Modifications to the Scattering Layer of a Dye-Sensitized Solar Cell Photoanode With Bifunctional WO3 Hollow Spheres for Increased Electron Transfer and Scattering Effect

Tungsten trioxide (WO
$_{{3}}{)}$
has already been researched and used in dye-sensitized solar cells (DSSCs) manufacturing, due to its energy band matching with titanium dioxide (TiO
$_{{2}}{)}$
and its high electron mobility. This study fabricates WO3 hollow spheres (WHSs) using the hydrothermal approach and mixes these with TiO2 in different weight percentage concentrations (1, 3, and 5 wt%). The resulting composite was used to create a scattering layer colloid for a DSSC photoanode. Using AM1.5G (100 mW/cm
$^{{2}}{)}$
light source to measure the photovoltaic parameters, it was found that the DSSC efficiency with the WHS 3% was 31.3% higher than that of bare TiO2. Short-circuit current density (
${J}_{\text {SC}}{)}$
was also increased, by 27%. The scattering ability of the various photoanodes was analyzed by diffused reflectance spectroscopy, and it was discovered that the addition of WHS effectively improved the light harvesting efficiency (LHE) of DSSCs. Electrochemical impedance spectroscopy (EIS) revealed that the addition of WHS effectively reduced electron transfer impedance at the photoanode. By quantum efficiency measurements, it was confirmed that the improved scattering ability and the high electron transfer ability had a positive effect on improving the
${J}_{\text {SC}}$
of DSSCs.