Few Chemicals (Germany)

Efficient energy transport in nanoscale photonic and optoelectronic systems requires excitons to remain delocalized in the presence of structural and environmental disorder, a central challenge for real-world applications ranging from artificial light harvesting to quantum information processing. Here we show that Frenkel excitons in two-dimensional supramolecular nanomaterials preserve extensive delocalization even in the presence of intentionally embedded deep-energy traps. Using fluorescent trap molecules introduced during the self-assembly of double-walled molecular nanotubes, we created a model system in which traps are incorporated without compromising the host lattice’s structural integrity. Polarization-resolved microscopy of individual nanotubes reveals that exciton delocalization is remarkably robust against trap incorporation. Complementary theoretical simulations based on realistic molecular geometries reproduce the experimental behaviour and further demonstrate that excitons adaptively redistribute to avoid trap sites. These results establish that higher-dimensional supramolecular architectures can sustain efficient exciton transport under fabrication-relevant levels of disorder, highlighting a key advantage of multidimensional excitonic materials and pointing toward the similar behaviour expected in fully three-dimensional systems.

Efficient energy transport in nanoscale photonic and optoelectronic systems requires excitons that remain delocalized despite structural or environmental disorder, a key challenge for real-world applications such as artificial light harvesting and quantum information processing. Here, we demonstrate that Frenkel excitons in two-dimensional supramolecular assemblies can maintain extensive delocalization even in the presence of embedded molecular defects that act as deep-energy traps. Using fluorescent dopant molecules introduced during the self-assembly of double-wall molecular nanotubes, we created a model system where exciton traps are integrated without compromising the host lattice’s structural integrity. Two-dimensional electronic spectroscopy directly revealed energy transfer from delocalized host excitons to the dopants, while time-resolved photoluminescence confirmed that exciton delocalization remains largely intact. Theoretical simulations using realistic molecular geometries, Redfield theory, and Monte Carlo analysis reproduced the observed dynamics and showed that excitons adaptively redistribute to avoid trap sites. These findings highlight the potential of multidimensional supramolecular architectures to support efficient exciton transport under fabrication-relevant conditions, with resilience to structural imperfections arising from their non-1D nature, a feature likely shared by 3D excitonic systems.

Encapsulant materials in photovoltaic (PV) modules are essential for ensuring transparency, mechanical stability, electrical insulation, and protection against environmental stress factors. While ethylene vinyl acetate (EVA) has traditionally dominated the market, recent advancements introduce new materials based on ethylene co-polymers. This shift is attributed to the potential drawbacks of EVA, such as acetic acid generation leading to corrosion under field exposure. The study evaluates commercially available encapsulants, focusing on thermal properties, chemical structure, crosslinking behavior, and rheology, with a specific emphasis on perovskite/Si tandem cells. Addressing the unique challenges posed by perovskite/Si tandem cells, the research emphasizes the need for encapsulant materials that accommodate the temperature-sensitive nature of perovskite solar cells. Factors like low residual stresses, minimal shrinkage and low viscosity are critical for successful encapsulation. The encapsulant materials are characterized with different methods to gain knowledge into crosslinking behaviors, chemical compositions, and viscoelastic properties. The results facilitate the selection of suitable encapsulants for perovskite/Si tandem cells, aiming to reduce failure rates during lamination, enhance stability, and support the industrial-scale implementation of this promising PV technology. The presented findings contribute valuable guidelines for encapsulant selection, essential for optimizing the performance and reliability of perovskite/Si tandem solar cells in real-world applications.

Abstract Oxonol dyes are classified as anionic polymethine dyes, which cover a wide variety of structural types. The name of the class originates from the oxygen atoms which terminate each end of the polymethine chains that form the backbone of their structure. In technically useful dyes, these oxygen atoms tend to be substituents of heterocycles. The main technical application of water soluble oxonol dyes was in silver halide photography as filter dyes and antihalation dyes. Lipophilic oxonol dyes are used in bio-analysis and medical diagnostics to stain cells, bacteria or liposomes for example. Their main bioanalytical usage is in the determination of membrane potentials in eukaryotic cells and prokaryotic bacteria.

Abstract Cyanines comprising either a benzo[e]‐ or benzo[c,d]indolium core facilitate initiation of radical photopolymerization combined with high power NIR‐LED prototypes emitting at 805 nm, 860 nm, or 870 nm, while different oxime esters function as radical coinitiators. Radical photopolymerization followed an initiation mechanism based on the participation of excited states, requiring additional thermal energy to overcome an existing intrinsic activation barrier. Heat released by nonradiative deactivation of the sensitizer favored the system, even under conditions where a thermally activated photoinduced electron transfer controls the reaction protocol. The heat generated internally by the NIR sensitizer promotes generation of the initiating reactive radicals. Sensitizers with a barbiturate group at the meso‐position preferred to bleach directly, while sensitizers carrying a cyclopentene moiety unexpectedly initiated the photosensitized mechanism.

Over the last decade, significant improvements in cost reduction as well as in conversion efficiency increase were achieved in large-scale industrial production, making PV cost competitive with other means of electricity generation. In many regions worldwide, PV achieves the lowest levelized cost of electricity. Several different factors made this tremendous achievement possible-namely economy of scale, a lean and efficient production process, and high conversion efficiencies. In this work, some of the key concepts and methods are described based on Hanwha Q CELLS’ experience. The methods and approaches for the fast transfer of cell technologies from laboratory to production and for accelerated progress in cell efficiency, quality, and reliability of the cell and module product are described. Over the last decade, the cell conversion efficiency increased by 0.5%abs per year. Currently, average cell conversion efficiencies exceeding 20% using boron-doped p-type multicrystalline (mc-Si) and 22%, using Czochralski-grown silicon (Cz-Si) substrates, are achieved on a multi-GW scale. Currently (as of Jan 2018) produced Q.ANTUM solar modules from these cells exhibit output powers of 325 Wp based on 120 half Cz cells and of 350 Wp based on 72 full multicrystalline cells. Besides just the performance, it is critical to investigate the reliability of solar modules based on p-type solar cells with dielectrically passivated rear. In terms of reliability, light-induced degradation (LID) is examined in detail, with conditions relevant for the activation of both the boron–oxygen (BO) defect, and “Light and Elevated Temperature Induced Degradation” (LeTID). While the formation of the BO defect has been considered the most prominent LID mechanism in boron-doped p-type Cz-Si, recently it was shown that LeTID is another important issue for passivated emitter and rear cells (PERC) on both mc-Si and Cz substrates. When not adequately suppressed, LeTID can occur on p-type PERC with degradation in output power of >6%; critically, it cannot be suppressed in a straightforward manner by conventional processing steps used to permanently deactivate the BO defect. In contrast to conventional PERC, Hanwha Q CELLS’ Q.ANTUM technology is shown to reliably suppress both LID due to BO defect formation and LeTID, for both p-type mc-Si and Cz-Si substrates.

Untersuchungen mit Bodenfallen zum Einfluss der Kulturarten auf die Dynamik von Arthropodengesellschaften werden vorgestellt. Sie betreffen vier perennierende Kulturen (extensives Grünland, Chinaschilf und die Baum­arten Pappel und Weide) sowie die Wintergerste als annu­elle Frucht. Die Kulturarten prägten die Diversität (Shannon-Weaver-Index) der Arthropodengesellschaften, wobei die Diversität der Baumkulturen statistisch meist von der Diversität in den Ackerbaukulturen unterschieden war. Dieser Befund war auf zeitliche Änderungen im Artenbestand (Artenidentität) sowie der Arten­dominanz (Dominanzidentität) zurück zu führen und belegt eine hohe Dynamik des Arthropodenauftretens inner­halb und zwischen den Kulturen. Über die Kultur­arten werden zeitlich und örtlich getrennte Teilpopula­tionen ausgebildet. Mögliche Triebkräfte für die Anpassung der Arthropodengesellschaften an die Fruchtarten wurden über die Erfassung des Energiestatus der Anbau­systeme analysiert. Grundlage waren Bewirtschaftungsdaten, die Pflanzenerträge sowie begleitende Informationen zum Anfall von Biomasse. Die Kennzahl „landwirtschaftlicher Energiegewinn“ fasst diese Einflüsse auf energetischer Ebene zusammen. Der Rückfluss von Biomasse in das Anbausystem wurde als „ökosystemarer Energiegewinn“ beschrieben. Beide Parameter beschreiben das Auftreten der Arthropoden in den Kulturen. Ansteigender landwirtschaftlicher Energiegewinn wirkte sich negativ aus, ökosystemarer Energiegewinn bewirkte das Gegenteil. Weiterhin konnte eine Zuordnung der Arthro­poden in funktionale Gruppen die Arten- und Dominanz­unterschiede der Arthropodengemeinschaften in den Kulturen erklären. Sie beruhen auf der Notwendigkeit der Energiedissipation und berühren den Energiefluss über die Trophiestufen. Die Stellung der Arthropodenarten im Nahrungsnetz wird modifiziert. Aus den Befunden ist ersichtlich, dass Energie basierte Daten Hinweise auf den Biodiversitätsstatus der Anbausysteme geben. Sie können Grundlage für die Ableitung indirekter Status- und Wirkungsindikatoren sein. Daneben fördern die Befunde das Verständnis über Ökosystemprozesse und zu den Inhalten des Begriffes „Intensität“ im Kontext der Bewertung ökologischer Nachhaltigkeit.

The photovoltaic industry is driven by manufacturing cost and is continuously working on optimizing its production output. As production sites are increasing significantly in size, large data sets are generated that require adequate processing for line optimization. As in other industries machine learning is one way to address this task. In this study a machine learning algorithm is used for trouble shooting of production data to identify parameters which are responsible to high variances in energy conversion efficiency.

Untersuchungen mit Bodenfallen zum Einfluss der Kulturarten auf die Dynamik von Arthropodengesellschaften werden vorgestellt. Sie betreffen vier perennierende Kulturen (extensives Grunland, Chinaschilf und die Baumarten Pappel und Weide) sowie die Wintergerste als annuelle Frucht. Die Kulturarten pragten die Diversitat (Shannon-Weaver-Index) der Arthropodengesellschaften, wobei die Diversitat der Baumkulturen statistisch meist von der Diversitat in den Ackerbaukulturen unterschieden war. Dieser Befund war auf zeitliche Anderungen im Artenbestand (Artenidentitat) sowie der Artendominanz (Dominanzidentitat) zuruck zu fuhren und belegt eine hohe Dynamik des Arthropodenauftretens innerhalb und zwischen den Kulturen. Uber die Kulturarten werden zeitlich und ortlich getrennte Teilpopulationen ausgebildet. Mogliche Triebkrafte fur die Anpassung der Arthropodengesellschaften an die Fruchtarten wurden uber die Erfassung des Energiestatus der Anbausysteme analysiert. Grundlage waren Bewirtschaftungsdaten, die Pflanzenertrage sowie begleitende Informationen zum Anfall von Biomasse. Die Kennzahl „landwirtschaftlicher Energiegewinn“ fasst diese Einflusse auf energetischer Ebene zusammen. Der Ruckfluss von Biomasse in das Anbausystem wurde als „okosystemarer Energiegewinn“ beschrieben. Beide Parameter beschreiben das Auftreten der Arthropoden in den Kulturen. Ansteigender landwirtschaftlicher Energiegewinn wirkte sich negativ aus, okosystemarer Energiegewinn bewirkte das Gegenteil. Weiterhin konnte eine Zuordnung der Arthropoden in funktionale Gruppen die Arten- und Dominanzunterschiede der Arthropodengemeinschaften in den Kulturen erklaren. Sie beruhen auf der Notwendigkeit der Energiedissipation und beruhren den Energiefluss uber die Trophiestufen. Die Stellung der Arthropodenarten im Nahrungsnetz wird modifiziert. Aus den Befunden ist ersichtlich, dass Energie basierte Daten Hinweise auf den Biodiversitatsstatus der Anbausysteme geben. Sie konnen Grundlage fur die Ableitung indirekter Status- und Wirkungsindikatoren sein. Daneben fordern die Befunde das Verstandnis uber Okosystemprozesse und zu den Inhalten des Begriffes „Intensitat“ im Kontext der Bewertung okologischer Nachhaltigkeit.