Highly efficient (N-benzothiazolyl)-cyanoacetamide based co-sensitizers for high efficiency dye-sensitized solar cells

Four novels (N-benzothiazolyl)-cyanoacetamide-based metal-free dyes SA17-20 with D-pi-A architecture were designed and synthesized as co-sensitizers for HD-2 for dye-sensitized solar cells (DSSCs). They contain strong donating moieties of trimethoxybenzene and N,N-dimethylaniline conjugated with the nitrile function of cyanoacetamide part (NHCOCH2CN) as an anchoring group. The role of donor/acceptor in the cyanoacetamide-based structure motifs of SA17-20 in the co-adsorption properties was characterized and their influence on the optical and electrochemical properties was discussed. Consistent with the experimental results, the equilibrium molecular geometries calculated using density functional theory (DFT), at the B3LYP/ 6-31 G (d, p) level, demonstrated the effect of (N-benzothiazolyl)-cyanoacetamide structures on the photovoltaic performance. Co-sensitization technique mainly depends on the uniqueness of the donor-acceptor unit of the co-sensitizer being used. Using (N-benzothiazolyl)-cyanoacetamide cosensitizers with HD-2 showed improved power conversion efficiency (PCE) than HD-2 alone. HD2 was used because of its high efficiency, molar extinction coefficient and photocurrent densities. While HD-2 sensitizer alone displayed PCE of (7.46%), among the co-sensitizers, SA20, containing methoxythiazole and trimethoxybenzene as a donor part attached to (CN) and (CO) as anchoring components, exhibited the best PCE of (8.27%) with Jsc (19.25 mA/cm2) and Voc (0.68 V). These results demonstrated that (N-benzothiazolyl)-cyanoacetamide dyes SA17-20 are promising candidates for efficient DSSCs.

Automated summary

The study focused on the influence of the (N-benzothiazolyl)-cyanoacetamide structure on the co-adsorption properties of SA17-20, and discussed their effects on the optical and electrochemical properties.