TY - JOUR
T1 - Persistent luminescence excitation spectroscopy of BaAl2O4:Eu2+,Dy3+
AU - Malkamäki, Marja
AU - Bos, Adrie J.J.
AU - Dorenbos, Pieter
AU - Lastusaari, Mika
AU - Rodrigues, Lucas C.V.
AU - Swart, Hendrik C.
AU - Hölsä, Jorma
N1 - Accepted Author Manuscript
PY - 2020
Y1 - 2020
N2 - BaAl2O4:Eu2+,Dy3+ is related, both by structure and luminescence, to one of the best persistent luminescent phosphors, SrAl2O4:Eu2+,Dy3+. At room temperature (RT), the green persistent emission of BaAl2O4:Eu2+,Dy3+ remains visible for hours after ceasing irradiation. Similar to SrAl2O4, BaAl2O4 with hexagonal P63 structure, has two M2+ sites, but, limited optical activity from the 2nd site is observed in the emission of BaAl2O4:Eu2+,Dy3+ - even at 77 K. Using combined approach of photoluminescence, thermoluminescence (TL), and persistent (excitation) luminescence measurements, the origin and properties of persistent luminescence of BaAl2O4:Eu2+,Dy3+ were studied in detail. Ultraviolet (UV) excited and persistent emission are identical and no contribution from the Eu2+ in the high-symmetry Ba site was observed. TL excitation spectra clarified the unstructured conventional excitation spectrum; now it is evident that defects or the Dy3+ co-dopant do not contribute to persistent luminescence via direct energy absorption. Mechanisms for persistent luminescence should thus be revised.
AB - BaAl2O4:Eu2+,Dy3+ is related, both by structure and luminescence, to one of the best persistent luminescent phosphors, SrAl2O4:Eu2+,Dy3+. At room temperature (RT), the green persistent emission of BaAl2O4:Eu2+,Dy3+ remains visible for hours after ceasing irradiation. Similar to SrAl2O4, BaAl2O4 with hexagonal P63 structure, has two M2+ sites, but, limited optical activity from the 2nd site is observed in the emission of BaAl2O4:Eu2+,Dy3+ - even at 77 K. Using combined approach of photoluminescence, thermoluminescence (TL), and persistent (excitation) luminescence measurements, the origin and properties of persistent luminescence of BaAl2O4:Eu2+,Dy3+ were studied in detail. Ultraviolet (UV) excited and persistent emission are identical and no contribution from the Eu2+ in the high-symmetry Ba site was observed. TL excitation spectra clarified the unstructured conventional excitation spectrum; now it is evident that defects or the Dy3+ co-dopant do not contribute to persistent luminescence via direct energy absorption. Mechanisms for persistent luminescence should thus be revised.
KW - BaAlO
KW - Eu+Dy co-doping
KW - Excitation
KW - Persistent luminescence
KW - Thermoluminescence
UR - http://www.scopus.com/inward/record.url?scp=85084553233&partnerID=8YFLogxK
U2 - 10.1016/j.physb.2019.411947
DO - 10.1016/j.physb.2019.411947
M3 - Article
AN - SCOPUS:85084553233
SN - 0921-4526
VL - 593
JO - Physica B: Condensed Matter
JF - Physica B: Condensed Matter
M1 - 411947
ER -