A Nanojunction pH Sensor within a Nanowire.
Anal Chem
; 94(35): 12167-12175, 2022 09 06.
Article
em En
| MEDLINE
| ID: mdl-36001648
ABSTRACT
pH sensors that are nanoscopic in all three dimensions are fabricated within a single gold nanowire. Fabrication involves the formation of a nanogap within the nanowire via electromigration, followed by electropolymerization of pH-responsive poly(aniline) (PANI) that fills the nanogap forming the nanojunction. All fabrication steps are performed using wet chemical methods that do not require a clean room. The measured electrical impedance of the PANI nanojunction is correlated with pH from 2.0 to 9.0 with a response time of 30 s. Larger, micrometer-scale PANI junctions exhibit a slower response. The measured pH is weakly influenced by the salt concentration of the contacting aqueous solution. An impedance measurement at two frequencies (300 kHz and 1.0 Hz) enables estimation of the salt concentration and correction of the measured pH value, preserving the accuracy of the pH measurement across the entire calibration curve for salt concentrations up to 1.0 M. The result is a nanoscopic pH sensor with pH sensing performance approaching that of a conventional, macroscopic pH glass-membrane electrode.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Nanofios
Idioma:
En
Revista:
Anal Chem
Ano de publicação:
2022
Tipo de documento:
Article