Kinetic selection of nonradiative excitation in photonic nanoparticles Gd2O3:Er

Abstract

In the present work, we separate and classify four different pathways for UV-vis energy conversion with participation of Gd³⁺_def and Er³⁺ ions located at dissimilar structural sites in the Gd₂O₃ lattice. The Gd³⁺_def centers represent host cations with a distorted environment due to the nearest defects of the anionic sublattice. Two non-equivalent types of both Gd³⁺_def donor and Er³⁺ acceptor centers occupying C₂ and S₆ structural sites are selected in Gd₂O₃:Er nanoparticles by the spectral-kinetic method. Such structural features provide the realization of several parallel channels of nonradiative Gd³⁺_def → Er³⁺ energy migration and lead to a multimodal distribution of emission centers over the lifetime of the Er³⁺ excited states. The widths and the maxima of the kinetic parameter distributions depend on the degree of disorder in the nearest environment of Gd³⁺_def donor centers. Our data show the possibility of practical realization of what is regarded as an additional pathway for the enhancement of excitation nonradiative transport in photonic devices.