Synthesis, Characterization and Application of Organic Dye-Sensitized Silver and Zinc doped NiO Nanoparticles in DSSC

Abstract

In this research work, the pure and transition metals (Silver and Zinc) doped NiO NPs were successfully synthesized by using the Co-precipitation method. The characterization of as-synthesized nanoparticles was done by UV-Visible spectroscopy, x ray diffraction (XRD), Fourier Transform Infrared spectroscopy (FTIR), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray spectroscopy (EDX), and I-V characterization. The optical properties of as-synthesized NPs were studied by UV-Visible spectroscopy and resulted absorption spectra thus obtained revealed that with the increase in dopants percentage from 1-5%, a red shift (Amax shifted towards longer wavelength) in the spectra was observed. To find the band gaps of pure and doped nanoparticles, Tauc's plots were used, and it shows tuning in band gaps for all doped nanoparticles. The band gap of pure NiO NPs was observed to be 3.17 eV which was tuned up to about 2.10 eV due to Ag and 2.00 eV due to Zn dopants. To estimate the average crystallite size and the purity of nanomaterial X-ray diffraction analysis was used. XRD analysis confirmed the formation of face centered cubic crystalline structure of NiO and its high degree of crystalline nature. The morphological changes in nanostructured material were analyzed by SEM studies. Some clusters of spherical and somewhat oval nanoparticles are visible in the SEM picture. The elemental composition of nanostructured material was analyzed by EDX studies. EDX studies revealed the presence of Ni, 0, Ag and Zn along with some extra peaks of impurities such as C, and Cl. FTIR studies helped in detecting the specific vibrational bands. Three cost effective and commercially available organic dyes (Carminic Acid, Coomassie Violet R200, Arsenazo III) were selected and investigated to be used as photo sensitizers for DSSCs (dye-sensitized solar cells). The FTIR peak for the -COOH functionality in the case of Carminic acid and -S03H group in the case of Coomassie violet R200 and Aesenazo III get vanished in the nanohybrid spectrum compared to pure dye, demonstrating efficient functionalization (grafting) of the nanoparticles with the corresponding dyes. The nanohybrid materials thus formed were used as semiconducting working electrode in DSSCs. To overcome the problems offered using liquid electrolyte, an organic hole conducting polymer (P3HT) was employed as a solid electrolyte in solid state DSSCs. The results obtained from above studies revealed that among all the fabricated devices, the greatest efficiency was acquired for devices sensitized with Arsenazo III in solid-state-DSSCs. For DSSC based on Carminic acid dye sensitized Ag-NiO the efficiency was obtained to be 0.40% with Jsc of 3.10 mA/cm2 and V oc of 0.31 V. For Arsenazo III dye sensitized Ag-NiO based DSSC, the maximum efficiency was observed to be 1.03% with Jsc of7.90 mA/cm2 and Voc of 0.31 V, as compared to the reference cell (0.07%).