Down- and Upconversion Phenomena in Gd₃(Al,Ga)₅O₁₂ Crystals Doped with Pr³⁺ and Yb³⁺ Ions

Abstract

Single crystals of Gd3Al2.5Ga2.5O12, single-doped with Pr3+ ions and double-doped with Pr3+ and Yb3+ ions, were fabricated by the Czochralski technique. Transition intensities and relaxation dynamics of Pr3+ ions were determined employing the Judd–Ofelt treatment. Crystal field splitting of excited multiplets of incorporated luminescent ions were determined on the basis of optical spectra recorded at liquid helium temperature. The Pr3+ → Yb3+ energy-transfer phenomena were determined analyzing the effect of Yb3+ concentration on luminescence spectra and decay curves of Pr3+ ions. It was concluded that the observed downconversion phenomenon involves a quantum-cutting mechanism consisting of a two-step energy transfer from Pr3+ to Yb3+. We observed a phenomenon of nonresonant conversion of femtosecond pulses of infrared light into visible Pr3+ emission that was weakly affected by the wavelength of incident light at least in the 1100–1600 nm region. It was concluded that excitation mechanisms consist of multiphoton absorption of incident infrared radiation involving interconfigurational 4f2–4f15d transitions of Pr3+ and/or indirect excitation of Pr3+ ions by energy transfer from electrons created in the conduction band of the host.

High-Performance Pr3+-Doped Scandate Optical Thermometry: 200 K of Sensing Range with Relative Temperature Sensitivity above 2%·K–1

“…It is mainly derived from the fact that as temperature is elevated, there is some overlap between 3 P 0 → 3 H 6 and 1 D 2 → 3 H 4 emissions, and hence, some partial 1 D 2 → 3 H 4 transition components would exist in the investigated decay curves with λ em = 627 nm. In addition, the room-temperature (310 K) lifetimes of the 3 P 0 and 1 D 2 energy states for Pr 3+ :CaSc 2 O 4 are 6.73 and 22.79 μs, respectively, which are comparable to those of Pr 3+ :La 2 MgTiO 6 (4.3 and 49.8 μs) and Pr 3+ :Gd 2 ZnTiO 6 (2.5 and 16.4 μs) and smaller than those of Pr 3+ :Na 2 La 2 Ti 3 O 10 (8 and 90 μs), Pr 3+ :Sr 2 GeO 4 (15 and 156 μs), and Pr 3+ :Gd 3 (Al,Ga) 5 O 12 (19 and 168 μs). − ,, …”

“…3 and 49.8 μs) and Pr 3+ :Gd 2 ZnTiO 6 (2.5 and 16.4 μs) and smaller than those of Pr 3+ :Na 2 La 2 Ti 3 O 10 (8 and 90 μs), Pr 3+ :Sr 2 GeO 4 (15 and 156 μs), and Pr 3+ :Gd 3 (Al,Ga) 5 O 12 (19 and 168 μs) [16][17][18]39,40. …”

Insights into the Relationship between Crystallite Size, Sintering Pressure, Temperature Sensitivity, and Persistent Luminescence Color of Gd2.97Pr0.03Ga3Al2O12 Powders and Ceramics

“…The lifetime of the 3 P 0 state should differ as compared to the 1 D 2 multiplet as was shown in earlier works. 42 The lifetime values for the 3 P 0 and 1 D 2 states have been calculated to be 21 and 206 μs, respectively. Figure S2 shows the decay curves of luminescence recorded for 3 P 0 (487 and 565 nm) and 1 D 2 (607 nm) states under 285 and 445 nm excitation recorded at 200 or 1000 μs time windows.…”

Area-selective atomic layer deposition of molybdenum oxide

“…Luckily, CaWO4/ CaMoO4 show promise as hosts for Pr 3+ with low loss due to quenching through the IVCT state [112,113]. The Pr 3+ / Yb 3+ down-conversion pair has already been realized in Gd3(Al, Ga)5O12 [114], LiYF4[106] and YF3 [80]. There are moreover a few reports on using organic dyes to sensitize the Pr 3+ / Yb 3+ couple, most successfully done with Coumarin on the surface of NaYF4: Pr 3+ , Yb 3+ nanoparticles [102].…”