Nowadays, one of the most important challenge facing humanity is developing a renewable source of energy able to replace our reliance on fossil fuels. Among the energy sources widely available on Earth, sunlight is one of the most attractive. Photosynthesis is the most efficient method to harvest, convert and store sunlight energy. Due to the key role of tetrapyrrolic systems in natural photosynthesis, porphyrins, phthalocyanines and related compounds have attracted a great attention in the range of solar technologies such as organic solar cells, solar thermal processes and solar fuels. Inspired by their involvment in the reaction center of the photosynthetic apparatus, some organized porphyrinoid nanostructures were developed in order to mimic the properties of these natural systems with potential utilization in solar fuels production systems.

Porphyrin dyes were also applied successfully in Dye-Sensitized Solar Cells (DSSCs). In DSSCs, a dye injects an electron into the conduction band of a nanocrystalline film of metal oxide such as TiO2 and is subsequently regenerated back to the ground state by electron donation from a redox couple present in the electrolyte. Among the commercially available dyes, porphyrin dyes stand out as attractive candidates due to their easy structural modification, abundant supply, photostability and their absorption in the UV-visible region. The donor–π–acceptor porphyrins have especially attracted attention for the construction of high performance DSSCs. The conversion efficiencies obtained with donor–π–acceptor porphyrins reached 13% when used with an iodide-based electrolyte. Porphyrin analogs such as phthalocyanines exhibit very high extinction coefficients in a wavelength range that extends to around 700 nm, where the maximum of the solar photon flux occurs. Hence, these derivatives turned out to be excellent dyes for incorporation into donor-acceptor systems and subsequent utilization in DSSCs.

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