In this article we describe the redshift of the charge transfer band of nanosized cubic (Y1−xEux)2O3 upon increasing the Eu3+ concentration. This redshift amounts to 0.43 eV (25 nm) in going from 0.1 Mol % Eu3+ to 100 Mol % (which is pure Eu2O3). The charge transfer band consists of two broad sub-bands; both shift almost parallel with the Eu3+ concentration and are related to the two symmetry sites for the cation, C2 and C3i, in the bixbyite-type lattice.
The area ratio of the bands is 3:1 and is the first direct evidence for the population of the two lattice sites by the Eu3+ cations being in accord with the crystal structure ratio. A model is presented that quantitatively describes the redshift of the charge transfer band of (Y1−xEux)2O3. This model is based on the Madelung energy of the transferred charge. Other models are briefly discussed, but are discarded.
den Engelsen, D., Ireland, T.G., Dhillon, R., Fern, G., Harris, P.G. and Silver, J., 2016. Red shift of CT-band in cubic Y2O3: Eu3+ upon increasing the Eu3+ concentration. ECS Journal of Solid State Science and Technology, 5(5), pp.R59-R66.
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Categories: Photonics & Optoelectronics