Insight into incident photon to current conversion efficiency in chlorophylls

Abstract

Photovoltaic 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.

Molecular engineering of triphenylamine‐based metal‐free organic dyes for dye‐sensitized solar cells

“…where λ is the absorption wavelength of the compound, and IPCE is an incident photon-to-current conversion efficiency, which can be described by Equation (5) [71]:…”

“…Short‐circuit current density means current flowing through the photovoltaic device when the device is irradiated and the electrodes are connected. J SC is calculated according to Equation () [70]: where λ is the absorption wavelength of the compound, and IPCE is an incident photon‐to‐current conversion efficiency, which can be described by Equation () [71]: where η coll is electron injection efficiency and can be considered to be constant in the systems whose components are the same, while different only in sensitizers [72,73]. Φ inj is charge collection efficiency which is considered equivalent to the Gibbs energy of electron injection from the excited states of dyes to the semiconductor substrate [74,75].…”

“…Therefore, to deal with such a massive demand for energy, we must use renewable sources, such as hydropower, wind energy, solar energy, geothermal energy, and biomass energy, in which solar energy is abundant, cheap, available, no polluting and unique natural source of clean energy [6‐10]. New technology for using solar energy is the solar cell, that converts solar light directly into electricity without any environmental pollution [11,12]. Dye‐sensitized solar cells (DSSCs) as the third generation of the solar cells, developed by O'Regan and Grätzel [13], have received a lot of attention due to advantages, such as simple manufacturing process, low cost, environmental compatibility, flexibility, transparency, and having a variety of dyes [14‐18].…”