Materials Research (Feb 2015)

Comparative Sensibility Study of WO3 ph Sensor Using EGFET and Ciclic Voltammetry

  • Renata de Castro Campos,
  • Dane Tadeu Cestarolli,
  • Marcelo Mulato,
  • Elidia Maria Guerra

DOI
https://doi.org/10.1590/1516-1439.252513
Journal volume & issue
Vol. 18, no. 1
pp. 15 – 19

Abstract

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In this present study, the investigation about pH sensorial properties of WO3, via sol-gel, was evaluated by Voltammetry and Extended Gate Field Effect Transistor techniques. The X-ray diffractogram indicates the presence of a lamellar structure, d = 0.69 nm, resulting in WO3.2H2O. From Scanning Electron Microscopy of WO3.2H2O was observed a process corresponding to the delamination which consists of irregular stacking with rounded platelets. The WO3.2H2O was investigated as a pH sensor in the pH range 2–12, by the EGFET and Voltametry techniques presenting a sensitivity of 52 mV/pH and 60 mV/pH, respectively. These results can indicate that both Voltammetry and EGFET techniques present values close to the theoretical limit (59.2 mV/pH) as well as the material is a promising candidate for applications as a pH sensor and as disposable biosensor in the future.

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