高速分光による希土類発光材料の光増感過程の実時間観測と機構解明

抄録

Trivalent lanthanide complexes are attractive candidates for light sources due to their exceptionally pure color emission. Enhancing the photoluminescence intensity through sensitization using ligands with high absorption efficiency is a powerful strategy. However, the microscopic energy transfer mechanisms from organic chromophores to lanthanide ions remain elusive. In this study, we investigated the energy transfer processes in luminescent trivalent europium (Eu³⁺) complexes using time-resolved photoluminescence spectroscopy and transient absorption spectroscopy. Our results successfully elucidated the energy transfer processes from two different ligands, revealing that both energy transfers occur via the triplet excited states of each ligand. Based on these findings, we proposed efficient sensitization using host-to-guest energy transfer in a host-guest film composed of aromatic organic molecules and Eu³⁺ complexes. Our approach resulted in a more than 400-fold enhancement of photoluminescence intensity compared to the intrinsic Eu³⁺ complex.