Spectroscopic properties and location of the Tb³⁺ and Eu³⁺ energy levels in Y₂O₂S under high hydrostatic pressure

Abstract

In this contribution, an extensive spectroscopic study of Y2O2S doped with Eu(3+) and Tb(3+) is presented. Steady-state luminescence and luminescence excitation spectra as well as the time-resolved spectra and luminescence kinetics were obtained at high hydrostatic pressures up to 240 kbar. It was found that pressure quenches the luminescence from the (5)D3 excited state of Tb(3+) and recovers additional luminescence related to transitions from the (5)D3 state of Eu(3+). These effects are related to the pressure-induced increases in the energies of the ground electronic manifold 4f(n) of Eu(3+) and Tb(3+) ions with respect to the band edges. Analysis of the emission and excitation spectra allowed the estimation of the energies of the ground states of all lanthanide (Ln) ions (Ln(3+) and Ln(2+)) with respect to the valence and conduction bands edges of the Y2O2S host. The bandgap energy and difference between energies of the ground states of Ln(2+) and Ln(3+) have been calculated as functions of pressure. The experimental high-pressure spectroscopy results allow the calculation of the absolute values (calculated with respect to the vacuum level) of the energies and pressure-induced shifts of the conduction and valence band edges and the ground states of Ln(3+) and Ln(2+) ions in Y2O2S.

Properties of Charge Carrier Traps in Lu2O3:Tb,Hf Ceramic Storage Phosphors Observed by High-Pressure Spectroscopy and Photoconductivity

“…When the pressure increases, the shift of the maximum of the excitation bands toward the lower energies is observed (see Figure a). As was recently resolved, the shift of the 4f → 5d excitation bands located in UV (below 320 nm at ambient pressure) mostly reflects the increase of the energy of the Tb 3+ ground state of Tb 3+ with respect to the conduction band . The red shift of the OSL excitation band peaking at 420 nm can be related to the increasing energy of Hf 3+ with respect to the conduction band (presented in Figure ) or with decreasing electron lattice coupling energy S ℏω or both.…”

“…This may be attributed to increasing quenching due to pressure diminishing of the energetic distance between the 5 D 4 excited state of Tb 3+ and the terbium-trapped exciton state, located somewhere below the conduction band, responsible for the quenching of Tb 3+ luminescence. 7,16 The trend of Tb 3+ luminescence diminishing is stopped above 100 kbar (hence, after the phase transition), and the luminescence intensity remains quite stable up to 300 kbar, the upper limit of the experiments.…”

“…As was recently resolved, the shift of the 4f → 5d excitation bands located in UV (below 320 nm at ambient pressure) mostly reflects the increase of the energy of the Tb 3+ ground state of Tb 3+ with respect to the conduction band. 16 The red shift of the OSL excitation band peaking at 420 nm can be related to the increasing energy of Hf 3+ with respect to the conduction band (presented in Figure 9) or with decreasing electron lattice coupling energy Sℏω or both. The latter effect can be presented by the shift of the Hf 3+ parabola in Figure 9 to the left (marked by the blue arrow).…”

Multifunctional Optical Sensors for Nanomanometry and Nanothermometry: High-Pressure and High-Temperature Upconversion Luminescence of Lanthanide-Doped Phosphates—LaPO4/YPO4:Yb3+–Tm3+

“…Thus, a continuous change of the interatomic distances can be performed, and the effect of the crystal structure on the f-electron states can be observed directly. The compression of Ln 3+ -based materials under high-pressure (HP) conditions is usually performed in a diamond anvil cell (DAC) and leads to the spectral shift of their absorption/emission bands (blue shift/red shift), changes in band intensity ratios, broadening in bands, longer/shorter luminescence lifetimes, etc. ,,− These changes can be used for pressure calibration purposes (nanomanometry). As some Ln 3+ -doped materials are sensitive to temperature alterations, their luminescence properties may change with temperature significantly.…”

Luminescence property tuning of Yb3+-Er3+ doped oxysulfide using multiple-band co-excitation

“…[23][24][25][26][27] Previous results show that micron sized rare-earth oxysuldes have very good UCL properties. 28 More importantly, microsized UCL materials with highly luminescence efficiency, colorful emission input, and which are environmentally friendly are required for many practical applications, such as up-conversion X-ray detection, full-color displays, laser anti-counterfeiting and so on.…”