The influences of Ni, Ag-doped TiO2 and SnO2, Ag-doped SnO2/TiO2 nanocomposites on recombination reduction in dye synthesized solar cells

Abstract

In this work, the effects of doped nanoparticles (NPs) and nanocomposites (NCs) such as SnO2/TiO2 NCs, Ni-doped TiO2 NPs, Ag-doped TiO2 NPs and Ag-doped SnO2/TiO2 NCs as photoanode on the performance of Dye synthesized Solar Cells (DSSCs) were studied. The compounds were successfully synthesized using hydrothermal and sol-gel methods. XRD was used to examine the crystalline structures and the effects of dopants and nanocomposites on the crystal form of TiO2. Moreover, FE-SEM and TEM analysis showed that the produced NPs and NCs were porous and their shape, size and dispersion degree were different. Furthermore, by using FTIR spectra, the chemical species of the grown crystals were identified. Besides, variations band-gap were observed through the analysis of optical absorption spectra. In addition, EIS was used to analyze the effect of dopants and nanocomposites TiO2 on charge transfer resistance in the DSSCs. These studies indicated that the DSSCs photovoltaic properties largely depend on the compounds and structure of photoanodes. To this end, the current-voltage characteristics and Incident Photon-to-electron Conversion Efficiency (IPCE) measurements were used to evaluate the performance of DSSCs. As seen, while the conversion efficiency of the DSSC samples varies from 1.2 to ~6.93%, the DSSC-based on Ag-doped SnO2/TiO2 exhibit the highest conversion efficiency, i.e., 6.93%. It is owing to its lower charge transfer resistance, recombination and higher short-circuit photocurrent.