Photophysical properties of near-IR cyanine dyes and their application as photosensitizers in dye sensitized solar cells.

The photophysical properties of eight structurally diverse near-infrared cyanine dyes were investigated with respect to their structural features and potential use as light-harvesting sensitizers of dye sensitized solar cells. The absorption, emission, and lifetime characteristics of the dyes were assessed under a variety of conditions. The photophysical properties and sensitizing efficiency of three of the eight dyes, with an additional six-membered cyclic ring, were markedly different from the other five. The dyes absorbed light of wavelength within the range of 779–823 nm and emitted within the range of 832–876 nm.The dyes had fluorescence quantum yield in the range of 14–22%. The surface morphology and elemental analysis of the cyanine dye sensitized photoanodes were characterized via Field-Emission Scanning Microscopy Imaging (FESEM) and Transmission Electron Microscopy (TEM). The performance of the fabricated cyanine dye sensitized solar cells was assessed via current-voltage and electrochemical impedance spectroscopic measurements. The solar-to-electric power conversion efficiency ranged from 0.04% to 0.24%. [ABSTRACT FROM AUTHOR]