Long-term air-stable Au doping of graphene by layer-by-layer assembly with graphene oxide for flexible transparent electrodes

In order to realize the most suitable hybrid structure for air-stable graphene-based transparent and flexible electrodes, we systematically compared graphene oxide (GO)/Au/graphene and graphene/Au/GO hybrid films fabricated by layer-by-layer assembly. The sheet resistance of graphene/Au/GO was proportional to the concentration of AuCl3 (1-5 mg/ml), which can be understood by a significant blue-shift in the G-band associated with the phonon stiffening. The size and density of formed Au nanoparticles strongly influenced their reduction reaction, which is a crucial factor for maximizing the doping effects. The optimized optical transmittance and sheet resistance of GO/Au/graphene were 94.9% and 198 ± 29 Ohm/sq, respectively. Furthermore, the hybrid films revealed stable doping effects (sheet resistance variation: 23-55%) against ambient conditions after 1 month. The variation in sheet resistance for GO/Au/graphene hybrid films corresponds to 30% with a bending radius of 10 mm after repeated bending tests (bending cycles of 105).

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