Incremental photocatalytic reduction of graphene oxide on vertical ZnO nanorods for ultraviolet sensing

Graphene oxide nanosheets were coated on thin films of vertical ZnO nanorods and incrementally reduced into rGO by the photocatalytic effect of ZnO for different times. The photocatalytic reduction (1) slightly decreased bandgap, considerably increased the ultraviolet absorption, and significantly enhanced the charge carrier separation in rGO-ZnO, while (2) increased the defects in rGO sheets. We tested the rGO/ZnO thin films for ultraviolet sensing and found that 60-min reduction is the optimal case. We discussed the result based on competition between the above (1) and (2) findings. (C) 2019 Elsevier B.V. All rights reserved.