The energy transition from the ground state to the first excited singlet of four organic dye candidates to be used as sensitizers in solar cells, D5, D7, D9, and D11, has been computationally explored and compared to experimental results with TDDFT (B3LYP, omega B97, and omega B97X functionals) and the CIS(D) and SOS-CIS(D) wave function based methods. The second-order perturbation correction to Cl singles' excitation energies are superior to any TDDFT functional employed here. The performance of SOS-CIS(D) is especially interesting, being in good agreement with absorption spectra and having important computational savings. The best TDDFT results are obtained by the omega B97X functional. Solvation effects on the excitation energies have been studied with three different models, i.e., the Onsager reaction field model, SS(V)PE, and SM8.
Mohammad Khaja Nazeeruddin, Yi Zhang