Porphyrins for photovoltaic applications

Porphyrins are characterized by strong light-harvesting abilities and chemical, photochemical and thermal stability. Since their energy levels can also be easily tuned by chemical modification, this kind of molecules are a good candidate to be implement in photovoltaic devices. Push-pull porphyrins featured by a strong internal charge transfer, have reached interesting photon-to-current conversion efficiencies in dye-sensitized solar cells (DSSCs),1 which best perform in diffuse light conditions2 and can be considered as a potential solution for the development of photovoltaic glass, both for the outdoor and the indoor, to be applied in the making of future zero-energy buildings (ZEBs). However push-pull porphyrins are obtained by multistep synthesis with low overall yields, on the contrary ?-functionalized porphyrins offer the possibility of a straightforward synthesis with higher yields, and therefore more adapted for a large scale production. 3 Here we will present our recent results in the study of ?-substituted porphyrins as dyes in DSSC prototype devices, where the components will be realized by means of different thin-film deposition techniques, such as screen and ink-jet printing. Finally, we will also present our preliminary results in the implementation of photoactive porphyrin thin layer in hetero-junction photovoltaic cells realized through physical vapor deposition. References 1. Urbani, M. et al. Meso-Substituted Porphyrins for Dye-Sensitized Solar Cells. Chem. Rev. 114, 12330-12396 (2014). 2. Freitag, M. et al. Dye-sensitized solar cells for efficient power generation under ambient lighting. Nat. Photonics 11, 372-378 (2017). 3. Di Carlo, G., Orbelli Biroli, A., Tessore, F., Caramori, S. & Pizzotti, M. ?-Substituted ZnIIporphyrins as dyes for DSSC: A possible approach to photovoltaic windows. Coord. Chem. Rev. 358, 153-177 (2018).