Synthesis and application of tungsten trioxide nanostructures by doping the active layer of PM6:Y7-based solar cells

Abstract

Different hydrothermal syntheses of tungsten trioxide (WO3) were used to modify the reaction conditions to achieve morphologies, sizes, and optoelectronic properties suitable for application in organic solar cells (OSCs). The nanostructures showed variations in their size and morphology, as confirmed by TEM. A band-gap modulation was attributed to the temperature and reaction time synthesis parameters. The nanostructures obtained at 180 °C for 4 h were highlighted due to their size range of 14–20 nm and a band-gap energy of about 2.7 eV; these nanostructures were incorporated in the active layer of OSCs based on PM6:Y7 at the concentrations of 0.5%, 1.0%, and 2% by volume. The average power conversion efficiency (PCE) of solar cells was 9.8% (with the best device reaching a PCE of 9.8%) at a 0.5% concentration, while the average PCE for control (without WO3) solar cells was 9.0% (with the best device reaching a PCE of 9.2%), reflecting a 8.9% increase for the doped OSCs.