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Development of naphthalimide-functionalized thermochromic conjugated polydiacetylenes and their reversible green-to-red chromatic transition in the solid state
摘要： Development of PDAs has received great attention in many fields due to their optical and chromatic properties towards external stimuli. In this article, two novel PDAs (NPI-PDA1 and NPI-PDA2) containing naphthalimide as a head group are designed and synthesized through self-assembly followed by topochemical polymerization, and these compounds show a reversible green-to-red colorimetric transition upon heating. PEO-embedded films are fabricated to facilitate the investigation of the thermochromic properties, and the surface morphologies of the films are observed by SEM analysis. The thermochromic behavior and color transitions are observed using photography and electronic absorption spectroscopy. The changes in the extended ene-yne conjugated system of the polymer during heat treatment are successfully monitored by Raman spectrometry. Moreover, PDA-embedded crayon wax-based hand-writable pens are fabricated and used efficiently on a solid substrate. NPI-PDA1 and NPI-PDA2 display excellent reversibility in the temperature ranges of 25–120 °C and 25–160 °C, respectively in the PEO polymer and paraffin wax matrices.
关键词： Thermochromism,PEO films,Green-to-red color transition,Polydiacetylene,Crayon pen
更新于2025-11-21 10:59:37
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Thermochromic Oxide-Based Thin Films and Nanoparticle Composites for Energy-Efficient Glazings
摘要： Today’s advances in materials science and technology can lead to better buildings with improved energy efficiency and indoor conditions. Particular attention should be directed towards windows and glass facades—jointly known as “glazings”—since current practices often lead to huge energy expenditures related to excessive inflow or outflow of energy which need to be balanced by energy-intensive cooling or heating. This review article outlines recent progress in thermochromics, i.e., it deals with materials whose optical properties are strongly dependent on temperature. In particular, we discuss oxide-based thin surface coatings (thin films) and nanoparticle composites which can be deposited onto glass and are able to regulate the throughput of solar energy while the luminous (visible) properties remain more or less unaltered. Another implementation embodies lamination materials incorporating thermochromic (TC) nanoparticles. The thin films and nanocomposites are based on vanadium dioxide (VO2), which is able to change its properties within a narrow temperature range in the vicinity of room temperature and either reflects or absorbs infrared light at elevated temperatures, whereas the reflectance or absorptance is much smaller at lower temperatures. The review outlines the state of the art for these thin films and nanocomposites with particular attention to recent developments that have taken place in laboratories worldwide. Specifically, we first set the scene by discussing environmental challenges and their relationship with TC glazings. Then enters VO2 and we present its key properties in thin-film form and as nanoparticles. The next part of the article gives perspectives on the manufacturing of these films and particles. We point out that the properties of pure VO2 may not be fully adequate for buildings and we elaborate how additives, antireflection layers, nanostructuring and protective over-coatings can be employed to yield improved performance and durability that make TC glazings of considerable interest for building-related applications. Finally, we briefly describe recent developments towards TC light scattering and draw some final conclusions.
关键词： thermochromism,vanadium dioxide,thin film,energy-efficient glazing,coating,sputter deposition,nanoparticle
更新于2025-09-23 15:21:01
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Temperature modulating rectifier behavior and photovoltaic response of VO<sub>x</sub> /Nb:SrTiO<sub>3</sub> heterojunctions
摘要： Vanadium oxide (VOx) is a promising candidate to be used for smart window and thermochromic photovoltaic modulating devices. The crystalline structure and electrical characteristics of VOx thin film deposited on NSTO were investigated. It was found that asymmetric hysteresis current between increasing and decreasing voltages occurs at 80, 300 and 360K. The photovoltaic effect was observed under irradiation by a pulse laser.
关键词： semiconductor-metal phase transition,photovoltaic modulating devices,heterojunction,thermochromism,resistance switch phenomena
更新于2025-09-23 15:19:57
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Plasmonic Thermochromism Based on Reversible Redox of Ag+/Ag on Au Nanorods
摘要： Reversible redox reaction-based thermochromism using plasmonic nanocrystals is challenging due to the requirements set by the complexity of the reaction system where the oxidation and reduction agents must not interfere with each other, and both should possess temperature sensitivity. Herein, we demonstrate plasmonic thermochromism based on reversible redox of Ag+/Ag on Au nanorods (AuNRs) by incorporating temperature-sensitive reduction and oxidation into a same system. The competition between the reduction and oxidation is solely dependent on temperature. When the temperature is above (below) the transition temperature, the reduction of Ag+ (oxidation of Ag) dominates on the surface of AuNRs, and the thermochromic nanostructure solution exhibits green (red) appearance. Experimental study on the mechanism reveals that HOCl produced at low concentration by H2O2 is the source of the observed temperature dependence of the Ag oxidation. Rationally tuning the transition temperature in a range from 27 to 40 °C can be realized by changing the concentration of some key chemical compounds in the solution. The thermochromic solution can be standalone-functional within multiple cycles of heating and cooling and long-term storage without any additional reagents. Our study provides new insights into plasmonic thermochromism and may pave the way for fabricating smart thermochromic materials.
关键词： temperature-sensitive,plasmonic thermochromism,reversible redox,Au nanorods,Ag+/Ag
更新于2025-09-19 17:13:59
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Reversible Wide‐Range Tuneable Luminescence of a Dual‐Stimuli‐ Responsive Silver Cluster‐Assembled Material
摘要： Silver cluster-assembled materials (SCAMs) are emerging multi-functional materials and have attracted great attention recently. In this work, we have prepared a new SCAM of {[Ag18(StBu)10(CF3COO)2(PhPO3)(PhPO3H)4(bpy-NH2)2]?(PhPO3H2)}n (denoted as Ag18bpy-NH2), by a facile one-pot method. Ag18bpy-NH2 adopts a chain-like structure made of Ag18 clusters bridged by bipyridyl linkers. Ag18bpy-NH2 exhibits reversible luminescent mechanochromism upon mechanical stimulation and solvent treatment. Moreover, it also displays luminescent thermochromism with a linear relationship of the temperature to the intensity ratio of the dual emissions over a wide temperature range of 83 to 303 K. This work might provide new insights into the assembly of multifunctional stimuli-responsive SCAMs.
关键词： luminescent mechanochromism,cluster-assembled material,silver cluster,luminescent thermochromism
更新于2025-09-19 17:13:59
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Temperature responsive self-assembled hydroxybutyl chitosan nanohydrogel based on homogeneous reaction for smart window
摘要： Chitosan (CS) based self-assembled nanohydrogels are considered as promising platform for biomedicine, petrochemical, agricultural and food applications due to their unique biodegradability, nano-interface effect, and intelligent responsiveness. However, the most CS derivatives are prepared in heterogeneous system, which is unstable and environmentally unfriendly. In this work, a series of hydroxybutyl chitosan (HBC) was synthesized based on a green and homogeneous system (potassium hydroxide (KOH)/urea), which given this derivative interesting temperature responsive phase transformation behavior. HBC could change from dissolved state into nanohydrogel state in deionized water, when the temperature exceed its critical phase change temperature, and this process could be repeated more than 50 cycles (one cycle/day) without coagulation. The nanohydrogels solution exhibited concentration and temperature-dependent ultraviolet absorption and visible light regulation, which had great application potential in smart windows. This study provided a novel preparation method and extended the application of chitosan-based temperature responsive self-assembled nanohydrogels.
关键词： Temperature responsiveness,Thermochromism,Hydroxybutyl chitosan,Self-assembled nanohydrogels,Smart windows,Homogeneous reaction
更新于2025-09-16 10:30:52
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Adsorption of Rose Bengal on a self-assembled fibrillar network affords a thermally switchable oxygenation photocatalyst and a thermochromic soft material
摘要： Adsorption of Rose Bengal on a self-assembled fibrillar network affords a thermally switchable oxygenation photocatalyst and a thermochromic soft material
关键词： self-assembly,photosensitizers,thermochromism,soft materials,supramolecular gels
更新于2025-09-16 10:30:52
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A silver cluster‐assembled material (SCAM) showing luminescent mechanochromism and thermochromism
摘要： A silver cluster-assembled material (SCAM) showing luminescent mechanochromism and thermochromism
关键词： luminescent mechanochromism,Silver cluster,luminescent thermochromism,cluster-assembled material
更新于2025-09-11 14:15:04
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New Lamellar Silver Thiolate Coordination Polymers with Tunable Photoluminescence Energies by Metal Substitution
摘要： The structures of two lamellar silver thiolate coordination polymers [Ag(p-SPhCO2H)]n (1) and [Ag(p-SPhCO2Me)]n (2) are described for the first time. Their inorganic part is composed of distorted Ag3S3 honeycomb networks separated by noninterpenetrated thiolate ligands. The main difference between the two compounds arises from dimeric hydrogen bonds present for the carboxylic acids. Indepth photophysical studies show that the silver thiolates implying luminescence exhibit multiemission properties, the synthesis of a thermochromism. More interestingly, the synthesis of a heterometallic lamellar compound, [Ag0.85Cu0.15(p-SPhCO2H)]n (3), allows to obtain mixed metal thiolate coordination polymers and to tune the photophysical properties with the excitation wavelengths from a green vibronic luminescence to a single red emission band.
关键词： lamellar silver thiolate,photoluminescence,thermochromism,metal substitution,coordination polymers
更新于2025-09-04 15:30:14
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A solid-state emissive and solvatofluorochromic fluorophore and its application in high-contrast, fast, and repeatable thermochromic blends
摘要： Organic thermochromic luminescent materials are very promising in applications of thermo-history recording, sensing and anti-counterfeiting. However, the current reported organic thermochromic systems still have the drawbacks of slow responsive speed, low colour contrast and unsatisfactory repeatability. In this paper, we reported a twisted fluorophore based on 1,4-bis[2,2-bisphenyl-vinyl]benzene skeleton with A-D-A structure (OD-CN), which shows strong solvatochromism in solution with emission shifts up to 135 nm, highly efficient red emission in solid state (660 nm, 11.62%) and unprecedented thermochromic behaviour in linear low density polyethylene matrix with high emission contrast (red to greenish yellow), fast responsiveness (within 1 s) and good repeatability (over 10 times). OD-CN doped LLDPE films show potential applications in anti-counterfeiting and as an example, it was applied as multi-channel anti-counterfeiting printings on paper money. What's more, the strategy of blending fluorophores with solvent effects and solid-state emission into apolar polymer matrixes to realize thermochromisms is general.
关键词： Thermochromism,Intramolecular charge transfer (ICT),Aggregation induced emission enhancement (AIEE),1,4-bis[2,2-bisphenyl-vinyl]benzenes
更新于2025-09-04 15:30:14