Nanostructured ZnO films: a study of molecular influence on transport properties by impedance spectroscopy

TL;DR

This study investigates how different solutions, including enzymes and buffers, influence the electrical transport properties of ZnO nanostructured films, providing insights for improved glucose biosensor design.

Contribution

It reveals the impact of ionic composition and enzymes on ZnO film conduction, advancing understanding of biosensor material interactions.

Findings

Ionic charge significantly affects ZnO film transport properties.

Enzyme GOx and phosphate buffers alter conduction by carrier entrapment.

Transport properties vary between thin films and single crystals.

Abstract

Nanomaterials based on ZnO have been used to build glucose sensors due to its high isoelectric point, which is important when a protein like glucose oxidase (GOx) is attached to a surface. It also creates a biologically friendly environment to preserve the activity of the enzyme. In this work we study the electrical transport properties of ZnO thin films (TFs) and single crystals (SC) in contact with different solutions by using impedance spectroscopy. We have found that the composition of the liquid, by means of the charge of the ions, produces strong changes in the transport properties of the TF. The enzyme GOx and phosphate buffer solutions have the major effect in the conduction through the films, which can be explained by the entrapment of carriers at the grain boundaries of the TFs. These results can help to design a new concept in glucose biosensing.