Harnessing the Sun

When Honors student Prineha Narang (B.S. Materials Engineering) graduated from Drexel University this spring, she did so with an impressive resume that included leadership within Drexel, an extensive service record, and international research experience as a DAAD-RISE (German Academic Exchange Organization - Research Internships in Science & Engineering) fellowship winner. Prineha has just begun graduate school at Caltech, where she is pursuing a Ph.D. in Materials Science and Applied Physics as a Resnick Fellow and National Science Foundation Fellow. She works as part of the U.S. Department of Energy’s Energy Innovation Hub for Fuels from Sunlight — Joint Center for Artificial Photosynthesis (JCAP) headed by Drs. Nathan Lewis and Harry Atwater (who are also her thesis advisors). Here, in her words, Prineha discusses the importance of her work, her commitment to service, and how her experiences at Drexel inspired both.

sunThe mission of JCAP is to demonstrate a scalable and cost‐effective solar fuels generator that, without use of rare materials or wires, robustly produces fuel from the sun 10 times more efficiently than typical current crops or any other solar device out there today. Finding a cost-effective way to produce fuels, by combining sunlight, water, and carbon dioxide, would be a transformational advance in carbon-neutral energy technology.

Consensus is that a solar-fuels generator must consist of several key elements. First, materials that efficiently capture and convert sunlight to charge carriers, while providing the voltage needed to drive the fuel-forming reactions. Second, catalysts to facilitate both water oxidation by photogenerated holes and water or carbon dioxide reduction to fuel by photogenerated electrons. Third, a membrane to separate oxygen from reacting with the energy-rich reduced products, as well as easily oxidized system components. The membrane separator must also pass protons (or hydroxide) to prevent a pH gradient that would otherwise build up and shut down the system.

At present, the development of each of these needed components is blocked by scientific and technological barriers. No simple semiconducting light-absorber combination exists that is made from Earth-abundant elements, is robust in sunlight, and is capable of providing the needed voltage to produce the fuels of interest. I work on this light absorber component of the project with the goal of discovering and developing light absorbers that consist of robust, photochemically stable, Earth‐abundant elements to provide the needed voltage and current density to effect fuel formation from sunlight, water, and carbon dioxide as the only inputs.

The development of low-carbon fuels that can meet demand while reducing carbon dioxide emissions is critical to energy security, environmental security, and economic security for the United States and the world. Biofuels are one potential option, but concerns remain about sustainability, practicality, implications of indirect land use issues on the carbon content of the atmosphere, and trade-offs of food for fuel. Another technology development approach, to be pursued in JCAP, involves the development of artificial photosynthesis, in which the system performs the same function as that of plants, but with a robustness and efficiency that is at least a factor of 10 greater than the best-known biological photosynthetic systems, would allow for installation of the systems in a diverse range of sites and environments, and would provide the direct production of a useful chemical fuel from the intermittent energy source, the sun. JCAP received $122 million from Department of Energy over five years to do this work (subject to Congressional appropriations).

While research and service are typically seen as separate endeavors, I believe that tackling some of the most pressing problems we face today, such as sustainable energy generation and storage, requires that the two realms be brought together, enabling those with strong technical backgrounds to invent creative solutions to very real problems. I envision a career that integrates science and service and gives me the opportunity to use my skills as an engineer to solve problems that people face on a daily basis. Through my research as a materials scientist, I would like to address the need for improved energy generation and storage solutions, critical to meet the projected energy demands of the future.

My commitment to a combination of service and engineering started with my involvement with the Drexel chapter of Engineers Without Borders (EWB). EWB is an organization focused on sustainable engineering projects in the rural communities of developing countries. As the president of Drexel EWB for two years, I led two engineering projects overseas. When I joined EWB, we were in the process of designing and implementing a water system in Miramar, El Salvador — our first project as a chapter. Soon after being elected president, I started a second initiative: a project in Middleton, Jamaica. In collaboration with a member of the Peace Corps, we worked to rebuild two pedestrian bridges washed away by tropical storm Gustav. It was during this project I realized how satisfying it is to work toward fulfilling the basic needs of a developing community, constantly engaging them in the design process and educating them in sustainable technology. As an added validation, multiple awards including Outstanding Student Organization in Service from Drexel’s Office of Student Life, recognized our work. Leading EWB motivated me to commit to “engineering a better world, one community at a time” and put into perspective my responsibility as a scientist. During the EWB projects, energy generation and storage (or the lack thereof) was a recurring problem faced by the communities I worked with, which hindered all aspects of their lives: education, health care, economic opportunities and much more. My work with EWB underlined the need for innovation in energy, specifically low cost solutions for energy generation and storage.

My goal beyond my doctoral research is to set a trajectory such that I am able to continue transformative research in energy applications, working at the interface of basic research and industrial applications, preferably in an energy-focused national lab. In the long term, inspired by prominent scientists I have worked with, I endeavor to pursue a leadership role in the Department of Energy to impact the focus and future of energy research in the United States.

My experience at IBM T.J. Watson Research Center as well as my research experiences as an undergraduate student at Drexel have helped me advance both personally and professionally, and with the opportunities provided by the Resnick- Goldhirsh Fellowship and the NSF fellowship, I will further develop my research skills to be a scientific leader in energy and materials research.

Image by rchughtai/CC BY-NC-SA 2.0