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

Abstract

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 (Voc = 0.89 V, Jsc = 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.