Formation of fluorescent H aggregates of a cyanine dye in LB films and its effect on energy transfer

TL;DR

This study reports the formation of fluorescent H aggregates of a cyanine dye in ultrathin films, revealing their unexpected fluorescence and significant impact on energy transfer efficiency to sRhb in both solution and film.

Contribution

It demonstrates the formation of fluorescent H aggregates of a cyanine dye in ultrathin films and their influence on energy transfer processes, which is a novel observation.

Findings

Fluorescent H aggregates of Oxa18 form in ultrathin films.

H aggregates enhance energy transfer to sRhb.

Fluorescence occurs due to imperfect stacking of aggregates.

Abstract

Here we report the formation of fluorescent H aggregates of a cyanine dye Oxa18 in ultrathin film and its effect on energy transfer between Oxa18 and sRhb. Ideally H aggregate do not fluoresce. However, due to imperfect stacking of Oxa18 molecules in the aggregates, fluorescence occurred from Oxa18 H aggregates. This H aggregated band has substantial effect on the enhancement of energy transfer from Oxa18 to sRhb both in solution and in ultrathin film.