Article from the Fall 2024 Edition of the MSEConnect Newsletter; image credit: University of Arizona

Georgia Tech will receive an x-ray photoelectron spectroscopy (XPS), and it’s all because of MSE’s newest faculty, Erin Ratcliff.

Ratcliff’s group “Laboratory for Interface Science for Printable Electronic Materials” explores both fundamental principles and device applications, focusing on technologies such as solar cells, transistors, photoelectrodes, capacitors, and batteries. This experimental group employs a variety of techniques, including electrochemistry, spectroscopy, microscopy, and synchrotron-based methods, to investigate the structure-property relationships of next-generation materials for energy conversion, storage, and biosensing. Their research spans materials like metal halide perovskites, π-conjugated compounds, colloidal quantum dots, and metal oxides. Current projects emphasize understanding electron transfer and transport mechanisms across interfaces, such as semiconductor/electrolyte boundaries, as well as enhancing the durability of printable electronic materials. The interdisciplinary nature of the group makes it an ideal environment for students and postdocs with backgrounds in materials science, chemical engineering, chemistry, physics, and related fields.

Ratcliff’s lab works with printable materials because they are scalable. This refers to materials that can be processed similarly to printing ink onto a surface. These materials, such as certain polymers or perovskites, can be deposited onto flexible or rigid substrates using scalable techniques like printing or coating. This enables the creation of thin, lightweight, and potentially flexible devices like solar cells or wearable electronics.

Scalability implies that these processes can be easily adapted for large-scale production, making it possible to produce energy technologies, such as solar panels or solar fuel devices, efficiently and at a lower cost. For example, perovskite materials, which Ratcliff’s work often involves, can be applied as inks and formed into solar cells via processes that are faster and less resource-intensive than traditional silicon-based methods​. This approach is especially valuable in sustainable energy, where achieving cost-effectiveness and high production levels is critical to meet global energy demands. 

However, Ratcliff did not envision herself as a professor, which is a small part of why she is so great at what she does. She took a unique path that allowed her to gain experience that has ultimately allowed her to make a great impact on the students she encounters. Ratcliff triple majored in Math, Chemistry, and Statistics while at St. Olaf College. She then went on to complete a doctorate in Physical Chemistry at Iowa State University. After graduating, she utilized her knowledge and determination to get a post-doctorate position in Regents Professor Neal Armstrong’s laboratory at the University of Arizona. While at the university, she led one of the Department of Energy's Energy Frontier Research Centers (EFRC) to advance energy conversion and storage technologies using soft organic polymer electronic materials. The EFRC was the Center for Interface Science: Solar Electric Materials. 

With $10.95 million in funding over four years, the University of Arizona-led Center for Soft PhotoElectroChemical Systems (SPECS) focused on the molecular science behind affordable and scalable soft semiconductors. 

These materials absorbed light, generated electricity, and used that electricity to power electrochemical reactions, producing solar fuels—a sustainable alternative to batteries and fossil fuels. One key achievement was using sunlight to produce hydrogen, highlighting the potential of renewable energy innovations. SPECS brought together experts in photovoltaics and photoelectric chemistry from institutions such as the University of Colorado-Boulder, National Renewable Energy Laboratory, University of Kentucky, Emory University, Purdue University, Stanford University, and Georgia Tech.

Ratcliff has brought her expertise to MSE. The concept behind the XPS is when one shines lights on a material, and if the light has a strong enough energy, it will release an electron fundamental charge out of that material and that electron goes speeding through space. The XPS shows what atom it came from and the bonds in which that atom participates. Currently, the university already houses a few XPS instruments. However, the one that Ratcliff helped to bring to campus is different. 

Because many of the materials Ratcliff’s laboratory is interested in researching have functionality or properties that are dependent on the environment that they're in, it is important to be able to emulate said environments. This instrument allows for looking at materials in oxygen and in water under electric fields where light can shine on them. Some research interests for the XPS instrument include batteries, catalysis, stability of materials and their chemical reactions and more. 

The addition of Ratcliff and the state-of-the-art XPS instrument marks a transformative chapter for MSE. Ratcliff’s innovative approach to scalable, sustainable materials and her dedication to fostering interdisciplinary research will undoubtedly pave the way for groundbreaking advancements in energy technologies. By enabling researchers to investigate materials under real-world conditions, the new XPS further solidifies Georgia Tech’s position at the forefront of materials science. Ratcliff’s journey, expertise, and leadership promise not only to advance the field but also to inspire the next generation of scientists and engineers tackling global energy challenges.

Read more articles from the Fall 2024 Edition of the MSEConnect Newsletter.