Relaxation of the photoexcited electrons in chevron-type graphene nanoribbons: Many-body theory and nonadiabatic molecular dynamics modeling

Abstract

The dynamics of photoexcited electrons associated with the absorption processes of the dominant peaks in pristine and nitrogen-doped chevron-type graphene nanoribbons (CGNRs and NCGNRs) have been investigated via nonadiabatic molecular dynamics simulations. The results show that the decay time in NCGNR is shorter than in CGNR. The results rationalized by the large energy difference between LUMO and LUMO+3 in CGNR (0.61 eV) and in NCGNR (0.37 eV), the comparable coherence timescales (22 fs and 21 fs) and nonadiabatic couplings (2.97 meV and 2.48 meV) of these two systems. Furthermore, phonon influence spectra show that the modes participate in the relaxation of the photoexcited electron in CGNR reside around in 101 cm−1 while in NCGNR they are in a broad range of frequencies between 210 cm−1 to 2304 cm−1, which means there exist more additional channels for accelerating the transfer in NCGNR, rationalizing why the photoexcited electrons decay faster in NCGNR.