Upconversion Visible Light Emission in Yb/Pr Co-Doped Yttria-Stabilized Zirconia (YSZ) Single Crystals

Abstract

As a development on previous research on single crystals of Pr3+-doped yttria-stabilized zirconia (YSZ), we report here the preparation and optical properties of Yb/Pr co-doped YSZ single crystals with different Yb2O3 concentrations. Results from X-ray diffraction (XRD) and Raman spectroscopy indicated that all of the crystal samples had a cubic phase structure, and transmission was ≥88% in the 550–780 nm range. Photoluminescence (PL) under excitation with a 980 nm laser showed upconversion emission, and several peaks were observed centered on 448 nm, 508 nm, 525 nm, 542 nm, 617 nm and 656 nm. The effects of excited state absorption (ESA), energy transfer upconversion (ETU), cross relaxation (CR), and cooperative energy transfer (CET) on the upconversion luminescence and energy transition mechanism in YSZ crystals were further studied. The fluorescence lifetime of the 3P0 → 3H5 transition at 542 nm reached 207 μs, which shows that the samples are of potential use for laser and fluorescence output.

Pr3+ doped NaYF4 and LiYF4 nanocrystals combining visible-to-UVC upconversion and NIR-to-NIR-II downconversion luminescence emissions for biomedical applications

“…38 Besides, a possibility to co-dope fluoride NCs with Yb 3+ and Pr 3+ has also been revealed, demonstrating the functionality of those NCs through the efficient generation of NIR DCL emission under excitation at 980 nm. 17,[39][40][41][42][43][44] Therefore, we suggested that it is possible to obtain the Pr 3+ doped NCs with UCL and DCL emissions switchable through the use of corresponding laser excitation wavelengths. The co-doping of Yb 3+ and Pr 3+ in fluoride phosphors for UCL and DCL has been reported previously, but it was mostly limited to microcrystals or bulk materials and for NIR-to-VIS/NIR UCL.…”

Upconversion phosphor thermometry for use in thermal barrier coatings

“…The peak excitation wavelength was found to be 965 nm which is quite far from the oftenused 980 nm excitation wavelength for phosphors with Yb 3+ . However, this is the expected excitation peak for YSZ doped with Yb 3+ [28,29]. The emission spectra obtained using an excitation wavelength of 965 nm are shown in figure 3.…”

Optical Upconversion in Mononuclear Lanthanide Co‐Crystal Assemblies

“…3 H 4 transition, respectively. In general, it is difficult for 980 nm to pump energy to populate 3 P 1 level and higher levels of Pr 3 + , [24] but a cross relaxation ( 3 H 5 , 3 P 0 ! 3 H 4 , 3 P 2 ) is able to occur because the energy gaps between 3 H 5 !…”

“…Then, 1 G 4 level absorbs another photon from the nearby excited Yb 3+ to populate 3 P 0 level, resulting in strong red emission from 3 P 0 → 3 H 6 and 3 P 0 → 3 F 2 transition, green emission from 3 P 0 → 3 H 5 transition and blue emission from 3 P 0 → 3 H 4 transition, respectively. In general, it is difficult for 980 nm to pump energy to populate 3 P 1 level and higher levels of Pr 3+ , [24] but a cross relaxation ( 3 H 5 , 3 P 0 → 3 H 4 , 3 P 2 ) is able to occur because the energy gaps between 3 H 5 → 3 H 4 and 3 P 0 → 3 P 2 levels are nearly equal [30] . A weak blue emission can be obtained from 3 P 2 → 3 H 4 transition.…”

“…explored the energy transfer between Pr 3+ ion pairs to better understand the upconversion mechanism of Pr 3+ [21] . In addition, upconversion luminescence of Pr 3+ has also been found in phosphors, [22] nanoparticles, [23] and single crystals [24] . However, to the best of our knowledge the upconversion luminescence from Pr 3+ complexes has not yet been discovered.…”