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Sacrificing trap density to achieve short-delay and high-contrast mechanoluminescence for stress imaging.
- Source :
-
Acta Materialia . Jun2018, Vol. 152, p148-154. 7p. - Publication Year :
- 2018
-
Abstract
- Trap-controlled mechanoluminescence (ML) enables the direct observation of stress concentration of load-bearing objects through imaging the ML distribution, showing numerous prospects in stress detection, bio-imaging and optical displays. However, the applications of trap-controlled ML materials universally require long-time delay to fade the noise of symbiotic persistent luminescence (PersL) in order to achieve high-contrast ML images. In view of the difficulty to solve the PersL problem through individually eliminating the PersL traps, herein we propose a novel strategy of sacrificing trap density which decreases PersL and ML traps as a whole. By employing Sr 2+ substitution to decrease the trap density of Ca 2 Nb 2 O 7 :Pr 3+ , we identify a novel composition of (Ca 0.5 Sr 0.5 ) 2 Nb 2 O 7 :Pr 3+ displaying short-delay and high-contrast ML images, and evaluate its practicability through a 2-dimensional in-situ imaging experiment of dynamic stress distribution. The underlying mechanism is ascribed to the greater decrease ratio of PersL intensity than ML intensity as a result of the larger detrapping rate of traps due to stress (leading to ML) than that due to thermal energy (PersL). Furthermore, multi-spectral investigations of (Ca,Sr) 2 Nb 2 O 7 :Pr 3+ system reveal a distinctive electron transition process co-regulated by trap levels, charge transfer state and crystal field. The proposed strategy and the associated phosphors are expected to initiate the reconstruction of PersL-type ML materials and bring important implications for real-world stress imaging. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 13596454
- Volume :
- 152
- Database :
- Academic Search Index
- Journal :
- Acta Materialia
- Publication Type :
- Academic Journal
- Accession number :
- 129996503
- Full Text :
- https://doi.org/10.1016/j.actamat.2018.04.011