Chemistry is progressively unraveling the processes that underlie the evolution of matter towards states of higher complexity and the generation of novel features along the way by self‐organization ...under the pressure of information. Chemistry has evolved from molecular to supramolecular to become adaptive chemistry by way of constitutional dynamics, which allow for adaptation, through component selection in an equilibrating set. Dynamic systems can be represented by weighted dynamic networks that define the agonistic and antagonistic relationships between the different constituents linked through component exchange. Such networks can be switched through amplification/up‐regulation of the best adapted/fittest constituent(s) in a dynamic set. Accessing higher level functions such as training, learning, and decision making represent future lines of development for adaptive chemical systems.
Chemistry is key for understanding the fundamental processes that underlie the evolution of matter towards states of increasing complexity through self‐organization. It has developed from the molecular to the supramolecular level and has, through constitution dynamic systems, acquired the features of adaptive chemistry. Hence, chemistry opens the door towards complex matter.
Surface nanostructuring enables the manipulation of many essential surface properties. With the recent rapid advancements in laser technology, a contactless large‐area processing at rates of up to m2 ...s−1 becomes feasible that allows new industrial applications in medicine, optics, tribology, biology, etc. On the other hand, the last two decades enable extremely successful and intense research in the field of so‐called laser‐induced periodic surface structures (LIPSS, ripples). Different types of these structures featuring periods of hundreds of nanometers only—far beyond the optical diffraction limit—up to several micrometers are easily manufactured in a single‐step process and can be widely controlled by a proper choice of the laser processing conditions. From a theoretical point of view, however, a vivid and very controversial debate emerges, whether LIPSS originate from electromagnetic effects or are caused by matter reorganization. This article aims to close a gap in the available literature on LIPSS by reviewing the currently existent theories of LIPSS along with their numerical implementations and by providing a comparison and critical assessment of these approaches.
After more than five decades of research on laser‐induced period surface structures (LIPSS), the competition of the two different main theories (electromagnetics vs matter‐reorganization) is over: both approaches are currently merging into a coherent view on LIPSS. Depending on materials and irradiation conditions, aspects supporting one of the two theory classes can dominate the experimental observations.
Chemistry, pure and applied, is a science and an industry. By its power over the expressions of matter, it also displays the creativity of art. It has expanded from molecular to supramolecular ...chemistry and then, by way of constitutional dynamic chemistry, towards adaptive chemistry. Constitutional dynamics allow for adaptation, through component exchange and selection in response to physical stimuli (e.g. light, photoselection), to chemical effectors (e.g. metal ions, metalloselection) or to environmental effects (e.g. phase change) in equilibrium or out‐of‐equilibrium conditions, towards the generation of the best‐adapted/fittest constituent(s) in a dynamic set. Such dynamic systems can be represented by two‐dimensional or three‐dimensional dynamic networks that define the agonistic and antagonistic relationships between the different constituents linked through component exchange. The introduction of constitutional dynamics into materials science opens perspectives towards adaptive materials and technologies, presenting attractive behavioral features (such as self‐healing). In particular, dynamic polymers may undergo modification of their properties (mechanical, optical, etc.) through component exchange and recombination in response to physical or chemical agents. Constitutional adaptive materials open towards a systems materials science and offer numerous opportunities for soft‐matter technologies.
Chemistry, pure and applied, is a science and an industry. By its power over the expressions of matter, it also displays the creativity of art. The field of chemistry is the universe of all possible entities and transformations of molecular matter, of which those actually realized in nature represent just one world among all the worlds that await to be created at the hand of the chemist.
Lead halide perovskite, as an emerging semiconductor, provides a fire‐new opportunity for high‐definition display and solid‐state lighting. Earthshaking improvements are implemented in green, red, ...and near‐infrared perovskite light‐emitting diodes (PeLEDs). However, blue PeLEDs are still far behind in performance, which restricts the development of PeLEDs in practical applications. Herein, a facile energy cascade channel strategy via one‐step self‐organized and controllable 2D/3D perovskite preparation by introducing guanidine hydrobromide (GABr) is developed that greatly improves the efficiency of blue PeLEDs. The 2D/3D perovskite structure boosts the energy cascade to induce energy transfer from the wide into the narrow bandgap domains and inhibit free charge diffusion, which increases the density of electrons and holes, and enhances the radiative recombination. Profiting from this energy cascade channels, the external quantum efficiency of blue PeLEDs, emitting at 492 nm, is considerably enhanced from 1.5% of initial blue device to 8.2%. In addition, device operating stability under ambient conditions is also improved by 2.6‐fold. The one‐step self‐organized 2D/3D hybrid perovskites induced by GABr pave a new and simple route toward high‐performance blue emission PeLEDs.
Highly efficient blue perovskite light‐emitting diodes (PeLEDs) are reported herein employing a facile energy cascade channel strategy via one‐step self‐organized 2D/3D perovskite preparation. The 2D/3D emitter induces energy transfer from the wide into the narrow bandgap domains and inhibits free charge diffusion, thereby increasing electron and hole density and enhancing radiative recombination, which makes blue PeLEDs have a peak external quantum efficiency of 8.2%.
Growing holes: With the aid of a new technique highly organized surface layers of TiO2 nanotubes that are open at one end (see picture) are formed by the anodization of titanium. The pore structure ...is determined by the pH gradient within the forming pore, this in turn is controlled by the electrochemical sweep rate and the electrolyte concentration.
7.7% Efficient All-Polymer Solar Cells Hwang, Ye-Jin; Courtright, Brett A. E.; Ferreira, Amy S. ...
Advanced materials (Weinheim),
August 19, 2015, Letnik:
27, Številka:
31
Journal Article
Recenzirano
By controlling the polymer/polymer blend self‐organization rate, all‐polymer solar cells composed of a high‐mobility, crystalline, naphthalene diimide‐selenophene copolymer acceptor and a ...benzodithiophene‐thieno3,4‐bthiophene copolymer donor are achieved with a record 7.7% power conversion efficiency and a record short‐circuit current density (18.8 mA cm−2).
Drawing upon the self-determination theory, we develop a two-stage multi-path mediation model in which psychological autonomy mediates the relationship between active engagement in entrepreneurship ...and well-being partially through its effect on psychological competence and relatedness. We test this model on a representative sample of 1837 working individuals (251 early-stage entrepreneurs) from Sweden. We find active engagement in entrepreneurial work tasks to be strongly associated with well-being relative to non-entrepreneurial work. Thus, we highlight the importance of individual self-organization—with autonomy at its core—which makes entrepreneurial work more beneficial in terms of basic psychological needs compared to other work alternatives.
•We examine variations in well-being and basic psychological needs between entrepreneurs and non-entrepreneurial employees.•We draw on a unique and representative data sample, originates from the 2011 Swedish Global Entrepreneurship Monitor.•Our analysis clearly shows that well-being is strongly and positively associated with entrepreneurial task engagements.•Our theorizing demonstrates the positive contribution of entrepreneurship to basic psychological needs and well-being.
Load‐bearing soft tissues, e.g., cartilage, ligaments, and blood vessels, are made predominantly from water (65–90%) which is essential for nutrient transport to cells. Yet, they display amazing ...stiffness, toughness, strength, and deformability attributed to the reconfigurable 3D network from stiff collagen nanofibers and flexible proteoglycans. Existing hydrogels and composites partially achieve some of the mechanical properties of natural soft tissues, but at the expense of water content. Concurrently, water‐rich biomedical polymers are elastic but weak. Here, biomimetic composites from aramid nanofibers interlaced with poly(vinyl alcohol), with water contents of as high as 70–92%, are reported. With tensile moduli of ≈9.1 MPa, ultimate tensile strains of ≈325%, compressive strengths of ≈26 MPa, and fracture toughness of as high as ≈9200 J m−2, their mechanical properties match or exceed those of prototype tissues, e.g., cartilage. Furthermore, with reconfigurable, noncovalent interactions at nanomaterial interfaces, the composite nanofiber network can adapt itself under stress, enabling abiotic soft tissue with multiscale self‐organization for effective load bearing and energy dissipation.
Water‐rich biomimetic composites from aramid nanofibers interlaced with poly(vinyl alcohol) emulate the collagen–proteoglycan network in load‐bearing soft tissues. The hydrogen bonding between stiff nanofibers and soft polymers affords synergistic stiffening and toughening, allowing the nanofiber network to self‐organize under stress for effective load bearing and energy dissipation. Their mechanics, biocompatibility, and high water content permit utilization as load‐bearing biomaterials and for other applications including durable high‐transport‐rate membranes, membranes in water desalination, fuel cells, and batteries.
Porphyrins and polyoxometalates can be combined into useful architectures for energy conversion, this Minireview highlights the most successful strategies developed to date. For more information, see ...the Minireview by Ruhlmann, Weiss et al. on page 16071
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