TY - JOUR A1 - Wegner, Karl David A1 - Resch-Genger, Ute T1 - The 2023 Nobel Prize in Chemistry: Quantum dots N2 - The 2023 Nobel Prize in Chemistry was awarded to Aleksey I. Ekimov (prize share 1/3), Louis E. Brus (prize share 1/3), and Moungi G. Bawendi (prize share 1/3) for groundbreaking inventions in the field of nanotechnology, i.e., for the discovery and synthesis of semiconductor nanocrystals, also termed quantum dots, that exhibit size-dependent physicochemical properties enabled by quantum size effects. This feature article summarizes the main milestones of the discoveries and developments of quantum dots that paved the road to their versatile applications in solid-state lighting, display technology, energy conversion, medical diagnostics, bioimaging, and image-guided surgery. KW - Quantum dots KW - Semiconductor nanocrystals KW - Luminescence KW - Quantitative spectroscopy KW - Quantum yield KW - Advanced nanomaterials KW - Quality assurance KW - Energy transfer PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-597843 DO - https://doi.org/10.1007/s00216-024-05225-9 VL - 2024 SP - 1 EP - 11 PB - Springer CY - Cham AN - OPUS4-59784 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mohammad, W. A1 - Wegner, Karl David A1 - Comby-Zerbino, C. A1 - Trouillet, V. A1 - Ogayer, M. P. A1 - Coll, J.-L. A1 - Marin, R. A1 - Jaque Garcia, D. A1 - Resch-Genger, Ute A1 - Antoine, R. A1 - Le Guevel, X. T1 - Enhanced brightness of ultra-small gold nanoparticles in the second biological window through thiol ligand shell control N2 - Gold-based nanoparticles below 2 nm in size are promising as luminescent probes for in vivo bioimaging, owing to their brightness and rapid renal clearance. However, their use as contrast agents in the near-infrared II (NIR-II, 1000–1700 nm) range remains challenging due to their low photoluminescence (PL) quantum yield. To address this, PL enhancement can be achieved by either rigidifying the ligand-shell structure or increasing the size of the ligand shell. In this study, we synthesized ultra-small gold nanoparticles stabilized by co-ligands, namely monothiol and short dithiol molecules. By precisely controlling the amount of reducing agent used during particle preparation, we successfully modulated the physicochemical properties of the co-ligand shell, including its size, composition, and structure. Consequently, we achieved a remarkable 60-fold increase in the absorption cross-section at 990 nm while maintaining the small size of the 1.5-nm metal core. The analytical and optical characterization of our thiol-capped gold nanoparticles indicates that the ligand shell size is governed by the quantity of the reducing agent, which, in turn, impacts the balance between radiative and non-radiative processes, thereby influencing the PL quantum yield. KW - Gold nanocluster KW - NIR-II fluorescence KW - SWIR KW - Nanomaterial design KW - Calibrated fluorescence measurements PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-588117 DO - https://doi.org/10.1039/D3TC03021K SN - 2050-7526 VL - 11 IS - 42 SP - 14714 EP - 14724 PB - Royal Society of Chemistry (RSC) AN - OPUS4-58811 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Stiegler, L. M. S. A1 - Wegner, Karl David A1 - Weigert, Florian A1 - Peukert, W. A1 - Resch-Genger, Ute A1 - Walter, J. T1 - Analysis of Giant-Shell CdSe/CdS Quantum Dots via Analytical Ultracentrifugation Combined with Spectrally Resolved Photoluminescence N2 - Knowledge of the structure–property relationships of functional nanomaterials, including, for example, their size- and composition-dependent photoluminescence (PL) and particle-to-particle variations, is crucial for their design and reproducibility. Herein, the Angstrom-resolution capability of an analytical ultracentrifuge combined with an in-line multiwavelength emission detection system (MWE-AUC) for measuring the sedimentation coefficient-resolved spectrally corrected PL spectra of dispersed nanoparticles is demonstrated. The capabilities of this technique are shown for giant-shell CdSe/CdS quantum dots (g-QDs) with a PL quantum yield (PL QY) close to unity capped with oleic acid and oleylamine ligands. The MWE-AUC PL measurements are calibrated and validated with certified fluorescence standards. The spectrally corrected and size-dependent PL spectra of the g-QDs derived from a single MWE-AUC experiment are then analyzed and compared with the results of single-particle spectroscopic studies, yielding the PL spectra, decay kinetics, and blinking behavior of individual g-QDs. This study underlines the vast potential of MWE-AUC with in-line optical detection for the characterization of advanced nanomaterials with a complex structure. KW - Quantum dots KW - Analytical ultracentrifugation KW - Photoluminescence KW - Advanced nanomaterial characterization KW - Calibrated fluorescence measurements KW - Reference materials PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-624357 DO - https://doi.org/10.1002/smtd.202401700 SN - 2366-9608 SP - 1 EP - 7 PB - Wiley VHC-Verlag AN - OPUS4-62435 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Scholtz, Lena A1 - Eckert, J. G. A1 - Graf, Rebecca T. A1 - Kunst, A. A1 - Wegner, Karl David A1 - Bigall, N. C. A1 - Resch-Genger, Ute T1 - Correlating semiconductor nanoparticle architecture and applicability for the controlled encoding of luminescent polymer microparticles N2 - Luminophore stained micro- and nanobeads made from organic polymers like polystyrene (PS) are broadly used in the life and material sciences as luminescent reporters, for bead-based assays, sensor arrays, printable barcodes, security inks, and the calibration of fluorescence microscopes and flow cytometers. Initially mostly prepared with organic dyes, meanwhile luminescent core/shell nanoparticles (NPs) like spherical semiconductor quantum dots (QDs) are increasingly employed for bead encoding. This is related to their narrower emission spectra, tuneability of emission color, broad wavelength excitability, and better photostability. However, correlations between particle architecture, morphology, and photoluminescence (PL) of the luminescent nanocrystals used for encoding and the optical properties of the NP-stained beads have been rarely explored. This encouraged us to perform a screening study on the incorporation of different types of luminescent core/shell semiconductor nanocrystals into polymer microparticles (PMPs) by a radical-induced polymerization reaction. Nanocrystals explored include CdSe/CdS QDs of varying CdS shell thickness, a CdSe/ZnS core/shell QD, CdSe/CdS quantum rods (QRs), and CdSe/CdS nanoplatelets (NPLs). Thereby, we focused on the applicability of these NPs for the polymerization synthesis approach used and quantified the preservation of the initial NP luminescence. The spectroscopic characterization of the resulting PMPs revealed the successful staining of the PMPs with luminescent CdSe/CdS QDs and CdSe/CdS NPLs. In contrast, usage of CdSe/CdS QRs and CdSe QDs with a ZnS shell did not yield luminescent PMPs. The results of this study provide new insights into structure–property relationships between NP stained PMPs and the initial luminescent NPs applied for staining and underline the importance of such studies for the performance optimization of NP-stained beads. KW - Quantitative spectroscopy KW - Energy transfer KW - Synthesis KW - Surface chemistry KW - Semiconductor quantum dot KW - Luminescence KW - Nano KW - Particle KW - Quantum yield KW - Lifetime KW - Quality assurance KW - Polymer particle KW - Quantum rod KW - Nanoplatelet PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-602206 DO - https://doi.org/10.1038/s41598-024-62591-1 SN - 2045-2322 VL - 14 SP - 1 EP - 16 AN - OPUS4-60220 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Godard, A. A1 - Kalot, G. A1 - Pliquett, J. A1 - Busser, B. A1 - Le Guével, X. A1 - Wegner, Karl David A1 - Resch-Genger, Ute A1 - Russelin, Y. A1 - Coll, J.-L. A1 - Denat, F. A1 - Bodio, E. A1 - Goze, C. A1 - Sancey, L. T1 - Water-Soluble Aza-BODIPYs: Biocompatible Organic Dyes for High Contrast In Vivo NIR-II Imaging N2 - A simple NIR-II emitting water-soluble system has been developed and applied in vitro and in vivo. In vitro, the fluorophore quickly accumulated in 2D and 3D cell cultures and rapidly reached the tumor in rodents, showing high NIR-II contrast for up to 1 week. This very efficient probe possesses all the qualities necessary for translation to the clinic as well as for the development of NIR-II emitting materials. KW - Aza-BODIPY KW - NIR-II Imaging KW - In vivo imaging KW - organic dyes KW - SWIR KW - Cancer KW - Fluorescence PY - 2020 DO - https://doi.org/10.1021/acs.bioconjchem.0c00175 VL - 31 IS - 4 SP - 1088 EP - 1092 PB - ACS Publications AN - OPUS4-50695 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rezvani, A. A1 - Wang, Z. A1 - Wegner, Karl David A1 - Soltanmoradi, H. A1 - Kichigin, A. A1 - Zhou, X. A1 - Gantenberg, T. A1 - Schram, J. A1 - Zubiri, B. A. A1 - Spiecker, E. A1 - Walter, J. A1 - Resch-Genger, Ute A1 - Segets, D. T1 - Separation of Indium Phosphide/Zinc Sulfide Core−Shell Quantum Dots from Shelling Byproducts through Multistep Agglomeration N2 - Semiconductor quantum dots (QDs) possess unique electronic and optical properties, making them promising candidates for applications in lightemitting diodes, solar cells, bioimaging, and photocatalysis. Precise control over their size, shape, and chemical and electronic structure is crucial to ensure the desired functional properties and optimize device performance. However, challenges in QD synthesis and post-synthesis modification persist, especially in large-scale production. This study addresses the classification of QDs synthesized in a tubular flow reactor consisting of a mixture of the desired InP/ZnS core−shell QDs and QDs made from the shell material, i.e., here ZnS QDs formed as a byproduct during the formation step of the ZnS shell. The homogeneous nucleation of ZnS nanoparticles from the shelling material introduces a heterogeneity in size and composition and affects the optical properties of the resulting QDs. To address this issue, we developed a size-selective agglomeration (SSA) technique by incrementally introducing ethanol as a poor solvent and classified the synthesized QDs into 13 distinct fractions. These 13 fractions are sorted into three distinct groups: (i) larger InP/ZnS QDs, (ii) a combination of smaller InP/ZnS QDs and larger ZnS QDs, and (iii) predominant ZnS QDs with some very tiny InP/ZnS QDs. The comprehensive characterization of the fractions was conducted using UV−visible absorption spectroscopy, photoluminescence spectroscopy, high-resolution scanning transmission electron microscopy, energy-dispersive X-ray spectroscopy, total reflection X-ray fluorescence, and analytical ultracentrifugation. We could demonstrate that our method effectively separated unwanted ZnS QDs from the target InP/ZnS QDs. In addition, the fractions enriched in smaller InP/ZnS QDs exhibited a higher photoluminescence quantum yield compared to the fractions with larger QDs. This demonstrates the efficacy of SSA in finetuning the composition of QD mixtures produced on a larger scale to improve their functional properties. This approach provides fundamental understanding toward the development of a scalable two-dimensional classification process for such ultrasmall nanoparticles by particle size and composition. KW - Quality assurance KW - Reference material KW - Nano KW - Particle KW - Quantum dot KW - Synthesis KW - Flow reactor KW - InP KW - Shell KW - ZnS KW - Surface chemistry KW - Method KW - Fluorescence KW - Quantum yield KW - TEM PY - 2025 DO - https://doi.org/10.1021/acsnano.4c18530 SN - 1936-086X VL - 19 IS - 20 SP - 19080 EP - 19094 PB - ACS Publications AN - OPUS4-63215 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Soares, J. X. A1 - Wegner, Karl David A1 - Ribeiro, D. S. M. A1 - Melo, A. A1 - Häusler, I. A1 - Santos, J. L. M. A1 - Resch-Genger, Ute T1 - Rationally designed synthesis of bright AgInS2/ZnS quantum dots with emission control N2 - In the blossoming field of Cd-free semiconductor quantum dots (QDs), ternary I–III–VI QDs have received increasing attention due to the ease of the environmentally friendly synthesis of high-quality materials in water, their high photoluminescence (PL) Quantum yields (QYs) in the red and near infrared (NIR) region, and their inherently low toxicity. Moreover, their oxygen-insensitive long PL lifetimes of up to several hundreds of nanoseconds close a gap for applications exploiting the compound-specific parameter PL lifetime. To overcome the lack of reproducible synthetic methodologies and to enable a design-based control of their PL properties, we assessed and modelled the synthesis of high-quality MPA-capped AgInS2/ZnS (AIS/ZnS) QDs. Systematically refined Parameters included reaction time, temperature, Ag:In ratio, S:In ratio, Zn:In ratio, MPA:In ratio, and pH using a design-of-experiment approach. Guidance for the optimization was provided by mathematical models developed for the application-relevant PL parameters, maximum PL wavelength, QY, and PL lifetime as well as the elemental composition in terms of Ag:In:Zn ratio. With these experimental data-based models, MPA:In and Ag:In ratios and pH values were identified as the most important synthesis parameters for PL Control and an insight into the connection of these parameters could be gained. Subsequently, the experimental conditions to synthetize QDs with tunable emission and high QY were predicted. The excellent agreement between the predicted and experimentally found PL features confirmed the reliability of our methodology for the rational design of high quality AIS/ZnS QDs with defined PL features. This approach can be straightforwardly extended to other ternary and quaternary QDs and to doped QDs. KW - Modelling KW - Nanoparticle KW - AIS KW - Semiconductor quantum dot KW - Design of experiment KW - Photoluminescence KW - Quantum yield KW - Surface chemistry KW - Synthesis KW - Lifetime PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-510075 DO - https://doi.org/10.1007/s12274-020-2876-8 VL - 13 IS - 9 SP - 2438 EP - 2450 PB - Springer AN - OPUS4-51007 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Goryacheva, O. A. A1 - Wegner, Karl David A1 - Sobolev, A. M. A1 - Häusler, I. A1 - Gaponik, N. A1 - Gorycheva, I. Y. A1 - Resch-Genger, Ute T1 - Influence of particle architecture on the photoluminescence properties of silica‑coated CdSe core/shell quantum dots N2 - Light-emitting nanoparticles like semiconductor nanocrystals (termed quantum dots, QDs) are promising candidates for biosensing and bioimaging applications based on their bright and stable photoluminescent properties. As high-quality QDs are often synthesized in organic solvents, strategies needed to be developed to render them water-dispersible without affecting their optical properties and prevent changes in postmodification steps like the biofunctionalization with antibodies or DNA. Despite a large number of studies on suitable surface modification procedures, the preparation of water-soluble QDs for nanobiotechnology applications still presents a challenge. To highlight the advantages of surface silanization, we systematically explored the influence of the core/multishell architecture of CdSe/CdS/ZnS QDs and the silanization conditions on the optical properties of the resulting silanized QDs. Our results show that the optical properties of silica-coated CdSe/CdS/ZnS QDs are best preserved in the presence of a thick CdS (6 monolayers (ML)) intermediate shell, providing a high photoluminescence quantum yield (PL QY), and a relatively thick ZnS (4.5 ML) external shell, effectively shielding the QDs from the chemical changes during silica coating. In addition to the QD core/shell architecture, other critical parameters of the silica-coating process, that can have an influence on the optical properties of the QD, include the choice of the surfactant and its concentration used for silica coating. The highest PL QY of about 46% was obtained by a microemulsion silica-coating procedure with the surfactant Brij L4, making these water-dispersible QDs to wellsuited optical reporters in future applications like fluorescence immunoassays, biomedicine, and bioimaging. KW - Nano KW - Nanomaterial KW - Particle KW - Semiconductor KW - Quantum do KW - Photoluminescence KW - Photophysics KW - Lifetime KW - Sensor KW - Mechanism KW - Surface KW - Shell KW - Silica KW - Silanization KW - Synthesis PY - 2022 DO - https://doi.org/10.1007/s00216-022-04005-7 SP - 1 EP - 13 PB - Springer AN - OPUS4-54546 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rodriguez, Santiago A1 - Kumanski, Sylvain A1 - Ayed, Zeineb A1 - Fournet, Aurélie A1 - Bouanchaud, Charlène A1 - Sagar, Amin A1 - Allemand, Frédéric A1 - Baulin, Vladimir A. A1 - Resch‐Genger, Ute A1 - Cortés, Juan A1 - Sibille, Nathalie A1 - Chirot, Fabien A1 - Wegner, Karl David A1 - Antoine, Rodolphe A1 - Le Guével, Xavier A1 - Bernadó, Pau T1 - Programming the Optoelectronic Properties of Atomically Precise Gold Nanoclusters Using the Conformational Landscape of Intrinsically Disordered Proteins N2 - The rational design of hybrid nanomaterials with precisely controlled properties remains a central challenge in materials science. While atomically precise gold nanoclusters (Au‐NCs) offer molecule‐like control over a metallic core, tuning their optoelectronic behavior via surface engineering is often empirically driven. Here, we establish a design principle by demonstrating that the conformational landscape of intrinsically disordered proteins (IDP) can be used as a programmable scaffold to rationally modulate the photophysical properties of a covalently bound Au‐NC. We synthesized a series of bioconjugates between Au 25 nanoclusters and bioengineered IDPs containing a variable number of cysteine anchoring points. A combination of mass spectrometry, small‐angle X‐ray scattering, and modeling on the conjugates indicates that increasing the number of covalent anchors systematically restricts the conformational ensemble, inducing a progressively more compact protein shell around nanoclusters. This structural rigidification at the interface directly translates into a 15‐fold enhancement of the Au‐NC near‐infrared photoluminescence and a six‐fold increase in its average lifetime. Our findings demonstrate that the conformational plasticity of IDPs and the capacity to engineer them can be harnessed as a molecular tuning knob, moving to a new regime of programmable soft‐matter control over the properties of quantum‐confined nanomaterials for tailored biotechnological applications. KW - Fluorescence KW - Custer KW - Nano KW - Advanced material KW - Characterization KW - Fluorescence quantum yield KW - Integrating sphere spectroscopy KW - Thiol ligands KW - Gold KW - Surface chemistry KW - SWIR KW - Mass spectrometry KW - Protein PY - 2026 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655086 DO - https://doi.org/10.1002/chem.202502991 SN - 0947-6539 SP - 1 EP - 9 PB - Wiley VHC-Verlag AN - OPUS4-65508 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ahmed, A. A. A. A1 - Alegret, N. A1 - Almeida, B. A1 - Alvarez-Puebla, R. A1 - Andrews, A. M. A1 - Ballerini, L. A1 - Barrios-Capuchino, J. J. A1 - Becker, C. A1 - Blick, R. H. A1 - Bonakdar, S. A1 - Chakraborty, I. A1 - Chen, X. A1 - Cheon, J. A1 - Chilla, G. A1 - Conceicao, A. L. C. A1 - Delehanty, J. A1 - Dulle, M. A1 - Efros, A. L. A1 - Epple, M. A1 - Fedyk, M. A1 - Feliu, N. A1 - Feng, M. A1 - Fernandez-Chacon, R. A1 - Fernandez-Cuesta, I. A1 - Fertig, N. A1 - Förster, S. A1 - Garrido, J. A. A1 - George, M. A1 - Guse, A. H. A1 - Hampp, N. A1 - Harberts, J. A1 - Han, J. A1 - Heekeren, H. R. A1 - Hofmann, U. G. A1 - Holzapfel, M. A1 - Hosseinkazemi, H. A1 - Huang, Y. A1 - Huber, P. A1 - Hyeon, T. A1 - Ingebrandt, S. A1 - Ienca, M. A1 - Iske, A. A1 - Kang, Y. A1 - Kasieczka, G. A1 - Kim, D.-H. A1 - Kostarelos, K. A1 - Lee, J.-H. A1 - Lin, K.-W. A1 - Liu, S. A1 - Liu, X. A1 - Liu, Y. A1 - Lohr, C. A1 - Mailänder, V. A1 - Maffongelli, L. A1 - Megahed, S. A1 - Mews, A. A1 - Mutas, M. A1 - Nack, L. A1 - Nakatsuka, N. A1 - Oertner, T. G. A1 - Offenhäusser, A. A1 - Oheim, M. A1 - Otange, B. A1 - Otto, F. A1 - Patrono, E. A1 - Peng, B. A1 - Picchiotti, A. A1 - Pierini, F. A1 - Pötter-Nerger, M. A1 - Pozzi, M. A1 - Pralle, A. A1 - Prato, M. A1 - Qi, B. A1 - Ramos-Cabrer, P. A1 - Resch-Genger, Ute A1 - Ritter, N. A1 - Rittner, M. A1 - Roy, S. A1 - Santoro, F. A1 - Schuck, N. W. A1 - Schulz, F. A1 - Seker, E. A1 - Skiba, M. A1 - Sosniok, M. A1 - Stephan, H. A1 - Wang, R. A1 - Wang, T. A1 - Wegner, Karl David A1 - Weiss, P. S. A1 - Xu, M. A1 - Yang, C. A1 - Zargarin, S. S. A1 - Zeng, Y. A1 - Zhou, Y. A1 - Zhu, D. A1 - Zierold, R. A1 - Parak, W. J. T1 - Interfacing with the Brain: How Nanotechnology Can Contribute N2 - Interfacing artificial devices with the human brain is the central goal of neurotechnology. Yet, our imaginations are often limited by currently available paradigms and technologies. Suggestions for brain−machine interfaces have changed over time, along with the available technology. Mechanical levers and cable winches were used to move parts of the brain during the mechanical age. Sophisticated electronic wiring and remote control have arisen during the electronic age, ultimately leading to plug-and-play computer interfaces. Nonetheless, our brains are so complex that these visions, until recently, largely remained unreachable dreams. The general problem, thus far, is that most of our technology is mechanically and/or electrically engineered, whereas the brain is a living, dynamic entity. As a result, these worlds are difficult to interface with one another. Nanotechnology, which encompasses engineered solid-state objects and integrated circuits, excels at small length scales of single to a few hundred nanometers and, thus, matches the sizes of biomolecules, biomolecular assemblies, and parts of cells. Consequently, we envision nanomaterials and nanotools as opportunities to interface with the brain in alternative ways. Here, we review the existing literature on the use of nanotechnology in brain−machine interfaces and look forward in discussing perspectives and limitations based on the authors’ expertise across a range of complementary disciplines from neuroscience, engineering, physics, and chemistry to biology and medicine, computer science and mathematics, and social science and jurisprudence. We focus on nanotechnology but also include information from related fields when useful and complementary. KW - Nanoneuro interface KW - Brain-on-a-chip KW - Nanostructured interface KW - Electrode arrays KW - Neuro-implants KW - Advanced nanomaterials KW - Quality assurance PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-634893 DO - https://doi.org/10.1021/acsnano.4c10525 SN - 1936-086X VL - 19 IS - 11 SP - 10630 EP - 10717 PB - ACS Publications AN - OPUS4-63489 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -