Enhancement of Dye-sensitized Solar Cells Efficiency Using Graphene Quantum Dots as Photoanode

Dye-sensitized solar cell (DSSC) is a candidate to substitute conventional photovoltaic devices due to efficiency, cost in comparison with silicon devices. In this report, graphene quantum dots have attracted considerable potential merit for the development of photo-electrodes of dye-sensitized photovoltaic cells. The incorporation of graphene quantum dots into DSSCs photo-electrodes induced lower recombination, enhanced electron transport, increased light scattering. The conventional semiconductor quantum dots usually has surface defect and instable. To overcome such limitations, we have developed a hydrothermal synthesis process fabricating graphene quantum dots (GQD) with strong visible range emission. The reduced GOs graphene oxide (RGO) underwent sonication, heating, filtering, and dialysis producing GQD. Various sizes of GQDs with circular shape determined using scanning electron microscopy, high-resolution transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and photoluminescence were successfully fabricated. In addition, the impedance nyquist plot, the electron transport resistance was smallest and the incident photo to charge carrier efficiency (IPCE) was the maximum when the size of graphene quantum dots (5 nm) was used. Thus, the GQD with unique optical and structural properties can be a very attractive candidate for dye-sensitized solar cells, optoelectronics, active layer of display, and bio-imaging devices.