Sextuplet luminescence with dynamically variable color/brightness in chromium activated gallium-silicate solid solution in R3 space group.

The development of dynamic multi-color luminescence is a tremendous challenge for anti-counterfeiting. Herein, we have successfully synthesized Cr3+ activated gallium-silicate base material systems as the effective luminescent materials responsive to multiple field stimulation, exhibiting sextuplet luminescence including photoluminescence, strong red persistent luminescence (PersL), photo/thermo stimulated luminescence (PSL/TSL), photo-stimulated PersL and up-conversion luminescence (UCL). The luminescence quenching temperature is also improved in Cr3+,Yb3+,Er3+ co-doping sample relatives to Cr3+ single-doping phosphor. Especially, when Er3+ and Yb3+ are co-doped into Cr3+ activated phosphor system, UV preirradiated phosphor not only demonstrates an additional UCL from Er3+ ions accompanied with red PSL from the Cr3+ under NIR laser irradiation, but also leads to a dynamic change in color/brightness under the extension of NIR laser irradiation time. The multimode luminescence mechanisms are also proposed. Based on excellent luminescence characteristics, multi-color and multi-mode anti-counterfeiting patterns have been designed, especially appearing of dynamic anti-counterfeiting on luminescent color/brightness, which provides new dimensions for anti-counterfeiting technologies. • ZGGSO:Cr,Yb,Er phosphor demonstrates new UCL modes and enhanced red PersL. • Luminescence quenching temperature is improved in Cr3+,Yb3+,Er3+ co-doped sample relative to Cr3+ single-doped phosphor. • Quintuplets-mode luminescence including PL, red PersL, PSL/TSL, PSPL and UCL can be detected. • A PersL enhancement mechanism of Cr3+ is proposed based on the formation of electron-hole pair traps. [ABSTRACT FROM AUTHOR]