Multi-mode anti-counterfeiting guarantees from a single material CaCd₂Ga₂Ge₃O₁₂:Tb³⁺,Yb³⁺ – two stimuli-responsive and four-state emission

Abstract

Luminescence anti-counterfeiting materials have drawn much attention in anti-counterfeiting applications due to their photochemical stability and emission patterns. However, conventional materials mainly use single-mode luminescence causing the growing demands of...

Investigation on the luminescence properties and mechanism of a novel Pr3+-based red persistent luminescence phosphor Cd3Ga2Ge3O12:Pr3+

“…It is well known that the morphology and size of a phosphor are significant factors affecting its emission intensity. 7,21,34 Consequently, the SEM image of CGGO:0.0015Pr 3+ was studied and is displayed in Fig. 4(a).…”

“…[1][2][3][4] Over past decades, PersL phosphors have attracted considerable attention and have been widely used in optical information storage, anti-counterfeiting, alternating current light emitting diodes (AC-LEDs), bio-imaging, etc. 1,[5][6][7][8][9] Unfortunately, compared to the abundance of green and yellow phosphors, red PersL phosphors are relatively scarce owing to the Purkinje effect. [10][11][12] Therefore, it is imperative and important to develop a superior red PersL phosphor.…”

Lanthanide-doped Na2MgScF7 exhibiting downshifting and upconversion emissions for multicolor anti-counterfeiting

“…The main challenge of optical anti-counterfeiting technology is to develop multicolor luminous materials with multicolor emissions. 5–7…”

Insights into blue-light activated red-emitting persistent luminescence from Pr3+-doped phosphors

“…To date, persistent phosphors excitable by blue light have received considerable attention for their wide applications in AC-LEDs, multi-cycle bio-imaging, anti-counterfeiting and indicator marks, 4,5,[11][12][13][14][15] for example BaLu 2 Al 2 Ga 2 SiO 12 :Ce 3+ (cyan), 16 SrAl 2 O 4 (green), 17 BaY 2 Al 2 Ga 2 SiO 12 :Ce 3+ ,Bi 3+ (green), 18 Sr 3 SiO 5 :Eu 2+ (yellow) 19 and CaS:Eu 2+ ,Dy 3+ (red). 4 Among the red long-lasting phosphors, europium activated sulfides (e.g., CaS:Eu 2+ ,Tm 3+ ) 5 and oxysulfides (e.g., Y 2 O 2 S: Eu 3+ ,Ti 4+ ,Mg 2+ ) 20 exhibit excellent PersL.…”

“…20 And the matrix has an adjustable band gap and abundant defect energy levels, which is conducive to the realization of super strong afterglow. 11,21 Furthermore, host materials with an excellent garnet structure have a stable lattice and have attracted considerable attention. 4,[22][23][24] Pr 3+ is a prominent and excellent activator and can exhibit a strong red emission band at 613 nm attributed to the 1 D 2 → 3 H 4 transition of the Pr 3+ ion.…”