Activated Diffusion of 1D J-Aggregates in Boron Nitride Nanotubes by Curvature Patterning

The directed assembly of molecules into micrometer-scale patterns and advanced materials holds broad relevance across fields such as life sciences, photovoltaics, and quantum photonics. However, these processes are often challenged by competing forces such as Brownian motion, capillary interactions, drift, and nonspecific adsorption. Here, we demonstrate a reactivated and guided diffusion mechanism of luminescent dye aggregates after encapsulation within boron nitride nanotubes (BNNTs). Correlative analyses between BNNT curvature and molecular positioning along the nanotube axis reveal efficient long-range migration of dye molecules from curved to straight sections of the BNNT. This curvature-activated diffusion leads to the formation of J-aggregate clusters, arranged in periodic patterns with precise spacings and defined lengths. A phenomenological model of curvature-guided molecular motility is developed to describe 1D diffusion within BNNTs, accurately predicting the size and spacing of J-aggregates as a function of the nanotube length. Finally, this mechanism is exploited using different substrates, such as exfoliated MoS₂ topological steps or micropatterned gratings on the photonic device, to induce local bending of the BNNTs and deterministically control molecular cluster formation.