All the DFT and TDDFT calculations were performed with Gaussian 16 package. The B3LYP hybrid functional together with D3 dispersion correction and 6-31G* basis set were employed for both geometry optimization and electronic property calculations. The maximum force tolerance is 0.02 eV/ Å. The initial xyz coordinates of polymers were generated from the SMILES strings with OpenBabel package. Before geometry optimization with DFT, we manually adjusted the oligomer backbone to be coplanar using the Avogadro package to more closely resemble a realistic configuration, as high planarity is favored in experiments to promote the performance of polymer-based electronic devices.