Sabrina Li '17

This is one in a series looking in on the work and projects Pomona students are carrying out this summer.

Project summary in Sabrina's words:

I'm making organic solar cells, which I believe will eventually become one of our main sources of energy. Right now solar cells are mostly made from inorganic material like silicon, but the materials are really expensive and the solar cells themselves are fragile. I'm making solar cells with carbon, which is a more abundant element that is more inexpensive than semi-metals. If we can make more of these thin-film, organic carbon-based solar cells, we can implement them in more places and help fight the energy crisis.

What is your mentor like?

Professor David Tannenbaum is my research professor, but I also work under one of his thesis advisees, Emily Yang '14, who worked on this project for four years before she graduated. Professor Tannenbaum is really enthusiastic about solar cell research because he worked in Denmark for a leading solar-cell research group. He really knows what he's doing. And Emily is the nicest mentor ever. I still refer back to her thesis a lot for this project. She's here often, which is helpful because Professor Tannenbaum has to split his time among all his lab groups. It's good to have Emily as a resource because she's so good at what she does. They're really supportive mentors and I'm very thankful for both of them.

What is the biggest problem you're running into right now?

Solar cells are stacks of different things. There's the electrode, which is followed by the electron-conducting layer of zinc oxide on the bottom. There's the active layer, which separates the positive charge from the electron when it is hit by photons. Then there's the molybdenum trioxide layer, which helps the positive charge move and increases the percent power conversion efficiency of the solar cell. The evaporator I'm using isn't giving me a consistent thickness of evaporated molybdenum trioxide, which I really need. I'm working with things that are 50 nanometers thick, and it's hard to get such consistency on such a small level.


Why are you doing summer research?

I wanted to get back into a lab environment and work on something that I'm enthusiastic about. I really like studying environmentalism and seeing how we can change our habits and our energy consumption. This is a project that really interested me because it has immediate real-world applications. It was also important to me to go to a college where I could get research experience as an undergraduate. I read about the SURP program when I applied to Pomona, and when I visited I asked the admissions tour guide about SURP. He walked us through the science buildings and I couldn't help but think, "Wow, this is a really nice school."