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Developing bioinspired camouflage materials that can adaptively change color in the visible and infrared (IR) regions is an intriguing but challenging task. Herein, we report an emerging strategy for fabricating dynamic visible and IR camouflage materials by the controlled in situ growth of novel photopolymerizable blue phase liquid crystals with cubic nanoarchitectures onto highly aligned MXene nanostructured thin films. The resulting MXene‐integrated 3D soft photonic crystals exhibit vivid structural colors and reversible switching between a bright colored state and a dark black state under a low DC electric field. As an illustration, proof‐of‐concept pixelated devices that allow for pixel‐controllable electrochromism are demonstrated. Furthermore, a free‐standing electrochromic flexible film of such 3D soft photonic crystals is fabricated, where visible electrochromism and thermal camouflage are enabled by leveraging the superior electrothermal conversion and low mid‐IR emissivity of MXene nanomaterials. [ABSTRACT FROM AUTHOR]

Two coordinated metallacycles (rhomboid for M1, hexagonal for M2) with selenoviologens (SeV2+) pendants were synthesized via coordination‐driven hierarchical self‐assembly. M1/M2 with rigid and discrete metallacyclic cores showed tunable optoelectronic properties due to strong π–π stacking and push–pull electron structures. Femtosecond transient absorption (fs‐TA) revealed that the formation of macrocyclic structure can not only enhance the stability of radical cation, but also improve the efficiency of intramolecular charge transfer and produce a long‐lived charge separation state. The electrochromic performances of M1/M2‐based devices were exhibited to show decent radical stabilization. By using M1/M2 as the photocatalyst, the improved catalytic efficiency (>80 %) of visible‐light‐induced cross‐dehydrogenative coupling (CDC) reactions was achieved due to the highly stable radical cations and long‐lived charge separation states, which were also confirmed by fs‐TA. [ABSTRACT FROM AUTHOR]

Tridecacyclene tetraimide, TCTI, an electron‐deficient non‐benzenoid nanocarbon with a C56N4 polycyclic framework was obtained in a concise synthesis. TCTI has a non‐planar structure and forms π‐stacked dimers in the solid state. In solution, it undergoes eight single‐electron reductions, yielding a range of negatively charged states up to an octaanion. Except for the latter species, which has a remarkably large electronic gap, the anions feature extended near‐infrared absorptions, with a particularly strong band at 1692 nm observed for the dianion. A computational analysis of the TCTI anions shows that their stability originates from the combined effects of electron‐deficient imide groups and the local aromaticity of reduced acenaphthylene units. The properties of TCTI make it potentially useful in electrochromic and charge storage applications. [ABSTRACT FROM AUTHOR]

Thermochromic phosphors are intriguing materials for realizing thermochromic behaviors of light‐emitting diodes. Here a highly luminescent and stable thermochromic phosphor based on one‐dimensional Cu4I6(4‐dimethylamino‐1‐ethylpyridinium)2 is reported. This unique ionic copper‐iodine chain‐based hybrid exhibits near‐unity photoluminescence efficiency owing to the through‐space charge‐transfer character of relevant electronic transitions. More importantly, an alternative mechanism of thermochromic phosphorescence was unraveled, supported by a first principles simulation of concerted copper atom migration in the copper‐iodine chain. Furthermore, we successfully fabricate a bright thermochromic light‐emitting diode using this Cu4I6(4‐dimethylamino‐1‐ethylpyridinium)2 thermochromic phosphor. Our reported flexible ionic copper‐iodine chain‐based thermochromic luminescent material represents a new type of cost‐effective functional phosphor. [ABSTRACT FROM AUTHOR]

Achieving blueshifted and enhanced emission from purely organic luminophors remains a major challenge. Herein, we report a tetracoordinate boron complex with polymorphism (Y‐phase and O‐phase)‐dependent luminescence. Impressively, the Y‐phase crystals exhibited rare piezochromic luminescent properties such as pressure‐induced blue‐shifted and enhanced emission. The results of theoretical and experimental tests demonstrated that this phenomenon results from the cooperative effect between the restriction of intramolecular motions and alterable charge transfer (CT) behavior during compression. This work provides an ideal model to investigate the optoelectronic properties of boron complexes. Importantly, manipulating the CT behavior through the electrophilicity of boron atoms may become a new principle for the design of piezochromic materials with blueshifted and enhanced emission. [ABSTRACT FROM AUTHOR]

Nanographene (NG) is a potential candidate for organic EC materials because of its large π‐conjugated system, chemical stability, absorption band covering the visible region, and tunable optical properties by postsynthetic modification. We show that NGs carrying redox‐active triphenylamine (TPA) units covalently linked to the NG edge function as EC materials in the NIR region. The hybrid materials can be obtained by the installation of TPA units onto the NG edge and display changes in the absorption spectrum in the NIR region extending to a wavelength of over 2000 nm upon one‐electron oxidation and reduction at low potentials (<1.1 V). Time‐dependent unrestricted density functional theory calculation of a model NG at the UB3LYP/6‐31G(d,p) level of theory suggests that a narrow energy gap between the basal plane and the oxidized TPA unit is responsible for the observed EC function in the NIR region. [ABSTRACT FROM AUTHOR]

Endowing a cholesteric liquid crystal elastomer (CLCE) exhibiting a helicoidal nanostructure with dynamically tailorable functionalities is of paramount significance for its emerging applications in diverse fields such as adaptive optics and soft robotics. Here, a mechanochromic, shape‐programmable and self‐healable CLCE is judiciously designed and synthesized through integrating dynamic covalent boronic ester bonds into the main‐chain CLCE polymer network. The circularly polarized reflection of CLCEs can be reversibly and dynamically tuned across the entire visible spectrum by mechanical stretching. Thanks to the introduction of dynamic boronic ester bonds, the CLCEs were found to show robust reprogrammable and self‐healing capabilities. The research disclosed herein can provide new insights into the development of 4D (color and 3D shape) programmable photonic actuators towards bioinspired camouflage, adaptive optical systems, and next‐generation intelligent machines. [ABSTRACT FROM AUTHOR]

A Kagome structure covalent organic framework (COF) film with three‐state NIR electrochromic properties was designed and synthesized. The COFTPDA‐PDA film is composed of hexagonal nanosheets with high crystallinity and has three reversible color states at different applied potentials. It has high absorption spectra changes in the NIR region, ascribed to the strong intervalence charge transfer (IVCT) interaction of the Class III mixed‐valence systems of the conjugated triphenylamine species. The film showed sub‐second response time (1.3 s for coloring and 0.7 s for bleaching at 1050 nm) and long retention time in the NIR region. COFTPDA‐PDA film shows superior NIR electrochromic properties in term of response time and stability, attributed to the highly ordered porous structure and the π–π stacking structure of the COFTPDA‐PDA architecture. The COFTPDA‐PDA film was applied in mimicking a flip‐flop logic gate with optical memory function. [ABSTRACT FROM AUTHOR]

Hydrogen‐bonded organic frameworks (HOFs) possess various merits, such as high porosity, tunable structure, facile modification, and ready regeneration. These properties have yet to be explored in the context of new functional HOF materials. The facile and inexpensive electrophoretic deposition (EPD) method applied in this study generated a transparent HOF film at room temperature in just 2 min and is applicable to other HOFs. The resulting film exhibited reversible electrochromism with the advantage of long cycle life (>500 cycles). More strikingly, this all‐organic film could be readily regenerated (through rinsing with DMF and redeposition) and showed tunable electrochromic behavior (through low‐cost postsynthetic modification) with the ability to undergo successive color changes, which is difficult to achieve with conventional electrochromic materials. An electrochromic device was manufactured to further demonstrate the application potential of the film. [ABSTRACT FROM AUTHOR]

Herein, the universal design of high‐efficiency stimuli‐responsive luminous materials endowed with mechanochromic luminescence (MCL) and thermally activated delayed fluorescence (TADF) functions is reported. The origin of the unique stimuli‐triggered TADF switching for a series of carbazole–isophthalonitrile‐based donor–acceptor (D–A) luminogens is demonstrated based on systematic photophysical and X‐ray analysis, coupled with theoretical calculations. It was revealed that a tiny alteration of the intramolecular D–A twisting in the excited‐state structures governed by the solid morphologies is responsible for this dynamic TADF switching behavior. This concept is applicable to the fabrication of bicolor emissive organic light‐emitting diodes using a single TADF emitter. [ABSTRACT FROM AUTHOR]

A mixed‐valence {MnII3MnIIIFeII2FeIII2} cyanide‐bridged molecular cube hosting a caesium cation, Cs⊂{Mn4Fe4}, was synthesized and structurally characterized by X‐ray diffraction. Cyclic‐voltammetry measurements show that its electronic state can be switched between five different redox states, which results in a remarkable electrochromic effect. Magnetic measurements on fresh samples point to the occurrence of a spin‐state change near room temperature, which could be ascribed to a metal‐to‐metal electron transfer converting the {FeII−CN−MnIII} pair into a {FeIII−CN−MnII} pair. This feature was only previously observed in the polymeric MnFe Prussian‐blue analogues (PBAs). Moreover, this novel switchable molecule proved to be soluble and stable in organic solvents, paving the way for its integration into advanced materials. [ABSTRACT FROM AUTHOR]

A series of electrochromic electron‐accepting poly(chalcogenoviologen)s with multiple, stable, and reversible redox centers were used as anodic materials in organic radical lithium‐ion batteries (ORLIBs). The introduction of heavy atoms (S, Se, and Te) into the viologen scaffold significantly improved the capacity and cycling stability of the ORLIBs. Notably, the poly(Te‐BnV) anode was able to intercalate 20 Li ions and showed higher conductivity and insolubility in the electrolyte, thus contributing to a reversible capacity of 502 mAh g−1 at 100 mA g−1 when the Coulombic efficiency approached 100 %. The charged/discharged state of flexible electrochromic batteries fabricated from these anodic materials could be monitored visually owing to the unique electrochromic and redox properties of the materials. This study opens a promising avenue for the development of organic polymer‐based electrodes for flexible hybrid visual electronics. [ABSTRACT FROM AUTHOR]

Sessile organisms have undergone long-term evolution to develop the unique ability by positioning themselves on wet solid surface through secreting adhesive proteins. The present study reveals that natural amino acid monomers can also exhibit similar adhesion capacity. This kind of biomimetic adhesives were created by the one-step aqueous assembly of basic amino acids with assistance of anionic polyoxometalates. The polyoxometalates not only serve as multivalent scaffold to initiate the supramolecular cross-linking of amino acid molecules, but also function as a redox component, bestowing the wet adhesives with electrochromic features. [ABSTRACT FROM AUTHOR]

Die stabilen Radikalkationen und langlebigen Ladungstrennungszustände der Selenoviologene (SeV SP 2+ sp ) gehen auf den metallazyklischen Effekt zurück. Electrochromism, Photocatalysis, Radical Cation, Selenoviologen, Transient Absorption Keywords: Electrochromism; Photocatalysis; Radical Cation; Selenoviologen; Transient Absorption EN Electrochromism Photocatalysis Radical Cation Selenoviologen Transient Absorption 1 1 1 10/13/22 20221017 NES 221017 B Selenoviologen-Metallazyklen M1 b (rhombisch) und B M2 b (hexagonal) wurden synthetisiert und in der Elektrochromie und Photokatalyse eingesetzt, wie Gang He et al. in ihrem Forschungsartikel (e202209054) berichten. [Extracted from the article]

Intercalation and conversion are two fundamental chemical processes for battery materials in response to ion insertion. The interplay between these two chemical processes has never been directly seen and understood at atomic scale. Here, using in situ HRTEM, we captured the atomistic conversion reaction processes during Li, Na, Ca insertion into a WO3 single crystal model electrode. An intercalation step prior to conversion is explicitly revealed at atomic scale for the first time for Li, Na, Ca. Nanoscale diffraction and ab initio molecular dynamic simulations revealed that after intercalation, the inserted ion-oxygen bond formation destabilizes the transition-metal framework which gradually shrinks, distorts and finally collapses to an amorphous W and M xO (M=Li, Na, Ca) composite structure. This study provides a full atomistic picture of the transition from intercalation to conversion, which is of essential importance for both secondary ion batteries and electrochromic devices. [ABSTRACT FROM AUTHOR]

Electroresponsive structurally colored materials composed of ordered arrays of polyaniline@poly(methyl methacrylate) (PANI@PMMA) core-shell nanoparticles have been successfully prepared. The core-shell nanoparticles were synthesized by deposition of PANI shells on the surfaces of the PMMA cores by the oxidative polymerization of anilinium chloride. Ordered arrays were then fabricated by using the fluidic cell method. Because the ordered arrays and the PANI shells generate structural and electrochromic colors, respectively, these core-shell colloidal crystals exhibited colors resulting from the combined effects of these materials. The crystal colors depended greatly on the size of PANI@PMMA particles and could also be varied by the application of a voltage. The electrochromic colors of these arrays were found to be quite different from those exhibited by pure PANI films prepared by electrochemical oxidation. [ABSTRACT FROM AUTHOR]

The incorporation of F atoms endows a diethenylbiphenyl-based electron donor with configurational stability and SNAr reactivity. The former enables the dynamic redox pair of ( Rax)- 1/( Rax, R, R)- 12+ to exhibit drastic UV/Vis and CD spectral changes upon electrolysis, whereas the latter makes it possible for ( Rax)- 1 to serve as a useful chiral synthon for the production of larger assemblies [( Rax, Rax)- 2 d,p,m and ( Rax, Rax, Rax)- 3] containing two or three dyrex units. These dyads and triad also exhibit a clean electrochiroptical response with isosbestic points owing to one-wave multi-electron transfer. [ABSTRACT FROM AUTHOR]

A diruthenium complex with a redox-active amine bridge has been designed, synthesized, and studied by single-crystal X-ray analysis and DFT and TDDFT calculations. It shows three well-separated redox processes with exclusive near-infrared (NIR) absorbance at each redox state. The electropolymerized film of a related vinyl-functionalized complex displays multistate NIR electrochromism with low operational potential, good contrast ratio, and long retention time. Flip-flop, flip-flap-flop, and ternary memories have been realized by using the obtained film (ca. 15-20 nm thick) with three electrochemical inputs and three NIR optical outputs that each displays three levels of signal intensity. [ABSTRACT FROM AUTHOR]

Electrochromism, Graphene, Graphene Quantum Dots, Material Chemistry, Nanographene Keywords: Electrochromism; Graphene; Graphene Quantum Dots; Material Chemistry; Nanographene EN Electrochromism Graphene Graphene Quantum Dots Material Chemistry Nanographene 1 1 1 04/12/22 20220419 NES 220419 B Das elektrochrome Verhalten b von funktionalisierten Nanographenen wird von Ryo Sekiya, Takeharu Haino und Mitarbeitern in ihrer Zuschrift beschrieben (e202200291). Rücktitelbild: Electrochromism of Nanographenes in the Near-Infrared Region (Angew. [Extracted from the article]