利用等离子体处理单层石墨烯, 并制成pH传感器, 通过接触角仪、拉曼光谱仪、X射线光电子能谱仪、原子力显微镜表征石墨烯处理前后微观结构, 探究等离子体处理对石墨烯pH传感器灵敏度的影响。随等离子体处理时间增加接触角逐渐减小,亲水性提高。在拉曼光谱中, 处理后的石墨烯出现了D和D′两个明显的缺陷峰, 同时2D峰宽化。分析X射线光电子能谱, 确定了缺陷的类型和引入的含氧官能基团类型。运用原子力显微镜研究了处理前后石墨烯的微观形貌, 发现处理后石墨烯的面粗糙度增加。在最佳条件下, 等离子体处理的石墨烯pH传感器灵敏度较未处理之前提升了约300%。

We report a process for the functionalization of graphene prepared by chemical vapor deposition with plasma treatment. A pH sensor is prepared by the treated graphene. The micro-structure of graphene before and after plasma treatment is investigated by contact angle meter, Raman spectrometer, X-ray photoelectron spectroscope and atomic force microscope. With plasma treatment time increased, the contact angle with water droplet is gradually reduced. Raman spectroscope result indicates the D and D′ defect peaks start to merge and 2D peak is suppressed and broadened. In the X-ray photoelectron spectroscopy, plasma treatment leads to the oxygenated functional groups on the graphene surface. It is found that surface roughness of graphene is increased after plasma treatment. Under the optimized conditions, the sensitivity of graphene pH sensor with plasma treatment can be improved by 3 times.