Moungi Bawendi speaks about approaching challenges, mentoring trainees, and the developing field of quantum dots

Bawendi: “Research is really about problem solving and not being discouraged by failure—just keep on going.”

MIT Chemistry professor Moungi Bawendi was awarded the Nobel Prize in Chemistry jointly with Louis E. Brus and Aleksey Yekimov on Oct. 4 for "the discovery and development of quantum dots, nanoparticles so tiny that their size determines their properties". 

The Tech spoke with Dr. Bawendi about his approach to and the content of his work. This interview has been edited for length and clarity.

TT: Can you describe your work in one sentence?

Bawendi: We’re exploring how to make and the properties and applications of materials that are in the size range between molecules and materials. 

TT: Can you describe the most challenging moment that you and your team faced when creating quantum dots, and how you overcame them? 

Bawendi: Before I came to MIT, I had devised a method to make quantum dots of one particular size at Bell Labs, and it worked. When I came to MIT, we tried to reproduce that—and it didn’t work, and I thought my career was over.

We had to start over from scratch and reinvent how to make the material, and through that reinvention process, we devised a new way to make quantum dots based on what I had learned from Bell Labs. This reinvention is what led to the invention of a well-defined process of creating these really well-defined particles, which then allowed us to be able to make other applications and so on. The challenge was that nothing worked, and it took us about a year and a half—almost two years—to reinvent everything, and when we did that, it was so much better than before. That was my first paper at MIT, written in 1993, and that’s what we got the Nobel for. 

Overcoming that challenge is what led to this paper. Suddenly we had a way to make a series of materials of good enough quality that you can really begin to understand the physics of the evolution from molecules to the bulk.

And a few years later there was the first real application in ’96 and ’97. In ’98, there was the first company created to work in biological applications. In ’04, there was another company [whose work] led to the commercial applications of displays.

TT: Can you talk to us about your mentality in approaching difficult scientific and engineering questions? 

Bawendi: We work as a team. As a professor, I don’t really do much hands-on work anymore, but I have always been working closely—especially back then—with the students.

My job is to keep up the enthusiasm and persevere. Research is slow and things don’t usually work the first time. You have to have a vision of what you want, and you have to solve problems. Research is really about problem solving and not being discouraged by failure—just keep on going. My job is to be that leader and make sure that everybody realizes that you just gotta keep going! It’s going to work!

TT: What possibilities can we see in the field of quantum dots that you can imagine in the next 20 or 30 years? 

Bawendi: No, I could not predict what would happen in 20 or 30 years. Absolutely. 30 years ago, 20 years ago, we had no idea about what could be manufactured on this scale. I would say that humans are really terrible at predicting 20 to 30 years in the future. We’re pretty good at predicting three to five years, but in terms of 20 to 30 years, we have no idea.

I’ll tell you some possibilities, which may or may not happen. People are working in areas called photocatalysis. Basically, using light to catalyze chemical reactions of all sorts, including chemical reactions that could help harness energy from the sun for potential fuels.

I don’t know if it’s going to lead anywhere, but people are working on this, and it would be great if it worked! 

I am interested in the light output of these materials at room temperature one at a time. There's a kind of light called “quantum light” that can be manipulated and used for quantum computing or quantum cryptography. There are many groups on campus that work on similar kinds of schemes with single photons that you can then coalesce together to form systems that are super interesting. 

We have some preliminary data that seems to show that some of these materials at room temperature could be single photon emitters and could have these quantum properties. And it would be really cool if we could then arrange these materials in arrays and really scale this out. So, I’m really excited about that. 

There are other people working on other applications. One application that I think is really interesting is to use these materials as photodetectors because right now, in the visible, you have silicon, and in the infrared, you have other kinds of materials. People are looking for a photodetector that is not only adequate but also available at the fraction of the cost of the materials that are used today. 

TT: Does synthesizing quantum dots or using them in real-world applications have unintended impacts toward the environment? Are you working on ways to address this?

Bawendi: That’s an important question. This is something that we certainly had in mind when we think about applications. Companies have thought really hard not just about the hazardous waste regulations but also what happens in the real world. These dots are embedded within glass. The risk of release of the hazardous material is very very small. 

TT: What qualities do you believe are most valuable in the making of a good mentor? How have you incorporated that into your mentorship approach?

Bawendi: It’s nice to be able to guide students to be able to achieve their very best. And that means that the student is able to grow as an independent researcher. I don't tell everybody what to do. I have to provide a vision and the tools for them to be able to succeed towards that vision. In the end, they might end up something different from what I expected. As they solve those problems, we work together and then I recognize something that they don't because I have more experience than they do and then I can choose a direction. Ultimately, my job is to get them to become independent and successful.