[19p-Z26-1~10] 13.8 Optical properties and light-emitting devices

▲ [19p-Z26-5] Insights into the multi-site emission from SrAl2O4:Eu2+-Dy3+ persistent phosphors by time-resolved streak imaging

〇Jian Xu¹, Kohsei Takahashi¹, Takayuki Nakanishi¹, Takashi Takeda¹, Naoto Hirosaki¹ (1.National Institute for Materials Science (NIMS))

Keywords:Phosphor, Persistent luminescence, Streak imaging

Low temperature time-resolved streak imaging of commercial SrAl₂O₄:Eu²⁺-Dy³⁺ powder phosphors is investigated in this work, in order to clarify the relationship of Eu²⁺ emission between the two kinds of Sr sites. It is suggested that, at low temperature (4 K), besides the well-known green emission from the Sr2 site, an additional emission in the blue region from the Sr1 site is clearly observed, which exhibits much faster decay kinetics (~0.44 μs) compared with that from the Sr2 site (~1.28 μs). However, at room temperature, the blue emission (~450 nm) from the Sr1 site is almost quenched, while the green emission (~530 nm) from the Sr2 site becomes dominant. The nonexponential decay profile of Eu²⁺ from the Sr1 site indicated the possible energy transfer (ET) process between Eu²⁺ in two sites, which contributes to the fast quenching behavior of Eu²⁺ emission at the Sr1 site.