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The N-doped Sr 2.985 Mg 1-y Si 2 O 8 :0.005Eu2+,0.01Dy3+,yMn2+ (0 ≤ y ≤ 0.15) phosphors were designed to obtain long-persistent phosphors for white LEDs. All the samples were determined to be single-phase by XRD analysis. The particles show smooth surface with the help of the H 3 BO 3 flux. The energy-dispersive X-ray spectrum indicates the existence of N element. Various Eu2+ emission centers have been gained and verified by the photoluminescence spectra and long-persistent emission spectra, and a red-shift of the Eu2+ emission was observed in the N-doped samples due to the nephelauxetic effect. In Eu2+-Mn2+ co-activated phosphors, tunable emission has been realized and an efficient energy transfer from Eu2+ to Mn2+ was found, which could belong to the dipole-dipole interaction mechanism. The optimal afterglow time was obtained in the Sr 2.985 MgSi 2 O 7.76 N 0.16 :0.005Eu2+,0.01Dy3+ sample, but doping Mn2+ reduces the afterglow time largely. The mechanism for the increase of luminescence intensity and afterglow time with N present was interpreted. The temperature-dependent luminescence was also evaluated. [ABSTRACT FROM AUTHOR]

In this work, a series of Ca 9(1- m - n) La(PO 4) 5 SiO 4 F 2 : m Eu, n Mn (CLPS: m Eu, n Mn, 0 ≤ m ≤ 3%, 0 ≤ n ≤ 4%) phosphors were designed for multifunctional applications. The phase purity was evaluated by XRD technique, which revealed that the obtained samples were single-phase. When the Eu was doped, it was found that the emission spectra exhibited different characteristics depending on the excitation wavelength. More than one Eu2+ emission center was confirmed in the Eu-activated CLPS phosphors, and the optimal Eu2+ doping concentration was determined to be 1 mol%. To realize tunable emission, the Eu-Mn codoped CLPS phosphors were synthesized, in which the efficient energy transfer (ET) from Eu2+ to Mn2+ occurred. The corresponding ET mechanism was discussed by using the Dexter's ET formula. Upon 365 nm excitation, the thermal quenching properties of both Eu-single-doped and Eu-Mn-codoped CLPS phosphors were evaluated, and the spectral features were interpreted. Under 300 nm excitation, it was found that the CLPS:1%Eu sample showed different decay rates for the Eu2+ and Eu3+ emission intensities with temperature, which was considered to apply to optical thermometry. High sensitivity was obtained in the present phosphor. • The tunable emission was realized in the Eu-Mn codoped CLPS phosphors. • The different thermal quenching properties for different Eu2+ centers were found. • High sensitivity was obtained in the wide temperature range for optical thermometer. • The CLPS:Eu, Mn phosphors show potential applications in LEDs and optical thermometer. [ABSTRACT FROM AUTHOR]