Symmetry breaking charge transfer in excited multibranched molecules and dimers: A unified standpoint

Symmetry breaking charge transfer (SBCT) in excited molecules plays a central role in photochemical energy conversion in both artificial and biological systems. The photophysical properties of chromophore aggregates can be tuned over a wide range, which opens up prospects for their application in optoelectronic devices, as well as photosensitizers-catalysts. SBCT occurs at a high rate, so its use at the stage of primary charge separation can be effective in the development of organic photovoltaic devices. The processes of symmetry breaking in quadrupolar and octupolar molecules and symmetrical dimers are analyzed from a unified standpoint. The manifestations of symmetry breaking in the IR and optical spectra are described. The most important experimental results and their theoretical description within simple models are discussed. Particular attention is paid to the physical interpretation of regularities observed in experiments.