title: Strain-Mediated Interfacial Dynamics during Au-PbS Core-Shell Nanostructure Formation.
abstract: An understanding of the hierarchical nanostructure formation is of significant importance for the design of advanced functional materials. Here, we report the in situ study of lead sulfide (PbS) growth on gold (Au) nanorod seeds using liquid cell transmission electron microscopy (TEM). By tracking the formation dynamics of Au-PbS core-shell nanoparticles, we found the preferential heterogeneous nucleation of PbS on the ends of a Au nanorod prior to the development of a complete PdS shell. During PbS shell growth, drastic sulfidation of Au nanorod was observed, leading to large volume shrinkage (up to 50%) of the initial Au nanorod seed. We also captured intriguing wavy interfacial behavior, which can be explained by our DFT calculation results that the local strain gradient at the core-shell interface facilitates the mass transport and mediates reversible phase transitions of Au ↔ Au2S during the PbS shell growth.
authors.affiliation: Department of Materials Science and Engineering, University of California , Berkeley, California 94720, United States.
authors.forename: Kai-Yang
authors.initials: KY
authors.lastname: Niu
authors.affiliation: Environmental Energy Technologies Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States.
authors.forename: Miao
authors.initials: M
authors.lastname: Liu
authors.affiliation: Environmental Energy Technologies Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States.
authors.forename: Kristin A
authors.initials: KA
authors.lastname: Persson
authors.affiliation: Advanced Membranes and Porous Materials Center, Physical Sciences and Engineering Division, King Abdullah University of Science and Technology (KAUST) , Thuwal 23955-6900, Kingdom of Saudi Arabia.
authors.forename: Yu
authors.initials: Y
authors.lastname: Han
authors.affiliation: Department of Materials Science and Engineering, University of California , Berkeley, California 94720, United States.|Materials Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States.
authors.forename: Haimei
authors.initials: H
authors.lastname: Zheng
keywords: core−shell nanostructure; gold nanorod; heterogeneous growth; interfacial strain; liquid cell TEM