Synthesis, Spectral, Electrochemical and Photovoltaic Studies of A₃B Porphyrinic Dyes having Peripheral Donors

Abstract

Abstract Three new ‘push‐pull’ A 3 B Zn(II)porphyrin dyes having meso ‐pyrenyl, carbazolyl and phenothiazine as electron donors ( A ) and phenylcarboxylic acid as acceptor/anchor ( B ) were synthesized and utilized for DSSC application. The spectral and electrochemical redox properties of these new dyes were studied and compared with trans ‐A 2 BC Zn(II) porphyrin dyes under similar experimental conditions. Red‐shifted, broadened absorption peaks, lower fluorescence quantum yields, and shortened lifetimes were observed for the A 3 B dyes as compared to zinc tetraphenylporphyrin control, ZnTPP. DFT optimized structures suggested effective charge separation related to enhanced charge injection efficiency. Driving force for electron injection (ΔG inj ) and dye regeneration (ΔG reg ) calculated from the spectral and electrochemical studies predicted facile electron injection from excited dye into semiconductor TiO 2 in the constructed solar cells. Phenothiazine appended dye ( KP ‐ TriPTZ ‐ Zn ) showed the highest η value of 7.3 % for PCE with greater J sc and V oc values due to its better light harvesting ability and reduced dye aggregation as compared to other dyes. Our studies demonstrate that the dyes having multiple electron‐donating groups exhibit higher photon‐to‐current conversion efficiency.