Materials, methods and devices to detect and quantify water vapor concentrations in an atmosphere
View Patent ↗We have demonstrated that a surface acoustic wave (SAW) sensor coated with a nanoporous framework material (NFM) film can perform ultrasensitive water vapor detection at concentrations in air from 0.05 to 12,000 ppmv at 1 atmosphere pressure. The method is extendable to other MEMS-based sensors, such as microcantilevers, or to quartz crystal microbalance sensors. We identify a specific NFM that provides high sensitivity and selectivity to water vapor. However, our approach is generalizable to detection of other species using NFM to provide sensitivity and selectivity.
1. A humidity sensor comprising;
a surface acoustic wave (SAW) device formed on one surface of a quartz substrate, the SAW device comprising a plurality of interdigitated electrodes; and
a material comprising a nanoporous framework material (NFM) coating, wherein the NFM coating is covalently bonded to at least a portion of the one surface between the plurality of interdigitated electrodes,
wherein the NFM coating is selected from the list consisting of copper (II) benzene-1,3,5-tricarboxylate, copper (II) biphenyl-3,3′,5,5′-tetracarboxylic acid, and copper (II) terphenyl-3,3′,5,5′-tetracarboxylic acid.
2. The sensor of claim 1 , wherein the NFM coating has a thickness of between about 50 nm to about 200 nm.
3. The sensor of claim 1 , wherein the NFM coating is comprised of copper (II) biphenyl-3,3′,5,5′-tetracarboxylic acid.
4. The sensor of claim 1 , wherein the NFM coating is comprised of copper (II) benzene-1,3,5-tricarboxylate.
5. The sensor of claim 1 , wherein the NFM coating is bonded to at least a portion of a silicon oxide surface of the SAW device.
6. The sensor of claim 1 , wherein the NFM coating is bonded over a substantial portion of a surface of the SAW device.
7. The sensor of claim 1 , wherein a first interdigitated electrode is disposed near one end of the quartz substrate and a second interdigitated electrode is disposed near an opposite end of the quartz substrate.
8. A humidity sensor comprising;
a surface acoustic wave (SAW) device formed on one surface of a quartz substrate, the SAW device comprising a plurality of interdigitated electrodes; and
a material comprising a nanoporous framework material (NFM) coating, wherein the NFM coating is covalently bonded to at least a portion of the one surface between the plurality of interdigitated electrodes,
wherein the sensor is configured to detect water vapor in an ambient atmosphere having a concentration of less than about 0.05 ppmv to at least 12,000 ppmv.
9. The sensor of claim 8 , wherein the NFM coating has a thickness of between about 50 nm to about 200 nm.
10. The sensor of claim 8 , wherein the NFM coating is selected from the list consisting of copper (II) benzene-1,3,5-tricarboxylate, copper (II) biphenyl-3,3′,5,5′-tetracarboxylic acid, and copper (II) terphenyl-3,3′,5,5′-tetracarboxylic acid.
11. The sensor of claim 8 , wherein the NFM coating is comprised of copper (II) benzene-1,3,5-tricarboxylate.
12. The sensor of claim 8 , wherein the NFM coating is bonded to at least a portion of a silicon oxide surface of the SAW device.
13. The sensor of claim 8 , wherein the NFM coating is bonded over a substantial portion of a surface of the SAW device.
14. The sensor of claim 8 , wherein the NFM coating is covalently bonded to a surface of the quartz substrate without a self-assembled monolayer.
15. The sensor of claim 8 , wherein a first interdigitated electrode is disposed near one end of the quartz substrate and a second interdigitated electrode is disposed near an opposite end of the quartz substrate.
16. A humidity sensor comprising;
a surface acoustic wave (SAW) device formed on one surface of a quartz substrate, the SAW device comprising a plurality of interdigitated electrodes; and
a material comprising a nanoporous framework material (NFM) coating, wherein the NFM coating is covalently bonded to at least a portion of the one surface between the plurality of interdigitated electrodes,
wherein the NFM coating is covalently bonded to a surface of the quartz substrate without a self-assembled monolayer.