BEGIN:VCALENDAR VERSION:2.0 PRODID:-//ZContent.net//ZapCalLib 1.0//EN CALSCALE:GREGORIAN METHOD:PUBLISH BEGIN:VEVENT SUMMARY:Directly Visualizing Carrier Generation and Transport at the Nanosc ale within Two-Dimensional Semiconducting Materials via Scanning Electroch emical Cell Microscopy LOCATION:Virtual Seminar TZID:America/Denver DTSTART:20201118T160000 UID:2026-04-25-09-46-21@natsci.colostate.edu DTSTAMP:20260425T094621 Description:Zoom Link:\n\nhttps://zoom.us/j/97032192900?pwd=VmJNbm5vQUJGNU9 1OHVFa0xXZ1Y1QT09\n\nMeeting ID: 970 3219 2900\n\nPasscode: 1872\n\nAbout the Seminar:\n\nNumerous “two-dimensional” (2D) semiconducting materia ls\, which possess covalent bonding in only two dimensions\, exhibit emerg ent physical properties at the mono/few-layer limit which could potentiall y revolutionize the design of electronic and photonic devices. While ultra thin layers of 2D materials have been successfully prepared through a vari ety of routes\, the resulting layers always contain various types of struc tural defects\, such as step/edge terminations or atomic vacancies\, which can impact performance (positively or negatively) in a given application. A firm understanding of how physical or chemical processes are altered at these defects would provide a rational basis for the design of improved d evices\, but such information has proven difficult to generate using conve ntional analytical tools\, which cannot differentiate the behavior of defe cts from that of the pristine bulk material. In this presentation\, studie s will be described which apply Scanning Electrochemical Cell Microscopy ( SECCM) as a tool for exploring the physical and chemical behavior of 2D se miconducting materials at the nanoscale\, clearly revealing the role struc tural defects play in the generation\, transport\, and extraction of minor ity carriers in these materials. Utilizing mechanically-exfoliated transit ion metal dichalcogenide (TMD) nanoflakes as a model system\, it will be s hown how SECCM can be employed to directly map photocurrents generated wit hin single-particle “solar cells”\, revealing how various types of nat ive and engineered defects alter carrier recombination and extraction in p hotoelectrochemical cells. A novel mode of SECCM\, “Carrier Generation-T ip Collection” (CG-TC)\, will then be described which allows carrier tra nsport within individual nanostructures to be directly visualized. CG-TC s tudies will be presented which quantitatively analyze carrier transport wi thin individual TMD nanoflakes\, allowing bulk carrier diffusion lengths a nd recombination velocities at individual\, nanoscale defects to be unambi guously evaluated. Applications of these methods to analyze carrier dissoc iation/transport within heterostructures of 2D materials will be presented at the outset.\n\nAbout the Speaker:\n\nCaleb M. Hill earned a B.S. in Ch emistry from Jacksonville State University in 2009 and a Ph.D. in Physical Chemistry from The University of Alabama in 2014. During his Ph.D. studie s\, he worked in the group of Shanlin Pan\, developing optical methods for probing electrochemical reactions at individual nanostructures. He then j oined the group of Allen J. Bard at the University of Texas as a postdocto ral researcher\, where he studied the effects of electron tunneling in pas sivated ultramicroelectrode systems and electrochemical methods for probin g individual nanoparticles. In 2016\, he began his independent career in t he Department of Chemistry at the University of Wyoming\, leading a resear ch group focused on the development of improved analytical methods for pro bing chemical processes at single reactive entities and the application of these methods to gain insights into systems for clean energy conversion a nd storage. 4:00 pm END:VEVENT END:VCALENDAR