Zhuang Wen, Jang Hyun-June, Sui Xiaoyu, Ryu Byunghoon, Wang Yuqin, Pu Haihui, Chen Junhong
Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois 60637, United States.
Chemical Sciences and Engineering Division, Physical Sciences and Engineering Directorate, Argonne National Laboratory, Lemont, Illinois 60439, United States.
ACS Appl Mater Interfaces. 2024 May 29;16(21):27961-27968. doi: 10.1021/acsami.4c03999. Epub 2024 May 15.
Two-dimensional nanomaterials such as reduced graphene oxide (rGO) have captured significant attention in the realm of field-effect transistor (FET) sensors due to their inherent high sensitivity and cost-effective manufacturing. Despite their attraction, a comprehensive understanding of rGO-solution interfaces (specifically, electrochemical interfacial properties influenced by linker molecules and surface chemistry) remains challenging, given the limited capability of analytical tools to directly measure intricate solution interface properties. In this study, we introduce an analytical tool designed to directly measure the surface charge density of the rGO-solution interface leveraging the remote floating-gate FET (RFGFET) platform. Our methodology involves characterizing the electrochemical properties of rGO, which are influenced by adhesion layers between SiO and rGO, such as (3-aminopropyl)trimethoxysilane (APTMS) and hexamethyldisilazane (HMDS). The hydrophilic nature of APTMS facilitates the acceptance of oxygen-rich rGO, resulting in a noteworthy pH sensitivity of 56.8 mV/pH at the rGO-solution interface. Conversely, hydrophobic HMDS significantly suppresses the pH sensitivity from the rGO-solution interface, attributed to the graphitic carbon-rich surface of rGO. Consequently, the carbon-rich surface facilitates a denser arrangement of 1-pyrenebutyric acid -hydroxysuccinimide ester linkers for functionalizing capturing probes on rGO, resulting in an enhanced sensitivity of lead ions by 32% in our proof-of-concept test.
诸如还原氧化石墨烯（rGO）之类的二维纳米材料因其固有的高灵敏度和具有成本效益的制造工艺，在场效应晶体管（FET）传感器领域引起了广泛关注。尽管它们具有吸引力，但鉴于分析工具直接测量复杂溶液界面性质的能力有限，全面了解rGO-溶液界面（特别是受连接分子和表面化学影响的电化学界面性质）仍然具有挑战性。在本研究中，我们引入了一种分析工具，旨在利用远程浮栅FET（RFGFET）平台直接测量rGO-溶液界面的表面电荷密度。我们的方法包括表征rGO的电化学性质，这些性质受SiO和rGO之间的粘附层影响，例如（3-氨丙基）三甲氧基硅烷（APTMS）和六甲基二硅氮烷（HMDS）。APTMS的亲水性有助于接受富氧的rGO，导致rGO-溶液界面处的pH灵敏度达到56.8 mV/pH，值得注意。相反，疏水性HMDS显著抑制了rGO-溶液界面的pH灵敏度，这归因于rGO富含石墨碳的表面。因此，富含碳的表面有利于1-芘丁酸-羟基琥珀酰亚胺酯连接体更密集地排列，用于在rGO上功能化捕获探针，在我们的概念验证测试中，铅离子的灵敏度提高了32%。
