Low-cost pH, temperature and ion concentration sensors utilizing laser machined touch panel film

• Published in: 2017 IEEE 12th International Conference on Nano/Micro Engineered and Molecular Systems (NEMS) pp. 110 - 113
• Main Authors: Wei-Hsin Kao, Che-Hsin Lin
• Format: Conference Proceeding
• Language: English
• Published: IEEE 01.04.2017
• Subjects: Chemical sensors; Conductivity; Electrical resistance measurement; Indium tin oxide; Temperature measurement; Temperature sensors
• ISSN: 2474-3755
• DOI: 10.1109/NEMS.2017.8016985

This paper presents a low-cost pH, temperature and ion concentration sensors utilizing laser direct writing the industrial grade touch panel film (TPF). The commercial touch panel film is composed of PET substrate with Ta 2 O 5 and ITO (indium-tin-oxide) coating layers. The conductive ITO layer exhibits excellent properties for adsorbing hydrogen ions and good temperature coefficient of resistance which can be used for high performance sensing purpose. Instead of wet chemical etching with corrosive aqua regia, the ITO sensing electrodes are produced by laser direct writing to destroy the continuity of the conductive ITO layer such that the process for producing the multi-sensors is rapid and low-cost. Results showed that the developed ITO multi-sensors exhibit a high sensing performance for pH (78.3 mV/pH, R 2 = 0.996), temperature (~ 2.00 Ω/°C, R 2 = 0.997) and ionic strength (0.9 uS·cm -1 /ppb for NaCl). The developed ITO multi-sensors on the low-cost TPF is potentially for constructing the distributed sensor network for environmental monitoring applications.