Oxygen-promoted synthesis of armchair graphene nanoribbons on Cu(111)

We report the systematic investigation of the effects of oxygen on the synthesis of 3 p sub-family armchair graphene nanoribbons (3 p -AGNRs), which revealed a strong catalytic effect with a reduction in the reaction temperature by approximately 180 K without degradation of the AGNRs. Poly(para-phenylene) (3-AGNR) was generated through Ullmann-type coupling of 4,4″-dibromo- p -terphenyl on Cu(111), which was then converted into wider 3 p -AGNRs via lateral fusion. Scanning tunneling microscopy (STM) and X-ray photoelectron spectroscopy demonstrated the formation of different ribbons up to 12-AGNR, which contained regions exhibiting increased STM contrast that we attribute to the intercalation of Br atoms during lateral fusion.