Abstract of Publication No. 472
A. Bessière, P. Dorenbos, C. W. E. van Eijk, L. Pidol, K. W. Krämer and Hans U. Güdel
A 10 ns fast luminescence was observed at 270 nm in
Cs2LiYCl6:Ce3+ in addition to the
5dt–4f Ce3+ doublet emission at 370 and 405 nm.
This anomalous luminescence occurs exclusively for an excitation of the
4f–5de transitions of Ce3+ around 210 nm. It is not
excited under across band gap excitation which makes it an uncommon phenomenon.
The emission shows a large Stokes shift of 1.2 eV that must be related to an
excited state with a very strong electron–lattice interaction or possible
involvement of conduction band states. The 270 nm emission undergoes thermal
quenching between 140 and 250 K while the 5dt–4f Ce3+
emission gains intensity. The shape of the decay time spectra of the
5dt–4f Ce3+ emission reflects a temperature activated
transfer from the anomalous state to the 5dt lowest Ce3+