Microwave flash synthesis of phosphorus and sulphur ultradoped graphene

Graphene, sp²-hybridized miracle material of 21st century possesses extra-ordinary physico-chemical properties and hence inspires several salient frontline applications. Lack of magnetic ordering limits its dream spintronic chips applications. Phosphorus and sulfur being large and electron-rich atoms, if adequately doped to graphene, will enable carrier injection (worth for electronic chips) and net spin-polarized electrons (worth for spintronic chips) in it. However, in-plane (preferentially) ultra-doping of graphene by phosphorus and sulfur is extremely challenging by conventional techniques. We report microwave doping of graphene by phosphorus and sulfur atoms up to record doping level of 15 and 12.5 % respectively which render graphene room temperature ferromagnetism with a saturation magnetization as high as 0.13 emu/g and 0.15 emu/g for phosphorus and sulfur doping “respectively”. Spin-polarized DFT band structure calculations suggest vivid spin asymmetry caused by doping which supports our experimental findings of primarily graphitic doped samples. Microwave doping of graphene by phosphorus and sulfur brings in dramatic changes in its magnetic behaviour and thus the present research establishes it as a novel doping strategy with excellent efficiency, scalability, and reproducibility, and will inspire new generations of graphene-based spintronic chips.