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

Abstract

The effect of oxygen vacancies (V O ) and the atmosphere influence on persistent luminescence (PersL) in Y 3 Al 2 Ga 3 O 12 (YAGG):Ce 3+ ,Yb 3+ are investigated by heating it in CO 2 , air, and 10% H 2 /90% Ar atmospheres. The V O -rich YAGG phosphors with outstanding PersL are successfully obtained by the common contribution of the reducing atmosphere and the incorporated Yb 3+ ions, and the concentration of oxygen vacancies in the phosphors is characterized by X-ray photoelectron spectroscopy and electron paramagnetic resonance measurements. Compared to the best sample prepared in neutral CO 2 , the reduced sample shows an increase of 30% in initial intensity and 100% in duration time, while the oxidized sample decreases drastically and shows a faint and undetectable PersL. The enhancement is mainly caused by the abundant formation of V O , which is achieved by the pairing of V O with Yb 2+ ions. The newly created V O by the reducing calcination is inferred to be adjacent to the Yb site and forms a compensation-type defect cluster due to the charge compensation effect. These findings reveal that understanding the effect and formation of V O is of great significance to design a high-performance phosphor.

Stable Metal–Organic Frameworks for Fluorescent Detection of Tetracycline Antibiotics

“…These results demonstrated the complicated chemical background of egg extracts negligibly interfered with detection (Tables S1 and S2). The LODs of BUT-179 toward TCs are lower than the maximum residue levels of TCs in eggs and comparable to those of reported MOFs (Table S3), − demonstrating the excellent detection performance of BUT-179 toward TCs. In addition, to evaluate the anti-interference ability of BUT-179 toward inorganic salts, the fluorescence titration experiments were carried out under the coexistence of various metal ions (Figures S14–S17), such as Na 2 SO 4 , Mg­(NO 3 ) 2 , CaCl 2 , and ZnCl 2.…”

Size-Dependent Persistent Luminescence of YAGG:Cr3+ Nanophosphors

“…This is because the peak has not shifted as the initial population of trapped charges decreases. From the point of view of the activation energy, the first maximum in all samples is the same and is about 0.75 ± 0.02 eV, which is close to the value observed previously for the same matrix with different co-dopants [17,40]. In contrast, the activation energy of the second maximum noticeably decreased from about 0.9 to 0.5 eV with increasing an annealing temperature.…”

Urea Glass Route as a Way to Optimize YAGG:Ce3+,Cr3+,Pr3+ Nanocrystals for Persistent Luminescence Applications

“…The presence of this band also in the PLE spectrum of Ce 3+ indicates a pronounced ET from the lowest-lying 4f5d state of Pr 3+ to the 5d state of Ce 3+ . In the excitation spectra of Ce 3+ emission (520 nm), the two bands centered at 350 and 435 nm are attributed to the well-known splitting of the 4f → 5d Ce 3+ state by the crystal field . In the excitation spectra of both Pr 3+ ( 1 D 2 → 3 H 4 , λ em = 606 nm) and Cr 3+ ( 4 T 2 → 4 A 2 , λ em = 710 nm), characteristic bands in the blue light range associated with f–f transitions of Pr 3+ were recorded.…”

“… 51 In the excitation spectra of Ce 3+ emission (520 nm), the two bands centered at 350 and 435 nm are attributed to the well-known splitting of the 4f → 5d Ce 3+ state by the crystal field. 52 In the excitation spectra of both Pr 3+ ( 1 D 2 → 3 H 4 , λ em = 606 nm) and Cr 3+ ( 4 T 2 → 4 A 2 , λ em = 710 nm), characteristic bands in the blue light range associated with f–f transitions of Pr 3+ were recorded. Additionally, in the PLE spectrum of Cr 3+ , a typical 4 A 2 → 4 T 2 transition in the red range with a maximum at 617 nm was found.…”