Insight into incident photon to current conversion efficiency in chlorophylls

Abstract

AbstractPhotovoltaic properties of the natural dyes of chlorophylls consist ofChl a,Chl b,Chl c2,Chl d,Phe a,Phe y, andMg‐Phe aand have been studied in the gas phases and water. The extension of the π‐conjugated system, the substitution of the central Mg2+, and proper functional groups in the chlorophyll structures can amplify the charge transfer and photovoltaic performance.Chl ashows more favorable dynamics of charge transfer than the other studied chlorophylls.Chl d,Phe a,Phe y, andMg‐Phe ahave a greater rate of exciton dissociation in comparison withChl a,Chl b, andChl c2originating from a lower electronic chemical hardness, a lower exciton binding energy, and a bigger electron‐hole radius. As a result, better efficiencies of light harvesting and energy conversion of the chlorophylls mainly appear in the Soret band. The light‐harvesting efficiency values of the chlorophylls in water show that solvent favorably affects the ability of light harvesting of the photosensitizers. Finally, based on the energy conversion efficiency,Chl a,Phe a, andMg‐Phe aare proposed as the best candidates for use in the dye‐sensitized solar cells.