Electronic Structures and Pr³⁺ Photoluminescence Characteristics in Fresnoite, Sr‐Frenoite, and Ge‐Frenoite

Abstract

The undoped and Pr3+‐doped Fresnoite (Ba2TiSi2O8), Sr‐frenoite (Sr2TiSi2O8), and Ge‐frenoite (Ba2TiGe2O8) were synthesized by solid‐state reaction at high temperature and their photoluminescence properties and electronic structures were investigated. All these undoped samples show luminescence upon UV irradiation at room temperature. The excitation band of intervalence charge transfer (IVCT) emerged only in Sr2TiSi2O8:Pr3+, which was located at 340 nm. Under 340 nm excitation, Sr2TiSi2O8:Pr3+ showed an efficient red emission at 616 nm, ascribing to the 1D2→3H4 transition of Pr3+. However, Pr3+ red emissions and the excitation band of IVCT were not observed for Ba2TiSi2O8 and Ba2TiGe2O8 and the possible reasons for such behaviors were discussed.

Observation of Intra‐ and Inter‐Configurational Luminescence of Pr3+‐Doped Strontium Phosphate Glasses

“…2(a), and the inset shows the energy diagram of Pr 3+ ions. The emission peaks locate almost at the same wavelengths as already published results [3][4][5][6] that are due to the f-f transitions of Pr 3+ ions between 3 P 1 -3 H 4 (481 nm), 3 P 0 -3 H 4 (488 nm), 3 P 0 -3 H 5 (522 nm), 1 D 2 -3 H J (597, 610 nm), and 3 P 0 -3 F 2 (638 nm) levels. The peak intensities of blue, green, and red emissions are illustrated as a function of Pr 2 O 3 concentration in Fig.…”

“…1,2 Among all REIs, trivalent praseodymium ions (Pr 3+ ) are characterized by their rich emissions extending from the UV to the infrared region due to both intra-configurational f-f and inter-configurational f-d electronic transitions. 7,8 Compared with a wealth of researches on the f-f transitions of Pr 3+ ions, [3][4][5][6] there have been relatively fewer reports on the inter-configurational 4f 1 5d 1 -4f 2 transitions. [3][4][5][6] The intra-configurational f-f emissions of Pr 3+ ions upon blue excitation are mainly due to the transitions from Pr 3+ 3 P J , 1 D 2 , 1 G 4 levels to different ground state levels.…”

“…They have been intensively investigated for potential applications in fiber amplifiers, scintillators, solid state lasers, etc. [3][4][5][6] The intra-configurational f-f emissions of Pr 3+ ions upon blue excitation are mainly due to the transitions from Pr 3+ 3 P J , 1 D 2 , 1 G 4 levels to different ground state levels. However, the intra-configurational emissions emanating from the 1 S 0 state that locates energetically much higher than the other f levels could be excited only by VUV radiation.…”

“…However, the intra-configurational emissions emanating from the 1 S 0 state that locates energetically much higher than the other f levels could be excited only by VUV radiation. 7,8 Compared with a wealth of researches on the f-f transitions of Pr 3+ ions, [3][4][5][6] there have been relatively fewer reports on the inter-configurational 4f 1 5d 1 -4f 2 transitions. Similar to Eu 2+ and Ce 3+ ions, 2,9-11 f-d transitions of Pr 3+ ions involve an extended 5d orbital, and the excitation and emission bands thus strongly depend on the chemical environment around rare-earth ions.…”

“…1 D 2 4f-4f transitions, respectively [3][4][5][6]. 1 D 2 4f-4f transitions, respectively [3][4][5][6].…”