Photoexcited Energy Relaxation in a Zigzag Carbon Nanobelt

Abstract

Progress in the synthesis of new carbon nanorings and nanobelts broadens the library of materials with unique structural and optical properties that can be attractive for further potential applications in host-guest chemistry, nanoelectronics, and photonics. Herein, we study the photoexcitation and subsequent energy relaxation and redistribution of a recently synthesized zigzag carbon nanobelt using nonadiabatic excited-state molecular dynamics simulations. A gradual change in the direction of transition dipole moments and spatial localization of the electronic transition density is observed for internal conversion from the initially excited electronic state to the lowest-energy excited state. Electronic relaxation involves long-lived states associated with large energy gaps, changes of symmetry, and low couplings with the corresponding states immediately below them. The passage through these long-lived states involves significant changes in the spatial localization of the electronic transition density. Our results reveal the excited-state dynamical properties of the zigzag-type nanobelt that differentiate this molecule from other nanobelts. These insights can stimulate further designs of zigzag nanobelts tailored for specific nanoelectronic and photonic applications.