Preparation of SrSi₂O₂N₂:Eu²⁺ Phosphor by SrSi Alloy Precursor and Its Long‐lasting Phosphorescence Properties

Abstract

Oxynitride long‐lasting phosphorescence (LLP) phosphor SrSi2O2N2:Eu2+ was prepared by a new method using SrSi alloy as a precursor. Its properties were systematically investigated utilizing XRD, photoluminescence, excited‐state decay curve, long‐lasting phosphorescence, and thermoluminescence spectrum. This phosphor was found to be well‐crystallized by calcinations of the Sr1−xEuxSi alloy and the SiO2 mixture at 1400°C for 3 h. After irradiation under the 280 nm UV light, the afterglow emission of Eu2+ (4f65d1 → 4f7) was obviously observed for at least 2 h in the limit of light perception of dark‐adapted human eyes (0.32 mcd/m2). Furthermore, the possible mechanism for the LLP of SrSi2O2N2:Eu2+ phosphor is also discussed in this article.

Persistent luminescence in nitride and oxynitride phosphors: A review

“…Synthesis is typically performed under reducing atmosphere at elevated temperature (typically 1400°C), using MCO 3 [37]. After excitation with 1000lux unfiltered Xe light (containing both visible and UV light), the afterglow duration was 400s (Ca), 6000s (Sr) and 2800s (Ba), when taking 0.32mcd/m² as the threshold value [37,38]. Although SrSi 2 O 2 N 2 :Eu and BaSi 2 O 2 N 2 :Eu start with similar afterglow intensity, the decay in the latter compound is somewhat faster, which could be related to a slightly smaller trap depth for BaSi 2 O 2 N 2 :Eu as derived from thermoluminescence measurements (Fig.…”

“…The thermoluminescence glow peaks of the MSi 2 O 2 N 2 :Eu phosphors are not straightforwardly interpretable, as they contain multiple, often overlapping peaks [37,38,40,42]. For BaSi 2 O 2 N 2 :Eu, the main TL glow peak lies at relatively low temperature (335K for a heating rate of 1.4K/s [41], 360K at 5K/s [37]), along with a less prominent deep trap at around 420K [37,41].…”

“…In terms of the trapping mechanism, oxygen and nitrogen related defects (vacancies or substitutions) were suggested as electron traps in BaSi 2 O 2 N 2 [38,41]. Cation vacancies were suggested as hole traps [38,40], although it is not clear why hole trapping would occur, if the same mechanism as in Eudoped aluminates (Eu 2+ -> Eu 3+ + trapped electron) is at play [20].…”

“…Cation vacancies were suggested as hole traps [38,40], although it is not clear why hole trapping would occur, if the same mechanism as in Eudoped aluminates (Eu 2+ -> Eu 3+ + trapped electron) is at play [20]. X-ray absorption measurements indicate the simultaneous presence of Eu 2+ and Eu 3+ in BaSi 2 O 2 N 2 :Eu (Fig.…”

Synthesis and luminescence characterization of Pr3+ doped Sr1.5Ca0.5SiO4 phosphor

“…for 0.5 wt% Pr 3+ . to the lifetime becomes highly significant at higher concentration of Pr 3+ and the decay curve shows a non-exponential behaviour [34][35]. So the decay curve, at x=0.5 wt% Pr 3+ concentration, was fitted by non-exponential function which can be expressed as τ =…”