Cr³⁺‐activated Li₅Zn₈Al₅Ge₉O₃₆: A near‐infrared long‐afterglow phosphor

Abstract

Near-infrared long-afterglow (LAG) materials have attracted considerable attention owing to their high potential for in vivo imaging applications. Here, we present a series of near-infrared LAG phosphors Li 5 Zn 8 Al 5Àx Ge 9 O 36 :xCr 3+ (LZAG:Cr 3+ ), which were synthesized using a solid-state reaction method. The pure LZAG host exhibits blue photoluminescence and LAG emission. We investigated the effect of the zinc vacancy contents on the photoluminescence and LAG performance by adjusting the zinc content and introducing Ga 3+ ions to substitute the Zn 2+ sites in LZAG host. When Cr 3+ ions were introduced into the LZAG host, LZAG:Cr 3+ produced a strong, broad blue emission band centered at 456 nm and a near-infrared emission band at 700 nm caused by the 2 E ? 4 A 2 transition of Cr 3+ . The energy transfer processes from the LZAG host to Cr 3+ were identified in the photoluminescence and LAG process. After irradiation at 258 nm for 10 minutes, the LAG emission of LZAG:0.008Cr 3+ can last nearly 2.5 hours. Moreover, the LAG intensity and duration of LZAG: 0.008Cr 3+ were significantly improved by introducing a small dose of Ga 3+ ions. Finally, the traps and mechanism of LAG in LZAG, LZAG:Ga 3+ , and LZAG:Cr 3+ were discussed in detail. K E Y W O R D Sluminescence, phosphors, vacancies

Recent advances and prospects of persistent luminescent materials as inner secondary self-luminous light source for photocatalytic applications

“…Unlike the above RE and non-RE MPLs that require at least an external RE or non-RE ion as the luminescent center, interesting to mention here is that the bandlike persistent luminescence are also observed frequently in some self-activated compounds, where the luminescence is assigned to the complex groups and/or defects [168,170,177,199,215,225,. In general, the emitted spectra are ultra-broad and excitation / temperature-dependent ( Table 5, and Figure 9).…”

Tuning the luminescence properties of blue and far‐red dual emitting Gd2MgTiO6: Bi3+, Cr3+ phosphor for LED plant lamp

“…29,30 The physics of resin under pressure is similar to the seepage pr lar approaches have been used also to mod into a mold containing fiber mats. 23,[31][32][33][34][35][36][37][38] T in these cases to determine the resin flow ing times corresponding to different infilt Preceramic polycarbosilane polymers as precursors to make ceramic fibers 10,3 trix. [7][8][9]40,41 The chemical and volume ch pany ceramization of the polymer during documented in several studies.…”

Li5Zn8Ga5Ge9O36: Cr3+, Ti4+: A Long Persistent Phosphor Excited in a Wide Spectral Region from UV to Red Light for Reproducible Imaging through Biological Tissue

“…The shells of their ions are all empty or full, meaning their only possible state is the 1 S 0 state. Therefore, the intrinsic emission center of LZGG can be identified based on lattice defects, as reported for Li 5 Zn 8 Al 5 Ge 9 O 36 , Na 2 CaSn 2 Ge 3 O 12 , Ca 2 Ge 7 O 16 , Na 2− y (Zn 1− x Ga x )GeO 4 , etc. The LZGG: 1.5 % Cr 3+ and LZGG: 1.5 % Cr 3+ , 0.5 % Ti 4+ LPPs exhibited a sharp 2 E→ 4 A 2 emission at 700 nm and a broad 4 T 2 → 4 A 2 emission from approximately 720–800 nm, centered at approximately 750 nm.…”