New sensitizers containing amide moieties as electron-accepting and anchoring groups for dye-sensitized solar cells

Abstract

In this study, we report three new dyes adopting an amide group as the electron-accepting and anchoring unit. Blue-black dye INPBA and INPDT consisting of indole donor, thiophene bridge and thioxo-pyrimidine-dione/pyrimidine-trione acceptors, exhibited maximum absorption wavelength (λ_max) at 615 nm and 585 nm, respectively, and extended the cut-off wavelength in near-infrared zone. INPOD exhibited significantly inferior spectral response (λ_max = 461 nm) because of the weak electron-withdrawing ability of aminothiazolone acceptor. Theoretical analysis indicated that the shrink of SC bond contributes to 30 nm red-shift of absorption when replacing the O atom with S in the INPDT. The efficiencies for device based on dye of INPDT, INPOD and INPBA are 3.9%, 3.2%, and 1.5%, respectively, which is partially evidenced by the variation trend of calculated binding energy (0.47 eV for INPDT, 0.38 eV for INPOD, 0.32 or 0.27 eV for INPBA).