Nonradiative Excited-State Decay via Conical Intersection in Graphene Nanostructures |
| |
Authors: | Shunwei Chen Naeem Ullah Yanling Zhao Prof Ruiqin Zhang |
| |
Institution: | 1. Department of Physics, City University of Hong Kong, Hong Kong SAR, China;2. Department of Physics, City University of Hong Kong, Hong Kong SAR, China
Shenzhen Research Institute, City University of Hong Kong, Shenzhen, China |
| |
Abstract: | Chemical groups are known to tune the luminescent efficiencies of graphene-related nanomaterials, but some species, including the epoxide group (−COC−), are suspected to act as emission-quenching sites. Herein, by performing nonadiabatic excited-state dynamics simulations, we reveal a fast (within 300 fs) nonradiative excited-state decay of a graphene epoxide nanostructure from the lowest excited singlet (S1) state to the ground (S0) state via a conical intersection (CI), at which the energy difference between the S1 and S0 states is approximately zero. This CI is induced after breaking one C−O bond at the −COC− moiety during excited-state structural relaxation. This study ascertains the role of epoxide groups in inducing the nonradiative recombination of the excited electron-hole, providing important insights into the CI-promoted nonradiative de-excitations and the luminescence tuning of relevant materials. In addition, it shows the feasibility of utilizing nonadiabatic excited-state dynamics simulations to investigate the photophysical processes of the excited states of graphene nanomaterials. |
| |
Keywords: | conical intersection excited-state dynamics graphene nanomaterials optical properties TD-DFT |
|
|