Mechanism for energy transfer processes between Ce3+ and Tb3+ in LaPO4:Ce,Tb nanocrystals by time-resolved luminescence spectroscopy

作者：Pankratov V^*; Popov A I; Chernov S A; Zharkouskaya A; Feldmann C

来源：Physica Status Solidi (B) Basic Research, 2010, 247(9): 2252-2257.

DOI：10.1002/pssb.200945369

• nanophosphors
• rare earth phosphates
• time-resolved luminescence spectroscopy

The energy transfer mechanisms between Ce3+ and Tb3+ in LaPO4:Ce, Tb nanocrystals have been studied by means of time-resolved luminescence spectroscopy in a wide temperature range (10-300 K). Special attention was paid to detailed comparative analysis of both rise and decay emission components of both Ce3+ and Tb3+. Surprisingly, a relatively slow rise (several microseconds) of Tb3+ emission under 266-nm laser excitation was detected, which corresponds to the 4f-5d transition of Ce3+ in LaPO4. It was shown that this rise of Tb3+ emission could not have arisen due to relaxation of Ce3+ ions, whose excited state has a lifetime of about 20 ns. It was demonstrated that the generally accepted concept of a resonant energy transfer from Ce3+ to Tb3+ in LaPO4 could not explain the time- resolved luminescence characteristics as well as the observed temperature dependence. Hence, a new concept of the energy transfer process from Ce3+ to Tb3+ in LaPO4 via host lattice states was suggested and elucidated by proposing several possible models.

• 出版日期2010-9