Tuning Spectral and Electrochemical Properties of Porphyrin-Sensitized Solar Cells

Abstract

Phenylethynyl-substituted porphyrin (PE1) sensitizers bearing a nitro, cyano, methoxy, or dimethylamino phenylethynyl substituent were prepared to examine the electron-donating or -withdrawing effects of dyes on the photovoltaic performance of the corresponding dye-sensitized solar cells. The overall efficiencies of power conversion of the devices show a systematic trend Me 2 N-PE1 > MeO-PE1 > CN-PE1 > NO 2 -PE1, for which Me 2 N-PE1 has a device performance about 90% of that of a N719-sensitized solar cell under the same experimental conditions. The superior performance of Me 2 N-PE1 is attributed to the effective electron-donating property of the dye that exhibits broadened and red-shifted spectral features. According to frontier orbitals based on DFT calculations, the electrons are effectively injected from the dye to TiO 2 for Me 2 N-PE1 and MeO-PE1 upon excitation, but that driving force reverses for NO 2 -PE1. Electrochemical tests indicate that both LUMO and HOMO levels show a systematic trend Me 2 N-PE1 > MeO-PE1 > CN-PE1 > NO 2 -PE1, consistent with the trend of variation of the short-circuit currents in this series of sensitizers.

Porphyrins as Active Components for Electrochemical and Photoelectrochemical Devices

“…Similar photovoltaic behavior as a function of immersion solvents was reported for the other porphyrins. 213 After selection of MeOH as the best solvent, functionalization of TiO 2 with 2,4,6-Me was evaluated at the three different times. Accordingly to the trend of Γ, the η value increased rapidly to reach a η max = 4.6% after one hour and then decreased to reach the constant value η = 3.7%.…”

2‐(1‐Acetyl‐2‐oxopropyl)‐5,10,15,20‐tetraphenylporphyrin and Its Transition‐Metal Complexes

“…Molecular orbitals were visualized by GaussView 3.0 software. [33] The method has been widely used for geometry optimizations and electronic calculations of porphyrin derivatives due to its accuracy, [4,5,6,34,35] which was further validated by the very similar bond angles and lengths in the optimized structures of MTPP-AOP (M = 2H + , Zn 2+ , Cu 2+ ) and single-crystal structures.…”

Porphyrin Based Dye Sensitized Solar Cells

“…They are attractive for such purposes as their synthesis is relatively straightforward and their optical and electronic properties can be tuned via chemical modification of the porphyrin core (Dos Santos, Morandeira et al, 2010), the number of porphyrin units (Mozer, Griffith et al, 2009), and the linker between the core and the inorganic oxide (Lo, Hsu et al, 2010). It was originally assumed that porphyrin dyes would function identically to other analogous chromophores inside a DSSC, however, extensive studies of porphyrin dyes have shown that they are distinctive, and possess very different photophysics to the majority of other sensitizers (Bessho, Zakeeruddin et al, 2010;Campbell, Jolley et al, 2007;Imahori, Umeyama et al, 2009).…”