Enhanced Photoelectronic Currents by the Self-Assembled Hybrid Layers of Graphene Oxide Quantum Dot and Liquid Exfoliated Graphene

Graphene oxide quantum dots (GOQD) attract great attention for their unique photo-electronic property and promising application potential. However, how to effectively separate the photogenerated carriers of GOQD is still a challenge which need to be overwhelmed for its application as a photoelectrochemical component. Herein, a hybrid film of liquid exfoliated graphene (LEG) with graphene oxide quantum dots (LEG@GOQD) was prepared. The enhanced photocurrents in the LEG@GOQD based device were evidenced in comparison with the only graphene oxide quantum dots (GOQD) based counterpart. It was found, the value of the photocurrent obtained by the LEG@GOQD based device can reach 2.95 μA, while the response time can be 160 ms, respectively. The explanation for the enhanced current is proposed, based on the measured energy band structure of GOQD by the linear sweep voltammetry method and the builtin electric field formed at the interface of GOQD and LEG (Ei). That is to say, the photo generated carriers in the GOQD layer are separated by Ei, transferred to the LEG layer and result in enhanced current. We believe the hybrid LEG and GOQD may be a practicable solution for promoting GOQDs’ application in photo-electrochemistry.