Role of oxygen vacancies in long persistent phosphor Ca₂Ga₂GeO₇: Zn²⁺

Abstract

Acting as the electron trap, oxygen vacancies can strongly influence the long persistent luminescence (LPL) properties were verified in Ca2Ga2GeO7: Zn2+ (CGGZ) phosphor. The existence of oxygen vacancies in this self‐excitation material was confirmed by a simple fluorescence probe method. The introduction of zinc ions promotes the generation of oxygen vacancies, as well as optimizes its LPL properties. Thermoluminescence (TL) analysis revealed that electrons in deep trap will effectively transfer to the shallow one via the bridge of interstitial zinc. Accordingly, a mechanism for PL and LPL in this Gallogermanates was provided.

Effect of Oxygen Vacancies on the Persistent Luminescence of Y3Al2Ga3O12:Ce3+,Yb3+ Phosphors

“…Then, it is inferred that the formation of the Yb 2+ ions at the original Yb 3+ site promotes the generation of a defect with positive charges, i.e., V O ·· , to imbalance the negative charge inside the lattice, leading to the dramatic enhancement in the TL intensity. Similar analyses have been extensively reported in the YAG host ,, and other hosts. ,− Contrary to Yb 3+ , Ce 2+ with the electron configuration [Xe]­4f 1 5d 1 is less stable because neither the 4f subshell nor the 5d subshell is half-filled or completely filled, hence making it difficult to reduce Ce 3+ into Ce 2+ . Without Yb as a stabilizer, charge neutrality inhibits mass generation of positive defects including the V O during the reducing heating, resulting in the insignificant increase in TL intensity of the reduced singly doped sample.…”

No‐Interference Reading for Optical Information Storage and Ultra‐Multiple Anti‐Counterfeiting Applications by Designing Targeted Recombination in Charge Carrier Trapping Phosphors

“…It illustrated that the Ca 3 Ga 4 O 9 :Bi 3+ system contained . The EPR signs at g = 1.995 also strongly agreed with this point (Figure d) . Based on the proximity distribution mechanism (Figure a) and the crystal structure of Ca 3 Ga 4 O 9 (Figure , Figure e), may exist in two states, and , which are derived from oxygen absence of the CaII‐O and CaI‐O, respectively.…”

A Photostimulated BaSi2O5:Eu2+,Nd3+ Phosphor‐in‐Glass for Erasable‐Rewritable Optical Storage Medium

“…From these observations, one may draw conclusions that 1) the number of deep traps is much more than that of shallow ones, and 2) there is no significant interference between shallow and deep traps. Notably, for most of the studied PSL hosts hitherto, the good PSL performance is usually accompanied by the ultra‐long PersL decay, since the electrons in deep traps can continuously replenish those escaped from shallow traps (there is a wide and continuous trap distribution in the host) . Therefore, it is quite unusual to observe in the present case that a good PSL performance along with a short PersL decay, probably ascribing to the shallow and deep traps are isolated from each other.…”

“…Notably, for most of the studied PSL hosts hitherto, the good PSL performance is usually accompanied by the ultra-long PersL decay, since the electrons in deep traps can continuously replenish those escaped from shallow traps (there is a wide and continuous trap distribution in the host). [25,30,[41][42][43] Therefore, it is quite unusual to observe in the present case that a good PSL performance along with a short PersL decay, probably ascribing to the shallow and deep traps are isolated from each other. We can also find the sample has a quick response to NIR stimulation, indicating the information readout rate is fast, which is an important advantage for optical data storage.…”