Optoelectrical vapor sensing
A chemical sensor can include a nanofiber mass of p-type nanofibers having a HOMO level greater than −5.0 eV. Additionally, the chemical sensor can include oxygen in contact with the p-type nanofibers. Further, the chemical sensor can include a pair of electrodes in electrical contact across the nanofiber mass, where the p-type nanofibers conduct an electric current that decreases upon contact with an amine compound.
1. A chemical sensor, comprising:
a) a nanofiber mass of p-type nanofibers, said nanofibers having a HOMO level greater than −5.0 eV;
b) oxygen in contact with the p-type nanofibers; and
c) a pair of electrodes in electrical association across the nanofiber mass;
wherein the p-type nanofibers conduct an electric current that decreases upon contact with a amine compound.
2. The chemical sensor of claim 1 , wherein the nanofibers comprise a plurality of alkyl-substituted, carbazole-cornered, arylene-ethynylene tetracyclic macromolecules of formula 1:
wherein R1-R4 are alkyl groups and wherein at least some of the macromolecules are cofacially stacked.
3. The chemical sensor of claim 2 , wherein R1-R4 are individually selected from C 3 to C 18 alkyl chains.
4. The chemical sensor of claim 2 , wherein R1-R4 are C 14 alkyl chains.
5. The chemical sensor of claim 1 , wherein the nanofibers comprise an indolocarbazole derivative.
6. The chemical sensor of claim 5 , wherein the indolocarbazole derivative is selected from the group consisting of
7. The chemical sensor of claim 1 , wherein the HOMO level is greater than −4.9 eV.
8. The chemical sensor of claim 1 , wherein the amine compound is an amine.
9. The chemical sensor of claim 1 , wherein the electrical current is decreased for at least 5 minutes after exposure to the amine compound.
10. The chemical sensor of claim 1 , wherein the amine compound adsorbs on the nanofiber mass for at least 5 minutes.
11. The chemical sensor of claim 1 , wherein the nanofiber mass is deposited on the electrode.
12. The chemical sensor of claim 1 , wherein the nanofiber mass is a film.
13. The chemical sensor of claim 1 , wherein the chemical sensor detects the amine compound in a concentration of at least 1 ppm.
14. The chemical sensor of claim 1 , wherein the chemical sensor is selective of the amine compound over other organic compounds.
15. The chemical sensor of claim 14 , wherein the chemical sensor is selective by measuring a different electric current affected by the amine compound compared to the other organic compounds or by measuring a different length of time that the electric current is affected by the amine compound as compared to the other organic compounds.
16. The chemical sensor of claim 1 , wherein the oxygen is free oxygen.
17. A method of detecting trace amine compounds, comprising:
a) contacting the amine compound with a nanofiber mass of p-type nanofiber, said nanofibers having a HOMO level greater than −5.0 eV;
b) measuring a change in electric current associated with the nanofiber mass before and after contacting the nanofiber mass with the amine compound.
18. The method of claim 17 , wherein the nanofibers comprise a plurality of alkyl-substituted, carbazole-cornered, arylene-ethynylene tetracyclic macromolecules of formula 1:
wherein R1-R4 are alkyl groups and wherein at least some of the macromolecules are cofacially stacked.
19. The method of claim 17 , wherein the nanofibers comprise an indolocarbazole derivative.
20. The method of claim 19 , wherein the indolocarbazole derivative is selected from the group consisting of
21. The method of claim 17 , wherein the change in electric current decreases by at least 1% after the nanofiber mass is contacted with the amine compound.
22. The method of claim 17 , wherein the amine compound is adsorbed on the nanofiber mass for at least 5 minutes.
23. The method of claim 17 , wherein the change in electric current is measurable when the nanofiber mass contacts the amine compound in a concentration of at least 1 ppm.
24. The method of claim 17 , further comprising differentiating between the amine compound and other organic compounds.
25. The method of claim 24 , wherein the differentiating is by measuring a different electric current affected by the amine compound compared to the other organic compounds or by measuring a different length of time that the electric current is affected by the amine compound as compared to the other organic compounds.
26. The method of claim 17 , wherein the method is used in the area selected from the group consisting of air pollution monitoring and controlling, food quality control, medical diagnosis, and security.