Zinc oxide nanorods grown on two-dimensional macroporous periodic structures and plane Si as a pH sensor

Abstract

p H determination is a strong prerequisite for many biochemical and biological processes. We used two methods, namely, the electrochemical potential method (experimental) and site binding method (theoretical), to study the sensitivity of zinc oxide (ZnO) nanorods grown on two-dimensional macroporous periodic structures (2DMPPS) (p-and n-type) and plane n-type Si substrates for use as an intracellular pH sensing device. The dimension of these nanorods varied in radius between 50 and 300 nm and lengths of 1–10 μm. We found that the sensitivity of ZnO nanorods increases with reductions in size, from 35 mV/pH for D=300 nm and L=10 μm, to 58 mV/pH for D=50 nm and L=1 μm, using the site binding model. The experimental electrochemical potential difference for the ZnO nanorods working electrode versus Ag/AgCl reference electrode showed a high sensitivity range for ZnO nanorods grown on 2DMPPS n-Si substrate as compared to plane n-Si at room temperature for pH ranging from 4 to 12 in buffer and NaCl solutions.

Effect of anions on the morphology of Co3O4 nanostructures grown by hydrothermal method and their pH sensing application

“…The output potential (EMF) of the nanostructures of Co3O4 is the potential difference between the working electrode (Co3O4) and the known potential of silver _ silver chloride as a reference electrode [45].…”

Selective potentiometric determination of uric acid with uricase immobilized on ZnO nanowires

“…Due to the presence of water (H-OH), it is a high probability that allantoin will accept a proton from (H-OH) converting it to allantoinium ion, which in turn will interact with ZnO nanowires and produce a potential change at the electrode. As the concentration of ions changes in surrounding the ZnO nanowires the electrode potential will change [38]. The potentiometric responses of the sensor electrodes were studied in uric acid solutions made in buffer (PBS pH 7.4) with concentration ranging from 1 µM to 1000 µM.…”

Optical characterization of ZnO nanopillars on Si and macroporous periodic Si structure

“…In this work, we have investigated ZnO nanopillars grown on twodimensional macroporous periodic silicon (PSi) structure substrates of n-and p-type (n-Psi and p-PSi), and nonporous, flat silicon (Si), n-and p-type Si (n-Si and p-Si). [1][2][3][4][5] The ZnO nanopillars on the Si substrates have a number of applications beyond of those described above. They can provide, for instance, high quality Si based pH sensors 1 and photonic crystals.…”

“…[1][2][3][4] It presents low toxicity and good chemical stability. This great versatility of applications is possible mainly because preparation conditions enhance different properties, such as insulator, conductor, semiconductor, photo-electrochemical, luminescent, and piezoelectric.…”