Gas sensor element

Patent metadata

Field	Value
Publication number	US-9739738-B2
Application number	US-201514723379-A
Country	US
Kind code	B2
Filing date	May 27, 2015
Priority date	May 28, 2014
Publication date	Aug 22, 2017
Grant date	Aug 22, 2017

Abstract

Described herein are sensor elements for detecting the presence of organic materials comprising a boron doped n-type semiconductor material with decrease in resistivity upon organic materials exposure with increase in resistivity upon organic materials exposure.

First claim

What is claimed is:

1. A method for determining acetone in a subject's breath comprising exposing a mammalian breath sample to a gas sensor, the sensor comprising a gas sensor element comprising:
a first electrode and second electrode, wherein the first electrode and the second electrode are separated by a gap of about 1 to about 10 mils; and
a polycrystalline n-type semiconductor material comprising:
epsilon phase WO 3 that is doped with boron; or
gamma phase WO 3 mixed with CeO 2 ;
wherein the polycrystalline n-type semiconductor material physically contacts both the first and second electrodes; and
wherein the presence of acetone is detected by a change in resistivity across the sensor.

2. The method of claim 1 , wherein the boron is present at about 0.001% to about 1% by weight of the polycrystalline n-type semiconductor material.

3. The method of claim 1 , wherein the polycrystalline n-type semiconductor material is combustion synthesized.

4. The method of claim 1 , wherein the polycrystalline n-type semiconductor is at a temperature of about 190° C. to about 360° C.

5. The method of claim 1 , further comprising a noble metal mixed with the polycrystalline n-type semiconductor material.

6. The method of claim 5 , wherein the noble metal is palladium, gold, platinum or iridium.

7. The method of claim 1 , wherein the gamma phase WO 3 is mixed with CeO 2 .

8. The method of claim 7 , wherein the polycrystalline n-type semiconductor material is exposed to blue light.

9. The method of claim 8 , wherein the polycrystalline n-type semiconductor material is at a temperature of about 10° C. to about 40° C.

10. The method of claim 8 , wherein the gamma phase WO 3 mixed with CeO 2 is about 40-60 molar % WO 3 .

11. The method of claim 1 , wherein the polycrystalline n-type semiconductor material is ball milled.

12. The method of claim 1 , wherein the gas sensor operating temperature is from about 10° C. to about 50° C. and the gas sensor element is exposed to blue light.

13. The method of claim 1 , wherein the gas sensor operating temperature is about 190° C. to about 360° C.

14. The method of claim 13 , wherein the sensor is not exposed to blue light.

15. The method of claim 13 , wherein the gas sensor operating temperature is from about 280° C. to about 360° C., and the gas sensor is more sensitive to isoprene than to acetone.

16. The method of claim 1 , wherein the gas sensor operating temperature is from about 180° C. to about 240° C., and the gas sensor is more sensitive to acetone than to isoprene.

Assignees

• Nitto Denko Corp

Inventors

• Sambandan Ekambaram

Classifications

• G01N2001/2244

  Exhaled gas, e.g. alcohol detecting · CPC title

• G01N2800/042

  Disorders of carbohydrate metabolism, e.g. diabetes, glucose metabolism · CPC title

• H01L29/24

  Electricity · mapped topic

• G01N33/0047

  Organic compounds · CPC title

• G01N2033/4975

  Physics · mapped topic