Photostimulated and Long Persistent Luminescence Properties from Different Crystallographic Sites of β‐Sr₂SiO₄: Eu²⁺, R³⁺ (R = Tm, Gd)

Abstract

Sintered ceramics of b-Sr 2 SiO 4 : Eu 2+ , R 3+ (R=Tm, Gd) were prepared and their spectroscopic properties were evaluated. A large enhancement of green photostimulated luminescence (PSL) was observed from β-Sr 2 SiO 4 :Eu 2+ codoping with Tm 3+ at a recognizable intensity level, and the most efficient PSL was obtained when the codoping concentration of Tm 3+ was 0.002. It was proved that the introduction of Tm 3+ created a large number of oxygen vacancies which serve as traps for electrons excited by UV irradiation. In addition, a distinguishable difference between the photoluminescence (PL) and PSL spectra of β-Sr 2 SiO 4 : Eu 2+ , Tm 3+ was observed, namely the PSL spectrum exhibits only a symmetric emission band peaked at about 540 nm while both 470 and 540 nm peaks were detected in the PL spectrum. It is safe to say that PSL only derives from one emission center of Eu2 in the crystallographic Sr2 sites, which could be ascribed to the different distribution of trap centers for two crystallographic Sr sites.

Tunable LLP via Energy Transfer between Na2–y(Zn1–xGax)GeO4 Sosoloid Host and Emission Centers with the Assistance of Zn Vacancies

“…[1][2][3] Such phosphors have long been of great research interest and are nowadays commercialized as night or dark environment vision materials for wide range of applications such as safety signage, night-vision surveillances, displays, decorations, and in vivo bio-imaging. [4][5][6] It is generally recognized that LLP properties are closely related to the defects in the phosphors.…”

Color Variation Between PSL and PL in CaAl2Si2O8:Tb3+ with the Assistance of Trap Level

“…The initial PSL intensity increases greatly as the concentration of Dy 3+ increasing and reaches the maximum when the concentration of Dy 3+ is 3%, which is 100 times stronger than that of the Dy 3+ free sample. So it implied that the increasing of Dy 3+ concentration may simultaneously increases the number of defects that are able to immobilize the carriers permanently at room temperature . These defects are more sensitive to the infrared stimulation than the original one in the Dy 3+ free sample that exhibits weak PSL intensity.…”

“…The trapped carriers can then be liberated by thermal, optical, or other physical stimulations, generating emissions from the emitting centers in the ETMs . The presence of deep and stable traps is able to immobilize the carriers permanently at room temperature, which is required for the PSL phosphor whose energy can be released by low‐energy light (photo) illumination …”

Blue to green emission and energy transfer between Ce3+ ions in Ca15Si20O10N30

“…[30][31][32] Thus, the emission wavelengths 40 of Ce 3+ originating from Ca1 to Ca5 will be different. As depicted in Fig.…”