Sensor, sensing system and sensing method based on analysis of relaxation time

Patent metadata

Field	Value
Publication number	US-11860119-B2
Application number	US-201816631468-A
Country	US
Kind code	B2
Filing date	Jul 16, 2018
Priority date	Jul 18, 2017
Publication date	Jan 2, 2024
Grant date	Jan 2, 2024

Abstract

A sensing method is described. The sensing method comprises providing a time-dependent electrical signal across a conductive connection between first and second terminals of a sensor, the conductive connection capacitively coupled to an environment via a mesoscopic probe element having an electroactive surface for exposure to the environment, the conductive connection having an associated relaxation time. The method further comprises receiving a time-dependent response signal from the sensor. The method further comprises analysing the time-dependent response signal with respect to the time-dependent electrical signal. The method further comprises determining, based on the analysis, a change in the relaxation time, the change in the relaxation time being correlated with an interaction between the electroactive surface and a measurand of the environment. A computer-readable medium, a sensing system and a sensor are also described.

First claim

The invention claimed is:

1. A sensing method, comprising:
providing a time-dependent electrical signal across a conductive connection between a first terminal and a second terminal of a sensor,
the first terminal coupled with the second terminal via the conductive connection such that no biasing potential exists between the first and second terminals,
the conductive connection quantum capacitively coupled to an environment via a density of states, DOS, sensitive mesoscopic probe element having an electroactive surface for exposure to the environment,
the mesoscopic probe element having at least one dimension less than 15 nm and an accessible DOS that is quantum capacitively coupled to the conductive connection,
wherein a quantum capacitance Cq varies as a function of the DOS occupancy of the mesoscopic probe element,
wherein an interaction between the mesoscopic probe element and a measurand in the environment affects the DOS of the mesoscopic probe element,
wherein the conductive connection having an associated resistive-capacitive relaxation time based on an capacitive property and an resistive property of the sensor;

receiving a time-dependent response signal from the sensor;
analysing the time-dependent response signal with respect to the time-dependent electrical signal;
determining, based on the analysis, a change in the relaxation time as a result of a change in the DOS of the mesoscopic probe element, wherein the change in the relaxation time is correlated with an interaction between the electroactive surface and the measurand of the environment.

2. The method according to claim 1 , wherein the time-dependent electrical signal is an alternating current.

3. The method according to claim 1 , wherein the time-dependent electrical signal is an electrical pulse.

4. The method according to claim 1 , wherein analysing the time-dependent response signal with respect to the time-dependent electrical signal comprises determining a phase difference between the time-dependent response signal and the time-dependent electrical signal.

5. The method according to claim 4 , wherein determining the change in the relaxation time comprises determining that a change in the relaxation time has occurred based on the phase difference.

6. The method according to claim 1 , wherein analysing the time-dependent response signal with respect to the time-dependent electrical signal comprises determining an immittance function of the sensor from the time-dependent electrical signal and the time-dependent response signal.

7. The method according to claim 6 , wherein analysing the time-dependent response signal with respect to the time-dependent electrical signal comprises determining the impedance of the sensor from the ratio of the time-dependent electrical signal to the time-dependent response signal.

8. The method according to claim 1 , wherein analysing the time-dependent response signal with respect to the time-dependent electrical signal comprises determining the capacitance of the sensor using impedance-derived capacitance spectroscopy.

9. The method according to claim 1 , further comprising determining a concentration of the measurand in the environment.

10. The method according to claim 1 , wherein the interaction between the electroactive surface and the measurand comprises an electronic interaction.

11. The method according to claim 1 , wherein the interaction between the electroactive surface and the measurand comprises a molecular binding event.

12. The method according to claim 1 , wherein the interaction between the electroactive surface and the measurand comprises a photon-electron interaction.

13. The method according to claim 1 , wherein the mesoscopic probe element comprises graphene oxide or titanium dioxide or a mixed valence oxide.

14. The method according to claim 1 , wherein the at least one dimension is less than or equal to 10 nanometres.

15. The method according to claim 1 , wherein the conductive connection comprises gold.

16. The method according to claim 1 , wherein the electroactive surface of the mesoscopic probe element is an exposed surface.

Assignees

• Univ Oxford Innovation Ltd
• Univ Estadual Paulista “Julio De Mesquita Filho”—Unesp

Inventors

• Davis Jason J
• Bueno Paulo R

Classifications

• G01N27/4146 Primary

  involving nanosized elements, e.g. nanotubes, nanowires · CPC title

• G01N27/221

  by investigating the dielectric properties (using microwaves G01N22/00; measuring loss factors or dielectric constants per se G01R27/26) · CPC title

• G01N27/4145 Primary

  specially adapted for biomolecules, e.g. gate electrode with immobilised receptors · CPC title

• G01N33/5438

  Electrodes · CPC title

• G01N27/026

  Dielectric impedance spectroscopy (electrochemical impedance spectroscopy for measuring corrosion G01N17/02) · CPC title