Identifying the unique optical phenomena of nanomaterials has been a central theme in understanding how we can leverage these materials for applications in fields including photocatalysis, bioimaging, and renewable energy. However, techniques often used to probe optical properties of these materials rely on detection of bulk material properties. Given the significant population of defects and structural variations that are innate to most nanomaterial syntheses, understanding precisely how heterogeneity affects the properties of these materials is critical, and requires single-particle techniques capable of probing both the structural and excited state electronic properties on the nm scale. To measure excited-state dynamics of single nanoparticles with spatial sub-nm resolution and temporal sub-ps resolution, our group employs an excited state imaging technique known as single-molecule absorption scanning tunneling microscopy (SMA-STM). We will discuss applications of this technique and preliminary STM data aimed at understanding the electronic and optical properties of carbon dots. In particular, our work focuses on differentiating between core and defect fluorescence mechanisms in blue, green, and red emitting carbon dots produced from varied phenylenediamine precursors.

Characterizing the electronic and excited state properties of carbon dots using single-molecule absorption scanning tunneling microscopy

Fall 2022 abstracts, posters, and presentations will launch in mid-September.

ACS Fall 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.