Studying Graphene Ribbons with Raman Spectroscopy
Dr. Mark Waterland’s research at Massey University in New Zealand is driven by an interest in the development and properties of new molecular and nanostructured materials for energy conversion, energy storage, and chemical sensing. His group has expertise in Raman spectroscopy, including resonance Raman spectroscopy, theory of Raman intensities, and surface- and plasmon-enhanced Raman.
“I can honestly say FERGIE is changing the way we do spectroscopy in our lab.”
— Dr. Mark Waterland
The group’s current research activities focus on the chemistry and spectroscopy of graphene nanoribbons. They use their expertise in Raman spectroscopy to analyze the edge structure of graphene nanoribbons produced by mechanical fracturing. Edge structure determines the physical properties and chemistry of the graphene nanoribbons. Controlling the functional groups at the nanoribbons provides a route to controlling the physical properties of nanoribbon suspensions and, ultimately, to controlling the self-assembly of nanoribbon structures.
The group applies Raman spectroscopy to complex analytical problems, collaborating with medical researchers, veterinarians, ecologists, plant biologists, engineers, and food scientists. They also work with statisticians and mathematicians to apply state-of-the-art data analysis to Raman datasets for the purpose of classification (e.g., skin cancers) or following chemical or physical changes to various materials.
“Already my students are spending most of their time thinking about which measurement to do next rather than setting up the current measurement.”
FERGIE in Action
Figure 1 is a photo of the group’s existing home-built microscope setup, whose 50 micron collection fiber connects to FERGIE via the spectrograph’s fiber port and Focusing CUBE.
A spectrum of PMMA is visible on the monitor in Figure 1. Dr. Waterland’s students have collected MoS2 nanoribbon spectra and graphene nanoribbon spectra using this setup.
Figure 2 shows the group’s cuvette setup. Using cage components from ThorLabs, the group has adapted the FERGIE spectrograph’s Cuvette CUBE to focus a 488 nm laser into the cuvette via a 50 mm f.l. achromat. In this photo, a 488 nm edge filter is mounted via a cage rotation mount.
Using 10 mW of excitation, the group has obtained 30,000 counts from toluene in a 1 sec exposure (with a 50 micron slit). Dr. Waterland’s students have also collected solution phase spectra of a rodenticide sample and control spectra for various nanoparticle solutions.
Dr. Waterland reports that setting up experiments with FERGIE is fast and simple (see Figures 3 and 4). For example, setting up the cuvette experimental configuration took less than 30 minutes, including tweaking.
“This is opening up a lot of possibilities, especially for undergrad students, who only have a few hours per week on their projects.”
Three Quick Questions
Princeton Instruments: Undergraduate research is becoming an increasingly important part of chemistry and nanoscience degree programs, correct?
Mark Waterland: Yes, providing a genuine research experience where undergraduate students manage their own projects and have access to the latest research equipment is a big focus in our undergraduate programs now.
PI: Why is FERGIE useful to such programs?
MW: FERGIE yields research-quality results… but without the learning curve of our previous system. The FERGIE spectrograph makes it a snap to set up and acquire spectra. An undergrad of mine switched the setup from the cuvette to the microscope in approximately 30 minutes! FERGIE’s ability to produce aberration-free data is very impressive, as is its versatility.
PI: Could you elaborate on the system’s versatility?
MW: For us, FERGIE’s compatibility with ThorLabs gear is a big plus. Also, with the aid of informative videos on the Princeton Instruments website, we intend to do fluorescence in the near future.
Associate Professor Mark Waterland
Institute of Fundamental Sciences
Massey University, New Zealand