Structural and luminescent properties of Eu~(3+)-doped GdSrAl3O7 nanophosphor

摘要

Eu~(3+)-doped GdSrAl_3O_7 nanophosphor with promising luminescent properties has been synthesized by low-temperature solution combustion synthesis. The structural properties examined by X-ray diffractometer, scanning electron microscopy, and transmission electron microscopy showed that pure tetragonal GdSrAl_3O_7: Eu~(3+) red nanophosphor having narrow size distribution in 50–55 nm range could be readily obtained at low temperature 550 ℃. The photoluminescent excitation and emission spectra, life time, and concentration effect were studied in detail. Under excitation at 266 nm, Eu~(3+)-doped GdSrAl_3O_7 nanophosphor revealed weak green emission and strong red emission attributed to ~5D1 → ~7F_(1–2) and ~5D_0 → ~7F_(0–3) transitions of Eu~(3+) ion, respectively in the region of 525–700 nm. The red emission from ~5D_0 → ~7F_2 transition at 616 nm exhibits the highest intensity under the optimized concentration of 10 mol% after which the quenching mechanism became relevant. Quenching behavior of the europium in the GdSrAl_3O_7 host was explained by nonradiative cross-relaxation phenomenon. Moreover, Eu~(3+)-doped GdSrAl_3O_7 nanophosphor can generate light from orange to deeper red by properly tuning the concentration of europium ions based on the energy transfer principle.