Nano-engineering the material structure of preferentially oriented nano-graphitic carbon for making high-performance electrochemical micro-sensors
Nano-engineering the material structure of preferentially oriented nano-graphitic carbon for making high-performance electrochemical micro-sensors
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DOI：
10.1038/s41598-020-66408-9
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发表时间：
2020-06-10
影响因子：
4.6
通讯作者：
Shahrjerdi, Davood
中科院分区：
文献类型：
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作者：
Cuniberto, Edoardo;Alharbi, Abdullah;Shahrjerdi, Davood
在氧化硅衬底上直接合成薄膜碳纳米材料为构建高性能的小型化（微米级）电化学传感器提供了一条可行的途径。然而，材料合成通常涉及许多参数，使得基于试错法的材料工程效率极低。在这里，我们报告了一种双管齐下的策略来生产具有纳米石墨结构的工程薄膜碳纳米材料。首先，我们介绍了金属诱导石墨化技术的一种变体，该技术直接在氧化硅衬底上生成纳米石墨碳材料的微米级岛屿。我们材料合成的一个新特点是，通过衬底工程，薄膜内石墨平面的方向优先与硅衬底对齐。这一特征使我们能够使用拉曼光谱来量化传感器表面的结构特性，电化学过程发生在那里。其次，我们找到了用于预测氧化还原电流和传感器电容从材料结构的振幅的现象学模型，通过拉曼量化。我们的研究结果表明，从纳米石墨碳中获得高性能微传感器的关键是增加点缺陷的密度和石墨晶体的尺寸。本研究为构建高性能的平面电化学微传感器提供了一种可行的策略。
Direct synthesis of thin-film carbon nanomaterials on oxide-coated silicon substrates provides a viable pathway for building a dense array of miniaturized (micron-scale) electrochemical sensors with high performance. However, material synthesis generally involves many parameters, making material engineering based on trial and error highly inefficient. Here, we report a two-pronged strategy for producing engineered thin-film carbon nanomaterials that have a nano-graphitic structure. First, we introduce a variant of the metal-induced graphitization technique that generates micron-scale islands of nano-graphitic carbon materials directly on oxide-coated silicon substrates. A novel feature of our material synthesis is that, through substrate engineering, the orientation of graphitic planes within the film aligns preferentially with the silicon substrate. This feature allows us to use the Raman spectroscopy for quantifying structural properties of the sensor surface, where the electrochemical processes occur. Second, we find phenomenological models for predicting the amplitudes of the redox current and the sensor capacitance from the material structure, quantified by Raman. Our results indicate that the key to achieving high-performance micro-sensors from nano-graphitic carbon is to increase both the density of point defects and the size of the graphitic crystallites. Our study offers a viable strategy for building planar electrochemical micro-sensors with high-performance.