Our Research Thrusts
CHOISE's scientific studies are organized around four research thrusts. Each thrust has two leaders: one from a national laboratory and one from a research university.
As shown in Figure 1, Thrust 1—Hybrid Organic-Inorganic Semiconductor (HOIS) Design and Synthesis—overarches the work within the other three thrusts. Furthermore, continual feedback between computation and experiment enables rigorous development of structure-property-function relationships and design rules for realizing emergent phenomena.
Learn about key scientific concepts that encompass our research.
Thrust 1: Crystalline HOIS Design, Synthesis, and Structure/Property Relationship
Thrust 1 leverages the distinct attributes of hybrid organic and inorganic chemical systems and employs new preparation and characterization approaches guided by computation to systematically advance rational synthesis of complex solids.
- Design/demonstrate complex hybrids to achieve novel physical behaviors.
- Develop novel preparative methods that balance the disparate requirements of the targeted inorganic/organic components to achieve high-quality crystal/films.
- Employ in-situ experimental probes and advanced ex-situ characterization to guide organic/inorganic hybrid synthesis.
- Build nanostructured components with unique functionality.
Thrust 2: Controlling Spin Degrees of Freedom
Long spin-coherence time present with large spin-orbit coupling (SOC) provides great opportunities for spintronics. What gives current Pb-based HOIS the unique ability to have large SOC yet exhibit long spin-coherence times? We hypothesize that we can control Rashba and Dresselhaus effects by compositional tuning of 3-dimensional/2-dimensional systems, along with incorporating strain and/or electric fields. These spin phenomena are necessarily related to topology. As we gain control and better understanding, we will examine novel topological phenomena at surfaces and interfaces.
- Elucidate how SOC relates to spin-coherence times by controlling/tuning Rashba splitting via strain, doping, dimensionality, and composition.
- Learn to inject and harvest spins in spin-based architectures.
- Explore the effects of dimensionality on controlling spin relaxation.
- Uncover how to realize topologically protected states.
Thrust 3: Controlling Light/Matter Interaction
Light/matter interactions play a fundamental role in many technologies, such as light-emitting diodes, photodetectors, lasers, non-linear optics, photovoltaics, and quantum information processing. Optical response is intimately tied to lattice and composition (both bulk and surface), density of electronic states and occupation in both conduction/valence bands, and spin degree of freedom. However, we lack detailed mechanistic understanding of these connections.
- Uncover the role of structure and composition on ordering of electronic states and optical selection rules, and tailor photo-physical phenomena.
- Elucidate and control the factors that govern narrow- and broad-band emission.
- Interrogate the level splitting, structural asymmetry, and Rashba terms by their connection to nonlinear optical interactions.
- Elucidate the mechanisms governing light-induced structural changes.
- Investigate the photocatalytic potential of HOIS systems.
Thrust 4: Harnessing Charge-Carrier Degrees of Freedom
Many unusual charge transport, recombination, thermal relaxation, and electromechanical behaviors have been observed—yet, the origins of these phenomena remain unclear. We elucidate structure/function properties that govern how charges interact with the lattice to induce unusual optoelectronic properties.
They address four areas of controlling charge-carrier phenomena:
- Interaction of charge carriers with defects, strain, and phonons.
- Charge transport/recombination near, at, and across interfaces.
- Emergent phenomena associated with lattice distortion, polarization, and doping.
- Interaction of carriers and phonons to slow carrier cooling (hot carriers).