Strong and efficient doping of monolayer MoS by a graphene electrode.

The efficient manipulation of the optoelectronic properties of layered semiconductors is essential for future applications of these unique materials. Here, we demonstrate that single-layer, large-area graphene can serve as a conductive spacer between an electrolyte solution and single-layer MoS2. In situ Raman and photoluminescence (PL) spectroscopies were employed to monitor the charge transfer from graphene to MoS2.