Abstract
Two conjugated organic dyes comprising the benzo[b]furan moieties as the electron donor and cyanoacetic acid moieties as the electron acceptor/anchoring groups have been investigated using a quantum chemical method. The molecular equilibrium geometries and ground state character were studied using density functional theory. Absorption spectra were obtained using time-dependent density functional theory and semiempirical ZINDO. The nature of absorption spectra was further studied using 2D and 3D real-space analysis; here, 2D real-space analysis showed electron–hole coherence, and 3D real-space analysis showed intramolecular charge transfer during photo-excitation. As important parameters, excited state oxidation potential and driving force energy were obtained to reveal the relationship between molecular structure and performance of two compounds.
Acknowledgements
This work was supported by the National Natural Science Foundation of China (Grant Nos. 10604012, 20703064 and 10874234) and SRF for ROCS, SEM (2006).