Development of a Fast Fiber Based UV-Vis Multiwavelength Detector for an Ultracentrifuge

Bhattacharyya, Saroj; Maciejewska, Patrycja; Börger, Lars; Stadler, Manfred; Gülsün, Akif Mehmet; Cicek, Hasan Basri; Cölfen, Helmut

doi:10.1007/2882_002

Cited by 41 publications

(53 citation statements)

References 44 publications

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“…In parallel, special emphasis has been devoted to the development of advanced evaluation routines and algorithms (Brookes E.H. and Demeler B., 2008;Walter J. et al, 2015b). More recently, AUC has been developed further to allow not only for the detection of a single wavelength but to extend for multiwavelength (MWL) data analysis (Balbo A. et al, 2005;Bhattacharyya S.K. et al, 2006;Strauss H.M. et al, 2008;Walter J. et al, 2014).…”

Section: Analytical Ultracentrifugationmentioning

confidence: 99%

Analysis of Particle Size Distributions of Quantum Dots: From Theory to Application

Segets

2016

KONA

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Small, quantum-confined semiconductor nanoparticles, known as quantum dots (QDs) are highly important material systems due to their unique optoelectronic properties and their pronounced structure-property relationships. QD applications are seen in the emerging fields of thin films and solar cells. In this review, different characterization techniques for particle size distributions (PSDs) will be summarized with special emphasis on strategies developed and suggested in the past to derive data on the dispersity of a sample from optical absorbance spectra. The latter use the assumption of superimposed individual optical contributions according to the relative abundance of different sizes of a colloidal dispersion. In the second part, the high potential of detailed PSD analysis to get deeper insights of typical QD processes such as classification by size selective precipitation (SSP) will be demonstrated. This is expected to lead to an improved understanding of colloidal surface properties which is of major importance for the development of assumption-free interaction models.

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Section: Analytical Ultracentrifugationmentioning

confidence: 99%

Analysis of Particle Size Distributions of Quantum Dots: From Theory to Application

Segets

2016

KONA

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“…The concentration of the sample for the determination of the particle size distribution was 10 −4 g mL −1 . A UV/Vis multi-wavelength analytical ultracentrifuge [63,64] developed as an open source instrument [65] was also used to determine the particle size distribution. UV/Vis optical spectra were obtained on a Varian Carey 100 spectrometer (Varian).…”

Section: Characterizationmentioning

confidence: 99%

The Effect of Centrifugal Force on the Assembly and Crystallization of Binary Colloidal Systems: Towards Structural Gradients

Chen

Cölfen

Polarz

2013

Zeitschrift Für Naturforschung B

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In this study, the effect of centrifugal force on the assembly and crystallization of binary colloidal mixtures is demonstrated. Monolithic pieces have been prepared which are characterized by a structural gradient along the direction of the centrifugal force. For a given number ratio of monodisperse 154 and 300 nm latex spheres, the absolute latex concentration was varied and with it the sedimentation velocity of the individual particle species. For three different concentrations it has been demonstrated that the structure of the binary colloidal assembly obtained after centrifugation is affected significantly. For the largest initial latex absolute concentrations, the structural variation along the packed latex column in the ultracentrifuge tube is minimal, while a decrease in the absolute concentrations leads to crystalline packing in defined regions of the column. The observation of the thermodynamically favored structure resembling NaCl, but also of the aluminum boride AlB 2 analog as well as unordered, glass-like packing depending on the mutual latex concentration under unchanged particle number and size ratio, shows that by centrifugation kinetically favored states can be realized. This result implies that centrifugation of binary latex mixtures is a promising route for investigating the self-organization of binary colloidal systems since the sedimentation velocities of the two particle species are different, and thus the local concentrations and mixing ratios vary continuously also enabling rare packing motifs.

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“…In enhancing these measurements, we developed a unique multi-wavelength detector for AUC (MWL). [13–14] This detector allows for the determination of sedimentation profiles with a full visible spectrum for each radial point instead of only a single wavelength as in conventional instruments. Already the MWL raw data contain important information.…”

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Simultaneous Identification of Spectral Properties and Sizes of Multiple Particles in Solution with Subnanometer Resolution

et al. 2016

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We report on an unsurpassed solution characterization technique based on analytical ultracentrifugation, which demonstrates exceptional potential for resolving particle size in solution with sub-nm resolution. We achieve this improvement in resolution by simultaneously measuring UV-Vis spectra while hydrodynamically separating individual components in the mixture. By equipping an analytical ultracentrifuge with a novel multi-wavelength detector, we are effectively adding a new spectral discovery dimension to traditional hydrodynamic characterization, and amplify the information learned by orders of magnitude. We demonstrate the power of this technique by characterizing unpurified CdTe nanoparticle samples, avoiding tedious and often impossible purification and fractionation of nanoparticles into apparently monodisperse fractions. By using our approach, we have for the first time identified the pure spectral properties and bandgap positions of discrete species present in the CdTe mixture.

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Development of a Fast Fiber Based UV-Vis Multiwavelength Detector for an Ultracentrifuge

Cited by 41 publications

References 44 publications

Analysis of Particle Size Distributions of Quantum Dots: From Theory to Application

Analysis of Particle Size Distributions of Quantum Dots: From Theory to Application

The Effect of Centrifugal Force on the Assembly and Crystallization of Binary Colloidal Systems: Towards Structural Gradients

Simultaneous Identification of Spectral Properties and Sizes of Multiple Particles in Solution with Subnanometer Resolution

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