A series of metal element (Al, Fe, Mg and Ni)-doped ZnO (M-ZnO) photocatalysts have been successfully synthesized on graphene-coated polyethylene terephthalate (GPET) flexible substrate via the hydrothermal method. The effects of doped metals in ZnO were also studied on the crystal structure, morphology and photocatalytic performance. The photocatalytic experiment results indicated that, compared with Al-, Mg- and Fe-ZnO/GPET photocatalysts under ultraviolet (UV) light irradiation, Ni-ZnO/GPET had better photocatalytic activity, and the degradation rate of methylene blue (MB) was 81.17%. Meanwhile, the mechanism of enhancing the photocatalytic activity of metal element-doped ZnO is also discussed. It is concluded that, after doping with metal elements, electrons and holes are prevented from recombination by trapping electrons of the ZnO/GPET conductive band, thereby improving the photocatalytic activity.

Based on flexible materials, optoelectronic devices with optoelectronic technology as the core and flexible electronic devices as the platform are facing new challenges in their applications, including material requirements based on functional electronic devices such as lightness, thinness, and impact resistance. However, there is still a big gap between the current preparation technology of flexible materials and practical applications. At present, the main factors restricting the more commercial development of flexible materials include preparation conditions and performance. In this work, B-N co-doped ZnO nanorod arrays (NRAs) were successfully synthesized on the polyethylene terephthalate (PET) substrate coated with indium tin oxide (ITO) by the hydrothermal method. Based on the density functional theory, the effect of B-N co-doping on the electronic structure of ZnO was calculated; the incorporation of B and N led to an increase in the lattice constant of ZnO. The B-N co-doped ZnO has obvious rectification characteristics with the positive conduction voltage of 2 V in the I–V curve.