Molecular-engineering of Tb2O3@TiO2 complexes sensitized with N719 dye photoanodes and evaluation of their realistic efficiencies in DSSC systems

Abstract

Solar energy is a promising replacement for rapidly depleting, non-renewable fossil fuel resources. For the efficient capture and use of solar energy, we fabricated new unconventional N719 dye-sensitized solar cells (DSSC) based on Tb2O3@TiO2 nanoparticles (NPs) with crystallite sizes in the range of 5–10 nm. The effect of loading concentrations of Tb2O3 (e.g., 0.001 to 0.010 M) on the photovoltaic performance of DSSC@Tb2O3-TiO2 complexes was assessed for comparison with that of a pristine TiO2 photoanode under simulated solar light (100 mW/cm2). Furthermore, the solar energy conversion of Tb2O3@TiO2 NPs was studied and explained in relation to their photoluminescence, photocatalytic, and surface properties. A 22% improvement in the efficiency was achieved for incident photon capture and electricity conversion in the DSSC-Tb2O3@TiO2 photoanode (at 0.001 M Tb2O3) as compared with the TiO2-based photoanode (η= 1.88 vs. 1.54). Tb2O3@TiO2 is thus demonstrated to have improved photoelectrochemical properties with enhanced charge carrier separation based on the high adsorption capability (against sensitized N719 dye: 1.74 × 10–7 mol/cm2) and photocurrent density (6.13 mA/cm2) (e.g., relative to pristine TiO2 (1.01 × 10–7 mol/cm2 and 4.66 mA/cm2, respectively). Therefore, the prepared Tb2O3@TiO2 NPs are recommended for use in photoanode applications to achieve highly efficient up-conversion of solar energy.