Long persistent and photo-stimulated luminescence in Cr3+-doped Zn–Ga–Sn–O phosphors for deep and reproducible tissue imaging

Dual mode NIR long persistent phosphorescence and NIR-to-NIR Stokes luminescence in La3Ga5GeO14: Cr3+, Nd3+ phosphor

“…At room temperature, shallow traps are easily emptied, while deep traps are hardly emptied, and parts of captured electrons are still stored in deep traps [35]. The higher density of the traps at the proper depths, the longer and higher intensity of afterglow will be [14].…”

“…For example, Chermont [14] and colleagues have demonstrated in vivo imaging by using a LPP probe with the duration of around 1 h. Maldiney [15] [18,19]. In a recent study, the in vivo distribution of the LiGa 5 O 8 : Cr 3+ -PEG-5000-OCH 3 in the abdomen of mouse can be detected in real time for more than 1 h [20].…”

Folic acid-conjugated chromium(III) doped nanoparticles consisting of mixed oxides of zinc, gallium and tin, and possessing near-infrared and long persistent phosphorescence for targeted imaging of cancer cells

“…It has been suggested that late time-gating (i.e., capturing the signal at a delayed time after exCitation) be applied to guarantee the photo-realistic, highresolution in vivo imaging [19][20][21]. In addition to the anticipated advantage of the strongly increased signal to noise ratio, the long phosphorescent phosphors (LPPs), which have the super long afterglow-emission of several minutes or hours after the stoppage of excitation, may overcome the stringent constraint of inherently small beam diameter of excitation source.…”

Tailoring of the trap distribution and crystal field in Cr3+-doped non-gallate phosphors with near-infrared long-persistence phosphorescence

“…In addition to ZnGa 2 O 4 : Cr 3+ , La 3 Ga 5 3+ , were investigated because of the excellent ability of Cr 3+ ions to substitute for Ga 3+ ions in distorted octahedral coordination. [9][10][11][12][13][14][15][16][17][18][19][20] The predominance of Cr 3+ -activated gallates might suggest that only gallates can be used as the hosts in Cr 3+ -doped NIR LPPs. Such a dependence would result in the trapping and de-trapping processes being closely associated with the crystalline structure or energy band structure, of gallates because a variety of defects in gallate materials, including antisite defects and Ga vacancies, have been proposed as an electron (or hole) reservoir to improve the afterglow properties.…”

“…6 Such biomarkers are expected to enable advanced optical imaging with high-resolution and minimal excitation disturbance to experimentally assess structural and functional processes in cells, tissues and other complexes in in vivo systems. 7 Over the past few years, substantial strides have been made in the research and development of LPPs for NIR wavelengths, [8][9][10][11][12][13][14][15][16][17][18][19][20] with the main focus of the research being Mn 2+ , Mn 4+ and Cr 3+ -activated NIR LPPs. In 2007, Chermont et al proposed a novel bio-imaging method using red-to-NIR persistent nanoparticles, Ca 0.2 Zn 0.9 Mg 0.9 Si 2 O 6 : Eu 2+ , Dy 3+ , Mn 2+ , and opened a new application area for NIR LPPs.…”