Luminescence and photoionization of X-ray generated Sm²⁺ in coprecipitated CaF2 nanocrystals
Date
2021
Authors
Rozaila, Z.S.
Riesen, N.
Riesen, H.
Editors
Advisors
Journal Title
Journal ISSN
Volume Title
Type:
Journal article
Citation
Dalton Transactions, 2021; 50(44):16205-16213
Statement of Responsibility
Z. Siti Rozaila, Nicolas Riesen and Hans Riesen
Conference Name
Abstract
We report photoluminescence and photoionization properties of Sm2+ ions generated by X-irradiation of nanocrystalline CaF2:Sm3+ prepared by coprecipitation. The nanocrystals were of 46 nm average crystallite size with a distribution of ±20 nm and they were characterised by XRD, TEM and SEM-EDS. At room temperature, the X-irradiated sample displayed broad electric dipole allowed Sm2+ 4f55d (A1u) → 4f6 7F1 (T1g) luminescence at 725 nm that narrowed to an intense peak at 708 nm on cooling to ∼30 K. The narrow f–f transitions of Sm3+ were also observed. The X-irradiation-induced reduction of Sm3+ + e− → Sm2+ as a function of X-ray dose was investigated over a very wide dynamic range from 0.01 mGy to 850 Gy by monitoring the photoluminescence intensities of both Sm2+ and Sm3+ ions. The reverse Sm2+ → Sm3+ + e− photoionization can be modelled by employing dispersive first-order kinetics and using a standard gamma distribution function, yielding an average separation of 13 Å between the Sm2+ ions and the hole traps (e.g. oxide ion impurities). The present results point towards potential applications of Sm doped CaF2 nanocrystals in the fields of dosimetry and X-ray imaging.
School/Discipline
Dissertation Note
Provenance
Description
Access Status
Rights
© The Royal Society of Chemistry 2021