Titanium Oxide Nanorods pH Sensors: Comparison between Voltammetry and Extended Gate Field Effect Transistor Measurements

Marcelo Mulato,Elidia Maria Guerra

doi:10.4236/msa.2014.57049

Abstract

In recent years there has increased interest in the characterization of titanium oxide nanorods for application in analytical devices. The titanium oxide nanorods (NRTiO) were obtained by hydrothermal reaction with a NaOH solution heated in the autoclave at 150°C for up to 50 h. Experimental data indicate that the prepared nanorods consist of anatase and rutile phases, with a possible interlayer structure. The NRTiO was investigated as pH sensor in the pH range 2 - 12, and the extended gate field effect transistor (EGFET) configuration presented a sensitivity of 49.6 mV/pH. Voltammetric data showed a sensitivity of 47.8 mV/pH. These results indicate that the material is a promising candidate for applications as an EGFET-pH sensor and as a disposable biosensor in the future.

Highlights

It is well known that the structure of a material influences its final properties, i.e., its characteristics depend on its structure
Many different types of sensors have been architected, such as those based on field effect devices, because there is a high demand for specificity
The sensitivity was studied by cyclic voltammetry, which led to a value of 47.8 mV/pH

Summary

Introduction

It is well known that the structure of a material influences its final properties, i.e., its characteristics depend on its structure. How to cite this paper: Guerra, E.M. and Mulato, M. The extraordinary properties of some nanostructured materials make them attractive for the fabrication of novel analytical devices that have advantages over traditional ones, for instance, low cost, simple design, selectivity, miniaturization and improved sensitivity [4]. Many different types of sensors have been architected, such as those based on field effect devices, because there is a high demand for specificity. Given the large demand for specific sensors, especially those based on field effect devices, many different types of materials have been developed as sensitive films or membranes. In the search for another alternative of ion-sensing membranes for use in pH sensors, one can point out the titanium oxide nanorods (NRTiO), which displays useful chemical, optical, and electronic properties [19]-[21], and has been synthesized in nanosized configuration such as nanoparticles, nanowires, nanotubes, nanofibers, etc. The NRTiO is nontoxic, biocompatible and environmentally safe, and it should offer large surface area compared with nanoparticles [24]-[29]

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