1. Tuning multicolour emission of Zn2GeO4:Mn phosphors by Li+ doping for information encryption and anti-counterfeiting applications
- Author
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Zihan Zhang, Qing Pang, Xiangyu Zhang, Dangli Gao, Peng Wang, Huan Jiao, Kaiwei Ma, and Xin Hong
- Subjects
Inorganic Chemistry ,Materials science ,Photoluminescence ,business.industry ,Annealing (metallurgy) ,Doping ,Optoelectronics ,Phosphor ,business ,Luminescence ,Excitation ,Hydrothermal circulation ,Afterglow - Abstract
Traditional fluorescent materials used in anti-counterfeiting field usually exhibit monochromatic luminescence at a single-wavelength excitation, which is easily be forged by sophisticated counterfeiters. In this work, Zn2GeO4:Mn, x%Li (x=0 and 20), Zn2GeO4NaLiGe4O9:Mn, x%Li (x=50 and 70) and NaLiGe4O9:Mn micro-phosphors with the multi-chromatic and multi-mode luminescence have been successfully synthesized via a hydrothermal approach followed by an annealing treatment. As expected that these Li+ doped Zn2GeO4:Mn and NaLiGe4O9:Mn phosphors exhibit a double peak emission including a long green afterglow (~540 nm) and a red photoluminescence (∼668 nm). By tuning Li+ doping concentrations, a gradual colour output and a tuneable afterglow duration are achieved. Particularly, the Zn2GeO4:Mn,Li and NaLiGe4O9:Mn phosphors exhibit excellent performance as security inks for printing luminescent numbers and anti-counterfeiting patterns, which shows an afterglow time-dependent or excitation wavelength-dependent luminescence colour evolution. This work proves the feasibility of Li+ doping strategy in emission tuning, which can stimulate further studies on multi-mode luminescent materials in anti-counterfeiting applications.
- Published
- 2022