Blue–Green–Yellow Color-Tunable Luminescence of Ce³⁺-, Tb³⁺-, and Mn²⁺-Codoped Sr₃YNa(PO₄)₃F via Efficient Energy Transfer

Abstract

Tunable blue–green–yellow emitting Sr3YNa­(PO4)3F (SYNPF):Ce3+,Tb3+,Mn2+ phosphors have been prepared via a high-temperature solid-state reaction method. The structural and luminescent properties, energy transfer (ET) mechanism, and thermal quenching of the samples are investigated in detail. The ET from Ce3+ to Tb3+ and Mn2+ in SYNPF is identified as the interaction of the electric dipole–quadrupole with ET efficiencies of 81.6% and 69.3%, respectively. The critical distances for Ce3+/Tb3+ and Ce3+/Mn2+ are calculated through the spectral overlap method to be 9.54 and 10.92 Å. Under UV excitation, high-efficiency tunable blue–green–yellow emissions from Ce3+ to Tb3+ and Mn2+ can be obtained. Moreover, white light can also be achieved by adjusting the stoichiometry of Ce3+ and Mn2+ properly in the SYNPF phosphor. In addition, the temperature-dependent luminescence spectra exhibit good thermal quenching behaviors for the as-prepared phosphors. The above results suggest that SYNPF:Ce3+,Tb3+,Mn2+ phosphors can act as color-tunable emission phosphors for potential applications in WLEDs.

A broadband cyan-emitting Ca2LuZr2(AlO4)3:Ce3+ garnet phosphor for near-ultraviolet-pumped warm-white light-emitting diodes with an improved color rendering index

“…Since the typical 5d -4f transition of Ce 3+ ions is sensitive to the crystal field strength, the doping of the Ce 3+ ions into different hosts can show considerably different optical properties. 1,[34][35][36][37] In particular, Ce 3+ -doped garnet compounds can exhibit green, yellow, or even orange-red emissions because the dodecahedral sites where Ce 3+ ions are located show strong crystal-field strength. [38][39][40] Garnet-structure compounds with a general formula of L 3 D 2 (AO 4 ) 3 , where L, D, and A are dodecahedral site, octahedral site, and tetrahedral site, respectively, exhibit stable optical and chemical properties.…”

Extension of Spectral Shift Controls from Equivalent Substitution to an Energy Migration Model Based on Eu2+/Tb3+-Activated Ba4–xSrxGd3–xLuxNa3(PO4)6F2 Phosphors

“…where I D0 (t) means the decay function of donors in the absence of the acceptors and f(t) is named as the energy loss of excited donors resulting from one-way energy transfer from donors to acceptors. Once the energy transfer rate from a donor to an acceptor is negatively correlated to the distance, via the use of the I−H model, the f(t) function could be deduced by the following formula 11) where n A stands for the activator number existing per unit volume and α means the constant for Eu 2+ → Tb 3+ energy transfer rate. When coefficient s = 6, 8, and 10, it corresponds to dipole−dipole, dipole−quadrupole, and quadrupole− quadrupole interactions, respectively.…”

Unraveling the Eu2+ → Mn2+ Energy Transfer Mechanism in w-LED Phosphors

“…With reference to each other or sometimes to an original paper by Dexter and Schulman, it is stated that these ratios are expected to increase with the Mn 2+ concentration C proportional to C 6/3 (dipole–dipole), C 8/3 (dipole–quadrupole), or C 10/3 (quadrupole–quadrupole). Often the best fit was obtained for C 8/3 , and a dipole–quadrupole ET mechanism was thus concluded. − Sometimes a better fit was found for C 6/3 or C 10/3 and was used to derive that dipole–dipole or quadrupole–quadrupole interaction was the operative transfer mechanism. ,− Finally, it is important to realize that these C S /3 vs I S0 / I S , η S0 /η S , or τ S0 /τ S fitting methods to derive ET mechanisms are also widely used for other donor–acceptor pairs, for example, Tb 3+ → Eu 3+ . The C S /3 model is widespread but, as will be shown below, incorrect for donor–acceptor energy transfer as it has been derived for concentration quenching by energy migration among donors.…”

“…In recent work, dipole–quadrupole interaction has consistently been favored as energy transfer mechanism. − The r –8 distance dependence of this interaction was used as evidence. With reference to a pioneering paper on concentration quenching in inorganic solids by Dexter and Schulman, a C Mn 8/3 dependence of the ratio I S0 / I S was taken as evidence for dipole–quadrupole interaction, where I S0 is the Eu 2+ emission intensity in singly Eu 2+ doped materials and I S is the intensity in Eu 2+ –Mn 2+ codoped materials.…”