Hydrothermal synthesis and photoluminescent properties of Li2Sr0.996SiO4:Pr3+0.004 phosphors for white-LED lightings

Red phosphors, Li2Sr0.996SiO4: Pr3+0.004, with different hydrothermal conditions were prepared via hydrothermal synthesis and then heat-treatment. The chemical structures of the phosphors were identified with X-ray diffraction (XRD). Surface morphological features were observed by scanning electron microscopic (SEM) investigation. Spectra of excitation and emission for the phosphors were also obtained by a spectrophotometer. Results showed that the optimum conditions were as follows: pH value of solution was 1−2, reaction temperature was at 180 °C for 24 h. The as-prepared phosphors exhibited two excitation dominant peaks at 451 and 486 nm, attributed to transitions of 3H4→3P2 and 3H4→3P0 of Pr3+, respectively. A narrow emission peak at 610 nm corresponded to the energy level transition of 3P0→3H6 of Pr3+ under excitation of light at 451 nm, which indicated promising candidate red phosphors for blue LED chips.

Graphical AbstractExcitation (dash line) and emission (solid line) spectra of LSSO phosphors under certain conditions (hydrothermal reaction conditions of pH=1–2, 180 °C for 24 h, and then heat-treated conditions of 850 °C for 4 h under a reducing atmosphere)Figure optionsDownload as PowerPoint slide