Materials Research (Feb 2015)
Comparative Sensibility Study of WO3 ph Sensor Using EGFET and Ciclic Voltammetry
Abstract
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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