Probing vacuum ultraviolet energy levels of trivalent gadolinium by two-photon spectroscopy

Abstract

The energy levels of lanthanide ions have been studied in great detail in the energy range up to 40 000 cm À1 (250 nm). Recently, an increased interest in the high-energy levels between 40 000 and 70 000 cm À1 has emerged, partly triggered by the need for new luminescent materials for vacuum ultraviolet (VUV) excitation. Using synchrotron radiation many new energy levels have been discovered for many lanthanide ions. However, the spectral resolution of a synchrotron is limited and to resolve the complete energy level structure higher-resolution tunable lasers are required. Unfortunately no tunable lasers are available in the VUV. To overcome this problem two-photon spectroscopy may be applied. In this contribution the use of resonant and non-resonant two-photon spectroscopy is applied to measure the energy level structure of Gd 3+ in fluorides. Non-resonant two-photon excitation and resonant excited state absorption from the 6 P 7/2 level is shown to provide high-resolution spectra of the high-energy levels of Gd 3+ . The extension of the energy level structure may be beneficial for energy level calculations, especially for Gd 3+ where only a limited number of energy levels is available from conventional laser spectroscopy. r

Influence of silicate sol–gel host matrices and catalyst agents on the luminescent properties of Eu3+/Gd3+ under different excitation wavelengths

“…The excitation of Gd 3+ ions into the higherlocated 6 G J levels was also examined. [13][14][15][18][19][20] The energy gap between the 6 G J and 6 P J excited states is sufficiently large, therefore emission from the 6 G J state may contain in visible spectral range between 560 nm-640 nm. [13][14][15] So, it results in the visible light range emission derived from Gd 3+ ions.…”

“…[13][14][15][18][19][20] The energy gap between the 6 G J and 6 P J excited states is sufficiently large, therefore emission from the 6 G J state may contain in visible spectral range between 560 nm-640 nm. [13][14][15] So, it results in the visible light range emission derived from Gd 3+ ions. This emission overlaps with the luminescence bands characteristic for Eu 3+ ions.…”

“…5 The 6 P 7/2 energy level of Gd 3+ is metastable, therefore it is probable that the 6 G J excited states of Gd 3+ ions can be achieved. 5,14,15 Fig. 2 shows the excitation spectra registered for obtained glass samples before heat treatment.…”

Luminescence of Eu3+/Gd3+ co-doped silicate sol–gel powders

“…These processes can significantly affect the increase of emission efficiency in light visible region, including red luminescence [4]. Thus, Gd 3 þ ions could be successfully used to enhance characteristic red emission of Eu 3 þ ions.…”

Near-infrared quantum-cutting luminescence and energy transfer properties of Ca3(PO4)2:Tm3+,Ce3+ phosphors

“…[1][2][3][4][5][6][7] QC consists in the absorption of a high energy photon and the subsequent emission of two or more photons of lower energy, such that the internal quantum efficiency (QE) can be over 100% and the thermalization losses in solar cells can be minimized if downconversion of one ultravioletvisible (UV-VIS) photon to two or more infrared (IR) photons is realized. 8 Multi-photon QC emission was proposed by Dexter in the mid-1950s, 9 and up to now, taking advantage of the excellent luminescence properties of rare earth (RE 3þ ) ions, QC efficiencies close to 200% have been claimed.…”