Super‐Long Persistent Luminescence in the Ultraviolet A Region from a Bi³⁺‐Doped LiYGeO₄ Phosphor

Abstract

Here, a novel super‐long, ultraviolet A region (UVA), persistent luminescent (PerL) material, LiYGeO4:Bi3+, is developed. After irradiation at 254 nm for 10 min, the UVA PerL of LiYGeO4:Bi3+ can persist for more than 300 h. In addition, the LiYGeO4:Bi3+ also possesses a strong UVA emission with a power density of 11.83 mW m−2 at 10 s after the removal of the excitation source. Even after 72 h, the UVA PerL emission spectrum can still be clearly detected, which is the same as the photoluminescence emission spectrum and originated from the Bi3+ emitting centers. Furthermore, LiYGeO4:Bi3+ also exhibits a photostimulated PerL property, which can be easily activated with a red light emitting diode (LED) or NIR laser irradiation after the long‐term decay. Combining the results of the PerL excitation, absorption, and thermoluminescence spectra, the excellent UVA PerL of LiYGeO4:Bi3+ can be ascribed to the existence of abundant trap sites created by the loss of Li+. This excellent PerL material can make up for deficiency of PerL materials in the UVA region and greatly expand the application of PerL materials in the biomedical, energy, environmental, and catalysis fields.

Recent advances and prospects of persistent luminescent materials as inner secondary self-luminous light source for photocatalytic applications

“…Bandlike persistent luminescence can also be achieved in MPLs doped with ns 2 cations like Bi 3+ [141,149,234,[257][258][259][260][261][262][263][264][265][266][267][268][269] or Pb 2+ ion [270][271][272][273] (Table 4). Unlike the Mn 4+ and Cr 3+ ions yet similar to the Eu 2+ , Ce 3+ , and Mn 2+ ions, single Bi 3+ ion, depending on different crystal hosts, can exhibit the fluorescence broadly spanning from UV, blue, yellow and to reddish/red [45,[274][275][276][277][278][279][280][281][282][283][284][285].…”

“…[151], and (ii) GdAlO3:Mn 4+ ,Ge 4+ @Au (A), GdAlO3:Mn 4+ ,Ge 4+ @SiO2 (B), and GdAlO3:Mn 4+ ,Ge 4+ (C) from 0 min to 24 h [154]. [164], (iii) excitation and emission spectra of Zn3Al2Ge2O10:0.01Cr 3+ [177], and (iv) excitation and emission spectra of ZnGa2O4:Cr 3+ ,Bi 3+ and ZnGa2O4:Cr 3+ pellets [196]; (b) (i) Digital photos and NIR images of Zn3Ga2GeO8:Cr 3+ (left) and Figure 6 Persistent spectra of (a) CaZnGe2O6:Mn 2+ recorded from 1 min to 8 min [199], (b) γ-Zn3(PO4)2:Mn 2+ ,Ga 3+ [203] xBi 3+ and the relationship between the persistent intensity and the Bi 3+ content (inset) [260], (ii) intensity-normalized photoluminescence (PL), long-lasting (LPL), and photostimulated (PSL) spectra of CaGa2O4:Bi 3+ and a photo (inset) [269], and (iii-iv) persistent spectra of Sr2.997Bi0.003Ga4O9 from 30 s to 246 min [261]; (b) Photographs of (i) Sr2.985Bi3xGa4O9 taken within the range of 0-600s after removal of 254 nm UV lamp [261], and (ii) LiYGeO4:Bi 3+ in the range of 24-300 h and its relevant PSL luminescent images under 980 nm, 808 nm, and a red LED irradiation and taken after 300 h (bottom row) [265]; (c) (i) Persistent spectrum of CdSiO3:Pb 2+ [270], (ii) florescence spectra of CaO:Pb 2+ (A) and SrO:Pb 2+ (B) and persistent spectrum of SrO:Pb 2+ (C) [271], (iii) persistent spectra of Sr2MgGe2O7:Pb 2+ [273]. Figure 9 (a) (i) Excitation, photoluminescence (PL) and persistent spectra of SrZrO3 [319], (ii) PL (1) and the persistent (PerL) spectra of SrZrSi2O7 sintered in reducing atmosphere (2) and air (3), the insets are persistent (left) and PL images (right) of the sample [328], (iii) persistent spectra of Na2(Zn1-xGax)GeO4 and the image of Na2(Zn0.8Ga0.2)GeO4 after removal of femtosecond laser (inset) [329], (iv) normalized PL and persistent spectra of ZrO2 [331]; (b) Persistent images of (i) Mg2SnO4 [320], and (ii) MgGa2O4 [322], (iii) PL colors of bazirite-type BaZr1-xTixSi3O9 under 254 nm and 312 nm light and persistent images of a pabstite-type BaSn1-yTiySi3O9 [327].…”

Recent advances in Pr3+-activated persistent phosphors

“…Studies on phosphors capable of PersL at the short-wavelength (high-energy) end of the spectrum, UV (200-400 nm) spectral range, especially UVC (200-280 nm, ''solar-blind''), have remained silent until very recently. To our best knowledge, only a few persistent phosphors have been reported emitting in the UV range, including UVA (320-400 nm) PersL activated by Bi 3+ , [114][115][116][117][118][119][120][121][122] Pb 2+ , 9 or Tb 3+ , 123 UVB (280-320 nm) PersL activated by Pr 3+ 124,125 or Gd 3+ 126-129 and UVC PersL activated by Pr 3+ 40,41,129-131 or Bi 3+ 129,132 and dual-band UVC and UVB PersL activated by Pr 3+ . 53,133 Due to the high 4f5d energy state (the first case in Fig.…”

Combinations of Superior Inorganic Phosphors for Level‐Tunable Information Hiding and Encoding

“…The loss of Li + should be responsible for outstanding afterglow emission. [ 18 ] To sum up, afterglow performance is associated closely with the number of traps and trap depth. Excellent afterglow emission is often obtained in aluminate and germanate matrixes.…”