Photovoltaic Performance of p-type Dye-Sensitised Solar Cells Based on Solid and Flexible Electrode Systems

The effect of carbon dots (C-dots) on the performance of nickel oxide nanoparticles (NiO NPs) based DSSCs were explored in this work. C-dots co-adsorbing with N719 dye on p-type semiconductor synergetically enhance the power conversion efficiency of solar cells. C-dots are the main sensitizer, and N719 tightly adsorbed on carbon dots and NiO behaves as an accelerator of a positive electron transfer and a restrainer of the electron-hole recombination. NiO NPs with a rectangular shape (average size: 11.4 x 16.5 nm) were mixed with C-dots, which were synthesized from CA and EDA. A photocathode consisting of a composite of NiO@C-dots was then used to measure the photovoltaic performance of a DSSC. A DSSC fabricated via the adsorption of N719 sensitizer co-adsorbing with a Cdot content of 12.5 wt % at a 1.5:1 EDA: CA molar ratio was achieved a 9.85 % (430 nm of a light source at 50m W/cm2 light of intensity) of power conversion efficiency (PCE). This synergetically higher PCE of the NiO@C-dots-based DSSC was due to the larger amount of sensitizer adsorbed onto the composites with a larger specific surface area and the faster charge transfer in the NiO@C-dots working electrode. The most important fact is that C-dots are the main sensitizer and that N719 tightly adsorbed on C-dots, and NiO behaves as an accelerator of a positive electron transfer and a restrainer of the electron-hole recombination. These results reveal that C-dots are a remarkable enhancer for NiO NPs in DSSCs.