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

Photoluminescent one-dimensional hybrid nano-structured materials having outstanding inorganic-organic advan-tages 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 incorpo-ration 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.