Effect of functional groups on sensitization of dye-sensitized solar cells (DSSCs) using free base porphyrins

Abstract

Dye-sensitized solar cells (DSSCs) were fabricated with six meso-substituted A[Formula: see text]B and A[Formula: see text] free base porphyrin dyes having different functional groups, as sensitizers. The two step synthesis and the effect of different functional groups and their positions on the photosensitization properties of these porphyrin dyes are reported. The highest power conversion efficiencies ([Formula: see text] of 3.26%, 2.94% and 2.84% were achieved for the DSSC fabricated using 5,10,15-tris(4[Formula: see text]-pyridyl)-20-(4[Formula: see text]-carboxyphenyl)porphyrin (H[Formula: see text]TriPyMCPP), 5,10,15,20-tetrakis(4[Formula: see text]-aminophenyl)porphyrin (H[Formula: see text]TAPP) and 5-(4[Formula: see text]-pyridyl)-10,15,20-tris(4[Formula: see text]-carboxyphenyl)porphyrin (H[Formula: see text]MPyTriCPP) dyes, respectively. The electron donating amino group is shown to enhance the power conversion efficiency while pyridyl appended porphyrin sensitizers are shown to be superior sensitizers as compared to carboxyphenylporphyrins. The investigation of effect of functional group and position of functional group of porphyrin dye on DSSC can serve as an important tool to guide further selection and synthesis of potential candidates as sensitizers.