Surface-Induced J Aggregation of Pseudoisocyanine Dye at a Glass/Solution Interface Studied by Total-Internal-Reflection Fluorescence Spectroscopy

An aqueous pseudoisocyanine dye solution in a soda lime glass optical cell exhibited the new absorption band of a J aggregate at around 577 nm ( J L aggregate) at room temperature. The J L band was slightly red-shifted and broader (hwhm: ∼130 cm -1 ) compared to the previously reported J band ( J S band; peak, ∼572 nm; hwhm, ∼70 cm -1 ). Since formation of the J L aggregate was not observed in a quartz glass cell, it was concluded that J L aggregate formation was induced by interactions between the dye and the soda lime glass surface. Total-internal-reflection fluorescence spectroscopy proved that the J L aggregate was distributed only in the vicinity of the glass surface, whereas the J S aggregate was produced in the bulk water phase.