Title: Hidden pathways in molecular and colloidal self-assembly revealed through the development of in situ characterization methods

Speaker: Dr. Yu Wang, University of California at Berkeley

Date: 2019-03-25 16:00

Location: Room 202, Lujiaxi Building

Abstract：

Molecular and colloidal self-assembly has been recognized as an important “bottom-up” approach to constructing functional materials and self-organized systems for various applications. An understanding of the self-assembly pathways is significant for designing routes to the desired structures and the emergence of novel properties. However, it remains a great challenge to unveil the hidden pathways and translate states during self-assembly due to the difficulty of in situ characterizations, especially in complex hierarchical and/or multi-component systems. In this talk, we report our developments on in situ characterization methods and their effectiveness in revealing the hidden pathways during molecular and colloidal self-assembly. For instances, using in situ combined spectroscopies, we elucidate the transient structures during the self-assembly of organic cages and provide deep insights into the chiral amplification in multi-component supramolecular systems. Through a variety of in situ studies on molecular assembly, we discover and establish a new assembly mode that we name catalyzed assembly (catassembly) for its resemblance to catalysis. Finally, we highlight our discovery of the dynamic deformation of individual PbSe nanocrystals during colloidal assembly into superlattice through in-situ liquid-phase TEM. We show an unprecedented phenomenon that inorganic semiconductors are “soft materials” at the nanoscale. The discovery is significant not only for the designing of nanocrystals and nanocrystal architectures with desired properties for various applications, but also for controlling the physical and chemical processes of a wide range of matter at the atomic or nanometric level.