Enhanced up-conversion persistent luminescence of Zn2GeO4:Mn phosphors by non-equivalent doping and sensitization of up-conversion nanocrystals

• Published in: Journal of luminescence 2024-01, Vol.265, p.120217, Article 120217
• Main Authors: Hou, Xiaochun, Du, Chengxue, Pang, Qing, Jia, Chaoyang, Wang, Xiaojun, Gao, Dangli
• Format: Article
• Language: English
• Subjects: Anti-counterfeiting; Non-equivalent doping; Photo-stimulated luminescence; Quintuple-mode luminescence; Zn2GeO4:Mn2+,Li
• ISSN: 0022-2313; 1872-7883
• DOI: 10.1016/j.jlumin.2023.120217

Up-conversion persistent luminescence (UCPL) nanoparticles have captured tremendous attention due to their unique optical operating performance such as the absence of auto-fluorescence and the charging capacity of near-infrared (NIR) light. However, the weak afterglow intensity as well as low duration limits their practical applications including multimode anti-counterfeiting and biological imaging, etc. Herein, typical green persistent luminescence (PersL) and photo-stimulated luminescence (PSL) of Zn2GeO4:Mn2+ phosphors were enhanced via non-equivalent Li+ co-doping, in which the preferred site selection of Mn2+ and Li + have been verified by using the first-principles theory. The possible luminescent enhancement mechanisms were proposed based on improving the oxygen vacancy density and promoting the formation of Mn4+ defect energy level in bandgap structure by non-equivalent doping of Li+. Interestingly, UCPL of Zn2GeO4:Mn2+,Li + can be achieved after charging of Vis to NIR light. It is worth noting that this UCPL can be further enhanced by the sensitization of NaYF4:Yb,Tm nanoparticles via simply mixing Zn2GeO4:Mn2+,Li+ and NaYF4:Yb,Tm under 980 laser stimulation. As a result, Zn2GeO4:Mn2+,Li+ phosphor exhibits the enhanced quintuple-mode luminescence including photoluminescence, PersL, PSL, photo-stimulated persistent luminescence and UCPL. In particular, the achieved NIR rechargeable UCPL hybrid phosphors exhibit enormous potential for higher order anti-counterfeiting and rewriteable data encryption and decryption applications. •Green PersL and PSL of Zn2GeO4:Mn2+ phosphors were enhanced via non-equivalent Li+ co-doping.•The possible luminescent enhancement mechanisms were proposed.•UCPL of Zn2GeO4:Mn2+,Li+ can be achieved after charging of Vis to NIR light.•The UCPL can be further enhanced by the sensitization of NaYF4:Yb,Tm nanoparticles.•NIR rechargeable hybrid phosphors exhibit enormous potential for anti-counterfeiting and rewriteable data encryption.