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Ultrathin, long-term stable, solid-state reference electrode enabled by enhanced interfacial adhesion and conformal coating of AgCl.

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Title: Ultrathin, long-term stable, solid-state reference electrode enabled by enhanced interfacial adhesion and conformal coating of AgCl.
Authors: Lim, Hyo-Ryoung1 (AUTHOR), Hillman, Nathan1 (AUTHOR), Kwon, Young-Tae1 (AUTHOR), Kim, Yun-Soung1 (AUTHOR), Choa, Yong-Ho2 (AUTHOR), Yeo, Woon-Hong1,3 (AUTHOR) whyeo@gatech.edu
Source: Sensors & Actuators B: Chemical. Apr2020, Vol. 309, pN.PAG-N.PAG. 1p.
Subjects: Standard hydrogen electrode, Conformal coatings, Adhesion, Surfaces (Technology), Silver chloride, Glucose oxidase, Composite membranes (Chemistry)
Abstract: • Ultrathin (800 nm) solid-state reference electrode (RE) demonstrates a long-term stability for two weeks. • The combination of enhanced interfacial adhesion and uniform coating of AgCl offers high stability. • Voltage response in a saline solution shows a change of 0.09 mV/h for 18 days. • Time-dependent EIS study shows enhanced interfacial stability of the fabricated RE. Continuous biochemical monitoring with a flexible electrochemical sensor offers a new wearable electronic system that can measure real-time voltage and current signals. The signal quality is determined by long-term stability of a silver/silver chloride reference electrode (Ag/AgCl RE). However, it is very challenging for any solid-state electrode to have a long-term stable operation. Even though new membrane technologies have improved the voltage stability, the existing thin film Ag/AgCl REs have limitations of insufficient film adhesion and structural instability. Here, this paper introduces an ultrathin, all-solid-state RE that demonstrates a long-term functional stability for more than two weeks via enhanced interfacial adhesion and conformal coating of AgCl. An optimization of chlorination factors allows a highly uniform, 800 nm-thick RE surface. The voltage response of the sensor in a saline solution shows a change of 0.09 mV/h for 18 days with a quasi-stable behavior, capturing the potential as an amperometric biosensor. Moreover, the characterization with an enzymatic working electrode verifies that two-electrode system using the thin-film RE has a sensitivity (S = 606 nA·mmol−1. cm−2), compatible to that with a commercial RE (S = 532 nA·mmol−1. cm−2). Collectively, this work provides a comprehensive study of materials and surface functionalization of all-solid-state REs for thin-film biosensors, which will pave the way for long-term usable wearable biosystems. [ABSTRACT FROM AUTHOR]
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Database: Engineering Source
Description
Abstract:• Ultrathin (800 nm) solid-state reference electrode (RE) demonstrates a long-term stability for two weeks. • The combination of enhanced interfacial adhesion and uniform coating of AgCl offers high stability. • Voltage response in a saline solution shows a change of 0.09 mV/h for 18 days. • Time-dependent EIS study shows enhanced interfacial stability of the fabricated RE. Continuous biochemical monitoring with a flexible electrochemical sensor offers a new wearable electronic system that can measure real-time voltage and current signals. The signal quality is determined by long-term stability of a silver/silver chloride reference electrode (Ag/AgCl RE). However, it is very challenging for any solid-state electrode to have a long-term stable operation. Even though new membrane technologies have improved the voltage stability, the existing thin film Ag/AgCl REs have limitations of insufficient film adhesion and structural instability. Here, this paper introduces an ultrathin, all-solid-state RE that demonstrates a long-term functional stability for more than two weeks via enhanced interfacial adhesion and conformal coating of AgCl. An optimization of chlorination factors allows a highly uniform, 800 nm-thick RE surface. The voltage response of the sensor in a saline solution shows a change of 0.09 mV/h for 18 days with a quasi-stable behavior, capturing the potential as an amperometric biosensor. Moreover, the characterization with an enzymatic working electrode verifies that two-electrode system using the thin-film RE has a sensitivity (S = 606 nA·mmol−1. cm−2), compatible to that with a commercial RE (S = 532 nA·mmol−1. cm−2). Collectively, this work provides a comprehensive study of materials and surface functionalization of all-solid-state REs for thin-film biosensors, which will pave the way for long-term usable wearable biosystems. [ABSTRACT FROM AUTHOR]
ISSN:09254005
DOI:10.1016/j.snb.2020.127761