For Materials Research, Mengxia Liu Wins Packard Fellowship

For research that aims to get a better understanding of how materials behave in actual devices, Prof. Mengxia Liu has received the prestigious Packard Fellowship for Science and Engineering.  

Each year, the David & Lucile Packard Foundation’s advisory panel of scientists and engineers carefully reviews nominations and selects 20 early-career researchers to receive individual grants of $875,000. The grant is distributed over five years to fund their research with few restrictions or requirements. Topics of study vary widely, and Packard Fellows are encouraged to think big and look at complex issues with a fresh perspective. They may use their funds in whatever way they believe will best advance their research.

Liu’s research focuses on developing methods to create thin-film semiconductors, optoelectronic materials and devices for applications in energy, sensing, and information technologies. Critical to all these energy-related systems is the behavior of energy carriers.

“For example, the charge dynamics determine the efficiency of a solar cell, and phonon transport is key to thermoelectric devices,” said Liu, assistant professor of electrical engineering. “So understanding and manipulating the behavior of these energy carriers is crucial to creating new device concepts and designing new materials.” 

The semiconducting materials that Liu’s laboratory mainly works with are the metal halide perovskite and nanocrystals known as quantum dots. One focus of her project is developing ways to observe carrier dynamics in these materials as they would appear in a functional device. Previous research in the field tends to examine these materials in isolation.  

“However, when materials are integrated into heterogeneous devices and tested under realistic conditions, there is a mismatch between the independent material property and observed device performance,” said Liu, a member of Yale’s Energy Sciences Institute. “And this presents a key barrier to realizing the full potential of these advanced semiconductors. It also prevents us from generating new ideas for optimizing these materials.”

Real devices often use multiple layers of different materials, she said. Further, these materials are also often in electric fields or have different stimuli applied to them - all of which can change the properties of these materials. To Liu, the key to tackling these challenges is to understand the carrier phenomena under multiple perturbations in functioning devices. 

“This is similar to how biologists study the living systems in vivo,” she said. “Similarly, we also want to understand the carrier phenomena under multiple stimuli in functioning devices.”

David Packard, co-founder of the Hewlett-Packard Company, established the Packard Fellowships in 1988. The Packard Foundation has since awarded $481 million to support 675 scientists and engineers from 54 national universities.