Enhanced thermal stability of reduced graphene oxide-Silicon Schottky heterojunction solar cells via nitrogen doping

We investigated the thermal stability and electrical properties of nitrogen-doped reduced graphene oxide (NrGO)/n-type Si solar cells. A NrGO layer was used as a transparent electrode as well as an electron-hole separation layer simultaneously. The effect of doping on the carbon and nitrogen bonding configurations in NrGO was investigated using X-ray photoelectron spectroscopy (XPS). The XPS data indicate that pyridinic-N is the dominant bonding configuration. This bonding configuration leads to a reduction in the power conversion efficiency and a decrease in the short circuit current. However, on being subjected to thermal oxidation, the NrGO/n-type Si solar cells exhibit a smaller variation in series resistance compared to the undoped rGO/Si solar cells. Results of accelerated thermal tests suggest that nitrogen doping prevents re-oxidation of the reduced graphene oxide layer.