title: A vacuum-annealing strategy for improving near-infrared super long persistent luminescence in Cr(3+) doped zinc gallogermanate nanoparticles for bio-imaging.
abstract: Novel Cr(3+) doped zinc gallogermanate (ZGGO) nanoparticles with 697 nm near-infrared (NIR) super long afterglow were prepared via a hydrothermal method. Subsequently, a vacuum-annealing strategy was adopted to improve NIR afterglow in ZGGO:Cr(3+) nanoparticles. For the sample annealed at 800 °C, no variation in the particle size is observed, the persistent luminescence increases by an order of magnitude (∼14 times) and the NIR afterglow time reaches more than 15 hours relative to the as-prepared sample. After annealing at temperatures higher than 880 °C, the persistent luminescence of the nanoparticles is enhanced, but they show aggregated-surface behavior. Meanwhile, shallow and deep traps are generated, related to the antisite defects and VGe-Cr(3+)-VO defect clusters, respectively. Finally, we apply ZGGO:Cr(3+) persistent luminescence nanoparticles (PLNPs) to a human serum albumin (HSA) colloid solution, and more than 1 h of NIR persistent luminescence is detected under 320 nm excitation. The quenching effect of NIR luminescence by OH(-) in the HSA solution is observed based on the reduced contribution of surface Cr(3+) in PLNPs to NIR luminescence. Our results suggest that ZGGO:Cr(3+) PLNPs have potential applications for in vivo bio-imaging.
authors.affiliation: School of Physics, Northeast Normal University, 5268 Renmin Street, Changchun 130024, China. yxliu@nenu.edu.cn.
authors.forename: Jian
authors.initials: J
authors.lastname: Yang
authors.affiliation: School of Physics, Northeast Normal University, 5268 Renmin Street, Changchun 130024, China. yxliu@nenu.edu.cn and Department of Physics, Georgia Southern University, Statesboro, GA 30460, USA. xwang@georgiasouthern.edu.
authors.forename: Yuxue
authors.initials: Y
authors.lastname: Liu
authors.affiliation: School of Physics, Northeast Normal University, 5268 Renmin Street, Changchun 130024, China. yxliu@nenu.edu.cn.
authors.forename: Duanting
authors.initials: D
authors.lastname: Yan
authors.affiliation: School of Physics, Northeast Normal University, 5268 Renmin Street, Changchun 130024, China. yxliu@nenu.edu.cn.
authors.forename: Hancheng
authors.initials: H
authors.lastname: Zhu
authors.affiliation: School of Physics, Northeast Normal University, 5268 Renmin Street, Changchun 130024, China. yxliu@nenu.edu.cn.
authors.forename: Chunguang
authors.initials: C
authors.lastname: Liu
authors.affiliation: School of Physics, Northeast Normal University, 5268 Renmin Street, Changchun 130024, China. yxliu@nenu.edu.cn.
authors.forename: Changshan
authors.initials: C
authors.lastname: Xu
authors.affiliation: Department of Physics, Georgia Southern University, Statesboro, GA 30460, USA. xwang@georgiasouthern.edu.
authors.forename: Li
authors.initials: L
authors.lastname: Ma
authors.affiliation: School of Physics, Northeast Normal University, 5268 Renmin Street, Changchun 130024, China. yxliu@nenu.edu.cn and Department of Physics, Georgia Southern University, Statesboro, GA 30460, USA. xwang@georgiasouthern.edu.
authors.forename: Xiaojun
authors.initials: X
authors.lastname: Wang
mesh_terms: D002857:Chromium / Q000737:chemistry*; D005708:Gallium / Q000737:chemistry; D005857:Germanium / Q000737:chemistry*; D006801:Humans; D007259:Infrared Rays; D049449:Luminescence; D053758:Nanoparticles / Q000737:chemistry*; D012709:Serum Albumin / Q000737:chemistry*; D014618:Vacuum
chemical_list: D012709:Serum Albumin; D005857:Germanium; D002857:Chromium; D005708:Gallium