A5086044611- Quantum Dots Synthesis And Properties
- Chalcogenide Semiconductor Thin Films
- Gold and Silver Nanoparticles Synthesis and Applications
- Nanocluster Synthesis and Applications
- Molecular Junctions and Nanostructures
- Electrocatalysts for Energy Conversion
- Electron Spin Resonance Studies
- Electrochemical Analysis and Applications
- Magnetism in coordination complexes
- CO2 Reduction Techniques and Catalysts
University of Notre Dame
2019-2023
University of Kansas
2019
The adaptation of colloidal semiconductor nanocrystals (NCs) in applications like displays, photovoltaics, and photocatalysis relies primarily on the core electronic structure NC materials that give rise to desirable optoelectronic properties broad absorption size-tunable emission. However, reduction or oxidation events at localized surface sites can greatly affect sample stability device efficiencies by contributing degradation carrier trapping. Understanding local composition, structure,...
Irradiation of cobalt metallocenes at the ligand-to-metal charge transfer energies results in labilization cyclopentadienyl–cobalt bond and radical release. The cyclopentadienyl is detected by electron paramagnetic resonance (EPR) spectroscopy using a spin trap can also be chemically trapped hydrogen-atom-donating reagents. This reaction presents new photochemical method generating complexes or forming cobalt(I) species that are active for catalytic [2 + 2 2] cyclotrimerization reactions....
Heterobimetallic tetracarbonylferrate compounds ([MFe(CO)4], M = Cd, Zn) were used as Z-type ligands that coordinate to surface chalcogenide sites of colloidal metal nanocrystals (CdSe, ZnS, and PbS). IR spectroscopy the carbonyl moieties permits in situ studies addition dissociation at nanocrystal surfaces provides mechanistic insight into trap passivation. In absence Lewis bases like amines, ligand coordination CdSe does not occur through simple donor–acceptor interactions between but...
EPR spectroscopy is used to interrogate nucleophilic and radical reactions at colloidal metal chalcogenide quantum dot surfaces via thermal or photochemical formation of surface-bound nitroxide radicals from spin trap molecules.
Organometallic surface functionalization of colloidal CdSe and CdS nanocrystals using iron tetracarbonyl moieties is demonstrated to enable study in situ nanocrystal redox chemistry. Spectroscopic measurements the surface-bound metal carbonyl C–O stretches were used elucidate coordination environments local symmetry sites. The stretching frequencies these fragments correlated electric field induced by charges shift energy upon reduction or oxidation. These revealed that can accumulate...
Characterizing the surfaces of colloidal semiconductor nanocrystals (NCs) remains a key challenge for understanding and controlling their physical properties chemical behavior. For this reason, development new methods to study NC is great interest. In paper, we report use (Me3Si)2Fe(CO)4 Et3SiCo(CO)4 as reagents functionalizing CdSe with organometallic metal tetracarbonyl fragments. This method avoids surface reduction can achieve high carbonyl densities. Surface or oxidation, well changes...
The possible participation of colloidal semiconductor nanocrystal quantum dot (QD) surfaces in QD-mediated photocatalytic reactions is an important factor that distinguishes QDs from other photosensitizers (e.g. noble metal complexes or organic dyes). Here, we probe nucleophilic and radical reactivity surface sulfides selenides chalcogenide (CdSe, CdS, ZnSe, PbS) using various chemical NMR spectroscopy. Additionally, the high sensitivity EPR spectroscopy adapted to study these...