strategies of miniaturised reference electrodes integrated in a silicon based “one chip” ph sensor小型的策略参考电极集成在基于硅的u201c芯片u201dph传感器.pdf

Sensors 2003, 3, 330-339 sensors ISSN 1424-8220 © 2003 by MDPI /sensors Strategies of Miniaturised Reference Electrodes Integrated in a Silicon Based “one chip” pH Sensor Anette Simonis 1,2, Hans Lüth 2, Joseph Wang 3, Michael J. Schöning 1,2* 1 University of Applied Sciences Aachen, Ginsterweg 1, 52428 Jülich, Germany 2 Institute of Thin Films and Interfaces, Research Centre Jülich GmbH, 52425 Jülich, Germany 3 New Mexico State University, Las Cruces, NM 88003-800 1, USA Author to whom correspondence should be addressed. Received: 07 Ap ril 2003 / Accep ted: 15 July 2003 / Published: 11 Sep tember 2003 Abstract: Different types of Ag/AgCl reference electrodes have been realised by means of thin- and thick-film technique. For inner electrolyte, KCl-containing membranes have been deposited and different coatings have been used to protect the reference electrode from a fast leaching out of KCl. The stability of the potential of the reference electrodes without KCl- containing membranes in 3 M KCl was about 7 hours for thin-film electrodes and up to 90 hours for thick-film electrodes. The reference electrodes with membrane were stable for more than two months. The thick-film reference electrode was integrated with a thin-film pH sensor onto one chip and the system pH sensor/reference electrode was investigated by means of capacitance/voltage (C/V) and constant capacitance (ConCap) mode. Keywords: reference electrode, thin-film technique, thick-film technique, “one chip” sensor, pH sensor. Introduction The d