However, the explanation of DPND6 spectra is not straightforward. To distinguish the contribution of electronic state or vibrational motions to the absorption peaks, we display the pure electronic-state oscillator strengths with vertical lines for a 10-monomer DPND6 aggregate and a 18-monomer DPND aggregate in Fig. . Obviously, two peaks in DPND aggregates indeed mainly correspond to pure electronic excitation, further confirming our above analysis. In the spectra of DPND6, the absorption peaks at 2.50 eV and 2.64 eV mainly correspond to the mixing between the FE and CT states. However, the peak at 2.36 eV corresponds to the vibrational state of the dark electronic state in DPND6 aggregates due to phonon-induced symmetry breaking. Concretely speaking, the first excited state is the dark state in the pure electronic spectra because of H aggregate. As the vibrational motions are incorporated, the oscillator strength from the ground state to the first excited state is not zero due to Franck-Condon factors which break the symmetry of the H-aggregate itself.