol. 20.106. – P. A977–A983.

22. Nurakhmetov, T. N., et al. Intrinsic emission and electronhole trapping centers in irradiated Na2SO4 // Optik. – 2021. – Vol. 242. – P. 167081.

23. Nurakhmetov, Turlybek N., et al. Energy Transfer in the C a SO4−Dy Thermoluminescent Dosimeter from the Excited State of the SO4 2− Anionic Complex to the Impurities // Crystals. – 2023. – Vol. 13.11. – P. 1596.

24. Nurakhmetov, T. N., et al. The creation spectra of intrinsic emission of a LiKSO4 crystal irradiated by ultraviolet photons // Optik. – 2019. – Vol. 185. – P. 156–160.

25. Nurakhmetov, T. N., et al. The energy transfer of electronic excitations to impurities in dosimetric phosphors BaSO4-Dy // Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms. – 2024. – Vol. 555. – P. 165459.

26. Byberg, J. R. O− detected by ESR as a primary electronexcess defect in x‐irradiated K2SO4 // The Journal of chemical physics. – 1986. – Vol. 84.11. – P. 6083-6085.

27. Nurakhmetov T. N. et al. Specific Features of Formation of Electron and Hole Trapping Centers in Irradiated CaSO4-Mn and BaSO4-Mn // Crystals. – 2023. – Vol. 13. – No. 7. – P. 1054