Surface characterization of colloidal nanoparticles with a widely applicable toolkit
Published on 21. September 2020
Book
Paperback/Softback
181 pages
978-3-8439-4557-8 (ISBN)
Description
Colloidal nanoparticles (NPs) have attracted a lot of attentions in various research areas such as optoelectronics, sensors, and bioimaging. At the nanoscale, the surface/interface of colloidal NPs is of great importance due to the high surface-to-volume ratio. Although being of major importance for all kinds of colloidal NPs-based applications, the unambiguous characterization of colloidal surface/interface is still an open and highly challenging task.
In this work, approaches for shedding new light on thermodynamic and kinetic aspects of the functionalization of colloidal NPs will be discussed. For thermodynamics, first, a widely applicable strategy (toolkit) based on a unique combination of highly complementary analytical methods was established to access the surface of colloidal NPs. Second, the toolkit was further expanded by applying small angle X-ray and neutron scattering techniques to characterize the complex interplay of NP-ligand-dispersing liquid. Third, the developed toolkit was applied to reveal the connections among tail groups of surface ligands with different electron-donating/-withdrawing properties, binding enthalpy, and photoluminescence quench during the functionalization of ZnO NPs. For demonstration of wide applicability even to highly complex nanostructures, the developed toolkit was applied to investigate the core and the surface of anisotropic core-shell-shell nanorods after multiple growth steps. Finally, regarding kinetics, a novel, fitting-free concept of using a spectral library in combination with stopped-flow UV/Vis measurements together with a "search best-match" Matlab algorithm was established. This allowed directly accessing the kinetics of ligand binding to colloidal NPs at high temporal resolution even with the presence of strong interactions between particle surface and bound ligands.
The developed concepts will affect fundamental research as well as various emerging fields where tailored NP surfaces are needed.
In this work, approaches for shedding new light on thermodynamic and kinetic aspects of the functionalization of colloidal NPs will be discussed. For thermodynamics, first, a widely applicable strategy (toolkit) based on a unique combination of highly complementary analytical methods was established to access the surface of colloidal NPs. Second, the toolkit was further expanded by applying small angle X-ray and neutron scattering techniques to characterize the complex interplay of NP-ligand-dispersing liquid. Third, the developed toolkit was applied to reveal the connections among tail groups of surface ligands with different electron-donating/-withdrawing properties, binding enthalpy, and photoluminescence quench during the functionalization of ZnO NPs. For demonstration of wide applicability even to highly complex nanostructures, the developed toolkit was applied to investigate the core and the surface of anisotropic core-shell-shell nanorods after multiple growth steps. Finally, regarding kinetics, a novel, fitting-free concept of using a spectral library in combination with stopped-flow UV/Vis measurements together with a "search best-match" Matlab algorithm was established. This allowed directly accessing the kinetics of ligand binding to colloidal NPs at high temporal resolution even with the presence of strong interactions between particle surface and bound ligands.
The developed concepts will affect fundamental research as well as various emerging fields where tailored NP surfaces are needed.