Triboluminescence of Lanthanide Complexes

AbstractThe photoluminescence of lanthanide complexes originating from f–f transitions is generally sensitized through energy transfer from the ligand to the lanthanide ion in the excited state under UV irradiation. This phenomenon is known as the photo-antenna effect. Luminescence driven by mechanical stimuli, such as tapping or rubbing, is called mechanoluminescence or triboluminescence (TL). In recent years, reports on TL in rare-earth complexes, which have attracted attention as novel luminescent materials that do not require an electrical excitation source, have steadily increased. In this chapter, we focus on triboluminescent lanthanide complexes. Specifically, we introduce the history and detection methods of TL and cite recent examples of materials demonstrating this phenomenon, particularly coordination polymer-like and discrete molecular crystalline lanthanide complexes. Finally, we summarize the application prospects of these complexes as soft crystals.