Energy migration and up-conversion in Cs2NaErxY1-xCl6 at 1.2 K

摘要

Low temperature, high resolution emission spectra have been measured for the pure and diluted erbium elpasolites, Cs$- 2$/NaEr$-x$/Y$-1$MIN@x$/Cl$-6$/ from the $+4$/G$-11/2$/, $+2$/G$-11/2$/, $+4$/S$-3/2$/, $+4$/F$-9/2$/, and $+4$/I$- 9/2$/ excited states of Er$+3$PLU$/ under 364 nm argon laser excitation. A number of these spectra show some unusual features which are consistent with migration of the excitation energy within the lattice leading to excitation of luminescence from defect sites. The nature of the defect sites is discussed and possible mechanisms leading to the migration of the excitation energy within the lattice are explored.