Synthesis and optical properties of powders of lutetium and yttrium double phosphates-doped by ytterbium

Abstract

This contribution is devoted to the new ytterbium-doped alkali metal lutetium double phosphates and their structural and spectroscopic characterisations. The absorption, emission and excitation spectra have been measured at 4, 10 and 293 K in the VUV to IR range. The results have been compared with the analogous yttrium phosphates. The luminescence spectra of the double phosphates have been recorded using various excitation lines, including the synchrotron radiation. The low temperature absorption and emission spectra in the region of the 2 F 7/2 ! 2 F 5/2 transition together with the IR spectra have been used to assign the electronic and vibronic components. Detailed analysis of the Yb 3+ -doped sodium lutetium double phosphates has been performed to determine the energy levels in these hosts and to compare their optical behaviour with analogous sodium yttrium double phosphates. The emission and excitation spectra have been investigated using synchrotron radiation and the origin of the emission has been analysed proving that the emission occurs from the charge transfer state.

Charge transfer and f–f emission of trivalent ytterbium observed in double phosphates MIMIII(PO4)2 (MI=Na, Rb; MIII=Lu, Y)

“…Knowledge about the crystal structure and spectroscopy of lutetium double phosphates with sodium and rubidium of the M 3 Lu(PO 4 However, these structural investigations are very important, since substitution of the Y 3+ ion by Lu 3+ in the materials codoped with the Yb 3+ ions reduces the solarisation effects and improves the lasing performance, as was reported by several authors [7]. In the current article, we continue our studies initiated in the last year and devoted to the new ytterbium-doped lutetium double phosphates of the sodium and rubidium salts [9][10][11]. A comparison of the luminescence characteristics of all the Yb-containing double phosphates will be made.…”

“…3). Since the results of the absorption measurements of ytterbium-doped M 3 Y(PO 4 ) 2 and M 3 Lu(PO 4 ) 2 at room temperature have been already studied in detail [9][10][11], we now present some additional results for these compounds. An important fact worth noting is that the absorption spectra for both rubidium and sodium yttrium double phosphates are more complex than those observed at 293 K. However, when one compares the yttrium and lutetium compounds, it becomes clear that the shape of the spectrum of M 3 Lu(PO 4 ) 2 :Yb 3+ is different than that of M 3 Y(PO 4 ) 2 :Yb 3+ .…”

“…Additional components and broadening of the bands observed in the spectra at 4 K can be due to strong electron-phonon coupling (much stronger for the Yb 3+ ion than for Eu 3+ ) and/or to cooperative effects. On the basis of superposition of absorption, emission and FT-IR spectra (not presented here), the vibronic components coupled with the 0-phonon lines at around 350, 480 and 690 cm −1 have been assigned [10]. The decrease of the intensity with lowering of the temperature both for the yttrium salt ( * P = 4366 at RT to 2039 at 4 K) 1 and the lutetium salt ( * P = 1122 at RT to 813 at 4 K) is due to depopulation of the 2 F 7/2 ground state Stark components.…”

“…Ytterbium doped compounds are constantly the object of extensive structural and spectroscopic investigations, which are motivated by their important physical and optical properties [1][2][3][4][5][6][7][8][9][10][11]. The Yb 3+ ion could be used as the laser-emitting center because of its luminescence occurring at about 1 m. Moreover, among the lanthanide (III) ions, Yb 3+ is the only one that exhibits the charge transfer emission.…”

Magnetic characterization of microcrystalline Na3Ln0.99–xEr0.01Crx(PO4)2 orthophosphates synthesized by Pechini method (Ln = La, Gd)

“…Depending on the radius of RE ion its coordination may increase to seven/eight and the symmetry may be lowered (from hexagonal to monoclinic). Their structural and optical properties have been studied in detail [16][17][18][19][20][21][22][23][24][25][26][27][28][29][30]. Main orthorhombic forms of sodium orthophosphates Na 3 RE(PO 4 ) 2 have been optically characterized [8, 18-20, 24, 30].…”