Li+ ions doping core–shell nanostructures: An approach to significantly enhance upconversion luminescence of lanthanide-doped nanocrystals

Low-temperature thermometry based on upconversion emission of Ho/Yb-codoped Ba0.77Ca0.23TiO3 ceramics

“…5 I 7 transition. All emission bands coincide well with earlier reports on Ho-doped other materials [13,32,34]. It can be seen that when the concentration of Ho was fixed at 0.005, the UC emission intensity increased gradually with the increment of Yb concentration, reaching its maximum value when x = 0.05 and starting to decrease with further increment of Yb concentration.…”

“…Clearly, for the unsaturated UC process, the number of photons (n) that are required to populate the upper emitting state can be obtained by the following formula [34][35][36]:…”

Enhanced and Stable Upconverted White-light Emission in Ho3+/Yb3+/Tm3+-doped LiNbO3 Single Crystal via Mg2+ Ion Doping

“…If the rare earth ions are placed at a low symmetry site, the forbidden transitions will be weakened, leading to the enhancement of upconversion emission. The similar phenomena are also found in the research reports, such as refs 22,23 . But when the Mg 2+ ion concentration is above optimum concentration, the doped ions may cause the lattice distortion around the rare earth ions, resulting in the quenching of the upconversion emission.…”

Enhanced upconversion fluorescent probe of single NaYF4:Yb3+/Er3+/Zn2+ nanoparticles for copper ion detection

“…[21][22][23][24][25] Many studies have been reported on the introduction of smaller radius ions (Li + , Mn 2+ , Mg 2+ , etc.) [26][27][28] in UCNPs to enhance the upconversion emission, but few studies on the introduction of Zn 2+ ions into the rare-earth doped hexagonal phase NaYF 4 nanoparticles are presented. 29 In this paper, NaYF 4 :Yb 3+ (20%)/Er 3+ (2%)/Zn 2+ (7%) nanoparticles with enhanced luminescence were successfully obtained by introducing Zn 2+ ions in the hydrothermal synthesis process to the UCNPs.…”