A zinc oxide nanorod sensor or ZnO nanorod sensor is an electronic or optical device detecting presence of certain gas or liquid molecules (e.g. humidity, NO, hydrogen, etc.) in the ambient atmosphere. The

sensor A sensor is often defined as a device that receives and responds to a signal or stimulus. The stimulus is the quantity, property, or condition that is sensed and converted into electrical signal. In the broadest definition, a sensor is a devi ...

exploits enhanced surface area (and thus surface activity) intrinsic to all nano-sized materials, including ZnO nanorods.

Adsorption Adsorption is the adhesion of atoms, ions or molecules from a gas, liquid or dissolved solid to a surface. This process creates a film of the ''adsorbate'' on the surface of the ''adsorbent''. This process differs from absorption, in which a ...

of molecules on the nanorods can be detected through variation of the

nanorod In nanotechnology, nanorods are one morphology of nanoscale objects. Each of their dimensions range from 1–100 nm. They may be synthesized from metals or semiconducting materials. Standard aspect ratios (length divided by width) are 3-5. Nan ...

s' properties, such as

photoluminescence Photoluminescence (abbreviated as PL) is light emission from any form of matter after the absorption of photons (electromagnetic radiation). It is one of many forms of luminescence (light emission) and is initiated by photoexcitation (i.e. phot ...

electrical conductivity Electrical resistivity (also called volume resistivity or specific electrical resistance) is a fundamental specific property of a material that measures its electrical resistance or how strongly it resists electric current. A low resistivity in ...

, vibration frequency, mass, etc. The simplest and thus most popular way is to pass

electrical current Electricity is the set of physical phenomena associated with the presence and motion of matter possessing an electric charge. Electricity is related to magnetism, both being part of the phenomenon of electromagnetism, as described by Maxwel ...

through the nanorods and observe its changes upon exposure to gas. Synthesis can be obtained by a hydrothermal method using 1:1 molar solution of

hexamine Hexamethylenetetramine (HMTA), also known as 1,3,5,7-tetraazaadamantane, is a heterocyclic organic compound with diverse applications. It has the chemical formula (CH2)6N4 and is a white crystalline compound that is highly soluble in water and p ...

and

zinc nitrate Zinc nitrate is an inorganic chemical compound with the formula . This colorless, crystalline salt is highly deliquescent. It is typically encountered as a hexahydrate . It is soluble in both water and alcohol. Synthesis Zinc nitrate is usually p ...

solution kept together for 56 hours in an autoclave at 60–70 degrees Celsius.

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For the future hydrogen economy, a tiny, self-powered sensor
Gas sensors Nanoelectronics

See also

References

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