The Chang lab aims to fundamentally understand light-matter interactions in organic and inorganic nanomaterials for the applications of catalysis and sensing. We utilize several microscopic techniques, including photothermal, dark-field scattering, fluorescence, and electron microscopy, to explore the structure-function relationship of nanostructures. We focus on the following topic.

Exploring photo- and electrocatalytic activity of metallic nanoparticles and 2D materials at the nanometer scale

Photocatalysts and electrocatalysts are the key elements to convert the atmosphere molecules, especially the greenhouse gas CO₂, into high valuable fuel molecules or chemicals. Nanostructures including metallic nanoparticles and 2D materials provide unique electronic structures and more accessible surface sites leading to higher activities. However, these nanostructures, when chemically synthesized, are inherently heterogeneous in size, shape, and defect sites, all of which are critical for the catalytic activity. Such heterogeneity hinders the direct correlation between these parameters to the catalytic activity. The Chang lab aims to probe the catalytic activity of metallic nanoparticle and 2D materials at the nanometer scale and correlate with their morphologies that are characterized by the electron microscopy.

 

Probing chiral molecules using chiral plasmonic structures

Chiral molecules exhibit extremely high stereoselectivity in chemical or biological reactions. The enantiomer, one of the stereoisomers of the chiral molecule, possesses different stereo nature in the reactions leading to different pathways from the initial purpose. Therefore, it is crucial to determine the chirality of the molecules accurately. However,  The conventional method to probe molecular chirality show limited sensitivity owing to the mismatch between the helical pitch of circularly polarized photons and length scales of chiral molecules. Plasmonic nanostructures are demonstrated to concentrate light into nanoscale. Chang Lab aims to design and fabricate plasmon nanostructures that create the superchiral field in the nanoscale and develop a spectroscopic technique to probe molecular chirality with high sensitivity.