Structural changes of casein micelles in a rennin gradient film with simultaneous consideration of the film morphology

The effect of rennin on the micelle structure and microstructure of casein films was investigated with micro-beam grazing incidence small angle X-ray scattering and optical microscopy. Size distributions of casein micelles and colloidal calcium phosphate particles were determined as a function of rennin concentration within a rennin gradient film. While the size of the casein micelles decreased with increasing rennin concentration, the size of the colloidal calcium phosphate clusters remained constant. In accordance with a first-order enzyme reaction mechanism, the rennin-induced decay of the micellar sizes could be well described by an exponential function. Two distinct film morphologies at high and low rennin concentration were observed. At intermediate rennin concentration a two-phase surface structure was found, in which both film morphologies coexisted. The conclusions drawn on the behaviour of casein micelles in films can generally be applied to the rennin-induced changes in casein micelles in bulk solutions.     

Matrix Manipulation of Directly-Synthesized PbS Quantum Dot Inks Enabled by Coordination Engineering

The direct-synthesis of conductive PbS quantum dot (QD) ink is facile, scalable, and low-cost, boosting the future commercialization of optoelectronics based on colloidal QDs. However, manipulating the QD matrix structures still is a challenge, which limits the corresponding QD solar cell performance. Here, for the first time a coordination-engineering strategy to finely adjust the matrix thickness around the QDs is presented, in which halogen salts are introduced into the reaction to convert the excessive insulating lead iodide into soluble iodoplumbate species. As a result, the obtained QD film exhibits shrunk insulating shells, leading to higher charge carrier transport and superior surface passivation compared to the control devices. A significantly improved power-conversion efficiency from 10.52% to 12.12% can be achieved after the matrix engineering. Therefore, the work shows high significance in promoting the practical application of directly synthesized PbS QD inks in large-area low-cost optoelectronic devices.     

Morphology Transformation Pathway of Block Copolymer-Directed Cooperative Self-Assembly of ZnO Hybrid Films Monitored In Situ during Slot-Die Coating

Cooperative self-assembly (co-assembly) of diblock copolymers (DBCs) and inorganic precursors that takes inspiration from the rich phase separation behavior of DBCs can enable the realization of a broad spectrum of functional nanostructures with the desired sizes. In a DBC assisted sol–gel chemistry approach with polystyrene-block-poly(ethylene oxide) and ZnO, hybrid films are formed with slot-die coating. Pure DBC films are printed as control. In situ grazing-incidence small-angle X-ray scattering measurements are performed to investigate the self-assembly and co-assembly process during the film formation. Combining complementary ex situ characterizations, several distinct regimes are differentiated to describe the morphological transformations from the initially solvent-dispersed to the ultimately solidified films. The comparison of the assembly pathway evidences that the key step in the establishment of the pure DBC film is the coalescence of spherical micelles toward cylindrical domains. Due to the presence of the phase-selective precursor, the formation of cylindrical aggregates in the solution is crucial for the structural development of the hybrid film. The pre-existing cylinders in the ink impede the domain growth of the hybrid film during the subsequent drying process. The precursor reduces the degree of order, prevents crystallization of the PEO block, and introduces additional length scales in the hybrid films.     

Combining mixed titania morphologies into a complex assembly thin film by iterative block-copolymer-based sol–gel templating

Sol–gel templating combined with iterative spin-coating steps are used to custom-tailor hierarchically structured titania thin films. Using poly(styrene-block-ethylene oxide) P(S-b-PEO) as the structure directing agent, a foam-like structure is combined with nanogranules. Both structural elements are merged into a complex assembly in thin film geometry. The resulting morphology is pictured by SEM and probed with GISAXS. The installed mesoporous titania sandwich structure exhibits holes with a size of 45 nm which makes it promising for applications in photovoltaics or photocatalysis. An optical characterization completes the structural investigation.     

Scalable Synthesis of Hierarchical Antimony/Carbon Micro-/Nanohybrid Lithium/Sodium-Ion Battery Anodes Based on Dimethacrylate Monomer

A facile scalable synthesis of hierarchical Sb/C micro-/nanohybrid has been addressed in this work,which possesses the advantages of both micrometer and nanometer scale structures as lithium-ion battery anode.Difunctional methacrylate monomers are used as solvent and carbon source as well.Liquid precursor of antimony(III) n-butoxide is dissolved in the resin monomer solution,and further incorporated into the cross-linking polymer network via photo polymerization.Through calcination in argon/hydrogen atmosphere,antimony nanoparticles are in situ formed by carbothermal reduction,and homogeneously embedded in the in situ formed micrometer sized carbon matrix.The morphology,structure,crystallinity,spatial dispersion,composition,and electrochemical performance of the Sb/C micro-/nanohybrid are systematically investigated.The cyclic and rate performance of the Sb/C micro-/nanohybrid anode have been effectively improved compared to the pure carbon anode.A reversible capacity of 362 m Ah g~(-1) is achieved with a reasonable mass loading density after 300 cycles at 66 m A g~(-1),corresponding to capacity retention of 79%.With reducing mass loading density,the reversible capacity reaches 793 m Ah g~(-1) after 100 cycles.Moreover,the electrochemical performance of Sb/C micro-/nanohybrid as sodium-ion battery anode is also investigated in this study.     

Hot Hydrocarbon-Solvent Slot-Die Coating Enables High-Efficiency Organic Solar Cells with Temperature-Dependent Aggregation Behavior

Organic solar cells (OSCs) have made rapid progress in terms of their development as a sustainable energy source. However, record-breaking devices have not shown compatibility with large-scale production via solution processing in particular due to the use of halogenated environment-threatening solvents. Here, slot-die fabrication with processing involving hydrocarbon-based solvents is used to realize highly efficient and environmentally friendly OSCs. Highly compatible slot-die coating with roll-to-roll processing using halogenated (chlorobenzene (CB)) and hydrocarbon solvents (1,2,4-trimethylbenzene (TMB) and ortho-xylene (o-XY)) is used to fabricate photoactive films. Controlled solution and substrate temperatures enable similar aggregation states in the solution and similar kinetics processes during film formation. The optimized blend film nanostructures for different solvents in the highly efficient PM6:Y6 blend is adopted to show a similar morphology, which results in device efficiencies of 15.2%, 15.4%, and 15.6% for CB, TMB, and o-XY solvents. This approach is successfully extended to other donor–acceptor combinations to demonstrate the excellent universality of this method. The results combine a method to optimize the aggregation state and film formation kinetics with the fabrication of OSCs with environmentally friendly solvents by slot-die coating, which is a critical finding for the future development of OSCs in terms of their scalable production and high-performance.     

Synthese und kristallstruktur von KCr0,8Al0,2Mo2O8

Single crystals of KCr_0.8Al_0.2Mo₂O₈ were prepared and investigated by the X-ray diffractometer technique. It shows a structure type related to trigonal KAIMo₂O₈, monoclinic NaCrMo₂O₈ or orthorhombic KInMo₂O₈, space group C_2h⁶—C2/c; a=17.445 Å, b=5.649 Å, c=8.997 Å, β=119.37°; Z=4. KCr_0.8Al_0.2Mo₂O₈ is characterized by isolated MoO₄ tetrahedra, isolated (Cr/Al)O₆ octahedra and a distorted square antiprism around K⁺. The crystal structure is discussed with respect to those of related compounds.

Zusammenfassung

Einkristalle von KCr_0.8Al_0.2Mo₂O₈ wurden synthetisiert und mit Vierkreisdiffraktometertechnik röntgenographisch untersucht. Sie zeigen einen mit trigonal-KA1Mo₂O₈, monoklin-NaCrMo₂O₈ oder orthorhombisch-KlnMo₂O₈ verwandten Strukturtyp, Raumgruppe C_2h⁶—C2/c; a=17,445 Å, b=5,649 Å, c=8,997 Å, β=119,37°; Z=4. KCr_0.8Al_0.2Mo₂O₈ zeichnet sich durch isolierte MoO₄-Tetraeder, isolierte (Cr/Al)O₆-Oktaeder und ein verzerrtes quadratisches Antiprisma um K⁺ aus. Die Kristallstruktur wird mit solchen verwandter Verbindungen diskutiert.     

Growth and morphology of sputtered aluminum thin films on P3HT surfaces

Growth and morphology of an aluminum (Al) contact on a poly(3-hexylthiophene) (P3HT) thin film are investigated with X-ray methods and related to the interactions at the Al:P3HT interface. Grazing incidence small-angle scattering (GISAXS) is applied in situ during Al sputter deposition to monitor the growth of the layer. A growth mode is found, in which the polymer surface is wetted and rapidly covered with a continuous layer. This growth type results in a homogeneous film without voids and is explained by the strong chemical interaction between Al and P3HT, which suppresses the formation of three-dimensional cluster structures. A corresponding three stage growth model (surface bonding, agglomeration, and layer growth) is derived. X-ray reflectivity shows the penetration of Al atoms into the P3HT film during deposition and the presence of a 2 nm thick intermixing layer at the Al:P3HT interface.