Presenter: Samuel Estrella
Faculty Mentor: John McGuire
Presentation Type: Poster 13
Primary Research Area: Science
Major: Physics
Quantum Dots are widely studied in hopes of using their tunable emission and absorption for photovoltaics and solar cells. Quantum dots are very small lattices containing around ten thousand to one million atoms. Due to their small size, it is easier for an electron that is excited from the core to reach the surface. The dangling bonds on the surface reduce the quantum efficiency of the dots by trapping carriers and preventing emission while trapped. Passivating these dangling bonds so carriers don’t get trapped is necessary to continue observations on more complex systems. Performing transient absorption with a 100 femtosecond laser, we were able to observe trapping in the quantum dots. We probed Cadmium (II) Selenide quantum dots that were treated with chlorine and mercaptoundecanoic acid ligands to passivate charge trapping on the surface and to prevent aggregation. The treatments that were used to passivate the surface traps showed no significant decrease in trapping. While we were not able to observe any benefit from the treatments, our collaborators at the Korea Institute for Science and Technology are developing different treatments to use on quantum dots. Upon decrease of trapping, quantum dots will be useful for quantum computing, biological marking, optical processing and tunable absorption and emission.