Photo-Activation of Single Molecules and Assemblies

Seminar series
Physical Chemistry Seminar
Thu, Dec 18 12:15pm
2033 Young Hall
Speaker Yuxi Zhao
University of California, Los Angeles
Dept. of Chemistry and Biochemistry

Abstract: Understanding energy/electron transfer at the molecular level is critical to the rational design and performance improvement of organic optoelectronics and photovoltaics. Scanning tunneling microscope (STM) facilitates measurement of electronic properties with atomic precision. Here, we introduce a custom-built, laser-assisted STM that integrates optical excitation into the tunneling junction. The evanescent field generated by incident laser light excites surface adsorbates on epitaxial gold films, enabling the monitoring of light-induced activities of isolated photoactive molecules under ambient conditions. Our method offers a versatile platform to elucidate the involvement of individual states or local environment that affect charge generation and separation in a C60-tethered 2,5-dithienylpyrrole triad, a molecular donor-acceptor heterojunction, and to correlate the particular molecular orientations with the measured local electronic structure of the anthracene-terminated aromatic thiolates in the tunneling junction.