Donor-Acceptor Copolymer with a Linear Backbone Induced Ordered and Robust Doping Morphology for Efficient and Stable Organic Electrochemical Devices.

Donor (D)-acceptor (A) copolymer-based organic mixed ionic-electronic conductors (OMIECs) exhibit intrinsic environmental stability for they have tailored energy levels. However, their figure-of-merit (µC*) is still falling behind the D-D polymers because of morphology deterioration during the electrochemical doping process. Herein, we developed two D-A copolymers with precisely regulated backbone curvature, namely PTBT-P and PTTBT-P. Compared to the curved PTBT-P and previously reported copolymers, PTTBT-P better keeps its backbone linear, leading to a long-range ordered doping morphology, which is revealed by the in operando X-ray technique. This optimized doping morphology enables a significantly improved operando charge mobility (µ) of 2.44 cm2 V-1 s-1 and a µC* value of 342 F cm-1 V-1 s-1, one of the highest values in D-A copolymer based on OECTs. Besides, we fabricated PTTBT-P-based electrochemical random-access memories and achieved ideal and robust conductance modulation. This study highlights the critical role of backbone curvature control in the optimization of doping morphology for efficient and robust organic electrochemical devices.

Operando Study Insights into Lithiation/Delithiation Processes in a Poly(ethylene oxide) Electrolyte of All-Solid-State Lithium Batteries by Grazing-Incidence X-ray Scattering.

Poly(ethylene oxide) (PEO)-based composite electrolytes (PCEs) are considered as promising candidates for next-generation lithium-metal batteries (LMBs) due to their high safety, easy fabrication, and good electrochemical stability. Here, we utilize operando grazing-incidence small-angle and wide-angle X-ray scattering to probe the correlation of electrochemically induced changes and the buried morphology and crystalline structure of the PCE. Results show that the two irreversible reactions, PEO-Li+ reduction and TFSI- decomposition, cause changes in the crystalline structure, array orientation, and morphology of the PCE. In addition, the reversible Li plating/stripping process alters the inner morphology, especially the PEO-LiTFSI domain radius and distance between PEO-LiTFSI domains, rather than causing crystalline structure and orientation changes. This work provides a new path to monitor a working battery in real time and to a detailed understanding of the Li+ diffusion mechanism, which is essential for developing highly transferable and interface-stable PCE-based LMBs.

Modular slot-die coater for in situ grazing-incidence x-ray scattering experiments on thin films.

Multimodal in situ experiments during slot-die coating of thin films pioneer the way to kinetic studies on thin-film formation. They establish a powerful tool to understand and optimize the formation and properties of thin-film devices, e.g., solar cells, sensors, or LED films. Thin-film research benefits from time-resolved grazing-incidence wide- and small-angle x-ray scattering (GIWAXS/GISAXS) with a sub-second resolution to reveal the evolution of crystal structure, texture, and morphology during the deposition process. Simultaneously investigating optical properties by in situ photoluminescence measurements complements in-depth kinetic studies focusing on a comprehensive understanding of the triangular interdependency of processing, structure, and function for a roll-to-roll compatible, scalable thin-film deposition process. Here, we introduce a modular slot-die coater specially designed for in situ GIWAXS/GISAXS measurements and applicable to various ink systems. With a design for quick assembly, the slot-die coater permits the reproducible and comparable fabrication of thin films in the lab and at the synchrotron using the very same hardware components, as demonstrated in this work by experiments performed at Deutsches Elektronen-Synchrotron (DESY). Simultaneous to GIWAXS/GISAXS, photoluminescence measurements probe optoelectronic properties in situ during thin-film formation. An environmental chamber allows to control the atmosphere inside the coater. Modular construction and lightweight design make the coater mobile, easy to transport, quickly extendable, and adaptable to new beamline environments.

INSIGHT: in situ heuristic tool for the efficient reduction of grazing-incidence X-ray scattering data.

INSIGHT is a Python-based software tool for processing and reducing 2D grazing-incidence wide- and small-angle X-ray scattering (GIWAXS/GISAXS) data. It offers the geometric transformation of the 2D GIWAXS/GISAXS detector image to reciprocal space, including vectorized and parallelized pixel-wise intensity correction calculations. An explicit focus on efficient data management and batch processing enables full control of large time-resolved synchrotron and laboratory data sets for a detailed analysis of kinetic GIWAXS/GISAXS studies of thin films. It processes data acquired with arbitrarily rotated detectors and performs vertical, horizontal, azimuthal and radial cuts in reciprocal space. It further allows crystallographic indexing and GIWAXS pattern simulation, and provides various plotting and export functionalities. Customized scripting offers a one-step solution to reduce, process, analyze and export findings of large in situ and operando data sets.

A Practical Approach Toward Highly Reproducible and High-Quality Perovskite Films Based on an Aging Treatment.

Solution processing of hybrid perovskite semiconductors is a highly promising approach for the fabrication of cost-effective electronic and optoelectronic devices. However, challenges with this approach lie in overcoming the controllability of the perovskite film morphology and the reproducibility of device efficiencies. Here, a facile and practical aging treatment (AT) strategy is reported to modulate the perovskite crystal growth to produce sufficiently high-quality perovskite thin films with improved homogeneity and full-coverage morphology. The resulting AT-films exhibit fewer defects, faster charge carrier transfer/extraction, and suppressed non-radiative recombination compared with reference. The AT-devices achieve a noticeable improvement in the reproducibility, operational stability, and photovoltaic performance of devices, with the average efficiency increased by 16%. It also demonstrates the feasibility and scalability of AT strategy in optimizing the film morphology and device performance for other perovskite components including MAPbI3 , (MAPbBr3 )15 (FAPbI3 )85 , and Cs0.05 (MAPbBr3 )0.17 (FAPbI3 )0.83 . This method opens an effective avenue to improve the quality of perovskite films and photovoltaic devices in a scalable and reproducible manner.

Trace Water in Lead Iodide Affecting Perovskite Crystal Nucleation Limits the Performance of Perovskite Solar Cells.

The experimental replicability of highly efficient perovskite solar cells (PSCs) is a persistent challenge faced by laboratories worldwide. Although trace impurities in raw materials can impact the experimental reproducibility of high-performance PSCs, the in situ study of how trace impurities affect perovskite film growth is never investigated. Here, light is shed on the impact of inevitable water contamination in lead iodide (PbI2 ) on the replicability of device performance, mainly depending on the synthesis methods of PbI2 . Through synchrotron-based structure characterization, it is uncovered that even slight additions of water to PbI2 accelerate the crystallization process in the perovskite layer during annealing. However, this accelerated crystallization also results in an imbalance of charge-carrier mobilities, leading to a degradation in device performance and reduced longevity of the solar cells. It is also found that anhydrous PbI2 promotes a homogenous nucleation process and improves perovskite film growth. Finally, the PSCs achieve a remarkable certified power conversion efficiency of 24.3%. This breakthrough demonstrates the significance of understanding and precisely managing the water content in PbI2 to ensure the experimental replicability of high-efficiency PSCs.

Decoding the Self-Assembly Plasmonic Interface Structure in a PbS Colloidal Quantum Dot Solid for a Photodetector.

Hybrid plasmonic nanostructures have gained enormous attention in a variety of optoelectronic devices due to their surface plasmon resonance properties. Self-assembled hybrid metal/quantum dot (QD) architectures offer a means of coupling the properties of plasmonics and QDs to photodetectors, thereby modifying their functionality. The arrangement and localization of hybrid nanostructures have an impact on exciton trapping and light harvesting. Here, we present a hybrid structure consisting of self-assembled gold nanospheres (Au NSs) embedded in a solid matrix of PbS QDs for mapping the interface structures and the motion of charge carriers. Grazing-incidence small-angle X-ray scattering is utilized to analyze the localization and spacing of the Au NSs within the hybrid structure. Furthermore, by correlating the morphology of the Au NSs in the hybrid structure with the corresponding differences observed in the performance of photodetectors, we are able to determine the impact of interface charge carrier dynamics in the coupling structure. From the perspective of architecture, our study provides insights into the performance improvement of optoelectronic devices.

Diblock copolymer pattern protection by silver cluster reinforcement.

Pattern fabrication by self-assembly of diblock copolymers is of significant interest due to the simplicity in fabricating complex structures. In particular, polystyrene-block-poly-4-vinylpyridine (PS-b-P4VP) is a fascinating base material as it forms an ordered micellar structure on silicon surfaces. In this work, silver (Ag) is applied using direct current magnetron sputter deposition and high-power impulse magnetron sputter deposition on an ordered micellar PS-b-P4VP layer. The fabricated hybrid materials are structurally analyzed by field emission scanning electron microscopy, atomic force microscopy, and grazing incidence small angle X-ray scattering. When applying simple aqueous posttreatment, the pattern is stable and reinforced by Ag clusters, making micellar PS-b-P4VP ordered layers ideal candidates for lithography.

Effect of Molecular Organization on the Properties of Fractionated Lignin-Based Thiol-Ene Thermoset Materials.

In this study, the combination of sequential solvent fractionation of technical Kraft lignin was followed by allylation of most OH functionalities to give highly functional thermoset resins. All lignin fractions were highly functionalized on the phenolic (≥95%) and carboxylic acid OH (≥85%) and to a significant extent on the aliphatic OH moieties (between 43 and 75%). The resins were subsequently cross-linked using thiol-ene chemistry. The high amount of allyl functionalities resulted in a high cross-link density. Dynamic mechanical analysis measurements showed that the thioether content, directly related to the allyl content, strongly affects the performance of these thermosets with a glass transition temperature (Tg) between 81 and 95 °C and with a storage modulus between 1.9 and 3.8 GPa for all thermosets. The lignin fractions and lignin-based thermosets' morphology, at the nanoscale, was studied by wide-angle X-ray scattering measurements. Two π-π stacking interactions were observed: sandwich (≈4.1-4.7 Å) and T-shaped (≈5.5-7.2 Å). The introduction of allyl functionalities weakens the T-shaped π-π stacking interactions. A new signal corresponding to a distance of ≈3.5 Å was observed in lignin-based thermosets, which was attributed to a thioether organized structure. At the same time, a lignin superstructure was observed with a distance/size corresponding to 7.9-17.5 Å in all samples.

Investigating the thermal stability of ultra-small Ag, Au and AuAg alloy nanoparticles embedded in a silica matrix.

Thermal growth kinetics of embedded bimetallic (AuAg/SiO2) nanoparticles are explored and compared with their monometallic (Au/SiO2 and Ag/SiO2) counterparts, as their practical applicability demands stability and uniformity. The plasmonic properties of these nanoparticles (NPs) significantly improve when their size falls in the ultra-small region (diameter < 10 nm), owing to their large active surface area. Interestingly, the bimetallic NPs exhibit better optical properties and structural stability as compared to their monometallic counterparts. This calls for a thorough understanding of the nucleation and temperature-dependent growth to ensure size stability against thermal coarsening that most bimetallic NPs completely lack. Herein, the atom beam sputtered AuAg NPs are systematically analysed over a wide range of annealing temperatures (ATs), and the results are compared with those of Au and Ag NPs. The X-ray photoelectron spectroscopy spectra and other experimental results confirm the formation of AuAg alloy NPs inside the silica matrix. Furthermore, techniques like transmission electron microscopy and grazing-incidence small-/wide-angle X-ray scattering were used to explore the temperature-dependent structural and morphological stability of the NPs. Our results show that the deposited AuAg NPs retain their spherical shape and remain as an alloy for the entire range of ATs. When the AT increases from 25 °C to 800 °C, the size of the NPs also increases from 3.5 to 4.8 nm; beyond that, their size grows substantially to 13.6 nm at 900 °C. We observed that the NPs remain in the ultra-small size range (∼5 nm) until an AT of 800 °C. Beyond that Ostwald ripening is ascribed to be the major cause of particle growth, resulting in an active surface area loss. Based on the outcomes, a three-step nucleation and growth mechanism is proposed.

In Situ Study of Structure Formation under Stress in Stretchable Conducting Nanocomposites.

One of the major limitations of flexible sensors is the loss of conductivity upon multiple stretching and bending cycles. Conducting fillers with two different geometries, carbon black and carbon nanotubes, were introduced in polydimethylsiloxane (PDMS) for physical insights into the structure formation of nanofillers by the application of periodic tensile stress. The loading of the nanofillers was selected beyond the percolation threshold to determine the cyclic stability of the resulting network channels. The surface chemistry of carbon nanotubes has been varied to understand the interfacial interactions at the molecular length scale. The combination of in situ stretching, annealing, and vis-à-vis conductometry of nanocomposite films with synchrotron-based ultra-small angle X-ray scattering experiments enables us to highlight the importance of the fractal dimensions of nanofillers for the molecular level interactions. The irreversible formation of nanofiller network geometries under cyclic stress and annealing was found to be responsible for the electrical properties of a flexible conducting film.

Correction: Luedemann et al. Prostate Cancer-Associated miRNAs in Saliva: First Steps to an Easily Accessible and Reliable Screening Tool. Biomolecules 2022, 12, 1366.

The authors wish to make the following corrections to their paper [...].

Hydrostatic pressure of the renal pelvis as a radiation-free alternative to fluoroscopic nephrostogram following percutaneous nephrolithotomy.

BACKGROUND: We evaluated the hydrostatic pressure of the renal pelvis (RPP) as a radiation-free alternative to fluoroscopic nephrostogram to assess ureteral patency after percutaneous nephrolithotomy (PCNL). METHODS: Retrospective non-inferiority study analyzing 248 PCNL-patients (86 female (35%) and 162 males (65%)) between 2007 and 2015. Postoperatively, RPP was measured using a central venous pressure manometer in cmH2O. The primary endpoint was to assess RPP depending on the patency of the ureter and the nephrostomy tube removal. Secondary, the upper limit of normal RPP of [Formula: see text] 20 cmH2O was assessed as an indicator of an unobstructed patency. RESULTS: The median procedure duration was 141 min (112-171.5) with a stone free rate of 82% (n = 202). RPP was significantly higher in patients with obstructive nephrostogram with 25.0 mmH2O (21.0-32.0) versus 20.0 mmH2O (16.0-24.0; p < 0.001). The pressure was lower in successful nephrostomy removal with 18 cmH2O (15-21) versus 23 cmH2O (20-29) in the leakage group (p < 0.001). The analysis of a cut-off of [Formula: see text] 20 cmH2O showed a sensitivity of 76.9% (95% CI [60.7%; 88.9%]) and a specificity of 61.5% (95% CI [54.6%; 68.2%]). The negative predictive value was 93.4% (95% CI: [87.9%; 97.0%]) and the positive predictive value 27.3% (95% CI [19.2%; 36.6%]). The accuracy of the model showed an AUC = 0.795 (95% CI [0.668; 0.862]). CONCLUSION: The hydrostatic RPP seems to allow a bedside evaluation of ureteral patency after PCNL.

Seam Properties of Overlap Welding Strategies from Copper to Aluminum Using Green Laser Radiation for Battery Tab Connections in Electric Vehicles.

Laser beam welding of metals has progressed dramatically over the last years mainly arising from joining applications in the field of electromobility. Allowing the flexible, automated manufacturing of mechanically, electrically, and thermally stressed components, the process is more frequently applied for joining highly reflective materials, for example for battery tab and busbar connections. The local, non-contact energy input favors this welding technology; however, joining of copper and aluminum sheets still poses a challenge due to the physical properties of the joining partners and intermetallic phases from dissimilar metal interaction, which reduce seam performance. The use of green laser radiation compared to infrared laser radiation offers the advantage of a significantly increased absorptivity for copper materials. A changed incoupling behavior is observed, and a lower deep penetration threshold has been already proven for 515 nm wavelength. When copper and aluminum are welded with the former as top sheet, this welding mode is essential to overcome limited aspect ratios from heat conduction welding. However, the opportunities of applying these beam sources in combination with spatial power modulation to influence the interconnection area of copper-aluminum joints have not yet been studied. The aim of this work is therefore to investigate the seam properties and process stability of different overlap welding strategies using green laser radiation for dissimilar metal welding. A microstructural analysis of the different fusion zones and mechanical strength of the joints are presented. In addition, the experimental parameter sets were analyzed regarding their application in battery module busbars by examining the electrical resistance and temperature distribution after welding. A parameter window was identified for all investigated welding strategies, with the stitched seam achieving the most stable results.

Superlattice deformation in quantum dot films on flexible substrates via uniaxial strain.

The superlattice in a quantum dot (QD) film on a flexible substrate deformed by uniaxial strain shows a phase transition in unit cell symmetry. With increasing uniaxial strain, the QD superlattice unit cell changes from tetragonal to cubic to tetragonal phase as measured with in situ grazing-incidence small-angle X-ray scattering (GISAXS). The respective changes in the optoelectronic coupling are probed with photoluminescence (PL) measurements. The PL emission intensity follows the phase transition due to the resulting changing inter-dot distances. The changes in PL intensity accompany a redshift in the emission spectrum, which agrees with the Förster resonance energy transfer (FRET) theory. The results are essential for a fundamental understanding of the impact of strain on the performance of flexible devices based on QD films, such as wearable electronics and next-generation solar cells on flexible substrates.

3D Printable Hybrid Gel Made of Polymer Surface-Modified Cellulose Nanofibrils Prepared by Surface-Initiated Controlled Radical Polymerization (SI-SET-LRP) and Upconversion Luminescent Nanoparticles.

A cellulose nanofibril-based hybrid gel material was developed by grafting the polymerized stearyl acrylate (PSA) and upconversion nanoparticles (UCNPs) onto cellulose nanofibrils (CNFs) via Cu0-mediated radical polymerization (SET-LRP) to create a highly cross-linked CNF system. A two-step strategy was exploited to surface-exchange the ligand of the UCNPs from a hydrophobic ligand (oleic acid) to a hydrophilic small-molecule ligand (2-acrylamido-2-methyl-1-propanesulfonic acid, AMPS) and therefore be suitable for SET-LRP. The characteristics and properties of the hybrid material (UCNP-PSA-CNF) were monitored by Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), rheology, X-ray diffraction (XRD), and microscopic analysis. Those characterization techniques prove the efficient modification of the CNF, with the presence of 1.8% UCNPs. The luminescence measurement was carried out using a homebuilt confocal microscope with a 980 nm laser source. The nanostructure of UCNPs and their incorporated CNF species were measured by small-angle X-ray scattering (SAXS). In addition, this CNF-based hybrid gel has decisive rheological properties, such as good viscoelasticity (loss tangent was below 0.35 for the UCNP-PSA-CNF gel, while the PSA-CNF gel reached the highest value of 0.42), shear-thinning behavior, and shape retention, and was successfully applied to three-dimensional (3D) gel printing throughout various 3D print models.

Scalable Paper Supercapacitors for Printed Wearable Electronics.

Printed paper-based electronics offers solutions to rising energy concerns by supplying flexible, environmentally friendly, low-cost infrastructure for portable and wearable electronics. Herein, we demonstrate a scalable spray-coating approach to fabricate tailored paper poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS)/cellulose nanofibril (CNF) electrodes for all-printed supercapacitors. Layer-by-layer spray deposition was used to achieve high-quality electrodes with optimized electrode thickness. The morphology of these electrodes was analyzed using advanced X-ray scattering methods, revealing that spray-coated electrodes have smaller agglomerations, resulting in a homogeneous film, ultimately suggesting a better electrode manufacturing method than drop-casting. The printed paper-based supercapacitors exhibit an areal capacitance of 9.1 mF/cm2, which provides enough energy to power electrochromic indicators. The measured equivalent series resistance (ESR) is as low as 0.3 Ω, due to improved contact and homogeneous electrodes. In addition, a demonstrator in the form of a self-powered wearable wristband is shown, where a large-area (90 cm2) supercapacitor is integrated with a flexible solar cell and charged by ambient indoor light. This demonstration shows the tremendous potential for sequential coating/printing methods in the scaling up of printed wearables and self-sustaining systems.

Evolution of Structure and Optoelectronic Properties During Halide Perovskite Vapor Deposition.

The efficiency of perovskite-based solar cells has increased dramatically over the past decade to as high as 25%, making them very attractive for commercial use. Vapor deposition is a promising technique that potentially enables fabrication of perovskite solar cells on large areas. However, to implement a large-scale deposition method, understanding and controlling the specific growth mechanisms are essential for the reproducible fabrication of high-quality layers. Here, we study the structural and optoelectronic kinetics of MAPbI3, employing in-situ photoluminescence (PL) spectroscopy and grazing-incidence small/wide-angle X-ray scattering (GI-SAXS/WAXS) simultaneously during perovskite vapor deposition. Such a unique combination of techniques reveals MAPbI3 formation from the early stages and uncovers the morphology, crystallographic structure, and defect density evolution. Furthermore, we show that the nonmonotonous character of PL intensity contrasts with the increasing volume of the perovskite phase during the growth, although bringing valuable information about the presence of defect states.