Abstract
In this paper, we have designed a robust graphene oxide (GO) based capacitive sensor which is highly sensitive to soil moisture. The sensor consists of inter-digitated electrode (IDE) with chemically synthesized GO as the sensing platform. We have used the MEMS fabrication technique to fabricate the IDE. We have performed the characterization such as AFM, RAMAN and XPS on the as-prepared GO to understand the surface properties of the GO. The sensor response changes by 340% and 370% over soil moisture changes from 1% to 55% for red and black soil, respectively. GO sensor array shows a fast response time of 100–120 seconds for the soil moisture measurements. For in situ soil moisture measurements, the diurnal temperature and salt concentration (soil conductivity) are the variable parameters, which might affect the sensor response. We observed that the sensor output changes by 6% when the ambient temperature varies from 25°C to 65°C, which leads to just 3% discrepancies for the soil moisture measurements. For the salt concentration (soil conductivity) measurements we noted that the sensor output changes by 4% when salt concentration in the soil sample varies from 0 mol to 0.35 mol (standard for the field measurement), and discrepancies in the soil moisture measurements is around 2%.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 1660-1669 |
| Number of pages | 10 |
| Journal | Sensors and Actuators B: Chemical |
| Volume | 273 |
| DOIs | |
| State | Published - Jul 21 2018 |
Bibliographical note
KAUST Repository Item: Exported on 2020-10-01Acknowledgements: The authors would like to thank the Central Scanning Probe Microscope (SPM) facility, Electron Spectrometer for Chemical Analysis (ESCA) facility, the Centre for Research in Nanotechnology and Science (CRNTS), IIT Bombay and Centres of Excellence in Nanoelectronics, IIT-Bombay. The authors are thankful for the support received from Prof. D. N. Singh, Environmental Geotechnical lab, IIT-Bombay for providing soil samples and characterizing of soil samples. The authors are thankful to Department of Science and Technology (DST) for fellowship assistance. HK would like to thank UGC-BSR for the start-up grant (No.F.30-386/2017(BSR)). HK would also like to thank ASTEC for the financial support under ITGA scheme of S&T division.