Institute of Modern Physics, Chinese Academy of Sciences , Lanzhou 730000, China.
University of Chinese Academy of Sciences , Beijing 100049, China.
ACS Appl Mater Interfaces. 2017 Mar 29;9(12):11000-11008. doi: 10.1021/acsami.6b16736. Epub 2017 Mar 15.
Graphene is an ideal candidate for the development of solid state nanopores due to its thickness at the atomic scale and its high chemical and mechanical stabilities. A facile method was adopted to prepare single graphene nanopore supported by PET membrane (G/PET nanopore) within the three steps assisted by the swift heavy ion irradiation and asymmetric etching technology. The inversion of the ion rectification effect was confirmed in G/PET nanopore while comparing with bare PET nanopore in KCl electrolyte solution. By modifying the wall charge state of PET conical nanopore with hydrochloric acid from negative to positive, the ion rectification effect of G/PET nanopore was found to be greatly enhanced and the large rectification ratio up to 190 was obtained during this work. Moreover, the high ionic flux and high ion separation efficiency was also observed in the G/PET nanopore system. By comparing the "on" and "off" state conductance of G/PET nanopore while immersed in the solution with pH value lower than the isoelectric point of the etched PET (IEP, pH = 3.8), the voltage dependence of the off conductance was established and it was confirmed that the large rectification effect was strongly dependent on the particularly low off conductance at higher applied voltage.
石墨烯因其原子级厚度和高化学及机械稳定性，是用于制备固态纳米孔的理想候选材料。本工作采用 swift 重离子辐照辅助的三步法制备了由 PET 膜支撑的单石墨烯纳米孔（G/PET 纳米孔），该方法结合了不对称刻蚀技术。在 KCl 电解质溶液中，与裸 PET 纳米孔相比，G/PET 纳米孔的离子整流效应发生了反转。通过将盐酸修饰的 PET 锥形纳米孔的壁电荷状态从负变为正，发现 G/PET 纳米孔的离子整流效应得到了极大增强，在这个过程中获得了高达 190 的大整流比。此外，在 G/PET 纳米孔体系中还观察到了高离子通量和高离子分离效率。通过比较 G/PET 纳米孔在浸入 pH 值低于刻蚀 PET 的等电点（IEP，pH = 3.8）的溶液时的“开”和“关”状态电导，建立了关态电导与电压的关系，并证实了大的整流效应强烈依赖于在较高外加电压下特别低的关态电导。
