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Analytical chemists are continually striving to advance techniques to make it possible to observe and measure matter and processes at smaller and smaller scales. Professor Vartkess Ara Apkarian and his team at the University of California, Irvine have made a significant breakthrough in this quest: They have recorded the Raman spectrum of a single azobenzene thiol molecule. The approach, which breaks common tenets about surface-enhanced Raman scattering/spectroscopy (SERS) and tip-enhanced Raman spectroscopy (TERS), involved imaging an isolated azobenzene thiol molecule on an atomically flat gold surface, then picking it up and recording its Raman spectrum using an electrochemically etched silver tip, in an ultrahigh vacuum cryogenic scanning tunneling microscope. For the resulting paper detailing the effort [1], Apkarian and his associates are the 2021 recipients of the William F. Meggers Award, given annually by the Society for Applied Spectroscopy to the authors of the outstanding paper appearing in the journal Applied Spectroscopy. We spoke to Apkarian about this research, and what being awarded this honor means to him and his team. This interview is part of an ongoing series with the winners of awards that are presented at the annual SciX conference. The award will be presented to Apkarian at this fall’s event, which will be held in person in Providence, Rhode Island, September 28–October 1.

Recording the Raman Spectrum of a Single Molecule 

Roy Goodacre, a professor of biological chemistry at the University of Liverpool in the United Kingdom, first used SERS to achieve whole-organism fingerprinting of bacteria and then explored SERS in a variety of other applications, including within biotechnology, disease diagnostics, quantitative detection, imaging, food security, and more. Goodacre is the 2021 winner of the Charles Mann Award for Applied Raman Spectroscopy. This interview is part of an ongoing series of interviews with the winners of awards that are presented at the annual SciX conference.

Quantitative Analysis Using Surface-enhanced Raman Scattering (SERS): Roy Goodacre, the 2021 winner of the Charles Mann Award for Applied Raman Spectroscopy

Using confocal Raman imaging and other advanced measurement techniques, we study the localized strain characteristics of tungsten diselenide (WSe2),
an important nanomaterial used for optoelectronic device applications.

A Comprehensive Study of WSe2 Crystals Using Correlated Raman, Photoluminescence (PL), Second Harmonic Generation (SHG), and Atomic Force Microscopy (AFM) Imaging

Using Raman imaging, wild-type and engineered yeast cells were compared for their ability to produce bioactive compounds. Raman imaging microscopy is able to visualize locales, relative abundance, and production efficiencies of biologically active compounds for the individual yeast cells.

Tracking Bioactive Compounds Produced by Genetically Engineered Yeast Cells Using Raman Imaging

SERS can amplify Raman signals, but to make the technique practical for industrial use, large quantities of substrate are needed. The approach described here could enable cost-effective, reproducible manufacturing of SERS substrates at large scale.

A Dual Nanostructured Approach to SERS Substrates Amenable to Large-Scale Production

Perovskites are known to be useful for fabrication of solar cells, and their crystalline structure plays an important role in their electronic properties. Here, we show how Raman analysis is able to confirm the presence of the required crystalline phase for solar cell production.

Raman Spectroscopy as a Tool for Rapid Feedback of Perovskite Growth Crystallinity and Composition

Zac Schultz of The Ohio State University and his team used tip-enhanced Raman spectroscopy (TERS) and surface-enhanced Raman spectroscopy (SERS) with gold nanostars to investigate chemical reactions involved in protein–ligand binding. He recently spoke with Spectroscopy about his findings.

Investigating Protein Receptors and Other Biomolecules Using SERS and TERS

Fran Adar is the Worldwide Raman Applications manager for Horiba Jobin Yvon.

We illustrate how matching the optical properties of the microscope objective with the sample properties improves the spatial resolution and chemical speciation in depth profile measurements using confocal Raman microscopy.

Effect of Sampling Optics on Raman Depth Profiling

Raman spectroscopy offers promise for the evaluation of breast cell lines and tissue. Rina Tannenbaum of Stony Brook University discusses this work.

Raman Spectroscopy in the Detection of Breast Cancer

Fran Adar is the winner of the 2021 Gold Medal Award from the New York and New Jersey Society of Applied Spectroscopy (SAS). 