Structural Photonics: Tailoring the Optical, Catalytic, and Plasmonic Properties of 2-D Transition Metal Dichalcogenides
Abstract
This proposal details a three-year plan to combine advanced magneto-optical and femtosecond multi- dimensional spectroscopy, computation, correlated light and electron microscopy (CLEM) and solution-phase assembly to describe optical properties and electronic dynamics in structurally well-defined transition metal dichalcogenides (TMDs). An overall goal is to understand the influence of both inter- and intra-layer structure/composition on energy flow through these systems. Our primary intellectual thrust is to test the hypothesis that selective excitation of exciton fine structure states determines electronic relaxation – including energy transfer – dynamics for these systems. We will determine if energy transfer can be controlled by spin-specific population of exciton states. Single- and few-layer MoS2 are chosen as model systems for examining these effects because exfoliation of ordered arrays is established. Because radiative recombination by high-spin excitons is forbidden, mixing with short-lived bright states is expected to increase the coherence lifetime of exciton superpositions. We will also quantify the interplay between incoherent relaxation processes (e.g. radiative decay and electron-phonon coupling) and coherence for structures with tailored bright-dark state spectral weights.These fundamental processes are critical for controlling energy at the molecular and nanoscale levels. Controlling energy flow through TMD assemblies can lead to new plasmonic effects at visible and near infrared (telecommunications) wavelengths, catalysis, nonlinear optical transduction, and room-temperature single-photon emission. Challenges in correlating TMD structure and photonic properties arise because state-resolved femtosecond measurements with the necessary spatial resolution are difficult. We will overcome these challenges through state-of-the-art combination of CLEM and magnetooptical measurements.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jul 11, 2018
- Source ID
- FA95501810347
Entities
People
- Kenneth L. Knappenberger
Organizations
- Air Force Office of Scientific Research
- Pennsylvania State University
- United States Air Force