Resaerchers from Japan's National Institute for Materials Science (NIMS) developed a method to tune the band-gap of graphene oxide. The new method changes the bonding state of carbon atoms that compose graphene through reversible absorption and desorption of oxygen atoms on the graphene, and tuning the band-gap in situ.
The researchers say that this method enables band-gap tuning in a non-volatile manner - the tuned band-gap continues to exist even when voltage supply is stopped. To control the absorption and desorption of oxygen atoms on the graphene, the group used solid electrolytes in which hydrogen ions can move, thereby causing electrochemical reactions between oxygen atoms, which are chemically bonded to the graphene, and hydrogen ions.