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4. Supramolecular citrate poly allylamine hydrochloride nanoparticles for citrate delivery and calcium oxalate nanocrystal dissolution

Author

Gianvincenzo, Paolo Di, Leyes, Marcos Fernandez, Boonkam, Kamonchat, Puentes, Alejandro Fábrega, Reyes, Santiago Gimenez, Nardi, Alessandro Nicola, Olivieri, Alessio, Pummarin, Siwanut, Kamonsutthipaijit, Nuntaporn, Amenitsch, Heinz, Ritacco, Hernan, D'Abramo, Marco, Ortore, Maria Grazia, Boonla, Chanchai, and Moya, Sergio E.

Published
2024
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14. SAXS measurements of azobenzene lipid vesicles reveal buffer-dependent photoswitching and quantitative Z→E isomerisation by X-rays

Author

Ober Martina F., Müller-Deku Adrian, Baptist Anna, Ajanović Benjamin, Amenitsch Heinz, Thorn-Seshold Oliver, and Nickel Bert

Subjects
azobenzene, high-energy x-ray, isomerization, lipid bilayer, photoswitch, saxs, Physics, QC1-999
Abstract

Photoresponsive materials feature properties that can be adjusted by light near-instantaneously, reversibly, and with high spatiotemporal precision. There is considerable interest in maximising the degree of photoswitching, and in measuring this degree during illumination in complex environments. We study the switching of photoresponsive lipid membranes that allow for precise and reversible manipulation of membrane shape, permeability, and fluidity. Though these macroscopic responses are clear, it is unclear how large the changes of trans/cis ratio are, and whether they can be improved. Here, we used small-angle X-ray scattering to measure the thickness of photoswitchable lipid membranes, and we correlate lipid bilayer thickness to trans/cis ratios. This reveals an unexpected dependency of photoswitching ratio upon aqueous phase composition. In buffer with ionic strength, we observe thickness variations twice as large as previously observed. Furthermore, soft X-rays can quantitatively isomerise photolipid membranes to the all-trans state; enabling X-ray-based membrane control. High energy X-rays do not influence the state of the photoswitches, presumably because they deposit less dose in the sample.

Published
2022
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21. Perovskite-type superlattices from lead halide perovskite nanocubes

Author

Cherniukh, Ihor, Rainò, Gabriele, Stöferle, Thilo, Burian, Max, Travesset, Alex, Naumenko, Denys, Amenitsch, Heinz, Erni, Rolf, Mahrt, Rainter F., Bodnarchuk, Maryna I., and Kovalenko, Maksym V.

Subjects
Lead compounds -- Usage -- Chemical properties -- Mechanical properties, Perovskite -- Usage -- Chemical properties -- Mechanical properties, Nanoparticles -- Production processes -- Materials, Halides -- Usage -- Chemical properties -- Mechanical properties, Environmental issues, Science and technology, Zoology and wildlife conservation
Abstract

Atomically defined assemblies of dye molecules (such as H and J aggregates) have been of interest for more than 80 years because of the emergence of collective phenomena in their optical spectra.sup.1-3, their coherent long-range energy transport, their conceptual similarity to natural light-harvesting complexes.sup.4,5, and their potential use as light sources and in photovoltaics. Another way of creating versatile and controlled aggregates that exhibit collective phenomena involves the organization of colloidal semiconductor nanocrystals into long-range-ordered superlattices.sup.6. Caesium lead halide perovskite nanocrystals.sup.7-9 are promising building blocks for such superlattices, owing to the high oscillator strength of bright triplet excitons.sup.10, slow dephasing (coherence times of up to 80 picoseconds) and minimal inhomogeneous broadening of emission lines.sup.11,12. So far, only single-component superlattices with simple cubic packing have been devised from these nanocrystals.sup.13. Here we present perovskite-type (ABO.sub.3) binary and ternary nanocrystal superlattices, created via the shape-directed co-assembly of steric-stabilized, highly luminescent cubic CsPbBr.sub.3 nanocrystals (which occupy the B and/or O lattice sites), spherical Fe.sub.3O.sub.4 or NaGdF.sub.4 nanocrystals (A sites) and truncated-cuboid PbS nanocrystals (B sites). These ABO.sub.3 superlattices, as well as the binary NaCl and AlB.sub.2 superlattice structures that we demonstrate, exhibit a high degree of orientational ordering of the CsPbBr.sub.3 nanocubes. They also exhibit superfluorescence--a collective emission that results in a burst of photons with ultrafast radiative decay (22 picoseconds) that could be tailored for use in ultrabright (quantum) light sources. Our work paves the way for further exploration of complex, ordered and functionally useful perovskite mesostructures. Through precise structural engineering, perovskite nanocrystals are co-assembled with other nanocrystal materials to form a range of binary and ternary perovskite-type superlattices that exhibit superfluorescence., Author(s): Ihor Cherniukh [sup.1] [sup.2] , Gabriele Rainò [sup.1] [sup.2] , Thilo Stöferle [sup.3] , Max Burian [sup.4] , Alex Travesset [sup.5] , Denys Naumenko [sup.6] , Heinz Amenitsch [sup.6] [...]

Published
2021
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22. Two-dimensional perovskites with alternating cations in the interlayer space for stable light-emitting diodes

Author

Zhang Yiyue, Keshavarz Masoumeh, Debroye Elke, Fron Eduard, Rodríguez González Miriam Candelaria, Naumenko Denys, Amenitsch Heinz, Van de Vondel Joris, De Feyter Steven, Heremans Paul, Roeffaers Maarten B. J., Qiu Weiming, Pradhan Bapi, and Hofkens Johan

Subjects
alternating interlayer cations, light-emitting diodes, stability, two-dimensional perovskites, Physics, QC1-999
Abstract

Lead halide perovskites have attracted tremendous attention in photovoltaics due to their impressive optoelectronic properties. However, the poor stability of perovskite-based devices remains a bottleneck for further commercial development. Two-dimensional perovskites have great potential in optoelectronic devices, as they are much more stable than their three-dimensional counterparts and rapidly catching up in performance. Herein, we demonstrate high-quality two-dimensional novel perovskite thin films with alternating cations in the interlayer space. This innovative perovskite provides highly stable semiconductor thin films for efficient near-infrared light-emitting diodes (LEDs). Highly efficient LEDs with tunable emission wavelengths from 680 to 770 nm along with excellent operational stability are demonstrated by varying the thickness of the interlayer spacer cation. Furthermore, the best-performing device exhibits an external quantum efficiency of 3.4% at a high current density (J) of 249 mA/cm2 and remains above 2.5% for a J up to 720 mA cm−2, leading to a high radiance of 77.5 W/Sr m2 when driven at 6 V. The same device also shows impressive operational stability, retaining almost 80% of its initial performance after operating at 20 mA/cm2 for 350 min. This work provides fundamental evidence that this novel alternating interlayer cation 2D perovskite can be a promising and stable photonic emitter.

Published
2021
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25. Orthogonal stimulation of structural transformations in photo-responsive MOF films through linker functionalization.

Author

Klokic, Sumea, Marmiroli, Benedetta, Naumenko, Denys, Birarda, Giovanni, Dal Zilio, Simone, Velásquez-Hernández, Miriam de J., Falcaro, Paolo, Vaccari, Lisa, and Amenitsch, Heinz

Subjects
ENERGY storage, STRUCTURAL dynamics, CHLORINE
Abstract

Controlling the magnitude of structural dynamics in flexible MOF films by an applied stimulus is largely desired for specific applications such as energy storage. Herein, by introducing chlorine substituents in an azobenzene-infiltrated Cl-DMOF-1 film structure, a significantly slowed structural response is obtained upon photo-switching of the system. [ABSTRACT FROM AUTHOR]

Published
2024
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26. A brominated M3 based non-fullerene acceptor: synthesis, material and photovoltaic properties.

Author

Zuccalà, Elena, Mallick, Suman, Habich, Lea-Marie, Amenitsch, Heinz, Rath, Thomas, and Trimmel, Gregor

Subjects
CONJUGATED polymers, CHARGE carrier mobility, MOLECULAR structure, SOLAR cells, STRUCTURAL engineering, FULLERENE polymers
Abstract

Molecular structure engineering has proved to be an efficient strategy to modify the properties of photoactive materials for organic solar cells. Several studies focused on the halogenation of donor and acceptor molecules, in order to tune the energy levels, the absorption properties or the molecular packing of the materials. In particular, bromination of small-molecule acceptors increases the film crystallinity of the bulk heterojunction, leading to higher charge carrier mobilities, and therefore, to a more efficient charge transport. In this study, we synthesized a mono-brominated non-fullerene acceptor derived from end-group modification of the M3 acceptor. This material showed slightly higher energy levels than M3 and a higher π–π stacking distance due to the larger size of bromine atoms compared to the fluorine atoms in M3. In addition, a second acceptor with non-halogenated rhodanine-based end groups was synthesized and investigated. While solar cells based on the latter NFA only showed negligible efficiencies, solar cells fabricated with the mono-brominated acceptor C1 and the conjugated polymer PM6 revealed power conversion efficiencies up to 11.6%. [ABSTRACT FROM AUTHOR]

Published
2024
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44. Protein-induced modifications in crystal morphology of a hydrogen-bonded organic framework.

Author

Flint, Kate L., Evans, Jack D., Carraro, Francesco, Renner, Simon, Linder-Patton, Oliver M., Amenitsch, Heinz, Falconer, Robert J., White, Nicholas G., Sumby, Christopher J., Falcaro, Paolo, and Doonan, Christian J.

Abstract

In this work, we studied the encapsulation of a range of proteins in a hydrogen-bonded organic framework (HOF) comprised of a tetraamidinium cation and diazobenzene-based dicarboxylate anion. We explore the use of external stimuli: light and temperature to modulate HOF crystal growth and size. In particular, we found photo-isomerisation can be used to control the concentration of the trans-azobenzene building block that contributes to HOF formation. When HOF growth was slowed sufficiently, deformation of the crystals and ultimately multicrystal aggregates were observed in the presence of some proteins. We propose that the extent of crystal deformation, consistent with better protein association, may be governed by differences in the type and strength of interactions between proteins and the surface of the growing HOF crystals. [ABSTRACT FROM AUTHOR]

Published
2023
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46. Silicon‐ and Germanium‐Functionalized Perylene Diimides: Synthesis, Optoelectronic Properties, and Their Application as Non‐fullerene Acceptors in Organic Solar Cells.

Author

Schlemmer, Bettina, Sauermoser, Aileen, Holler, Sarah, Zuccalà, Elena, Ehmann, Birgit, Reinfelds, Matiss, Fischer, Roland C., Amenitsch, Heinz, Marin‐Beloqui, Jose M., Ludvíková, Lucie, Slanina, Tomáš, Haas, Michael, Rath, Thomas, and Trimmel, Gregor

Subjects
PERYLENE, SOLAR cells, CHARGE carrier mobility, POLYMERS, CONJUGATED polymers, ORGANIC synthesis, ELECTROPHILES, GROUP 14 elements
Abstract

Organic solar cells have been continuously studied and developed through the last decades. A major step in their development was the introduction of fused‐ring non‐fullerene electron acceptors. Yet, beside their high efficiency, they suffer from complex synthesis and stability issues. Perylene‐based non‐fullerene acceptors, in contrast, can be prepared in only a few steps and display good photochemical and thermal stability. Herein, we introduce four monomeric perylene diimide acceptors obtained in a three‐step synthesis. In these molecules, the semimetals silicon and germanium were added in the bay position, on one or both sides of the molecules, resulting in asymmetric and symmetric compounds with a red‐shifted absorption compared to unsubstituted perylene diimide. Introducing two germanium atoms improved the crystallinity and charge carrier mobility in the blend with the conjugated polymer PM6. In addition, charge carrier separation is significantly influenced by the high crystallinity of this blend, as shown by transient absorption spectroscopy. As a result, the solar cells reached a power conversion efficiency of 5.38 %, which is one of the highest efficiencies of monomeric perylene diimide‐based solar cells recorded to date. [ABSTRACT FROM AUTHOR]

Published
2023
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50. Implication of the double-gating mode in hybrid photon counting detector for measurements of transient heat conduction in GaAs/AlAs superlattice structures

Author

Naumenko, Denys, Burian, Max, Marmiroli, Benedetta, Haider, Richard, Radeticchio, Andrea, Wagner, Lucas, Piazza, Luca, Glatt, Lisa, Brandstetter, Stefan, Zilio, Simone Dal, Biasiol, Giorgio, and Amenitsch, Heinz

Subjects
Condensed Matter - Materials Science, Materials Science (cond-mat.mtrl-sci), FOS: Physical sciences, Applied Physics (physics.app-ph), Physics - Applied Physics
Abstract

Understanding and control of thermal transport in solids at nanoscale is crucial to engineer and to enhance properties of a new generation of optoelectronic, thermoelectric, and photonic devices. In this regard, semiconductor superlattice structures provide a unique platform to study phenomena associated with phonon propagations in solids such as heat conduction. Transient X-ray diffraction can directly probe atomic motions and therefore is among the rare techniques sensitive to phonon dynamics in a condensed matter. Here, we study optically induced transient heat conduction in GaAs/AlAs superlattice structures using EIGER2 detector. Benchmark experiments have been performed at the Austrian SAXS beamline at Elettra Sincrotrone Trieste that operated in the hybrid filling mode. We demonstrate that drifts of experimental conditions, such as synchrotron beam fluctuations, become less essential when utilizing EIGER2 double gating mode that results in a faster acquisition of high quality data and facilitates data analysis and data interpretation., 15 pages, 9 figures, 1 table

Published
2023

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