Theoretical Insights into Ultrafast Separation of Photogenerated Charges in a Push-Pull Polarized Molecular Triad.

Herein, we propose a purely-organic donor-acceptor (D-A) molecular triad, with a light-absorbing polarized molecular wire (PMW) used as a central linkage, as a proof of concept for the possible future applications of the D-PMW-A arrangement in molecular photovoltaics. This work builds upon our earlier study on the PMW unit itself, which proved to be highly promising for the ultrafast photogeneration of free charge carriers. Quantum-chemical calculations performed for the D-PMW-A triad at a semi-empirical level of theory reveal a large electric dipole moment of the system, and show strong charge-transfer (CT) character of its lowest-energy excited electronic states, including the , which favours efficient dissociation of an exciton initially formed upon the absorption of light.

Conformation of the Ester Group Governs the Photophysics of Highly Polarized Benzo[]coumarins.

Photosensitizers that display "unusual" emission from upper electronically excited states offer possibilities for initiating higher-energy processes than what the governing Kasha's rule postulates. Achieving conditions for dual fluorescence from multiple states of the same species requires molecular design and conditions that favorably tune the excited-state dynamics. Herein, we switch the position of the electron-donating NMe group around the core of benzo[]coumarins (BgCoum) and tune the electronic coupling and the charge-transfer character of the fluorescent excited states.