Graphene-TiO2 for scattering layer in photoanodes of dye-sensitized solar cell

The scattering layer in the TiO2 photoanode (PAs) of dye-sensitized solar cells (DSSCs) is doped with single-layer graphene (G), and DSSC is prepared by doctor blade coating method. A small amount of graphene (0.0016 wt.%) in a graphene aqueous solution (G-AS) and a G-TiO2 paste was prepared to make 2-20 wt.% of G-AS in the deionized water (DIW). The UV-Vis measurement results show that the TiO2 scattering layers doped with graphene effectively improve the visible light absorption intensity of DSSC PAs and increase the current density (Jsc) from 13.84 mA/cm(2) to 16.20 mA/cm(2). The Electrochemical Impedance Spectroscopy (EIS) measurement showed that the internal structural impedance Rk (Omega) decreased from 12.086 (Omega) (without graphene doping) to 9.875 (Omega) at 5 wt.% of the graphene doping. The photoelectric conversion efficiency (PCE) increased from 6.56% of the original un-doped graphene to the maximum PCE value of 7.57% at 5 wt.%. The results show that the best PCE is obtained when the concentration of G-AS is 5 wt.%.

Automated summary

The study demonstrated that doping TiO2 scattering layers with graphene can effectively enhance visible light absorption and increase current density in DSSCs, showing potential for improving the photoelectric conversion efficiency.