Ag-nanowires-doped graphene/Si Schottky-junction solar cells encapsulated with another graphene layer

Graphene/silver nanowires (Ag NWs)-doped graphene stacks are employed for Si Schottky-junction solar cells as transparent conductive electrodes (TCEs). The doping of graphene by Ag NWs decreases the series resistance of the solar cells and enhances the electrical conductivity of the graphene TCEs, resulting in remarkable improvements of the diode properties of the solar cells. In addition, the Ag NWs on the graphene reduces the reflectance of the solar cells as well as the transmittance of the graphene TCEs. This trade-off correlation makes the power-conversion efficiency maximized to 3.51% at concentration of Ag NWs (n_A) = 0.1 wt%. The long-term stabilities of the photovoltaic properties are greatly improved by the encapsulation of the Ag NWs/graphene TCEs with another graphene because of the excellence of graphene as a gas-barrier. These and other n_A-dependent behaviors of Raman spectra, work function, sheet resistance, external quantum efficiency, and DC conductivity/optical conductivity ratio are discussed to explain the photovoltaic properties of the solar cells.