Au-doped mesoporous SiO2 scattering layer enhances light harvesting in quasi Solid-State dye-sensitized solar cells

This study investigates the morphological effect of different Au-doped SiO₂ scattering layers on the performance of dye-sensitized solar cells (DSSCs). Particularly, the SiO₂ sources were varied to yield different geometries, i.e., tetraethyl orthosilicate (TEOS) templated SiO₂, Sidoarjo mud (LuSi) extracted SiO₂, and commercial silica glass sphere. The microstructure, as well as physical, electronic, and optical properties of different Au-doped SiO₂ particles, were characterized using SEM-EDX, TEM, BET, XRD, and various spectroscopy techniques. The photoelectrochemical performance of quasi-solid state DSSCs was indicated by current density–voltage (J-V) response, external quantum efficiency spectra, and the impedance response. The results indicate that the performance of TiO₂-based DSSCs is enhanced quite significantly due to the improved photocurrent generation and fill factor. The short circuit current density is found up to 370% higher (and hence, the conversion efficiency) than the reference cell upon incorporating Au-doped crystalline SiO₂ extracted from LuSi (V_oc = 0.89 V, J_sc = 1.28 mA‧cm⁻², FF = 0.65, and η = 0.75%). This substantial photocurrent enhancement stems from the combined effect of efficient light scattering by submicron SiO₂ particles, surface plasmon resonance, and reduced interfacial recombination by SiO₂ insulation. In addition, the optimum size of SiO₂ particles is deduced as the results indicate the size-scattering dependency which controls the gain and loss of photocurrent due to the type of scattering.