Photoluminescence (PL) decay induced by the displacement of an ionic fluorescence component, Tb3+, with alkali and alkaline earth metal cations was investigated using photoluminescent spherical self-assemblies as optical probes. The photoluminescent spherical self-assembly was prepared by the self-organization of a tyrosine-containing bolaamphiphile molecule with a photosensitizer and Tb3+ ion. The lanthanide ion, Tb3+, electrically bound to the carboxyl group of the bolaamphiphile molecule, was displaced by alkali and alkaline earth metal cations that had stronger electrophilicity. The PL of the self-assembly decayed remarkably due to the substitution of lanthanide ions with alkali and alkaline earth metal cations. The PL decay showed a positive correlation with cation concentration and was sensitive to the cation valency. Generally, the PL decay was enhanced by the electrophilicity of the cations. However, Ca2+ showed greater PL decay than Mg2+ because Ca2+ could create various complexes with the carboxyl groups of the bolaamphiphile molecule. Microscopic and spectroscopic investigations were conducted to study the photon energy transfer and displacement of Tb3+ by the cation exchange. This study demonstrated that the PL decay by the displacement of the ionic fluorescent compound was applied to the detection of various cations in aqueous media and is applicable to the development of future optical sensors.
Bibliographical noteFunding Information:
This research was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science, and Technology (2012R1A1A2008543).
All Science Journal Classification (ASJC) codes
- Surfaces and Interfaces
- Physical and Theoretical Chemistry
- Colloid and Surface Chemistry