Enhanced Photostability Luminescent Properties of Er³⁺-Doped Near-White-Emitting Dy_xEr_(1–x)-POM Derivatives

Abstract

A series of Dy Er-polyoxometalates (POMs) were successfully synthesized and characterized well by various physicochemical analysis. The structurally isolated compounds exhibit three characteristic emissions at 480 nm (blue, F → H transition), 573 nm (yellow, F → H transition), and 663 nm (red, F → H transition) whose luminescent color coordinates appear in the near-white area in the CIE 1931 chromaticity diagram. Time-resolved emission spectroscopy was used in Dy Er-POM to further authenticate energy transfer from the photoexcitation O → M ligand to the metal charge-transfer state of phosphotungstate components to active Dy/Er ions and energy transfer between Dy ion and Er ion via intramolecular energy transitions. The relative emission intensity of ∼32%, ∼53%, and ∼85% for Dy-POM, DyEr-POM, and DyEr-POM respectively, were obtained under 300 min of UV irradiation, which indicates better photostability of DyEr-POM. Furthermore, Dy Er-POM samples can emit macroscopic white light under blue irradiation.

A systematic study of the optical properties of mononuclear hybrid organo–inorganic lanthanoid complexes

“…At room temperature the average lifetime τ AV of the multiplet 4 F 9/2 , 5 D 0 , and 5 D 4 for Dy III , Eu III and Tb III , respectively, was calculated to be 4.1(7) μs, 0.94(3) ms and 0.35(2) ms. These values are in good agreement with other reported Ln-POM systems 28,68,69. Forexample, these values are practically the same as for [Eu(W 5 O 18 ) 2 ] 9− , with a value of 2.8 ms at 300 K, and approximately 3 times higher than [Eu 3 (H 2 O) 3 (SbW 9 O 33 )(W 5 O 18 ) 3 ] 18− compound, with a value of 1.1 ms in all the temperature range (4.2 to 300 K).…”

pH-Controlled Assembly of Two Polynuclear Dy(III)-Containing Polytungstoarsenates with Magnetic and Luminescence Properties

“…Based on the ET analysis described above, the schematic ET processes from arsenotungstate components to Dy 3+ ions in 1 and 2 are shown in Figures c and d. Upon photoexcitation of the O → W LMCT triple state, electrons on the 1 A 1g ground level absorb energy under irradiation and jump to the higher 1 T 1u excited level, then immediately down to the lower 3 T 1u excited level by a nonradiative transition . During the decay process, the energy in the 3 T 1u state promotes the 3 T 1u → 1 A 1g emission transition, meanwhile that is reabsorbed by Dy 3+ 6 P 7/2 ← 6 H 15/2 , 6 P 5/2 ← 6 H 15/2 and 4 I 13/2 ← 6 H 15/2 excited transitions in the form of nonradiative relaxation, further leading to the 4 F 9/2 → 6 H K (K = 15/2, 13/2, and 11/2) emission transitions emission of Dy­(III) centers.…”

“…For example, the [EuP 5 W 30 O 110 ] 12– polyanions was encapsulated by polyelectrolytes to prepare photoluminescent multilayer films . The photoluminescent of [Dy x Er (1– x ) (C 4 H 2 O 6 )­(α-PW 11 O 39 )] 2 16– ( x = 0–1) can be fine-tuned by changing the ratios of Ln 3+ ions …”

Enhanced Fluorescence of La3+, Gd3+ doped EuW10 for Temperature sensing performance

“…[22][23][24][25] Meantime, because of the difficulty of directly exciting Ln 3 + ions, so it is necessary to introduce ligands, such as POMs, which can overcome the low molar absorption coefficient caused by the 4f-4f transition of Laporte, and sensitize the emission center of Ln 3 + ions through LMCT mediated intramolecular energy transfer. [26] Furthermore, in order to enhance the temperature sensing performance of the rare earth ion complexes, nonfluorescent rare earth ions (La 3 + , Gd 3 + ) are doped into the luminescent rare earth complexes to obtain better temperature sensing performance. At present, most of the reported effective ranges of measuring temperature are cryogenic (< 100 K), medium (100 K-300 K) and biological temperature (298 K-323 K).…”