Ongoing Projects
scientist: Dr. Avijit Saha
duration: 2023-2025
external source: EU, : HORIZON TMA MSCA Postdoctoral Fellowships - European Fellowship
Supervisor: Dr. Lesnyak
In this project we will develop novel hybrid plasmonic‒excitonic nanostructures active in the near-infrared (NIR) region. As a material platform for the fabrication of these composite structures we choose copper chalcogenide (Cu2‒xA, where x = 0–1 and A = S, Se or Te) two dimensional (2D) nanocrystals. Our selection relies on polymorphism of Cu2‒xA which exhibits a range of different stoichiometries adapting various crystal phases and a feasibility of chemical transformations of these nanocrystals via cation exchange.The project will combine the following two main parts: 1) development of a direct colloidal synthesis of semiconductor Cu2‒xA 2D nanomaterials with well controlled dimensions and crystal structure and their chemical transformations via cation exchange reactions into semiconductor 2D metal chalcogenides, such as CdA, PbA, HgA, and Ag2A, including their hetero-structures; 2) fabrication of composite fluorescent‒plasmonic materials in the form of planar layered assemblies and investigation of interactions between the layers using advanced optical spectroscopy techniques. Degrees of compositional and structural manipulation of the 2D materials targeted in this project will go far beyond the existing state-of-the-art methods for their direct wet chemical synthesis as well as chemical vapor deposition or exfoliation. Control of their structure and composition is a key to the precise engineering of their optoelectronic properties. From practical point of view, the combination of semiconductor nanocrystals with high absorption coefficients and high photoluminescence quantum yields and nanoparticles with a strong plasmon resonance is promising for the improvement of the efficiency of optoelectronic devices. Such a concept is of great importance for the NIR region, where a high efficiency is difficult to achieve. The lack of synthetic protocols for the synthesis of NIR-active copper, lead, mercury, and silver chalcogenide 2D nanomaterials on one hand, and practically not investigated yet interactions between plasmonic and excitonic structures in the NIR region on the other, motivate us to pursue these goals. The work plan of the project is assigned to a doctoral researcher supported by two student assistants.This work is expected to have impact not only on the fundamentals of chemistry of colloidal 2D semiconductor nanomaterials and their synthetic methodology, but also to provide a range of various materials with a well-defined application potential. The resulting materials and structures with tunable photophysical properties will be very promising candidates for applications in solar cells, luminescent solar concentrators, LEDs, and photodetectors.
project leader: PD Dr. Vladimir Lesnyak
duration: 2023-2026
external source: DFG
project scientist: M.Sc. Varvara Alabusheva
Following the recent successful fabrication of two-dimensional, nanometer-thick and square centimeter-wide gold networks, we intend to work on both ends of this new research field: the deeper understanding of the formation mechanism and on selected applications. The understanding-driven first field is governed by questions about the factors influencing the interfacial gelation of colloidal metal particles and the possibility of extending the synthesis route to multimetallic structures. The answers from both subfields will help to learn to assess the limitations of the new fabrication route and open up possible processing options such as upscaling and printability. In the application-driven second field, we will initially limit ourselves to the potential use of the networks in electrocatalysis and biomedicine. For the first subfield, we will try to use the knowledge gained on three-dimensional gels (for example, the use of PtNi gels as highly active and robust cathodes in fuel cells) to achieve reduced material usage while maintaining activity and stability through layer-by-layer stacking of 2D gels. The second application will be in the fabrication of flexible electrodes for neuroscience. For investigations on the brain, which consists of very soft matter, biocompatible, mechanically soft electrodes are needed to avoid damaging the tissue under investigation by the application. Our studies on mechanical properties of three-dimensional metal gels suggest that these conditions are fulfilled for two-dimensional gels as well as the biocompatibility by the choice of (noble) metals from which the networks are formed.
duration: 2022-2025
project leader: Prof. Alexander Eychmüller
external source: DFG
Semiconductor nanoparticles for novel transistor structures (project A2)
in DFG-RTG: Devices Supracolloidal Structures: From Materials to Optical and Electronic Components
scientist: Metzkow, Nadia
project leader: Dr. Juliane Simmchen
scource: DFG GEPRIS - DFG financed projects
project duration: 2022- 2025
partner: Antonio Stocco, Strassburg
scientist: Wittmann, Martin
Active matter has developed into an active and exciting field of research and it is posing challenges to the interdisciplinary community working on it. One of these challenges is image analysis and data handling, that is frequently taught in depth in physics, but somewhat neglected in chemistry.
This proposal joins cutting edge active matter research and builds the opportunity for students to improve on their computational skills.
winner: Dr. Juliane Simmchen
duration: 2021-2024
external source: Fulbright Kommission FULBRIGHT Germany
see also: Fulbright-Cottrell Workshop 2023
MINARECO will develop microfluidic sensor platform based on nanogels and will establish long-time cooperation between project partners from Germany and Turkey.
From the point of view of nanosensors for health and the environment, the development of microfluidic systems based on nanogels represents a novel, convenient and very general platform that will serve as a basis for the development of a variety of multiparametric sensors of a new generation. They will enable, for example, multiparametric detection of some diagnostic-relevant antibodies, of antibiotics as well as of reactive oxygen species.
In more details, the project will focus on the fabrication of light-emitting nanogels consisting of environmentfriendly colloidal inorganic nanocrystals. The gel networks will incorporate the biorecognition complexes specific to the antibodies, antibiotics or reactive oxygen species. Both chemical interactions and optical coupling between the components of the hybrid gel will be investigated. The sensing function will be realized by combining the specific recognition capability with the modulation of the optical properties of the hybrid nanogel. The resulting nanostructured optical microsensors will be precisely positioned within the microfluidic channels, moreover, several optimal layouts of the microfluidic systems enabling their combination with the spectroscopic multichannel setup will be demonstrated.
duration: 2021-2024
project leader: Prof. Dr. Alexander Eychmüller
source: BMBF
DLR project link 01DJ21009
partner:
Bilkent University, Ankara
external source: DLR Projektträger, Europäische und internationale Zusammenarbeit
scientist: Starzynski, Thorben
Das Projekt A07 unter Leitung von Prof. Alexander Eychmüller konzentriert sich auf die Anwendung chemischer Ansätze, um 2D Anordnungen geschichteter Nanoplättchen (NPLs), in verschiedenen Geometrien zu generieren. Dies impliziert ebenso größere NPL-Netzwerke, die über ihre Spitzen miteinander verbunden sind, 2D Schichten in verschiedenen Auslegungen, die über ihre Spitzen und Kanten miteinander verbunden sind sowie Strukturen die durch Sintern von NPLs und 2D Wachstum gewonnen wurden. Bei den eingesetzten NPLs handelt es sich zunächst um CdSe NPLs mit einer genau kontrollierten Dicke, d.h. drei, vier, fünf und sechs CdSe-Monolagen. Auch andere experimentell etablierte NPLs wie InSe und PbS können folgen, ebenso wie deren Kombinationen und solche, die durch Ionenaustauscherreaktionen produziert werden. Darüber hinaus werden die optoelektronischen Eigenschaften der 2D Baugruppen und die kollektiven Wechselwirkungen innerhalb von Baugruppen charakterisiert.
project leader: Prof. Dr. Alexander Eychmüller
duration: 2020-2024
external source: DFG
collaborate research center 1415
scientist: Shamraienko, Volodymyr
In the last decade the generation of movement at the microscale has evolved to a fascinating new field that connects several fields of modern science. Micro- and nanomotors are novel devices which can transform energy into movement, in conditions dominated by viscosity and Brownian diffusion. Unlike large scale engines that rely widely on inertia, the movement of objects at the microscale requires a constant energy input, but the on-board carriage of fuel is strongly restricted. The scope of this proposal is to develop a light based motion mechanism relying on water as non-toxic fuel in presence of a photocatalyst and sunlight as a renewable energy source. Nowadays the use of "solar fuels" is currently still restricted by the lack of a highly productive photocatalyst, which we aim at developing within this Freigeist project. In the subsequent step those photocatalysts have to be assembled to actual microswimmers.
This proposal connects the two innovative fields of photocatalysts and nanomotors to open new horizons for the use of such nanomotors driven by renewable energy in several environmental and analytical applications.
project leader: Dr. Julianne Simmchen
duration: 2016 - 2023
external source: foundation Volkswagenstiftung Project data