Institution
Nanosystems Initiative Munich
Facility•Munich, Germany•
About: Nanosystems Initiative Munich is a facility organization based out in Munich, Germany. It is known for research contribution in the topics: Quantum dot & Perovskite (structure). The organization has 323 authors who have published 549 publications receiving 24316 citations.
Topics: Quantum dot, Perovskite (structure), Exciton, Nanowire, Charge carrier
Papers
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TL;DR: The concluding guidelines provided herein should enable new nanostructures to be accessed facilely, and the properties of PVP-capped NPs for surface enhanced Raman spectroscopy (SERS), assembly, catalysis, and more are discussed.
Abstract: Colloidal synthesis offers a route to nanoparticles (NPs) with controlled composition and structural features. This Perspective describes the use of polyvinylpyrrolidone (PVP) to obtain such nanostructures. PVP can serve as a surface stabilizer, growth modifier, nanoparticle dispersant, and reducing agent. As shown with examples, its role depends on the synthetic conditions. This dependence arises from the amphiphilic nature of PVP along with the molecular weight of the selected PVP. These characteristics can affect nanoparticle growth and morphology by providing solubility in diverse solvents, selective surface stabilization, and even access to kinetically controlled growth conditions. This Perspective includes discussions of the properties of PVP-capped NPs for surface enhanced Raman spectroscopy (SERS), assembly, catalysis, and more. The contribution of PVP to these properties as well as its removal is considered. Ultimately, the NPs accessed through the use of PVP in colloidal syntheses are opening new applications, and the concluding guidelines provided herein should enable new nanostructures to be accessed facilely.
1,054 citations
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TL;DR: By the rational design of COFs on a molecular level, it is possible to precisely adjust their structural and optoelectronic properties, thus resulting in enhanced photocatalytic activities, which is expected to spur further interest in these photofunctional frameworks where rational supramolecular engineering may lead to new material applications.
Abstract: Hydrogen evolution from photocatalytic reduction of water holds promise as a sustainable source of carbon-free energy. Covalent organic frameworks (COFs) present an interesting new class of photoactive materials, which combine three key features relevant to the photocatalytic process, namely crystallinity, porosity and tunability. Here we synthesize a series of water- and photostable 2D azine-linked COFs from hydrazine and triphenylarene aldehydes with varying number of nitrogen atoms. The electronic and steric variations in the precursors are transferred to the resulting frameworks, thus leading to a progressively enhanced light-induced hydrogen evolution with increasing nitrogen content in the frameworks. Our results demonstrate that by the rational design of COFs on a molecular level, it is possible to precisely adjust their structural and optoelectronic properties, thus resulting in enhanced photocatalytic activities. This is expected to spur further interest in these photofunctional frameworks where rational supramolecular engineering may lead to new material applications.
851 citations
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TL;DR: Understanding of the quantum size effects in perovskite nanoplatelets and the ability to tune them provide an additional method with which to manipulate the optical properties of organometal halide perovkites.
Abstract: Organometal halide perovskites have recently emerged displaying a huge potential for not only photovoltaic, but also light emitting applications. Exploiting the optical properties of specifically tailored perovskite nanocrystals could greatly enhance the efficiency and functionality of applications based on this material. In this study, we investigate the quantum size effect in colloidal organometal halide perovskite nanoplatelets. By tuning the ratio of the organic cations used, we can control the thickness and consequently the photoluminescence emission of the platelets. Quantum mechanical calculations match well with the experimental values. We find that not only do the properties of the perovskite, but also those of the organic ligands play an important role. Stacking of nanoplatelets leads to the formation of minibands, further shifting the bandgap energies. In addition, we find a large exciton binding energy of up to several hundreds of meV for nanoplatelets thinner than three unit cells, partially ...
731 citations
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TL;DR: In this paper, a photoactive COF capable of visible-light driven hydrogen generation in the presence of Pt as a proton reduction catalyst (PRC) was reported. But the Pt-doped COF was not shown to be able to produce hydrogen from water.
Abstract: Covalent organic frameworks (COFs) have recently emerged as a new generation of porous polymers combining molecular functionality with the robustness and structural definition of crystalline solids. Drawing on the recent development of tailor-made semiconducting COFs, we report here on a new COF capable of visible-light driven hydrogen generation in the presence of Pt as a proton reduction catalyst (PRC). The COF is based on hydrazone-linked functionalized triazine and phenyl building blocks and adopts a layered structure with a honeycomb-type lattice featuring mesopores of 3.8 nm and the highest surface area among all hydrazone-based COFs reported to date. When illuminated with visible light, the Pt-doped COF continuously produces hydrogen from water without signs of degradation. With their precise molecular organization and modular structure combined with high porosity, photoactive COFs represent well-defined model systems to study and adjust the molecular entities central to the photocatalytic process.
713 citations
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TL;DR: “coordination-activity plots” are introduced that predict the geometric structure of optimal active sites on platinum (111) surface using a weighted average of surface coordination that includes second-nearest neighbors to assess optimal reactivity.
Abstract: A good heterogeneous catalyst for a given chemical reaction very often has only one specific type of surface site that is catalytically active. Widespread methodologies such as Sabatier-type activity plots determine optimal adsorption energies to maximize catalytic activity, but these are difficult to use as guidelines to devise new catalysts. We introduce “coordination-activity plots” that predict the geometric structure of optimal active sites. The method is illustrated on the oxygen reduction reaction catalyzed by platinum. Sites with the same number of first-nearest neighbors as (111) terraces but with an increased number of second-nearest neighbors are predicted to have superior catalytic activity. We used this rationale to create highly active sites on platinum (111), without alloying and using three different affordable experimental methods.
690 citations
Authors
Showing all 323 results
Name | H-index | Papers | Citations |
---|---|---|---|
Thomas Bein | 109 | 677 | 42800 |
Ernst Wagner | 96 | 537 | 36723 |
Jochen Feldmann | 91 | 417 | 31049 |
Peter Hänggi | 90 | 788 | 42272 |
Markus Fischer | 85 | 490 | 28454 |
Martin Stutzmann | 84 | 781 | 30938 |
Gerhard Abstreiter | 77 | 791 | 25631 |
Oliver Eickelberg | 75 | 329 | 19447 |
Rudolf Gross | 68 | 532 | 17739 |
Dirk Trauner | 65 | 821 | 16279 |
Peter Müller-Buschbaum | 63 | 605 | 17603 |
Bettina V. Lotsch | 62 | 248 | 14599 |
Christoph Bräuchle | 58 | 267 | 12032 |
Jonathan J. Finley | 56 | 353 | 11100 |
Paolo Lugli | 55 | 739 | 14706 |