Oxygen-incorporated few-layer MoS2 vertically aligned on three-dimensional graphene matrix for enhanced catalytic performances in quantum dot sensitized solar cells

An in situ hydrothermal method is employed to vertically grow Few-layer MoS2 (3-5 layers) sheets on three dimensional graphene. Oxygen atoms are spontaneously incorporated into the MoS2 layers due to the inert MoO bonds from the precursor and the abundant oxygen-content groups distributed on the graphene oxide sheets, which reduces the bandgap and improves the conductivity and catalyzing activity of the MoS2. In addition, the three dimensional composite exhibits good mechanical strength, interconnected electron transfer network, high surface area of 117.9 cm2 g−1, and multi-level porous structures from micro- to macro- scale, which enhances the charge and mass transport when used as counter electrode for quantum dot sensitized solar cells. Therefore, an optimized power conversion efficiency of 4.13% is demonstrated, indicating ∼63% and ∼34% enhancement compared with Pt and pure MoS2 counter electrodes.

An in situ wet method was employed to vertically grow few-layer MoS2 on 3D graphene. Thanks to the interconnected electron transport network, high SSA and multi-level porous structures, the CE materials show good conductivity, catalytic activity and high wettability for electrolyte diffusion, which gives rise to a higher PCE of 4.13% compared with that adopting Pt and pure MoS2 based CEs.273