The interpretation and prediction of optical properties of natural and artificial light harvesting systems can be greatly facilitated by a computational support. For instance, it can help identifying the most interesting chromophores among a large number of potential candidates for the design of new solar cells, or unraveling the many effects contributing to the complex light harvesting processes in natural photosystems. As examples of light absorbing devices, we can mention the luminescent solar concentrators, which have seen a growing interest thanks to their intrinsic properties, making them less dependent on the direct exposure to sunlight. In this context, the best candidates must possess a good Stokes shift and preferably emit toward the infrared wavelength. Then, rationalization of structure-function relationships in natural and artificial photosynthetic devices and the mechanisms influencing the efficiency of energy transfer and charge separation is crucial for understanding and then mimicking natural photosynthesis. Currently, most computations are still limited to electronic transitions, which are in turn convoluted to simulate the natural broadening in real conditions. In doing so, the experimental asymmetry of the band-shape, due to the vibronic structure is lost, leading to an incorrect estimate of the absorption and emission maxima and their relative intensities. Thanks to the availability of efficient procedures, simulation of vibrationally-resolved electronic spectra can be routinely done even for medium-to-large systems, including environment and temperature effects. Moreover, multiple electronic states can be taken into account, making possible the full characterization of the photophysical properties of natural compounds. Some of the possibilities of such tools will be illustrated in this contribution for model chromophoric systems (organic dyes and chlorophyll-a) taking also into account tuning by the environment (solvent, transparent polymer matrix or other chromophores) of their spectroscopic properties, along with an identification of the main inter- and intra-molecular degrees of freedom coupled strongly to electronic transitions, which are possibly relevant for the energy transfer processes. [1] V. Barone, F. Bellina, M. Biczysko, J. Bloino et al. Phys. Chem. Chem. Phys. 17, 26710 (2015) [2] V. Barone, M. Biczysko, M. Borkowska-Panek, J. Bloino, ChemPhysChem 15, 3355 (2014)

Simulation of realistic electronic spectra bandshapes of chromophoric systems relevant for solar light harvesting

251st National Meeting (2016)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.