ABSTRACT
A comparative study has been attempted on 1-substituted 2-(pyridin-2-yl)-1H-benzo[d]imidazole ligand-coordinated copper and cobalt metal complex electrolytes Cu+/2+[nbpbi]2(PF6-)1/2, Cu+/2+[npbi]2(PF6-)1/2, Co2+/3+[nbpbi]3(PF6-)2/3, and Co2+/3+[npbi]3(PF6-)2/3 in dry acetonitrile coupled with both N3 and N719 dyes in dye-sensitized solar cell (DSSC) devices. Impressively, the copper metal sites coordinated with ligands nbpbi (L1) and npbi (L2) shift the redox potential about 190-200 mV and pave the way to achieve remarkably higher power current efficiency, which is clarified with cyclic voltammetry, electrochemical impedance spectrum, electron lifetime, and quasi Fermi-level experimental results. Overall efficiencies of 4.99, 4.82, 3.26, and 3.19% under 1 sun conditions (100 mW cm-2) were obtained for Cu+/2+[nbpbi]2(PF6-)1/2 and Cu+/2+[npbi]2(PF6-)1/2 electrolytes coupled with the sensitizers (N3 and N719 dyes), which are considerably higher than those acquired for devices containing the cobalt electrolytes. These results signify a record for copper complex-based electrolytes coupled with ruthenium dyes in liquid DSSCs. In particular, bulky acceptor 4-nitro benzyl moiety-substituted 2-(pyridin-2-yl)-benzimidazole (on the N-H position) (ligand L1)-coordinated copper metal complex electrolytes achieved higher efficiency, approaching a suitable redox potential of 0.68 V versus NHE. At the same time, the napthyl moiety-substituted 2-(pyridin-2-yl)-benzimidazole (ligand L2)-coordinated copper metal complex electrolytes showed less redox potential due to its donating nature. It was determined that the Jsc and PCE increment of the devices consisting of Cu+/2+[nbpbi]2(PF6-)1/2 electrolytes was mainly attributed to various factors such as higher chemical capacitance, larger charge, longer electron life time, a downward shift in the quasi Fermi level of TiO2, the slow recombination process, and fast dye regeneration. These results make easily tunable metal complexes bearing a new sort of 1-substituted 2-(pyridin-2-yl)-1H-benzo[d]imidazole ligand-based electrolytes as very promising copper electrolytes for further improvements of extremely efficient liquid DSSCs.
ABSTRACT
A bacterial and viral infection causes life threatening diseases owing to the abuse of antibiotics and the development of antibiotic resistance microbes. Currently, biopolymers have been considered as the most promising materials in the medical field. Herein, the biogenic chitosan-functionalized MoS2 nanocomposite was prepared by the hydrothermal method with the liquid exfoliation process. The X-ray diffraction (XRD) results of chitosan-MoS2 hybrid nanocomposite revealed that MoS2 nanoparticle was found to be 42 nm with a hexagonal crystal structure. FTIR and Raman spectrum revealed that the nitrogen functionalities in the chitosan interacted with MoS2 to form the nanocomposite. The XPS spectrum of chitosan-MoS2 nanocomposite confirms that C, N, O, Mo, and S exist in the nanocomposite. Thermal gravimetric analysis (TGA) and Differential thermal analysis (DTA) analysis showed that the chitosan-MoS2 nanocomposite has higher thermal stability up to 600 °C. In the antibacterial application the chitosan-MoS2 hybrid nanocomposite shows zones of inhibition against S. aureus as 22, 28, and 32 mm, and against E. coli as 26, 30, and 35 mm. In the anticancer analysis, chitosan-MoS2 hybrid nanocomposites showed a maximum cell inhibition of 65.45% at 100 µg/mL-1, resulting in the most significant MCF-7 cell inhibition.