Long-persistent luminescence in the near-infrared from Nd³⁺-doped Sr₂SnO₄for in vivo optical imaging

Abstract

We discovered a new near-infrared (NIR) persistent luminescent material Sr2SnO4:Nd3+, which exhibited NIR luminescence ranging from 850 to 1400 nm. Furthermore, we successfully enhanced the intensity of NIR persistent luminescence by increasing the firing temperature. The intensity of NIR persistent luminescence, which penetrates through a human finger and can be used to visualize a finger vein pattern by using a charge-coupled device camera, reached approximately 1.1 mW/m2 (λ = 900 nm) at a decay time of 10 s after ceasing the excitation. We proposed the enhancement process of the NIR persistent luminescence for Sr2SnO4:Nd3+ in conjunction with photoluminescence, absorption, thermoluminescence, and structural properties.

Near-infrared luminescence from double-perovskite Sr₃Sn₂O₇:Nd³⁺: A new class of probe for in vivo imaging in the second optical window of biological tissue

“…18) This structure produces unique optical properties, including mechanoluminescence and photoluminescence (PL). Indeed, in an earlier study we showed the luminescence of Sm 3+ -doped Sr n+1 Sn n O 3n+1 (n =¨, 1, 2) was influenced by the intra-layer configuration, 19) with the PL and piezoluminescence intensities increasing in the order SrSnO 3 :Sm 3+ (n =¨) < Sr 2 SnO 4 :Sm 3+ < Sr 3 Sn 2 O 7 :Sm 3+ (n = 2).…”

“…The observed NIR PL spectrum was composed of three bands located at (903, 953), (1079, 1146), and 1350 nm, which were assigned to the electron transitions in Nd 3+ ions from the excited state 4 F 3/2 to the ground state 4 I J (J = 9/2, 11/2, 13/2). 20) As shown in the figure insets, NIR PL intensities were affected by the intra-layer configuration, for example, the PL intensity of Sr 3 Sn 2 O 7 :Nd 3+ was 10 2 times higher than that of SrSnO 3 :Nd 3+ . The PL enhancement process may arise from a local lattice relaxation around the rare-earth ion in the two-dimensional structures, which would be similar to other RuddlesdenPopper phases.…”

Chemically engineered persistent luminescence nanoprobes for bioimaging

“…Recently, the NIR persistent luminescence ranging from 800 to 1300 nm has been found in phosphors. Upon examining a number of Nd 3+ doped phosphors, Fujihala and co-workers discovered a new NIR persistent luminescent material Sr 2 SnO 4 :Nd 3+ 139. The NIR persistent luminescence observed in Sr 2 SnO 4 :Nd 3+ ranged from 850 to 1400 nm with a major peak at around 1079 nm, which was ascribed to the electron transition of Nd 3+ ions.…”

“…(d) Dark field image of the persistent luminescence from Sr 2 SnO 4 :Nd 3+ . Reproduced with permission from reference 139.…”

First-principles energy band calculation of Ruddlesden–Popper compound Sr3Sn2O7 using modified Becke–Johnson exchange potential

“…Recently, Ruddlesden-Popper phase Sr n þ 1 Sn n O 3n þ 1 (n ¼1, 2, 1) have been attracting a great deal of interest due to their functional optical properties, such as photoluminescence, photochromism, near-infrared long-persistent luminescence, and mechanoluminescence [1][2][3][4]. In previous research, we have revealed that the optical properties in Sr n þ 1 Sn n O 3n þ 1 (n ¼1, 2, 1) were altered by the crystal structure; in particular, Sr 2 SnO 4 (n ¼1; lattice parameter a ¼5.735, b¼5.729, c ¼12.587 Å, space group Pccn) [5], and Sr 3 Sn 2 O 7 (n ¼2; a¼ 20.688, b¼5.736, c¼ 5.710 Å, space group Cmcm) [6], exhibited excellent optical properties.…”