IIT Guwahati Develops Low-Cost Materials For Detection of Trace Chemicals

Indian Institute of Technology Guwahati researchers have developed a new form of a semiconductor, that can be used to identify trace chemicals using a technique called Surface Enhanced Raman Spectroscopy (SERS). This finding can help in the development of SERS techniques that are cheaper and more reliable than existing ones.

The research has been led by Prof. P.K. Giri, Department of Physics and Centre for Nanotechnology, IIT Guwahati. The details of the fabrication of the 2D dendritic semiconductor nanostructures and their ability to enhance SERS signals have been published in the Nature Partner Journal – 2D Materials and Applications. The paper has been co-authored by Tadasha Jena, Tarik Hossain, Upasana Nath, Manabendra Sarma, Hiroshi Sugimoto, Minoru Fujii, and Prof. P.K. Giri.

Prof. P.K. Giri said, “The problem with using noble metal nanostructures is that they are costly, have poor environmental stability, and poor reproducibility of detection. Semiconductors – materials that have electrical conduction properties intermediate to metals (conductors) and insulators – are being studied as alternatives to metal nanostructures. This is because they offer better chemical stability, a wider range of options, and lower cost than noble metal SERS substrates. However, the signal amplification in semiconductors is much lower than that of metal nanostructures.”

The IIT Guwahati team designed an ultrathin two-dimensional (2D) dendritic nanostructure of the semiconductor, palladium di-selenide (PdSe2) and found that it exhibits high SERS amplification properties. They used a method called Chemical Vapour Deposition (CVD) to produce these structures.

The researchers used the semiconductor-based SERS technique to detect minuscule amounts of a dye called Rhodamine-B deposited. They tested the semiconductor-based SERS over many months, and found no deterioration of performance, showing that these substrates are more stable than metal-based ones.

SERS is useful for the detection of trace amounts of chemicals in various situations – pollutants in water, biomarkers in blood, etc.  The researchers report that cost-effective dendritic 2D PdSe2 can replace the costly metal-nanoparticle-based plasmonic SERS substrates.

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