Ligation in data-driven synthesis studies of nanoparticles: A case study of phosphine-stabilized gold
Nanoparticles are promising materials for electrocatalysis due to their large surface area to facilitate reactions and their diverse properties that are tunable by composition, geometry, and surface chemistry. However, the informed synthesis of precise shapes and sizes of nanoparticles is still out of reach due to limited theory relating synthesis parameters directly to outcomes. Previous data-driven studies have aimed to map the potential energy surface of specific systems of nanoparticles by generating and calculating the energies of thousands of reasonable structures. This talk will show that it is crucial to include surface-stabilizing ligands as an additional factor in studies of solution-based synthesis. In solution-based synthesis, environmental ions and ligands can energetically stabilize specific sizes and shapes, different from those without such interactions. Phosphine-stabilized gold is considered as a test system and DFT calculations are performed for particles with and without ligands, producing a first of its kind database containing 11,000 structures for Au_n(PH3)_m (n<=12,m<=n). The study found that the addition of phosphines affects the thermodynamic stability, bonding, and electronic structure of Au nanoparticles. New ground state cluster geometries were stabilized that do not exist in the pure gold system. Further, the addition of phosphine introduced steric effects that induced an earlier non-planar transition size than previously predicted for bare clusters. Our work highlights the importance of considering the environment in the prediction of nanoparticle morphology and functionality, which adds complexity as well as a rich opportunity for tunability. This talk will detail the study as well as promote the corresponding database of 11,000 phosphine-stabilized gold clusters that will be available to the public for further use.
Caitlin McCandler is a graduate student researcher at the University of California Berkeley where she works in Prof. Kristin Persson's lab in collaboration with the Alivisatos, Ceder, Jain, and Sutter-Fella groups as part of an effort to accelerate nanoparticle synthesis using high-throughput techniques. Caitlin’s research investigates the impact of ligation on the dynamics of nanoparticle synthesis with first-principles computational methods. She received her BS in Materials Science and Engineering at MIT. Caitlin’s research is funded by the NDSEG fellowship.