| Autor: |
Alberto Rivera-Calzada, J. Isasi-Marín, Jesus Santamaria, Carlos Díaz-Guerra, Carlos León, Marta Pérez-Estébanez |
| Rok vydání: |
2013 |
| Předmět: |
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| Zdroj: |
Solid State Ionics. 241:36-45 |
| ISSN: |
0167-2738 |
| DOI: |
10.1016/j.ssi.2013.04.001 |
| Popis: |
Optical and electrical properties of samples with Li 1 + x Cr x Ti 2 − x (PO 4 ) 3 composition ( x = 0, 0.05 and 0.1) prepared by a low temperature sol-gel method have been investigated. XRD and Raman spectroscopy measurements respectively reveal the rhombohedral-Nasicon structure of the grown samples and a disorder of Li + ions with increasing chromium content. Electrical properties were studied by impedance spectroscopy and both dc and grain boundary ionic conductivity increase with Cr content. A high ionic conductivity value of 1.4·10 − 4 S cm − 1 at room temperature and an activation energy of 0.31 eV have been obtained for x = 0.1, which are comparable to those measured in the best ionic conductors reported to date. Photoluminescence and cathodoluminescence spectra indicate that self-trapped excitons and oxygen defects related to the TiO 6 octahedra structural units are responsible for the observed luminescence in the visible spectral range, explaining the possible electronic origin of a residual conductivity measured in all the samples. Cr incorporation gives rise to infrared emission bands, attributed to different Cr 3 + and Ti 3 + intraionic transitions, that may be related to the better grain connectivity achieved by Cr doping. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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