Exciton Spatial Dynamics and Self-Trapping in Carbon Nanocages

Three-dimensional cage-shaped molecules formed from chainlike structures hold potential as unique optoelectronic materials and host compounds. Their optical, structural, and dynamical features are tunable by changes in shape and size. We perform a comparison of these properties for three sizes of strained conjugated [n.n.n]carbon nanocages composed of three paraphenylene chains (bridges) of length n = 4, 5, or 6. The exciton intramolecular redistribution occurring during nonradiative relaxation has been explored using nonadiabatic excited-state molecular dynamics. Our results provide atomistic insight into the conformational features associated with the observed red- and blue-shift trends in the absorption and fluorescence spectra, respectively, with increasing nanocage size. Their internal conversion processes involve intramolecular energy transfer that leads to exciton self-trapping on a few phenylene units at the center of a single bridge. The dependence of these dynamical features on the size of the nanocage can be used to tune their host-guest chemical properties and their use for organic electronics and catenane-like applications.Fil: Rodríguez Hernández, Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología; ArgentinaFil: Nelson, Tammie. Los Alamos National Laboratory; Estados UnidosFil: Oldani, Andres Nicolas. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología; ArgentinaFil: Martinez Mesa, Aliezer. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología; Argentina. Universidad de La Habana; CubaFil: Uranga Piña, Llinersy. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología; Argentina. Universidad de La Habana; CubaFil: Segawa, Yasutomo. Los Alamos National Laboratory; Estados Unidos. Nagoya University; Japón. Institute for Molecular Science; JapónFil: Tretiak, Sergei. Los Alamos National Laboratory; Estados UnidosFil: Itami, Kenichiro. Los Alamos National Laboratory; Estados Unidos. Nagoya University; JapónFil: Fernández Alberti, Sebastián. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología; Argentin