Eu2+:SrMg1−xMnxP2O7 (x = 0–1) phosphors with tunable yellow–red emissions

Eu2+:SrMg1−xMnxP2O7 (x = 0–1) yellow–red emitting phosphors were prepared by a solid-state reaction. X-ray diffraction, emission and excitation spectra, time-resolved emission spectra as well as decay curves were measured to characterize the synthesized products. The spectral overlap of Eu2+ emission and Mn2+ excitation evidenced the efficient energy transfer from Eu2+ to Mn2+. As a result, Mn2+ emission in the 0.03Eu2+:Sr0.97Mg0.7Mn0.3P2O7 sample was greatly intensified (for about 120 times) compared to that in the SrMg0.7Mn0.3P2O7 one, due to the high Eu2+ : 4f → 5d absorption cross-section, when excited at 350 nm. Interestingly, Mn2+ dopants in the SrMgP2O7 host exhibited dual-band emission centered at 556 and 659 nm respectively, and their emission intensity ratio could be easily tuned by adjusting Mn2+ doping content, which resulted in color-tunable luminescence in yellow and red regions. Analyses on crystal structure, time-resolved emission spectra and decay curves of Eu2+/Mn2+:SrMgP2O7 demonstrated that the color-tunable emission was attributed to the partition of Mn2+ into two distinct crystal field environments, i.e., Mg2+ sites as well as Sr2+ ones in the host lattice.

► Pure Eu2+:SrMg1−xMnxP2O7 (x = 0–1) phosphors successfully synthesized.
► Mn2+ ions can substitute both Sr2+ and Mg2+ sites in the SrMgP2O7 hosts.
► The phosphors can present tunable color under 365 nm lamp excitation.
► The analyses of phosphors were carried out by many measurements.