2D Nanomaterial-Directed Molecular Aggregation and Energy Transfer between Edge-Bound Donor-Acceptor Pairs

Fo''rster resonance energy transfer(FRET) is aphenomenonthat is observed between an excited energy donor and ground-stateacceptor in close proximity. The efficiency of FRET varies with thedistance and orientation of the donor-acceptor pair, solvent,and other competing processes. Layered silicates, with their abilityto stack in pillars with a certain interlayer spacing,present a useful platform to influence the interactions of edge-boundgroups. In this study, asymmetric perylene and naphthalene diimideswere grafted to the edge of the layered silicate Laponite, and theirphotophysical properties and aggregation behavior were studied indifferent compositions of water and dimethylformamide. FRET was observedfrom naphthalene diimide- to perylene diimide-functionalized Laponite,and pillaring of Laponite with a cationic surfactant led to significantlyenhanced FRET, which was attributed to the reorientation of chromophoresdue to the organized stacking of pillared particles. This study reportshow ordering of the discoidal layered silicate nanoparticles intoorganized stacks can tune the aggregation of edge-bound FRET pairs.This can aid in understanding donor-acceptor interactions atthe interface of anisotropic nanomaterials and improve control overthe distance and orientation of donor-acceptor pairs and resultingenergy transfer processes. Furthermore, this is the first exampleof the attachment of naphthalene diimides to layered silicate edgesites. This study opens the door to further studies of geometry-dependentenergy flows in inorganic-organic hybrid materials and willadvance applications in sensing, energy, and molecular electronics.

Automated summary

This study investigates the photophysical properties and aggregation behavior of asymmetric perylene and naphthalene diimides grafted to the edge of layered silicate Laponite. FRET was observed from naphthalene diimide- to perylene diimide-functionalized Laponite, with significantly enhanced FRET achieved by pillaring Laponite with a cationic surfactant. The results demonstrate the ability to tune donor-acceptor interactions and energy transfer processes in inorganic-organic hybrid materials.