Ultra-thin optical sensors for the detection of toxic chemicals

July 2013

Development of a new, ultra-thin 2D optical material enables the rapid, sensitive and inexpensive detection of toxic chemicals in air, water and soil.

Surface Enhanced Raman Scattering (SERS) is an extremely powerful technique with the potential to identify fingerprint vibrations of trace chemical species. However, the high cost, portability and reproducibility are factors which prevent SERS from widespread use - commercially available Klarite^® SERS substrates cost around $40 dollars. In addition, SERS-active structures are supported on rigid glass surfaces, which limits where can Klarite^® SERS substrate be used. This makes it difficult for trace chemical identification on a topographically complex surfaces such as door handles.

To combat these problems, Associate Professor Wenlong Cheng has used nanofabrication facilities at MCN to successfully fabricate ultra-thin, plasmonic nanosheets for rapid, inexpensive and sensitive detection of toxic species in air, water and solids.

Associate Professor Cheng’s group has developed simple, yet efficient wet chemical nanofabrication approaches to obtain free-standing, monolayered, highly-ordered plasmonic nanosheets. The sheets could be as thin as 2.5nm but could have macroscopic lateral dimensions, corresponding to an aspect ratio of above 1 million. Such nanosheets are high-performance SERS substrates which achieve at least 10 times more sensitivity than commercial Klarite^® SERS substrate.

The unique technology developed for ultrathin 2D optical has potentially huge impacts in society. This may include smart diagnostics, better displays, and more efficient solar energy systems. The project is currently expanding the potential to translate the technology into real-world products.

You can read more about this project in Free-Standing Plasmonic-Nanorod Superlattice Sheets, published in ACS Nano.