Upconversion based near white light emission, intrinsic optical bistability and temperature sensing in Er³⁺/Tm³⁺/Yb³⁺/Li⁺:NaZnPO₄ phosphors

Abstract

NaZnPO4:Er3+/Tm3+/Yb3+/Li+ phosphors have been prepared which show UC based near white light emission, intrinsic optical bistability and temperature-dependent population re-distribution ability.

Upconversion luminescence and temperature sensing properties of NaGd(WO4)2:Yb3+/Er3+@SiO2 core–shell nanoparticles

“…7,8 The energy difference is required to be in the range of 200-2000 cm À1 to enable a Boltzmann distribution for the population ratio of two neighboring excited states. 9 The Yb 3+ and Er 3+ ions are the most popular ion couple to realize UC luminescence. The 2 H 11/ 2 and 4 S 3/2 levels within Er 3+ are thermally coupled with energy gap of $800 cm À1 .…”

Optical property evaluation of thoria doped with heavier rare‐earth oxides LnO1.5 (Ln = Er3+, Ho3+, Tm3+, and Yb3+)

“…Similarly, from the presence of bands at 328, 470, 690, and 792 nm attributable to the transitions, 3 H 6 (ground state) to 1 D 4 , 1 G 4 , 3 F 3 , and 3 H 6 , (excited states), presence of Tm 3+ in the sample was evident . In the spectra of Yb 3+ codoped samples, extra band at 976 nm related to the 2 F 7/2 → 2 F 5/2 transition of Yb 3+ was observed . The photoluminescence emission spectra of the singly doped Ho 3+ , Er 3+ , and Tm 3+ have been compared with the spectra of samples codoped with Yb 3+ (Figure ).…”

“…For Ho 3+ (5 mol%)‐doped thoria sample, in addition to strong absorption band at 220‐230 nm (due to ligand to metal charge transfer (LMCT) transition), additional absorptions at 361, 418, 454, 483, 538, and 642 nm from the intraconfigurational f‐f transitions of Ho 3+ ‐ion ( 4 I 8 (ground state) to 4 G 9/2 , 5 G 5 , 5 G 6 , 5 F 3 , 5 S 2 (and 5 F 4 ), and 5 F 5 (excited states)) were seen . Similarly, transitions of Er 3+ ‐ions from 4 I 15/2 (ground state) to 4 G 11/2 , 4 F 7/2 , 2 H 11/2 , 4 S 3/2 , 4 F 9/2 , 4 I 9/2 , and 4 I 11/2 (excited states) appeared at 377, 487, 519, 546, 650, 795, and 972 nm in the UV‐visible spectrum of Er 3+ ‐doped thoria sample . Similarly, from the presence of bands at 328, 470, 690, and 792 nm attributable to the transitions, 3 H 6 (ground state) to 1 D 4 , 1 G 4 , 3 F 3 , and 3 H 6 , (excited states), presence of Tm 3+ in the sample was evident .…”

Morphology control and enhancement of 1.5 μm emission in Ca2+/Ce3+ codoped NaGdF4:Yb3+, Er3+ submicrorods

“…20 Impressively, host lattice manipulation via impurity doping, which has the ability to modify the electron charge density and crystal symmetry of rare earth ions, could simultaneously enhance the emission intensity and control the well-dened morphology in a facile and straightforward way. 21,22 Although many previous works have adopted this strategy to enhance the visible or NIR UC emission, [23][24][25] enhancing the luminescence in the NIR DC emission range has rarely been studied.…”