Researchers from Vanderbilt say they now understand for certain why graphene is so sensitive to its electrical environment. Solving this issue will allow to have better electron mobility in graphene at room-temperature, and come close to graphene's theoretical (but not practical) high electron mobility.
The problem is charged impurities on the surface of graphene. This was suspected before, but is now confirmed. Now the challenge will be to make graphene without those charged impurities.