Zhao Zhuo, Fang Fang, Wu Junsheng, Tong Xinru, Zhou Yanwen, Lv Zhe, Wang Jian, Sawtell David
School of Chemical Engineering, University of Science and Technology Liaoning, Anshan 114051, China.
Research Institute of Surface Engineering, University of Science and Technology Liaoning, Anshan 114051, China.
Materials (Basel). 2021 May 11;14(10):2481. doi: 10.3390/ma14102481.
Research on the preparation and performance of graphene composite materials has become a hotspot due to the excellent electrical and mechanical properties of graphene. Among such composite materials, zinc oxide/graphene (ZnO/graphene) composite films are an active research topic. Therefore, in this study, we used the vacuum thermal evaporation technique at different evaporation voltages to fabricate an amorphous ZnO/graphene composite film on a flexible polyethylene terephthalate (PET). The amorphous ZnO/graphene composite film inherited the great transparency of the graphene within the visible spectrum. Moreover, its electrical properties were better than those of pure ZnO but less than those of graphene, which is not consistent with the original theoretical research (wherein the performance of the composite films was better than that of ZnO film and slightly lower than that of graphene). For example, the bulk free charge carrier concentrations of the composite films (0.13, 1.36, and 0.47 × 10 cm corresponding to composite films with thicknesses of 40, 75, and 160 nm) were remarkably lower than that of the bare graphene (964 × 10 cm) and better than that of the ZnO (0.10 × 10 cm). The underlying mechanism for the abnormal electrical performance was further demonstrated by X-ray photoelectron spectroscopy (XPS) detection and first-principles calculations. The analysis found that chemical bonds were formed between the oxide (O) of amorphous ZnO and the carbon (C) of graphene and that the transfer of the π electrons was restricted by C=O and C-O-C bonds. Given the above, this study further clarifies the mechanism affecting the photoelectric properties of amorphous composite films.
由于石墨烯具有优异的电学和力学性能，石墨烯复合材料的制备及性能研究已成为一个热点。在这类复合材料中，氧化锌/石墨烯（ZnO/石墨烯）复合薄膜是一个活跃的研究课题。因此，在本研究中，我们使用真空热蒸发技术，在不同的蒸发电压下，在柔性聚对苯二甲酸乙二醇酯（PET）上制备了非晶态的ZnO/石墨烯复合薄膜。该非晶态ZnO/石墨烯复合薄膜在可见光范围内继承了石墨烯的高透明度。此外，其电学性能优于纯ZnO，但低于石墨烯，这与最初的理论研究不一致（其中复合薄膜的性能优于ZnO薄膜且略低于石墨烯）。例如，复合薄膜（对应厚度为40、75和160 nm的复合薄膜，其体自由电荷载流子浓度分别为0.13、1.36和0.47×10 cm）显著低于裸石墨烯（964×10 cm）且优于ZnO（0.10×10 cm）。通过X射线光电子能谱（XPS）检测和第一性原理计算进一步证明了异常电学性能的潜在机制。分析发现，非晶态ZnO的氧化物（O）与石墨烯的碳（C）之间形成了化学键，并且π电子的转移受到C=O和C-O-C键的限制。鉴于此，本研究进一步阐明了影响非晶态复合薄膜光电性能的机制。
