Luminescence efficiency and nonradiative transitions in lanthanide formates.

Absolute quantum yields and luminescence lifetimes were measured for Eu, Tb, Gd, formates and Y formate activated by Eu as functions of temperature, deuterium substitution in ligands, and Eu concentration in Y formates. Radiative and nonradiative transition probabilities in the lanthanide formates were determined using the quantum yield φ and luminescence lifetime τ. The probabilities of radiative transitions in Eu were also found by employing corrected luminescence spectra. Relaxation mechanisms of electronic excitation energy in the studied crystals were discussed. [ABSTRACT FROM AUTHOR]