Correlating HR-TEM and XPS to elucidate the core-shell structure of ultrabright CdSE/CdS semiconductor quantum dots
- Controlling the thickness and tightness of surface passivation shells is crucial for many applications of core-shell nanoparticles (NP). Usually, to determine shell thickness, core and core/shell particle are measured individually requiring the availability of both nanoobjects. This is often not fulfilled for functional nanomaterials such as many photoluminescent semiconductor quantum dots (QD) used for bioimaging, solid state lighting, and display technologies as the core does not show the application-relevant functionality like a high photoluminescence (PL) quantum yield. This calls for a whole nanoobject approach. Moreover, the thickness of the organic coating remains often unclear. By combining high-resolution transmission electron microscopy (HR-TEM) and X-ray photoelectron spectroscopy (XPS), a novel whole nanoobject approach is developed representatively for an ultrabright oleic acid-stabilized, thick shell CdSe/CdS QD with a PL quantum yield close to unity. The size of thisControlling the thickness and tightness of surface passivation shells is crucial for many applications of core-shell nanoparticles (NP). Usually, to determine shell thickness, core and core/shell particle are measured individually requiring the availability of both nanoobjects. This is often not fulfilled for functional nanomaterials such as many photoluminescent semiconductor quantum dots (QD) used for bioimaging, solid state lighting, and display technologies as the core does not show the application-relevant functionality like a high photoluminescence (PL) quantum yield. This calls for a whole nanoobject approach. Moreover, the thickness of the organic coating remains often unclear. By combining high-resolution transmission electron microscopy (HR-TEM) and X-ray photoelectron spectroscopy (XPS), a novel whole nanoobject approach is developed representatively for an ultrabright oleic acid-stabilized, thick shell CdSe/CdS QD with a PL quantum yield close to unity. The size of this spectroscopically assessed QD, is in the range of the information depth of usual laboratory XPS. Information on particle size and monodispersity were validated with dynamic light scattering (DLS) and small angle X-ray scattering (SAXS) and compared to data derived from optical measurements. The results of the different methods match very well within the different measurement uncertainties. Additionally, results obtained with energy-resolved XPS using excitation energies between 200 eV and 800 eV are discussed with respect to a potential core/shell intermixing. Moreover, the future application potential of this approach correlating different sizing and structural methods is discussed considering the method-inherent uncertainties and other core/multi-shell nanostructures.…
Autor*innen: | Jörg RadnikORCiD |
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Koautor*innen: | Florian Weigert, I. Häusler, Daniel Geißler, Ute Resch-GengerORCiD |
Dokumenttyp: | Vortrag |
Veröffentlichungsform: | Präsentation |
Sprache: | Englisch |
Jahr der Erstveröffentlichung: | 2021 |
Organisationseinheit der BAM: | 1 Analytische Chemie; Referenzmaterialien |
1 Analytische Chemie; Referenzmaterialien / 1.2 Biophotonik | |
6 Materialchemie | |
6 Materialchemie / 6.1 Oberflächen- und Dünnschichtanalyse | |
DDC-Klassifikation: | Naturwissenschaften und Mathematik / Chemie / Analytische Chemie |
Technik, Medizin, angewandte Wissenschaften / Ingenieurwissenschaften / Ingenieurwissenschaften und zugeordnete Tätigkeiten | |
Freie Schlagwörter: | Core-shell nanoparticles; High-resolution transmission electron microscopy; Quantum dots; X-ray Photoelectron Spectroscopy |
Themenfelder/Aktivitätsfelder der BAM: | Chemie und Prozesstechnik |
Material | |
Material / Nano | |
Veranstaltung: | E-MRS Fall Meeting |
Veranstaltungsort: | Online meeting |
Beginndatum der Veranstaltung: | 20.09.2021 |
Enddatum der Veranstaltung: | 23.09.2021 |
Verfügbarkeit des Dokuments: | Datei im Netzwerk der BAM verfügbar ("Closed Access") |
Datum der Freischaltung: | 27.09.2021 |
Referierte Publikation: | Nein |
Eingeladener Vortrag: | Nein |