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Dynamically Switching the Electronic and Electrostatic Properties of Indium Tin Oxide Electrodes with Photochromic Monolayers: Toward Photo-Switchable Optoelectronic Devices
摘要： The chemical modification of electrodes with organic materials is a common approach to tune the electronic and electrostatic landscape between interlayers in optoelectronic devices, thus facilitating charge injection at the electrode/semiconductor interfaces and improving their performance. The use of photochromic molecules for the surface modification allows dynamic control of the electronic and electrostatic properties of the electrode and thereby enables additional functionalities in such devices. Here, we show that the electronic properties of a transparent indium tin oxide (ITO) electrode are reversibly and dynamically modified by depositing organic photochromic switches (diarylethenes) in the form of self-assembled monolayers (SAMs). By combining a range of surface characterization and density functional theory calculations, we present a detailed picture of the SAM binding onto ITO, the packing density of molecules, their orientation, as well as the work function modification of the ITO surface due to the SAM deposition. Upon illumination with ultraviolet and green light, we observe a reversible shift of the frontier occupied levels by 0.7 eV, and concomitantly a reversible work function change of ca. 60 meV. Our results prove the viability of dynamic switching of the electronic properties of the electrode with external light stimuli upon modification with a monolayer of photochromic molecules, which could be used to fabricate ITO-based photo-switchable optoelectronic devices.
关键词： self-assembled monolayer,diarylethene,ITO,photochromic switch,interface electronic properties
更新于2025-11-14 14:32:36
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[Zn(OOCH)2(4,4′-bipyridine)] : A metal-organic-framework (MOF) with x-ray-induced photochromic behaviour at room temperature
摘要： Materials that may show photochromism under X-rays have higher spatial resolution for visual low-energy X-rays detection over the commercial instruments and greater X-ray sensitivity than silver salt-based radiographic films. In this work, we discovered that the known MOF, [Zn(OOCH)2(Bpy)]n (Bpy = 4,4′-bipyridine), showed rare photochromic behaviour upon irradiation of hard and soft X-rays at room temperature.
关键词： Metalloviologen,MOF,Photochromic,Radical,X-ray detection,Electron transfer
更新于2025-09-23 15:23:52
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Tunable Luminescence Contrast in Photochromic Ceramics (1-x)Na0.5Bi0.5TiO3-xNa0.5K0.5NbO3:0.002Er by an Electric Field Poling
摘要： A binary solid solution of Er3+ doped (1-x)Na0.5Bi0.5TiO3-xK0.5Na0.5NbO3 (x=0.02, 0.04, 0.06, 0.08, 0.10, 0.12) ferroelectric ceramics has been developed, and a reversible photochromic (PC) reaction and its associated luminescence modulation are realized via alternating the 405-nm light irradiation and thermal stimulation (200 oC). The basic crystal structure, domain structure, ferroelectricity and dielectric behavior of the ceramics were measured. A moderate luminescence contrast ΔRt over 50% is obtained in the fresh samples. Meanwhile, a greatly enhanced luminescence contrast ΔRt is obtained via an electric poling for compositions x=0.02, 0.04, 0.06. For example, ΔRt is promoted from 53.4% to 85.3% for x=0.02. However, the luminescence contrast ΔRt of compositions x=0.08, 0.10, 0.12 is depressed after poling. The mechanisms of enhanced PC reaction and luminescence contrast ΔRt are discussed and proposed. The present study may open a window for enhancing the PC reaction.
关键词： Luminescence modulation,Poling,Ceramics,ferroelectrics,photochromic
更新于2025-09-23 15:21:21
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Transparent-to-dark photo- and electrochromic gels
摘要： Smart windows in which the transmittance can be controlled on demand are a promising solution for the reduction of energy use in buildings. Windows are often the most energy inefficient part of a building, and so controlling the transmittance has the potential to significantly improve heating costs. Whilst numerous approaches exist, many suitable materials are costly to manufacture and process and so new materials could have a significant impact. Here we describe a gel-based device which is both photo- and electrochromic. The gel matrix is formed by the self-assembly of a naphthalene diimide. The radical anion of the naphthalene diimide can be formed photo or electrochemically, and leads to a desirable transition from transparent to black. The speed of response, low potential needed to generate the radical anion, cyclability of the system, temperature stability and low cost mean these devices may be suitable for applications in smart windows.
关键词： Smart windows,Gel-based device,Naphthalene diimide,Electrochromic,Photochromic
更新于2025-09-23 15:21:01
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Microencapsulation of energy conversion photochromic materials with epoxy resin shell by interfacial polymerization
摘要： In this study, a novel type of photochromic spirooxazine microcapsule was prepared by interfacial polymerization between epoxy resin and polyamine compound. The effects of different process parameters on the formation, microstructure and performance of microcapsules, such as curing reaction temperature, emulsification shear rate and the addition of silica nanoparticles were studied in this paper. The morphology, microstructure, diameter and distribution, as well as the thermal stability of microencapsulated photochromic spirooxazine were also investigated by field emission scanning electron microscope, laser particle size analyzer and thermogravimetric analysis systematically. In addition, the photochromic performance of microcapsule was studied as well.
关键词： microencapsulation,photochromic,epoxy resin,spirooxazine,interfacial polymerization
更新于2025-09-23 15:21:01
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Preparation and photochromic behavior of spiropyran-containing fluorinated polyacrylate hydrophobic coatings
摘要： In this study, spiropyran (SP)-containing fluorinated polyacrylate (F-PA-SP) latex was prepared by emulsion polymerization using fluorinated and SP-based acrylic monomers as raw materials. FT-IR and 1H-NMR demonstrate that the F-PA-SP copolymer has been successfully synthesized, and DLS and TEM analyses indicate that the synthesized latex has presented a uniform particle size of approximately 200 nm. XPS, AFM and water contact angle (WCA) analysis were used to investigate the surface properties of the F-PA-SP coating and demonstrate that its hydrophobicity is enhanced by addition of a fluorinated acrylic monomer. The photochromic properties of the coating were investigated by UV-Vis spectroscopy, and the results reveal that the F-PA-SP coating possesses better photo-responsiveness, fatigue resistance, and photo-reversibility under UV/Vis irradiation than the coating prepared using fluorinated polyacrylate/SP blended latex. Moreover, the WCA of the F-PA-SP coating subjected to UV/Vis irradiation shows minimal changes and retains its excellent hydrophobicity. Finally, the F-PA-SP latex was applied to cellulosic paper, and the resulting photochromic paper exhibits outstanding reversible color changes and hydrophobicity.
关键词： emulsion polymerization,hydrophobicity,fluorinated polyacrylate,spiropyran,photochromic
更新于2025-09-23 15:21:01
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Photoactive Functional Soft Materials (Preparation, Properties, and Applications) || Photoresponsive Soft Materials Based on Reversible Proton Transfer
摘要： Proton transfer is one of the most fundamental processes in nature and numerous chemical, material, and biological processes are driven by proton transfer. For example, biological systems use proton gradient as an energy form to synthesize ATP for their biological functions; many organic reactions are catalyzed by Bronsted acids; and many materials have pH‐sensitive properties. Proton transfer is also involved in different aspects of polymer science relative to preparation, property, and processing. For example, cationic polymerizations can be initiated by proton transfer from a strong acid to a monomer. It has been reported that many polymers are sensitive to the pH (proton concentration) of the environment, and their properties including mechanical, geometrical, electric, optical, and magnetic properties, change with pH due to proton transfer between the polymers and the environment. Polymers with acid‐labile bonds have been studied for drug delivery; and photoinduced cationic polymerization using photoacid‐generators (PAGs) has been applied to photolithography.
关键词： Proton transfer,photoacid,fragrant‐releasing polymers,photoresponsive nanoparticles,photochromic materials,photoresponsive polymers,reversible
更新于2025-09-23 15:21:01
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Multilayer plasmonic photonic structures embedding photochromic molecules or optical gain molecules
摘要： We study the optical properties of different functional molecular systems in order to embed them in properly designed photonic structures for photochromic switching and lasing. We study the light absorption of two photochromic molecules and of 4,4’-bis[(N-carbazole)styryl]biphenyl (BSB-Cz) with density functional theory. For the photochromic diarylethene we derivate the refractive index with Kramers-Kronig relations and we design multilayer photonic structures alternating diarylethene with either poly vinyl carbazole or fluorine indium co-doped cadmium oxide (FICO) nanoparticle-based layers. For BSB-Cz we design a one-dimensional photonic crystal alternating BSB-Cz layers wit SiO2 layers and a microcavity embedding BSB-Cz between indium tin oxide (ITO) / FICO nanoparticle-based multilayers.
关键词： multilayer plasmonic photonic structures,photochromic molecules,density functional theory,Kramers-Kronig relations,optical gain molecules
更新于2025-09-23 15:19:57
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Wide-range line shape control of Fano-like resonances in all-dielectric multilayer structures based on enhanced light absorption in photochromic waveguide layers
摘要： We have succeeded in controlling the line shape of Fano-like resonances in all-dielectric multilayer structures in a wide range by UV light irradiation. Multilayer structures consisting of a waveguide layer supporting a half-leaky guided mode, a spacer layer, and another waveguide layer supporting a planar waveguide mode are known to exhibit Fano-like line shapes in attenuated total reflection spectra due to coupling between the half-leaky guided mode and the planar waveguide mode. Using a photochromic layer, i.e., a layer doped with spiropyran molecules, as one of the waveguide layers, we controlled the amount of light absorption in the waveguide layer by varying the UV irradiation dose. We demonstrated that the line shape changes dramatically depending on the UV dose, from the electromagnetically induced transparency-like to electromagnetically induced absorption-like line shape (or vice versa) passing through the Fano-like line shape. We also demonstrated that the photochromic response induced by UV irradiation in the Fano-resonant multilayer structure is enhanced by a factor of ～100 relative to that in a single photochromic layer. Our analyses based on electromagnetic calculations suggest that the dramatic line shape change and the enhanced photochromic response are the consequences of enhanced local electric fields inside the photochromic waveguide layer combined with the photoinduced increase in the imaginary part of the dielectric constant.
关键词： electromagnetically induced transparency,all-dielectric multilayer structures,Fano-like resonances,UV light irradiation,electromagnetically induced absorption,photochromic waveguide layers
更新于2025-09-23 15:19:57
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Synthesis of organic–inorganic hybrids <i>via</i> a high-pressure-ramp process: the effect of inorganic nanoparticle loading on structural and photochromic properties
摘要： Organic polymerization remains a limiting step in the preparation of organic–inorganic hybrid materials with a strong concentration of the inorganic component. In this work, a high-pressure-ramp process was applied to achieve pHEMA–TiO2 nanoparticulate solids with an unprecedentedly high concentration (12 mol l?1) of the inorganic component, which is four times higher than that obtained after radical polymerization induced thermally or by photons. The inorganic nanoparticles underwent morphological and structural changes with an increase of Ti concentration above 1.5 mol l?1: they slightly coarsen and crystallize into an anatase polymorph. The material possesses a strong photochromic response related to the electron–hole separation at the organic–inorganic interface and can store 1e? per 5 Ti atoms. The electron storage capacity of the titania nanoparticles decreases upon crystallization.
关键词： high-pressure-ramp process,polymerization,TiO2 nanoparticles,photochromic properties,organic–inorganic hybrids
更新于2025-09-19 17:15:36