Coordination Compound Guided a Novel Composite Film with ZnVO Nanoflake and VO@ZnVO Nanoparticle for Enhanced Thermochromism Smart Window.

Thermochromic vanadium dioxide (VO) can intelligently modulate the transmittance of indoor solar radiation to reduce the energy consumption of air conditioning in buildings. Nevertheless, it remains a great challenge to simultaneously improve the luminous transmittance (T) and solar modulation ability (ΔT) of VO. In this study, a novel approach is employed utilizing a coordination compound to finely tune the growth of a VO based composite film, yielding a hierarchical film comprising ZnVO nanoflakes and VO@ZnVO core-shell nanoparticles.

Negative Poisson's ratio of sulfides dominated by strong intralayer electron repulsion.

Geometrical variations in a particular structure or other mechanical factors are often cited as the cause of a negative Poisson's ratio (NPR). These factors are independent of the electronic properties of the materials. This work investigates a class of two-dimensional (2D) sulfides with the chemical formula MX (M = Ti, Cr, Mn, Fe, Co, X = S) using first-principles calculations.

One stimulus-induced two-step photophysical response with high contrast and tunable switching time for dynamic displaying.

One stimulus-induced two-step photophysical response, especially with tunable switching time, is a great challenge for organic chromophores. Herein, a polymorphic material 2,7-DCF could undergo in situ two sequential dual-channel responses upon dichloromethane fuming. Both the appearance color and the fluorescence change from red to yellow to deep red with high contrast.

Multistimuli-Responsive Squaraine Dyad Exhibiting Concentration-Controlled Vapochromic Luminescence.

Stimuli-responsive organic materials with controllable luminescence are of enormous importance because of their potential applications in sensing, data security, and display devices. In this study, a multistimuli-responsive squaraine dyad () composed of two rigid squaraine moieties and a flexible ethylene linker was rationally designed and synthesized. exhibits polymorphic luminescence, which can be reversibly switched by various external stimuli, including solvent vapor exposure, heat, and shear force.

Crystallization-Induced Reversal from Dark to Bright Excited States for Construction of Solid-Emission-Tunable Squaraines.

Squaraines (SQs) with tunable emission in the solid state is of great importance for various demands; however a remaining challenge is emission quenching upon aggregation. Herein, a unique SQ, named as CIEE-SQ, is designed to exhibit strong emission in crystal, undergoing crystallization-induced reverse from dark (n+σ,π*) to bright (π,π*) excited states. Such an excited state of CIEE-SQ can be subtly tuned by molecular conformation changes during the unexpected temperature-triggered single-crystal to single-crystal (SCSC) reversible transformation.

Halogenated Tetraazapentacenes with Electron Mobility as High as 27.8 cm V s in Solution-Processed n-Channel Organic Thin-Film Transistors.

Molecular engineering of tetraazapentacene with different numbers of fluorine and chlorine substituents fine-tunes the frontier molecular orbitals, molecular vibrations, and π-π stacking for n-type organic semiconductors. Among the six halogenated tetraazapentacenes studied herein, the tetrachloro derivative (4Cl-TAP) in solution-processed thin-film transistors exhibits electron mobility of 14.9 ± 4.

Engineering Thin Films of a Tetrabenzoporphyrin toward Efficient Charge-Carrier Transport: Selective Formation of a Brickwork Motif.

Tetrabenzoporphyrin (BP) is a p-type organic semiconductor characterized by the large, rigid π-framework, excellent stability, and good photoabsorption capability. These characteristics make BP and its derivatives prominent active-layer components in organic electronic and optoelectronic devices. However, the control of the solid-state arrangement of BP frameworks, especially in solution-processed thin films, has not been intensively explored, and charge-carrier mobilities observed in BP-based materials have stayed relatively low as compared to those in the best organic molecular semiconductors.

Extension of N-Heteroacenes through a Four-Membered Ring.

The synthesis of novel π-extended N-heteroacenes, which have a large tetraazaacene subunit and a quinoxaline subunit connected through a four-membered ring, is reported. They were studied with experimental and computational methods in comparison to the corresponding tetraazaacenes. As found from the DFT calculation, the four-membered ring is a better linker than a five-membered ring or a C-C single bond to extend N-heteroacenes for a new design of n-type semiconductors in terms of the spatial delocalization and energy level of LUMO as well as the reorganization energy.

Molecular packing and n-channel thin film transistors of chlorinated cyclobuta[1,2-b:3,4-b']diquinoxalines.

Novel chlorinated cyclobuta[1,2-b:3,4-b']diquinoxalines were synthesized and investigated in the solid state. It is found that their molecular packing can be tuned by varying the number and position of chlorine substituents, and 2,8-dichloro-cyclobuta[1,2-b:3,4-b']diquinoxaline either in pure form or as a mixture with its regioisomer functions as n-type semiconductors in organic thin film transistors with a field effect mobility of up to 0.42 cm(2) V(-1) s(-1) and 0.

Synthesis, solution-processed thin film transistors and solid solutions of silylethynylated diazatetracenes.

Silylethynylated diazatetracenes were synthesized in a more efficient way and applied as n-type semiconductors in solution-processed thin film transistors with an electron mobility of 0.65 cm(2) V(-1) s(-1). Co-crystallization of these diazatetracenes with silylethynylated tetracene resulted in solid solutions, which exhibited interesting electrical and optical properties.

Regiospecific N-heteroarylation of amidines for full-color-tunable boron difluoride dyes with mechanochromic luminescence.

Colors to dye for: Palladium-catalyzed regiospecific N-heteroarylations of amidines with 2-halo-N-heteroarenes leads to a structurally diverse library of BF2 /amidine-based complexes. These dyes not only present full-visible-color solid-state emissions with large Stokes shifts and high fluorescence quantum yields, but also exhibit a full-color-tunable mechanofluorochromic nature.

Facile access to extremely efficient energy-transfer pairs via an unexpected reaction of squaraines with ketones.

We have discovered that squaraine NCSQ easily react with ketones in the presence of ammonium acetate to form a novel type of squaraine CCSQ. It is interesting to find that NCSQs exhibit unusual solid-state fluorescence, whereas CCSQs only exhibit fluorescence in solution. The quantum yield of solid NCSQ-g is measured to be 0.

Ultrasound-induced switching of sheetlike coordination polymer microparticles to nanofibers capable of gelating solvents.

We herein demonstrate a new gelation mechanism based on a readily available coordination polymer {Zn(bibp)(2)(OSO(2)CF(3))(2)}(n), in which ultrasound changes the morphology of the material from sheetlike microparticles into nanofibers, resulting in the immobilization of organic solvents.

Helical nonracemic tubular coordination polymer gelators from simple achiral molecules.

A novel class of helical nonracemic tubular coordination polymers, which can immobilize a wide range of solvents at very low concentrations, have been synthesized for the first time in the absence of chiral influences and appended groups.