Germanium substitution endowing Cr3+-doped zinc aluminate phosphors with bright and super-long near-infrared persistent luminescence. (15th August 2018)

• Record Type: Journal Article
• Authors: Zhang, Yi; Huang, Rui; Li, Hongliang; Hou, Dejian; Lin, Zhenxu; Song, Jie; Guo, Yuzheng; Lin, Huihong; Song, Chao; Lin, Zewen; Robertson, John
• Is Part Of: Acta materialia. Volume 155(2018)
• Page Start: 214
• Page End: 221
• Publication Date: 2018-08-15
• Subjects: Persistent luminescence -- Near-infrared -- First-principles -- Antisite defects -- Energy storage; Materials -- Periodicals; Materials science -- Periodicals; Materials -- Mechanical properties -- Periodicals; Metallurgy -- Periodicals; Chemistry, Inorganic -- Periodicals; 620.112
• DOI: 10.1016/j.actamat.2018.06.020
• Languages: English
• ISSNs: 1359-6454

Abstract

Abstract: We present novel near-infrared (NIR) Cr 3+ -doped non-gallate super-long-persistence phosphors (Zn1+x Al2-2x Gex O4 :Cr 3+ ) by Germanium substitution in the original ZnAl2 O4 :Cr 3+ . Unlike the negligible NIR persistent luminescence of ZnAl2 O4 :Cr 3+ upon UV or visible light excitation, the Ge substituted phosphors feature strong and super-long-persistent luminescence at approximately 650–750 nm for more than 120 h. The relation between the Ge substitution and the defect trapping states is investigated systematically. The experimental results combined with the first-principles calculations reveal that Ge Zn ○○ and Ge Al ○ in the spinel structure would introduce shallow and deep defect states in the band gap to serve as new efficient traps, which are mainly responsible for the strong and super-long-persistent luminescence upon UV or visible light excitation. The present advanced phosphors is an alternative candidate for applications in biomedical imaging and night-vision surveillance. Graphical abstract: Novel Cr 3+ -doped Zn1+x Al2-2x Gex O4 near-infrared persistent phosphors exhibit persistent luminescence lasting for more than 120 h. Through studying the presence of antisite defects, distribution of trap states, luminescence behaviors and first principle calculations, the super-long-persistent luminescence is found to mainly from the Ge Zn ○○ and Ge Al ○ in the spinel structure that inducing shallow and deep defect states to serve as efficient traps. Image 1