Graphene, with its outstanding electrical properties, has appealed to the attention of researchers all over the world for biosensing applications. So far, much of the research has been conducted on the field-effect modulations of carriers in the basal plane of graphene after adsorbing charged biomolecules. However, another essential aspect--the graphene edge--has been largely ignored due to the difficulties in both manufacture and characterization. Here, we propose a facile intercalation and pressure sintering approach that enables the fabrication and exposure of only graphene edges. The quantum capacitance of the exposed edges is proportional to the local density of state (DOS) and can be harvested for biochemical sensing. Notably, due to fringe electric field enhancement and biomolecular convergence at the one-dimensional graphene edges, we are able to detect four representative amino acids at 0.01 fg/mL concentrations within several minutes. These achievements in innovative quantum capacitance measurements of graphene edges, combined with simple and robust device fabrication by eliminating complex micro-nano processing, offer a new avenue for the next generation of biochemical sensors with ever-demanding sensitivities.

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石墨烯边缘的超灵敏量子电容探测器

石墨烯以其优异的电学性能，在生物传感应用方面引起了全世界研究人员的关注。到目前为止，大部分研究都是针对吸附带电生物分子后石墨烯基面载流子的场效应调制进行的。然而，由于制造和表征方面的困难，另一个重要方面——石墨烯边缘——在很大程度上被忽视了。在这里，我们提出了一种简便的插层和压力烧结方法，可以仅制造和暴露石墨烯边缘。暴露边缘的量子电容与局域态密度 (DOS) 成正比，可用于生化传感。值得注意的是，由于一维石墨烯边缘的边缘电场增强和生物分子会聚，我们能够在几分钟内检测到 0.01 fg/mL 浓度的四种代表性氨基酸。这些在石墨烯边缘的创新量子电容测量方面取得的成就，与通过消除复杂的微纳米处理而实现的简单而稳健的器件制造相结合，为具有不断要求的灵敏度的下一代生化传感器提供了新的途径。