Integrating Highly Luminescent Lanthanides with Strongly Coupled Dye J‑Aggregates on Nanotubes for Efficient Cascade Energy Transfer

Photoluminescent one-dimensional hybrid nanostructured materials having outstanding inorganic–organic advantages are gaining significant attention on account of their intriguing applications in nanoscale optoelectronic devices, (bio)­sensors, and energy harvesting and conversion technologies. Here, we first report on the development of highly photoluminescent lanthanide organic hybrid nanotubular assemblies through in situ incorporation of a trivalent lanthanide ion, terbium (Tb3+), along with organic photosensitizers 2,3-dihydroxynaphthalene (DHN) or 1,10-phenanthroline (Phen) into the self-assembled nanotubes of sodium lithocholate (NaLC). Both the photosensitizers (DHN/Phen) are effective in sensitizing intense narrow emission peaks of Tb3+ on the nanotubes. Next, we utilize these luminescent lanthanides containing hybrid nanotubular assemblies as templates for spontaneous integration of strongly coupled pseudoisocyanine (PIC) dye J-aggregates with a sharp J-band absorption at 555 nm and strong fluorescence emission at 570 nm. The presence of the significant spectral overlap between the luminescence peak of Tb3+ at 545 nm and the J-aggregate absorption band results in efficient cascade energy transfer from photosensitizers to Tb3+ to the coherently coupled PIC dye J-aggregates. These NaLC nanotube-templated photosensitizer-Tb3+-J-aggregate hybrid systems have great potential for sensing and optoelectronic applications.