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A Light-activated Polymer Composite Enables On-demand Photocontrol of Biomimetic Swimming Towards Transportation at Liquid/Air Interface
摘要： Swimmers at liquid/air interface have drawn enormous attention for their potential applications while conventional devices face problems such as dependence on fuel, difficulty in motion control and accompanying high temperature. Herein, we show one novel light-driven swimmer based on bimorph composite structure of photoresponsive liquid-crystalline polymer network and commercially available polyimide (Kapton) whose motion is highly controllable with photoirradiation. The bilayer-structured film shows quickly photoinduced bending towards the Kapton side on exposure to UV light and recovers immediately after removal of light. When placed on liquid surface, the swimmer propels itself continually though rhythmic beating the liquid like a dolphin moving forward with its tail fin. Besides, light-powered rotation of the swimmer is successfully achieved by simply changing the length-width ratio and the irradiation site, mimicking the function of a dolphin’s pectoral fin. Combining the together, on-demand forward movement and rotation motion directional control of the photo-driven swimmer can be readily obtained at room temperature, showing promising for miniaturized transportation.
关键词： bionic motion,azobenzene,photomechanical oscillation,miniaturized transportation,light-driven device
更新于2025-09-23 15:22:29
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Control of excited state conformation in B,N-acenes
摘要： Herein we show a new concept to control conformation in molecules through harvesting negative hyperconjugation. The strategy was realized with the 2,3,1,4-benzodiazadiborinane scaffold that was prepared by a new synthetic protocol. Photochemical studies identify dual light emission that can be assigned to originate from well-defined conformers. The emission at longer wavelength can be switched off by restricting the rotational degrees of freedom in the solid-state as well as by controlling the energy level of the excited states through solvent polarity.
关键词： B,dual fluorescence,azobenzene,N heterocycles,azaborine,synthetic methods
更新于2025-09-23 15:22:29
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Control of excited state conformation in B,N-acenes
摘要： Herein we show a new concept to control conformation in molecules through harvesting negative hyperconjugation. The strategy was realized with the 2,3,1,4-benzodiazadiborinane scaffold that was prepared by a new synthetic protocol. Photochemical studies identify dual light emission that can be assigned to originate from well-defined conformers. The emission at longer wavelength can be switched off by restricting the rotational degrees of freedom in the solid-state as well as by controlling the energy level of the excited states through solvent polarity.
关键词： dual fluorescence,azobenzene,B,N heterocycles,azaborine,synthetic methods
更新于2025-09-23 15:22:29
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Tenfold increase in the photostability of an azobenzene guest in vapor-deposited glass mixtures
摘要： Improvements to the photostability of organic glasses for use in electronic applications have generally relied on the modification of the chemical structure. We show here that the photostability of a guest molecule can also be significantly improved—without chemical modification—by using physical vapor deposition to pack molecules more densely. Photoisomerization of the substituted azobenzene, 4,4'-diphenyl azobenzene, was studied in a vapor-deposited glass matrix of celecoxib. We directly measure photoisomerization of trans- to cis-states via Ultraviolet-visible (UV-Vis) spectroscopy and show that the rate of photoisomerization depends upon the substrate temperature used during co-deposition of the glass. Photostability correlates reasonably with the density of the glass, where the optimum glass is about tenfold more photostable than the liquid-cooled glass. Molecular simulations, which mimic photoisomerization, also demonstrate that photoreaction of a guest molecule can be suppressed in vapor-deposited glasses. From the simulations, we estimate that the region that is disrupted by a single photoisomerization event encompasses approximately 5 molecules.
关键词： photostability,organic glasses,azobenzene,photoisomerization,physical vapor deposition,molecular simulations,UV-Vis spectroscopy
更新于2025-09-23 15:21:21
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Self-assembled star-shaped liquid crystals based on 1,3,5-trihydroxybenzene with pendant alkyloxylated azobenzene arms
摘要： Designing and self-assembly of unconventional star-shaped mesogens or ‘hekates’ are of interest to materials science and molecular electronics. This work presents the synthesis of several symmetric trimeric liquid crystalline compounds comprising 1,3,5-trihydroxybenzene (phloroglucinol) as central core. The liquid crystalline behaviour was induced by attaching three rod-like azo-aromatic semi-flexible units to the central core via esteric linkages. Based on differential scanning calorimetry and polarising optical microscopy, the mesophase stability mainly depends on the alkyl chain length. The compounds showed monotropic or enantiotropic behaviour, except the compound with nine atoms on the chain end which is non-mesomorphic. In addition to the synthesis and mesophase characterisation, the self-assembled structures and individual properties have been characterised by molecular simulations.
关键词： azobenzene,Star-shaped liquid crystals,discotic,phloroglucinol,hekates
更新于2025-09-23 15:21:01
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Theoretical Investigation of Azobenzene-Based Photochromic Dyes for Dye-Sensitized Solar Cells
摘要： Two donor-π-spacer-acceptor (D-π-A) organic dyes were designed as photochromic dyes with the same π-spacer and acceptor but di?erent donors, based on their electron-donating strength. Various structural, electronic, and optical properties, chemical reactivity parameters, and certain crucial factors that a?ect short-circuit current density (Jsc) and open circuit voltage (Voc) were investigated computationally using density functional theory and time-dependent density functional theory. The trans-cis isomerization of these azobenzene-based dyes and its e?ect on their properties was studied in detail. Furthermore, the dye-(TiO2)9 anatase nanoparticle system was simulated to understand the electronic structure of the interface. Based on the results, we justi?ed how the trans-cis isomerization and di?erent donor groups in?uence the physical properties as well as the photovoltaic performance of the resultant dye-sensitized solar cells (DSSCs). These theoretical calculations can be used for the rapid screening of promising dyes and their optimization for photochromic DSSCs.
关键词： azobenzene,dye-sensitized solar cells,density functional theory
更新于2025-09-23 15:21:01
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Light-Triggered Reversible Self-Engulfing of Janus Nanoparticles
摘要： Block copolymers containing azobenzene liquid crystalline (LC) mesogen are used to prepare snowman-like Janus nanoparticles (NPs) by emulsion solvent evaporation. The azobenzene-containing poly(methacrylate) (PMAAz) head of the Janus NPs is in the smectic LC phase with ordered stripes, which becomes amorphous and enlarged due to trans/cis transformation under UV irradiation. The expanded PMAAz can consequently engulf the other head. The self-engulfed NPs can recover to their original state in both shape and LC state via visible-light irradiation. This strategy is promising for programmable load and release of different payloads by remote trigger using light.
关键词： emulsion solvent evaporation,azobenzene,liquid crystalline,Block copolymers,Janus nanoparticles,programmable load and release,UV irradiation,visible-light irradiation
更新于2025-09-23 15:21:01
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Photoactive Functional Soft Materials (Preparation, Properties, and Applications) || A Photoresponsive Multi-Bilayered Film for a Tunable Photonic Crystal
摘要： Over the last half‐century, advances in science based on the evolution of semiconductor physics and transistor electronics have greatly influenced the development of our lives. The key to this was the ability to design crystalline materials that tailor the conduction properties of electrons to suit diverse applications. More recently, the optical communication revolution has shifted the frontier in high‐speed, multiplex, and wide‐bandwidth information processing from electrons to photons, a shift that demands a new kind of synthetic soft material to mold the gigabits. To address this need, recent research has suggested a way to tailor the propagation of light much like that of electrons, via the creation of periodic optical media dubbed photonic crystals (PCs).
关键词： azobenzene,photonic crystals,multi‐bilayered film,photoresponsive,tunable
更新于2025-09-23 15:21:01
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Photoactive Functional Soft Materials (Preparation, Properties, and Applications) || Azobenzene Polymers as Photoactive Materials for Shape Changes of Micro/Nano-objects
摘要： Azobenzene Polymers as Photoactive Materials for Shape Changes of Micro/Nano‐objects
关键词： Polymers,Shape Changes,Micro/Nano‐objects,Photoactive Materials,Azobenzene
更新于2025-09-23 15:21:01
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Synthesis, electrochromic characterization and solar cell application of thiophene bearing alternating copolymers with azobenzene and coumarin subunits
摘要： In this study, azobenzene and coumarin functionalized thiophene comprising two copolymers (poly (4-((3000-hexyl-[2,20:50,200:500,2000-tetrathiophene] (cid:2) 30-yl)methoxy) - 2H-chromen-2-one (P1) and poly (1-(4-((4000-hexyl-[2,20: 50, 200: 500, 2000 - tetrathiophene] (cid:2) 30-yl) methoxy) phenyl) (cid:2)2-phenyldiazene) (P2)), were designed and synthesized according to the donor–acceptor (D–A) approach to investigate their electrochemical, optical and photovoltaic behaviors. Among the various copolymerization methods to obtain P1 and P2, Stille copolymerization reaction was preferred. The HOMO and LUMO values were determined via cyclic voltammetry (CV) as (cid:2)5.64 eV and (cid:2)3.76 eV for P1 and (cid:2)5.47 eV and (cid:2)3.83 eV for P2, respectively. The optical band gaps of the polymers for P1 and P2 were calculated as 1.88 eV and 1.64 eV using UV-VIS spectrophotometer. Electrochemical and spectroelectrochemical studies for synthesized copolymers support their usage in organic solar cell applications. The organic solar cells (OSCs) were designed using polymer as an electron donor group and PC60BM as an electron acceptor group. Performances of OSCs based on P1 and P2 were investigated with the device structure of ITO/PEDOT:PSS/ Polymer(P1/P2):PC60BM/LiF/Al. The preliminary solar cell results were reported here and studies are going on in our laboratories to increase the efficiency. The highest power conversion efficiency was obtained as 0.81% for P1 based device with 0.47 V open-circuit voltage (Voc) and 4.92 mA/cm2 current density (Jsc) values. The highest efficiency for P2 comprising device was found to be 0.96% under optimum conditions with 0.60 V and 4.98 mA/cm2, Voc and Jsc values, respectively.
关键词： Azobenzene,solar cell,coumarin,conducting polymers,thiophene bearing copolymers
更新于2025-09-23 15:19:57