Vitals
Current affiliation: Columbia University
Age: 37
PhD alma mater: University of Sheffield
If I were an element, I’d be: “Neon, because I like the way it sounds, and I admire its capacity to avoid (over)reacting to anything!”
My role model is: “Louis Brus, for his ability to identify truly important questions, his unceasing scientific curiosity, his unique combination of extraordinary scientific rigor with humility and kindness, and his incredible mentorship to so many.”
Milan Delor’s website features a simple cartoon. On the left, a photon enters a solar cell, sending a positive and a negative charge carrier in looping, meandering paths toward opposite electrodes. That, according to the figure, is what we have. What we want—what Delor wants—is shown on the right, where the charge carriers are making beelines for the electrodes.
The diagram shows how electrons and other particles lose energy when they move through materials due to disorder in the materials’ lattices. If scientists can find ways to minimize those losses, we could make more efficient solar panels, quantum computers, and other devices.
Delor, a chemistry professor at Columbia University, comes at the challenge from two directions: the molecules and the material. Citing theoretical chemist Roald Hoffmann, who won the 1981 Nobel Prize in Chemistry, Delor says chemists are used to thinking about more-or-less real objects: molecules, electrons, orbitals. Physicists, on the other hand, prefer more abstract concepts, like electronic band structures, which are energy levels an electron can occupy in a material.
“There’s a huge advantage to being able to think in both realms,” Delor says. For instance, the chemist’s approach lets him understand how an electron would strain the lattice structure of a material. But the physicist’s tells him how an electron will act when it moves through the material, as it would in a solar cell or computer chip.
He recently showed several ways that energetic particles can move through excited materials with almost zero resistance. The concept is similar to a superconductor, the key difference being that the materials are in an excited state rather than a ground state. In one example, hybrid vibrational and electronic excitation makes particles so heavy that disorder in the material lattice can’t slow them down. In another, the wavelength of hybrid light and electronic particles is so large that the particles miss anything in the material that would disrupt their path. Delor says the next step is to show how these effects could be harnessed in technologically useful ways.
Naomi Ginsberg, Delor’s postdoctoral adviser at the University of California, Berkeley, says he is changing the way people think about energy transport and light-matter interactions. “I think he’s making people think about what’s possible,” she says.
Delor did not make a beeline to physical chemistry. He got his master’s degree in astrophysics, but along the way he became more interested in the energy transition from fossil fuels to renewable sources. So he applied to a green energy PhD program at the University of Sheffield that let him rotate through different departments.
That experience led him to the world of ultrafast laser spectroscopy and a project on charge separation and electron transfer in solution. Using a donor and acceptor molecules bridged by a platinum atom, Delor and his colleagues showed they could control electrons’ movement using laser pulses. “It was assumed to be impossible,” says his PhD adviser, Julia A. Weinstein, because the solution would prevent clean charge transfers. Delor was able to pull it off.
For his postdoc, Delor wanted to apply to materials what he had learned about observing and manipulating the movement of energy. He also wanted to develop his microscopy skills to better understand the materials he was studying. He developed a new microscopy technique that uses light scattering to track electrons, heat, and other energy movements in different materials.
Delor’s path to New York City was no more straightforward than his path to experimental physical chemistry. Born in France, he moved to Réunion, an island in the Indian Ocean, at 2 years old. His dad was setting up a vocational program for textile and fashion design there. Delor describes it as “a very chilled-out childhood” that included a lot of surfing, sailing, and time in the mountains, one of which is an active volcano.
Next his family moved to the Shanghai area, where Delor attended an international school. That got him interested in going to university in an English-speaking country. Hence, Sheffield, then Berkeley, and now Manhattan. When he isn’t exploring interactions between light and matter, Delor and his wife have been enjoying walking in New York City and enjoying its jazz clubs, and hiking in the Adirondack and Shawangunk mountains.
