Tuning of Emission by Eu³⁺ Concentration in a Pyrophosphate: the Effect of Local Symmetry

Abstract

The local symmetry of a Eu3+ ion has a crucial effect on its luminescence properties. In this work, we show that the red/orange ratio in the emission of Eu3+-doped MgIn2P4O14 phosphors is tunable by adjusting the Eu3+ concentrations, due to the change in the local symmetry of metal ions. The substitution of Eu3+ for In3+ lowers the distortion in the lattice of monoclinic MgIn2P4O14, and an increase in Eu3+ doping concentration causes the metal ion sites to shift closer to an inverse center, leading to a reversal of the relative emission intensity of a magnetic dipole transition to an electric dipole transition. Meanwhile, the higher asymmetry of metal ion sites occupied by Eu3+ in MgIn2P4O14 makes the luminescence less thermally stable than that in Mg3In4P6O24.

The composition engineering of red‐emitting Eu3+‐doped Ca10.5(PO4)7‐type solid solution phosphors and application in LED

“…The sharp peaks at 317, 362, 380, 395, 415, and 464 nm are attributed to the transitions from 7 F 0 of Eu 3+ to 5 H J , 5 D 4 , ( 5 G J , 5 L 7 ), 5 L 6 , 5 D 3, 2, 1 , and 5 D 2 , respectively. 36,37,[40][41][42] The PL spectra of Eu 3+ -doped CNYP-I (0 ≤ x ≤ 1/2) and CNYP-II (0 ≤ y ≤ 1) compounds under 395 nm excitation show several sharp peaks, corresponding to 5 D 0 -7 F 0 (578 nm), 5 D 0 -7 F 1 (590 nm), 5 D 0 -7 F 2 (612 nm), 5 D 0 -7 F 3 (652 nm), and 5 D 0 -7 F 4 (698 nm) Eu 3+ transitions, respectively (shown in Figure 5B). [43][44][45][46][47] Figure 5C depicts the diagram of energy level related to Eu 3+ ions.…”

In‐air self‐reduction synthesis and luminescence properties from Mg21Ca4Na4(PO4)18:Eu2+–Eu3+ excited using ultraviolet light

“…By monitoring the emission at 620 nm, as shown in the Figure 5, the excitation peaks at 320 nm, 364 nm, 383 nm, 396 nm, 416 nm, and 467 nm were attributed to the transitions from 7 F 0 to 5 D 1 , 5 D 2 , 5 D 3 , 5 L 6 , 5 L 7 , and 5 D 4 , respectively. [28] The broad band absorption peaks at 240-300 nm was assigned to the absorption transition from the ground state of Eu 3+ to the charge transfer state, that is the transition of electrons from the coordination oxygen atom to the 4f shell of Eu 3+ .…”

Multipath optical thermometry realized in CaSc2O4: Yb3+/Er3+ with high sensitivity and superior resolution

“…In particular, the fluorescence intensity ratio ( FIR ) between two thermally coupled energy levels of trivalent rare earth ions is considered to be a promising technology to provide fast and accurate optical thermometry, due to its rapid response capability, high spatial resolution, strong anti‐jamming ability, etc 12‐17 . Up to date, numerous trivalent rare earth ions are used for ratiometric thermometry, such as Er 3+ , Ho 3+ , Tm 3+ , Nd 3+ , and Eu 3+ 18‐25 . Among these ions, Er 3+ is the most widely used activator for temperature sensing which has been realized in an enormous variety of materials, due to the excellent thermal coupling between the green emitting levels 2 H 11/2 and 4 S 3/2 of Er 3+ as well as their strong UC intensity under the excitation of 980 nm excitation with the sensitization of Yb 3+ 26,27 .…”

“…[12][13][14][15][16][17] Up to date, numerous trivalent rare earth ions are used for ratiometric thermometry, such as Er 3+ , Ho 3+ , Tm 3+ , Nd 3+ , and Eu 3+ . [18][19][20][21][22][23][24][25] Among these ions, Er 3+ is the most widely used activator for temperature sensing which has been realized in an enormous variety of materials, due to the excellent thermal coupling between the green emitting levels 2 H 11/2 and 4 S 3/2 of Er 3+ as well as their strong UC intensity under the excitation of 980 nm excitation with the sensitization of Yb 3+ . 26,27 Nevertheless, the thermometric sensitivity and resolution as well as the signal to noise ratio (SNR) of Er 3+typed optical thermometer are still need to be improved.…”