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In this work, tungsten oxide (WO3) films were deposited at room temperature and annealed for 2 h at 400°C. The electrochromic and electrochemical properties were studied for two different electrolytes. The films were deposited at different oxygen flow rates of 2, 4, and 6 standard cubic centimeters per minute (SCCM). X-ray diffraction analysis revealed structural characterization of amorphous and crystalline phases. UV-visible spectroscopy optical transmittance revealed 91% transmittance, and energy-dispersive x-ray spectroscopy (EDS) analysis revealed the absence of impurities and the presence of W and O. An electrochemical analyzer was used to characterize the deposited and annealed WO3 films immersed in the two different electrolyte solutions (H2SO4 and LiClO4 with oxygen flow rates ranging from 2 SCCM to 6 SCCM). It was found that the H2SO4 electrolyte of an annealed WO3 thin film at 2 SCCM demonstrated high coloring efficiency of 50.18 cm2/C, and the LiClO4 electrolyte of an annealed WO3 thin film at 4 SCCM demonstrated high coloring efficiency of 20.06 cm2/C. [ABSTRACT FROM AUTHOR]

The electrochromic (EC) mechanisms of inorganic materials are usually based on reversible cation insertion/extraction or metal deposition/dissolution, which are plagued by ion trapping and dendrite growth, respectively. In this paper, a novel conversion-type electrochromic mechanism is proposed, by making good use of the CuI/Cu redox couple. This CuI-based electrochromic system shows a neutral color switching from transparent and dim grey. By simply increasing the bleaching voltage, I 3 − / I − redox couple can be further activated. The generated I 3 − will readily react with Cu, effectively improving the conversion reversibility and thereby rejuvenating the degraded electrochromic performance. Thanks to the well-designed electrode and the self-healing ability, this conversion electrochromic system achieves rapid response times (tcoloring: 23 s, tbleaching: 6 s), decant optical modulation amplitude (26.4%), high coloration efficiency (86.15 cm2·C−1), admirable cyclic durability (without performance degradation after 480 cycles) and excellent optical memory ability (transmittance variation < 1% after 10 h open-circuit storage). The establishment of this conversion-type electrochromism may inspire the exploration of novel electrochromic materials and devices. [ABSTRACT FROM AUTHOR]

The influence of the coating method (spray-coating or drop-casting onto horizontal substrate) on the electrochromic characteristics of the layers of water-soluble polyaniline–polyacid complex was investigated. It was shown that, in the case of adding single-wall nanotubes, the polyaniline–polyacid layers prepared by the scalable spray-coating technology demonstrate high coloration speed and electrochromic efficiency. [ABSTRACT FROM AUTHOR]

Simplified two-electrode electrochemical deposition technique with glass/tin-doped indium oxide (glass/ITO) has been used to grow Mg-doped CdS thin films. As precursors, CdCl2, MgCl2 and Na2S2O3 were utilized. To study the physico-chemical properties of the obtained Mg-doped CdS thin-film instruments such as grazing incidence X-ray diffraction and Raman spectroscopy for structural analysis, UV–Vis spectrophotometry for optical properties and scanning probe microscopy for morphological properties have been used. It is observed from grazing incidence X-ray diffraction (GIXRD) data that the films are polycrystalline with only hexagonal phase. Because more metallic ions are deposited on the substrate, the material becomes more crystalline and increases the intensity of distinctive peaks observed. From the obtained optical characterization, it is observed that deposition time significantly influences the bandgap of the film. As deposition time raised from 10 to 25 min the bandgap decreases from 2.44 to 2.39 which makes the film to become more transparent and absorbs less light at shorter deposition times. According to scanning electron microscope (SEM) images, the surface morphology is uniform with tightly packed grains, and as deposition time goes on the grain shapes become less apparent. [ABSTRACT FROM AUTHOR]

The solid-state electrolytes have attractive properties for electrochromic (EC) devices and battery industries. Li+ ion is the most applied and investigated carrier ion in this field together with less commonly ions Mg2+, Na+ H+ and Al3+. In this study, we have investigated Al3+ solid electrolytes for WO3 based EC devices as alternative to Li+ ions. We have fabricated a series of AlSiOx thin films by applying different target powers of 0–15 W by magnetron sputtering method. The resulting films were characterized by Grazing incidence X-ray diffraction, atomic force microscopy, scanning electron microscopy, energy disperse spectroscopy, ultraviolet–visible-infrared spectrophotometer, X-ray photoelectron spectroscopy and electrochemical impedance spectroscopy (EIS). All samples showed high transparency in the visible range (~ 90%) while the transparency decreased about 10% in the near infrared region. Analysis of EIS data by Kramers–Kronig and Voigt models showed that some of the films have good ionic conductivity. The ionic conductivities of films grown with 10 W, 13 W and 15 W Al target powers were 1.54 × 10–6, 5.68 × 10–7 and 2.72 × 10–8 S/cm, respectively. The results indicate that AlSiOx solid electrolytes are promising for EC applications. [ABSTRACT FROM AUTHOR]

The current investigation is focused on modify optical, structural, electrical and electrochemical behaviors of PVA matrix by new hybrid ZnWMoO7 nanoparticles (NPs). The PVA/ZnWMoO7 nanocomposite (NCs) films have been fabricated via intercalation technique, where its structural and morphological features were investigated by XRD, SEM and FTIR. TEM result indicates that the size of nanoparticles (NPs) lies in the range of 7–18 nm. Current (I)–voltage(V) results showed dc-conductivity increased with increasing dosage of ZnWMoO7 NPs and I–V behavior indicates to ohmic dominant at voltage < 7 V followed by higher increasing in conductivity. The cyclic voltammetry (CV) displayed the PVA NCs have electrochemical stability between − 0.2 V and 0.8 V at a scan rate of 10 mV/S and the specific capacitance improved to 3.98 F/g for PVA/8wt% ZnWMoO7 NCs which is higher by 2 times compared to host PVA. The optical study reveals an increased refractive index from 1.18 to 2.16 at a wavelength of 300 nm, while the band gap energy (Eg) is reduced from 5.34 to 3.13 eV after inclusion PVA by 8wt% ZnWMoO7 NPs. Such results indicate that the NC films based on PVA/ZnWMoO7 NCs may be suitable for potential uses in opto-electronic and super capacitor applications. [ABSTRACT FROM AUTHOR]

The results of pure tungsten oxide WO3, 0.5% Fe-doped WO3 and 4% Fe‐doped WO3 deposited on the crystalline sapphire substrates by reactive pulsed laser deposition technique are reported. The crystalline structure of the thin films was investigated by X-ray diffraction. The thin films presented γ monoclinic and orthorhombic phases depending on the substrate temperature. The (200) and (400) diffraction peaks of the film grown at 600 °C and 650 °C have vanished. This effect was attributed to the Fe presence in the deposited layer. When the temperature increases to 720 °C, the films doped with Fe (0.5% and 4% Fe-doped WO3) behaved like an undoped WO3. The X Photoelectron Spectroscopy confirmed the existence of the W, Fe, and O species in the deposited layer of 4% Fe-doped WO3. Four dominant peaks of Fe 2p, detected by XPS measurements, show the existence of Fe3+. Two components O 1 s peaks were observed. The big peak located at 530 eV was responsible for the oxygen lattice in the WO3 matrix, and the additional peak at 532 eV presents oxygen deficiencies, dangling bonds, and O2 chemisorbed at the surface. The optical bandgap of thin films for 4% Fe-doped WO3 was slowly reduced from 3 to 2.7 eV as the substrate temperature increased from 600 to 720 °C. These values were compared with the optical bandgap of WO3 undoped thin film. The optical bandgap of the WO3 thin film was 3.1 eV at 720 °C. The optical emission of the pulsed laser deposition plasma plume shows the presence of the FeI and WI spectral lines. The rough estimation of the Fe percentage concentration was found from the FeI spectral line intensity ratio detected in the plasma plume and targets. [ABSTRACT FROM AUTHOR]

The nonlinear absorption (NLA) properties of ITO thin films were performed by utilizing femtosecond (100 fs), a high-repetition rate (80 MHz), and near-infrared (NIR) (750–820 nm) laser pulses. A radio frequency (RF) magnetron sputtering system was used to prepare ITO thin films of two different thicknesses. A scanning electron microscope was used to determine the film thickness and a UV–Visible spectrophotometer was used to observe the linear optical properties of the thin films. The open aperture Z-scan technique's nonlinear absorption studies of ITO thin films exhibited a reverse saturable absorption. The NLA properties of the ITO films varied depending on ITO thickness, incident laser power, and excitation wavelength, attributed to the increasing localized defect states in the band gap. The results showed that increasing the excitation wavelength from 750 to 820 nm reduces the nonlinear absorption coefficient of the ITO thin films from 15.88 × 10−7 to 9.43 × 10−7 cm/W and from 6.72 × 10−7 to 5.15 × 10−7 cm/W at ITO thicknesses of 280 and 170 nm, respectively. In contrast to the film thickness, the nonlinear absorption coefficient was inversely proportional to the excitation laser wavelength. Additionally, the optical limiting of ITO thin films was investigated, and it was found that there is a clear correlation between optical limiting and thin film thickness. [ABSTRACT FROM AUTHOR]

6-thioguanine (6-TG) is an anticancer drug with narrow safe dose range and intense toxic reactions, so it is urgently necessary to evaluate its clinical usage. Therefore, from the point of view of human health control, the 6-TG determination in biological matrices is of great significance. The current attempt was made to produce magnetic core–shell Fe3O4@SiO2/MWCNT nanocomposite (MCFSMW) to construct a novel selective and sensitive electrochemical 6-TG sensor. The characteristics of synthesized nanocomposite were determined by X-ray Diffraction, Fourier Transform Infrared Spectrometry, Scanning Electron Microscopy and Energy-Dispersive X-ray. The sensor fabrication was based on the surface modification of screen-printed electrode (SPE) with MCFSMW (MCFSMW/SPE). The MCFSMW/SPE possessed an appropriate response and an appreciable electrooxidation behaviors toward the 6-TG detection. There was a significant enhancement in the 6-TG electro-oxidation signal on the MCFSMW/SPE surface compared to the bare SPE. The proposed protocol was explored by chronoamperometry, cyclic voltammetry, and differential pulse voltammetry (DPV). The DPV findings clarified a broad linear relationship between the 6-TG concentrations and the peak height ranged from 0.01 to 280.0 µM with a limit of detection as narrow as 1.0 nM. The practical potency of MCFSMW/SPE was confirmed by sensing of 6-TG in the biological matrices. [ABSTRACT FROM AUTHOR]

This study presented a new method for surface temperature measurement using thermochromic liquid crystals. In the proposed method, the temperatures over the surface of a sheet of thermochromic liquid crystals were measured using the ratio of the spectral intensities of two specific wavelengths less than 450 nm. The measurable temperature range was broadened by approximately three times that of the conventional methods based on color change. In the experiment, the target object for measuring the surface temperature was a planar copper plate with a sheet of thermochromic liquid crystals on its surface having a color-change range of 10–20 °C; a white light emitting diode was used as the light source. Two monochrome charge-coupled device cameras were used to acquire images of the spectral intensities to eliminate the effect of spatial fluctuations of the light emission on measurement accuracy. The results demonstrated that a measurable temperature range of 21–51 °C with a temperature resolution higher than 0.04 °C was obtained using the ratio of the spectral intensities of two wavelengths, i.e., 442 nm and 436 nm. The uncertainty of the measured temperature was also analyzed. The minimum temperature uncertainty of 0.06 °C was obtained through image processing analysis using a spatial filtering window of size five times five pixels and 500 sequential images for time averaging. [ABSTRACT FROM AUTHOR]

In this article, we report the growth of Cu2ZnSnS4 (CZTS) films using a pulsed-laser deposition technique, to use as a counter electrode (CE) for dye-sensitized solar cells (DSSCs). A pulsed Nd-YAG laser in third harmonic generation (wavelength: 266 nm; pulse width: 9 ns and pulse frequency: 5 Hz) was used to ablate CZTS target. The ablated CZTS material was deposited on fluorine-doped tin oxide-coated glass substrate kept at 200°C under the vacuum of 6×10–6 mbar followed by annealing at 500°C to obtain CZTS films. Detailed characterization of the CZTS films was performed using X-ray diffraction, Raman spectroscopy and X-ray photoelectron spectroscopy. The ablation of the CZTS target by 1000 laser pulses (energy: 200 mJ) was found to result in the formation of a well-crystalline CZTS with characteristic weak and strong Raman modes at 287 and 337 cm–1. The CZTS films with different thicknesses were prepared by varying the number of laser pulses. Thickness-dependent electrocatalytic ability and electrochemical properties of the CZTS CEs were studied by cyclic voltammeter, electrochemical impedance spectroscopy and Tafel polarization. The thickness-dependent performance of DSSCs made with CZTS CEs was measured through J–V characterization. The DSSC based on CZTS CEs deposited with the thickness ~ 225 nm (ablated with 1000 laser pulses) showed maximum power conversion efficiency of 3.98%. The results indicated the potentiality of CZTS to replace Pt CE (5.53%) in DSSCs. [ABSTRACT FROM AUTHOR]

Hexagonal molybdenum oxide (h-MoO3) micro-rods were synthesized through a facile hydrothermal method. Thermogravimetric and differential thermal analysis (TGA-DTA) of the sample, over temperatures ranging from 30°C to 700°C, was carried out to analyze the phase transition characteristics and thermal stability. The effect of post-thermal treatment on the structural, morphological, and optical characteristics of as-prepared samples were investigated in detail. X-ray diffraction (XRD) patterns of the sample confirmed the formation of h-MoO3, and the presence of hexagonal-shaped micro-rods were observed through scanning electron microscopy (SEM). The crystalline phase was transformed to a thermodynamically stable orthorhombic structure (α-MoO3) on thermal treatment, with the micro-rods transformed to flake-like morphology. Elemental composition was confirmed through energy dispersive x-ray spectroscopy (EDS) and x-ray photoelectron spectroscopy (XPS). Band gap energy estimated from the absorption spectra lies in the range 2.70–2.94 eV. The material exhibited a superior irreversible thermochromic property, which has been observed as color bands, in the visible to NIR region of the absorption spectra. The phenomenon was well explained with the support of the XPS scan for the Mo-3d and O-1 s states. Furthermore, the photoluminescence (PL) spectra, at an excitation of 330 nm (3.76 eV), showed five emission peaks centered between 360 nm and 550 nm, with enhanced intensity on thermal treatment. The physico-chemical characteristics revealed that the material can be applicable in thermo-chromic smart windows and as host material in light-emitting diodes. [ABSTRACT FROM AUTHOR]

Highlights: A timely and updated comprehensive overview focusing on integration of electrochromic aqueous batteries is provided. The key prerequisites of integration, basic operating mechanism, and compatibility of the respective components are examined. The latest advances and emerging applications are discussed, as well as the future roadmap. Multifunctional electrochromic-induced rechargeable aqueous batteries (MERABs) integrate electrochromism and aqueous ion batteries into one platform, which is able to deliver the conversion and storage of photo-thermal-electrochemical sources. Aqueous ion batteries compensate for the drawbacks of slow kinetic reactions and unsatisfied storage capacities of electrochromic devices. On the other hand, electrochromic technology can enable dynamically regulation of solar light and heat radiation. However, MERABs still face several technical issues, including a trade-off between electrochromic and electrochemical performance, low conversion efficiency and poor service life. In this connection, novel device configuration and electrode materials, and an optimized compatibility need to be considered for multidisciplinary applications. In this review, the unique advantages, key challenges and advanced applications are elucidated in a timely and comprehensive manner. Firstly, the prerequisites for effective integration of the working mechanism and device configuration, as well as the choice of electrode materials are examined. Secondly, the latest advances in the applications of MERABs are discussed, including wearable, self-powered, integrated systems and multisystem conversion. Finally, perspectives on the current challenges and future development are outlined, highlighting the giant leap required from laboratory prototypes to large-scale production and eventual commercialization. [ABSTRACT FROM AUTHOR]

A new electrochemical impedimetric sensor for direct detection of urea was designed and fabricated using nanostructured screen-printed electrodes (SPEs) modified with CuO/Co3O4 @MWCNTs. A facile and simple hydrothermal method was achieved for the chemical synthesis of the CuO/Co3O4 nanocomposite followed by the integration of MWCNTs to be the final platform of the urea sensor. A full physical and chemical characterization for the prepared nanomaterials were performed including Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), contact angle, scanning electron microscope (SEM) and transmission electron microscopy (TEM). Additionally, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used to study the electrochemical properties the modified electrodes with the nanomaterials at different composition ratios of the CuO/Co3O4 or MWCNTs. The impedimetric measurements were optimized to reach a picomolar sensitivity and high selectivity for urea detection. From the calibration curve, the linear concentration range of 10−12–10−2 M was obtained with the regression coefficient (R2) of 0.9961 and lower detection limit of 0.223 pM (S/N = 5). The proposed sensor has been used for urea analysis in real samples. Thus, the newly developed non-enzymatic sensor represents a considerable advancement in the field for urea detection, owing to the simplicity, portability, and low cost-sensor fabrication. [ABSTRACT FROM AUTHOR]

Prussian blue (Fe4[Fe(CN)6]3, PB) has become a widely studied anodic electrochromic material due to its advantages such as large optical modulation range, fast response speed and low voltage demand. Tungsten oxide (WO3) as a cathode electrochromic materials, have various advantages, while their low color rendering efficiency and poor cycling stability limit their applications. To this end, the following solution was proposed for the first time in this study: the hydrothermal method was adopted to prepare tungsten oxide nanorods and then coat Prussian blue on the rod-shaped tungsten oxide to form an inorganic–organic core–shell structure (WO3/PB) to improve electrochromic performance. Through comparative experiments, the effects of WO3/PB core–shell structure for the electrochromic properties of films and its mechanism were explored. The Li+ diffusion coefficient of WO3/PB core–shell structure films is 35% and 720% higher than that of single WO3 and PB, respectively. At the same time, compared with the single PB and WO3 films, the electrochromic response speed of the WO3/PB film is fast, and the light transmittance after coloring is low, with good optical properties. Relevant experimental data displayed that WO3 is wrapped by PB to form a core–shell structure, which makes the film have high electrochromic properties. The reasons are the formation of electron pair donor–acceptor system in the film and the formation of double electrochromic effect. WO3/PB forms a rod-like nano core–shell structure, which increases the surface area for the reaction and facilitates the transfer of ions and electrons into and out of the film. This method of combining anodic electrochromic materials and cathodic electrochromic materials to form a core–shell structure to improve electrochromic performance provides a new direction for future electrochromic research. [ABSTRACT FROM AUTHOR]

Nano-WO3:EU3+ powder was prepared by Pechini method under acidic and alkaline condition, and the prepared acidic nano-WO3:Eu3+ mixed with the silver nanowires (AgNWs) in ethanol and acetone solution. The solution was mixed with PMMA and EP, respectively. Then, drops of the solutions were added to the indium tin oxide (ITO) conductive glass as the substrate; a AgNWs/WO3:Eu3+ composite film was obtained with spin coating by spin coater and solidification process. Microstructure, morphology, optical properties, preparation process and UV transmittance of the prepared nano-WO3:Eu3+ and AgNWs/WO3:Eu3+ composite films were investigated by XRD, SEM, fluorescence spectroscopy and UV spectrophotometer. The results show that the prepared acidic nano-WO3 is triclinic, and the average particle size is 71.63 nm. The prepared alkaline nano-WO3 is monoclinic, with an average particle size of 95.66 nm. Both of them have good luminescence properties. Under different monitoring wavelengths, in the emission range of 450–500 nm, it belongs to the green light region, and its excitation peak is the largest, indicating that green light is the best excitation light source for WO3:Eu3+ powder. The transmittance of EP/AgNWs/WO3:Eu3+ composite film is the highest when the spin coating time is more than 30 s and above 3000 rpm, no more than three layers spin coating and the content of curing agent is between 0.1 and 0.2 g. [ABSTRACT FROM AUTHOR]

This research concerns the development of lithium ions conductive electrolyte from poly(vinyl butyral) (PVB) resin for use as a special interlayer film in electrochromic glass. To obtain the final PVB film with high ionic conductivity and thermal stability, a masterbatch was firstly prepared by mixing of PVB resin with lithium salt (LiClO4) and additives in an aqueous ethanol solution. After this, the dried masterbatch were converted into final films by an extrusion process. In this study, PVB film with the highest ionic conductivity value of 4.85×10−6 was obtained when the masterbatch was diluted with the neat PVB resin at the weight ratio of 2:1 in the extruder prior to fabrication. The results from cyclic voltammetry over 100 cycles, showed that performance of the electrochromic device (ITO/WO3/PVB electrolyte/ITO) fabricated by using the above PVB film is stable and reversible. In overall, this work demonstrates that ion conductive PVB films with compromised ionic conductivity and thermal stability can be prepared via an extrusion process without the need to modify chemical structure of PVB. This was carried out through the masterbatch approach, by introducing LiClO4 salts into the plasticized PVB via a solution mixing process prior to converting it into a final film via the extrusion process. [ABSTRACT FROM AUTHOR]

An electrochemical sensor based on the three-dimensional flower-like Fe3O4/Au porous microstructure to determine chloramphenicol (CAP) was successfully fabricated. This microstructure was synthesized hydrothermally with controlled reaction time in the presence of urea and decorated with Au nanoparticles via a simple chemical reduction method. The as-synthesized Fe3O4 and Fe3O4/Au porous microstructures were characterized by using scanning electron microscopy, transmission electron microscopy, energy-dispersive x-ray spectroscopy, elemental mapping, x-ray diffraction, nitrogen adsorption/desorption isotherms, UV–visible spectroscopy (UV–VIS), Fourier transform infrared spectroscopy, and electrochemical impedance spectroscopy. The electrochemical performance of the sensor was investigated with cyclic voltammetry and differential pulse voltammetry. The sensor exhibits excellent stability, reproducibility, and repeatability with a low CAP detection limit of 0.14 µM and a linear range of 1.0 to 12 µM. More importantly, it can be employed to determine chloramphenicol in the urine samples. [ABSTRACT FROM AUTHOR]

An experimental investigation is carried out to modulate the optical properties of electrochromic devices (ECD) by varying the thickness of electrochromic polymer (ECP) layer. Polyaniline (PANI) is preferred as ECP due to its ability to change colors from light green to green to blue at different voltages. ECDs are fabricated having varying thickness (250–650 nm) of the PANI layer. Topography, morphology, and optical measurements show that the roughness, porosity, and shade of green color depend on the thickness of PANI layer. The effect of ECP layer thickness on the optical performance of ECDs is evaluated through detailed electrochemical, optical, spectroelectrochemical measurements, and spectral colorimetry. ECD shows different shades of green and blue color with higher color contrast for the thicker PANI layer. It is attributed to the roughness and porosity-induced multiple scattering and trapping of incident light in the ECP layer. The reflectance spectra are later used to define the color space for all the ECDs. While the color difference of the ECD fabricated with 250-nm-thick ECP is small, the ECDs prepared using thicker ECP layers show noticeable color difference of greater than 2. Finally, it is shown that varying PANI-based ECP layer thickness is a feasible strategy to modulate the shade of green color in ECDs. [ABSTRACT FROM AUTHOR]

Electrochromism refers to the change in the reversible color of certain materials in response to an electric field to regulate light. In this paper, WO3 thin films were prepared by hydrothermal method, and then PANI was deposited on the surface of WO3 by electrodeposition method. The organic and non-electrochromic materials were combined together, and the core–shell structure of WO3/PANI was finally obtained. The electrochromic properties of core–shell composite films are significantly improved. In particular, the cyclic stability of core–shell composite films is superior to that of single material electrochromic films. At the same time, the composite film demonstrates fast electrochromic response and large ion diffusion coefficient. The Li+ diffusion coefficient of WO3 film is 4.37 × 10–10 cm2/s, and that of WO3/PANI film is 4.93 × 10–10 cm2/s, 13% higher than that of the single film. The number of electrons and ions entering the film is greatly increased, and these improvements optimize the electrochromic properties of the film. The results show that WO3/PANI core–shell structure has broad research and application prospects as electrochromic materials. [ABSTRACT FROM AUTHOR]

In the present work, we analyzed the electrochromic behavior of tungsten oxide (WO3) and effect of hafnium (Hf) doping on its performance. The electrochromic performance of pristine WO3 and (2, 5, 7, 10%) Hf-doped WO3 was tested in lithium and calcium electrolyte. Hf-doped outperformed the pristine WO3, and 7% doped sample showed best results. The performance was also affected by the electrolyte used. In Ca electrolyte, 7% Hf-doped WO3 exhibited highest optical contrast of 75% (714 nm), fast switching (1.28s tc/3.14s tb), and highest coloration efficiency of 161.87 cm2 C−1 of all the samples tested. A device fabricated from the 7% Hf-doped WO3 exhibited fast switching (1.53s tc/5.83s tb) and excellent stability and proved the practical applicability of Hf doped WO3/Ca electrolyte electrochromic system. [ABSTRACT FROM AUTHOR]

In the present work, we analyzed the electrochromic behavior of tungsten oxide (WO3) and effect of hafnium (Hf) doping on its performance. The electrochromic performance of pristine WO3 and (2, 5, 7, 10%) Hf-doped WO3 was tested in lithium and calcium electrolyte. Hf-doped outperformed the pristine WO3, and 7% doped sample showed best results. The performance was also affected by the electrolyte used. In Ca electrolyte, 7% Hf-doped WO3 exhibited highest optical contrast of 75% (714 nm), fast switching (1.28s tc/3.14s tb), and highest coloration efficiency of 161.87 cm2 C−1 of all the samples tested. A device fabricated from the 7% Hf-doped WO3 exhibited fast switching (1.53s tc/5.83s tb) and excellent stability and proved the practical applicability of Hf doped WO3/Ca electrolyte electrochromic system. [ABSTRACT FROM AUTHOR]

Over the years, vanadium dioxide, (VO2(M1)), has been extensively utilised to fabricate thermochromic thin films with the focus on using external stimuli, such as heat, to modulate the visible through near-infrared transmittance for energy efficiency of buildings and indoor comfort. It is thus valuable to extend the study of thermochromic materials into the mid-infrared (MIR) wavelengths for applications such as smart radiative devices. On top of this, there are numerous challenges with synthesising pure VO2 (M1) thin films, as most fabrication techniques require the post-annealing of a deposited thin film to convert amorphous VO2 into a crystalline phase. Here, we present a direct method to fabricate thicker VO2(M1) thin films onto hot silica substrates (at substrate temperatures of 400 °C and 700 °C) from vanadium pentoxide (V2O5) precursor material. A high repetition rate (10 kHz) femtosecond laser is used to deposit the V2O5 leading to the formation of VO2 (M1) without any post-annealing steps. Surface morphology, structural properties, and UV–visible optical properties, including optical band gap and complex refractive index, as a function of the substrate temperature, were studied and reported below. The transmission electron microscopic (TEM) and X-ray diffraction studies confirm that VO2 (M1) thin films deposited at 700 °C are dominated by a highly texturized polycrystalline monoclinic crystalline structure. The thermochromic characteristics in the mid-infrared (MIR) at a wavelength range of 2.5–5.0 μm are presented using temperature-dependent transmittance measurements. The first-order phase transition from metal-to-semiconductor and the hysteresis bandwidth of the transition were confirmed to be 64.4 °C and 12.6 °C respectively, for a sample fabricated at 700 °C. Thermo-optical emissivity properties indicate that these VO2 (M1) thin films fabricated with femtosecond laser deposition have strong potential for both radiative thermal management or control via active energy-saving windows for buildings, and satellites and spacecraft. [ABSTRACT FROM AUTHOR]

Driven by the urgent need for adaptive infrared (IR) electrochromic devices, the improvement in electrochromic performance based on polyaniline (PANI) conducting polymers has become an outstanding challenge. In recent years, the acid doping strategy has been proven to increase the IR modulation ability of PANI, in particular for the Bronsted acid doping. Herein, the effects of copper ions, a Lewis acid, on the structure and electrochromic properties of polyaniline were investigated. Compared to pure polyaniline, the Cu-doped PANI porous films show better IR modulation ability. With the increasing concentration of copper ions, the Cu-doped PANI porous films exhibit a trend in volcanic patterns for the emittance variation (∆ε), depending on the number of polarons and bipolarons. The optimal IR emissivity (ε) modulation obtained on Cu-doped PANI films shows the ∆ε modulation of 0.35 and 0.3 in the wavelength range of 8–14 µm and 2.5–25 µm, superior to previously reported pure sulfuric acid-doped PANI. Furthermore, a flexible IR electrochromic device was fabricated with the present Cu-doped PANI porous films. The modulation of the emittance variation varied between 0.513 and 0.834 (∆ε = 0.32 in ranges of wavelength 8–12 µm), suggesting the great potential for applications in military camouflage and intelligent IR thermal management. We believe that the results in this work will provide a novel perspective and avenue for improving the IR modulation ability of electrochromic devices based on polyaniline conducting polymers. [ABSTRACT FROM AUTHOR]

Highly efficient single-component white light emitters (SWLEs), are attractive candidates for the simple and cost-effective fabrication of high-performance lighting devices. This study introduced a donor–π–acceptor and a donor–π–donor stilbene-based chromophores, representing pH-responsive fluorescence. The emitters showed yellow and green fluorescence in their neutral form. At the same time, protonation of the chromophores caused blue fluorescence color with a strong hypsochromic shift. The white light emission (WLE) for these chromophores was observed at approximately pH 3 due to the simultaneous presence of the neutral and protonated forms of the chromophores, covering almost all the emission spectra in the visible region (400–700 nm). These chromophores presented exceptional white light quantum yields (Φ) between 31 and 54%, which was desirable for producing white light-emitting devices. Density functional theory (DFT) and time-dependent (TD)-DFT were applied to study the structural and electronic properties of the chromophores. [ABSTRACT FROM AUTHOR]

X-ray reflectometry characterization of tungsten oxide nanolayers deposited onto glass supports via magnetron sputtering in a stationary mode and using the rotating support revealed that non-stationary deposition mode involving the support rotation provides coatings with a complex structure featuring with a periodic electron density modulation in depth that is promising for the adjustment of the target performances. Particularly, the application of this approach provided a significant increase of the electrochromic efficiency and coloration/bleaching rate for electrochromic devices in comparison with counterparts obtained by tungsten oxide layer deposition onto a stationary support. [ABSTRACT FROM AUTHOR]

The optical and electromagnetic properties of graphene oxide (GO)-modified WO3 electrochromic nanocomposite films obtained by electrochemical deposition of the W and GO ions from a solution synthesized using peroxotungstic acid (PTA) with the addition of GO were studied. Controlled electrochemical deposition of electrochromic WO3 films was carried out by the multistage amperometry (MSA) procedure in which the initial and final values of the electrodeposition potential of –0.5 and –1.5 V, as well as the number of cycles were set. [ABSTRACT FROM AUTHOR]

Amorphous ternary Tantalum Silicon Nitride (Ta–Si–N) is an oxidation/diffusion barrier layer for microelectronic devices. The transparency of Ta–Si–N with increased nitrogen content in the wavelength range 200–1700 nm was investigated. Good transmittance was obtained with low amount of nitrogen in the layer. Passivity of Ta–Si–N to the thermochromic property of VO2 films and the high oxidation temperature for vanadium are reported. The relative nitrogen content in each layer was determined with Energy-Dispersive x-ray Spectroscopy. Both the transparency and passivity Ta–Si–N made it a suitable candidate for opto-electronic device applications. [ABSTRACT FROM AUTHOR]

A simple one-pot reaction method was used to synthesize NiCoMn-MOF with Li+ adsorption, which was used as the precursor to prepare LiNi1/3Co1/3Mn1/3O2 cathode materials. The microscopic structural features of LiNi1/3Co1/3Mn1/3O2 were investigated using scanning electron microscopy, x-ray diffraction, and Fourier-transform infrared spectrometry. The electrochemical properties of LiNi1/3Co1/3Mn1/3O2 are investigated by charge–discharge cycles and impedance experiments. The obtained results suggest that LiNi1/3Co1/3Mn1/3O2 obtained by using NiCoMn-MOF as a precursor had uniform particle size and good crystallinity. The initial discharge capacity could reach 193 mAh g−1 at 0.1C in the voltage range of 2.5-4.3 V. The capacity retention rate was 90% after 50 cycles at 1C. This showed that LiNi1/3Co1/3Mn1/3O2 synthesized from a NiCoMn-MOF precursor had good structure, morphology, and electrochemical performance. [ABSTRACT FROM AUTHOR]

The structural and optical properties of electrodeposited Cd1-xZnxS nanostructured thin films were investigated in the present paper for compositions of x = 0, 0.03, 0.06 and 0.09. X-ray diffraction patterns of the deposited thin films consisted of diffraction peaks related to cubic crystal lattice. The atomic compositional ratios were determined by performing energy dispersive spectroscopy measurements. Scanning electron microscopy images indicated that deposited thin films have nanostructured forms. Raman spectra of the Cd1-xZnxS thin films exhibited two vibrational modes associated with longitudinal optical mode and its first overtone. Transmission measurements were performed on the deposited thin films to get their band gap energies. It was seen from the analyses of absorption coefficient that band gap energy of Cd1-xZnxS thin films increases almost linearly from 2.40 to 2.51 eV as the composition was increased from x = 0 to x = 0.09. [ABSTRACT FROM AUTHOR]

Mechanochromic polymers are intriguing materials that allow to sense force of specimens under load. Most mechanochromic systems rely on covalent bond scission and hence are two-state systems with optically distinct "on" and "off" states where correlating force with wavelength is usually not possible. Translating force of different magnitude with gradually different wavelength of absorption or emission would open up new possibilities to map and understand force distributions in polymeric materials. Here, we present a mechanochromic donor-acceptor (DA) torsional spring that undergoes force-induced planarization during uniaxial elongation leading to red-shifted absorption and emission spectra. The DA spring is based on ortho-substituted diketopyrrolopyrrole (o-DPP). Covalent incorporation of o-DPP into a rigid yet ductile polyphenylene matrix allows to transduce sufficiently large stress to the DA spring. The mechanically induced deflection from equilibrium geometry of the DA spring is theoretically predicted, in agreement with experiments, and is fully reversible upon stress release. Force sensing using mechanochromic polymers is currently limited to two state systems and does not allow directly correlating the force with the absorption or emission wavelength. Here, the authors present a mechanochromic donor-acceptor torsional spring that undergoes force-induced planarization during uniaxial elongation leading to force dependent red-shifted absorption and emission spectra. [ABSTRACT FROM AUTHOR]

The paper presents the preparation of nanostructured ZnO and TiO2 binary thin films by pulsed laser deposition at different temperatures ranging from 298 K (as deposited) to 923 K. The films have been characterized by SEM, EDAX, XRD, and UV. The presence of nanospheres is detected by SEM. The XRD spectra extrapolates the film's amorphous existence below 773 K. Thin film deposited at 923 K confirmed ZnTiO3 formation. The optical energy band gap measured by the Tauc plot was found to be 3.7–3.9 eV. The electrochemical impedance spectroscopy with a sweeping frequency of 1 Hz to 1 MHz was used to examine the films for temperatures between 298 K and 473 K. The EIS results revealed that these films have not denied an impedance and modulus relaxation. Activation energy dependent on impedance and module relaxation was calculated from the Arrhenius plot. The mean capacitance was obtained and statistically tested using the SPSS statistics software tool. [ABSTRACT FROM AUTHOR]

A Poly (3, 4-dioxyethylthiophene)–Carbon Nanotubes (PEDOT–CNT) composite electrochromic material, connected by interfacial covalent bonds, was successfully synthesized by electrochemical copolymerization of 3, 4-dioxyethylthiophene with thiophene-2-methylamine functionalized CNT. The molecular and aggregate structures of PEDOT–CNT were investigated by Fourier transform infrared spectroscopy, Raman spectroscopy, scanning electron microscopy and transmission electron microscopy. The electrochemical behavior and electrochromic properties of PEDOT–CNT were measured by CV (cyclic voltammetry), UV–Vis (ultraviolet visible spectroscopy) and EIS (electrochemical impedance spectroscopy). The test results show that the electrochromic performance of PEDOT–CNT is better than that of neat PEDOT. As the percentage of carbon nanotubes increases, the contrast and response speed of the composites increase accordingly. The PEDOT film has a contrast under square-wave potential of 0.54, a coloring time of 6.42 s, and a fading time of 2.54 s. Compared with PEDOT, the contrasts of PEDOT–CNT-3%, PEDOT–CNT-5% and PEDOT–CNT-7% are increased by 31%, 33%, and 89%, respectively. The response speeds of PEDOT–CNT-5% increase to coloring time of 3.51 s and fading time of 1.37 s. [ABSTRACT FROM AUTHOR]

SrAl2O4: Eu2+, Dy3+ (SAOED) and Y2O2S: Eu3+, Mg2+, Ti4+ (YOS), as two kinds of important rare earth luminescent materials, are widely used in fibers due to their excellent luminescent properties. However, the lack of sensing property limits the application areas of the fibers in intelligent materials. In this work, the thermochromic luminescent fiber (TLF) was prepared by wet spinning from the cellulose acetate (CA)/dimethyl formamide (DMF) spinning solution. The rare earth luminescent materials serviced as the luminescent sources and thermochromic pigments (TP) acted as the thermochromic agent in this color changing system. The absorptivity curves and fluorescence spectra were recorded at 25 and 45 °C to investigate the thermosensitive characteristics of the fiber. The scanning electron microscope (SEM) observation presents that the TLFs were cylindrical with the diameters of 300–400 µm and three kinds of particles were evenly distributed in the cellulose matrix. X-ray diffraction (XRD) results confirm that cellulose matrix and the wet spinning process did not destroy the phase of rare earth luminescent materials in the fiber. Thermal stability of TLF was illustrated by differential scanning calorimetry (DSC) and thermal gravity analysis (TGA). Absorptivity and emission spectra measurement indicates that the TLF had perspicuous thermochromic luminescence properties. Decay curves showed that the TLF glowed continuously. This work exploits a new type of intelligent luminescent fiber that can respond to ambient temperature, which broadens its application in sensors. [ABSTRACT FROM AUTHOR]

This paper presents a study of physical and electrochemical properties relevant to the lithium ion diffusion process governing WO3 thin films electrochromic phenomenon. The films were prepared from a solution obtained by the sol–gel process and deposited via dip-coating. They were characterized by chronocoulometry, chronoamperometry and in and ex situ ultraviolet–visible spectroscopy during coloring/bleaching of the films. To analyze the experimental data, a mathematical model was applied considering a reaction kinetics controlled by the diffusion of ion pairs. The effects of the intercalation of Li+, Na+ and K+ ions was compared. Theoretical and experimental results for the current, charge density and absorbance profiles in function of time are included in this paper. The highest values obtained were η = 29.98 C/cm 2 for electrochromic efficiency, ΔT = 61.6% for optical modulation, Q i = 81.78 mC/cm 2 for charge density, and reversibility of coloring/bleaching in the range of 75–90%. X-Ray diffractometry measurements confirmed the amorphous structure of the films. Fourier transform infrared spectroscopy was employed to analyze the functional groups present in the films structure, while their topology was studied via atomic force microscopy. The collected results confirmed a relationship between the electrochromic and electrochemical reactions, definitively associating color change with cations injection and the reduction of W6+ to W5+. [ABSTRACT FROM AUTHOR]

Organometallic halide perovskites have been arisen as a class of multi-purpose materials with exciting applications in optoelectronic devices such as solar cells, light-emitting diodes, photo detectors, and laser diodes. In spite of a significant hope in performance, still production process in ambient air and its stability must be addressed as the main issues for this type of material. In this work, a versatile and scalable fabricating process of halide mixed perovskite layers through electrochemical deposition of PbO2 on FTO (fluorine-doped tin dioxide–coated glass) substrates and double-vapor transformation with HX and CH3NH3X (X = I & Br) vapors without using a glove box or a high vacuum system is demonstrated. Highly crystalline hollow-free electrodeposited perovskite layers on FTO substrate were achieved. Treatments with CH3NH3Br/CH3NH3I precursors were also investigated to check the possible impact on the quality of the final perovskite layer. It was illustrated that the use of CH3NH3I or CH3NH3Br precursors in the last step of the electrochemical synthesis can determine the properties of the perovskite film. When PbI2 and PbBr2 films exposed to CH3NH3Br vapor, bromine-treated perovskites were achieved with uniform grain size of ~ 1.5 to 2.3 μm. Similar treatment with CH3NH3I vapor led to the smaller grain size perovskite layers (~ 0.7 μm). Final properties of all fabricated layers, including optical absorption, bandgaps the crystalline phases, and chemical composition, were characterized and compared. [ABSTRACT FROM AUTHOR]

Chromogenic thin films are crucial building blocks in smart windows to modulate the flux of visible light and heat radiation into buildings. Electrochromic materials such as tungsten oxide are well established in those devices. Sputter deposition offers a well-suited method for the production of such layers, which can also be used on an industrial scale. Tungsten oxide films were prepared by means of reactive ion-beam sputter deposition. The choice of distinct gas mixtures as well as the growth temperature during the sputtering process allows to tune the properties of the resulting layers. Especially, the variation in the growth temperatures was found to have an impact on the structure of the resulting samples and, as a consequence, on their optical and electrochemical properties. By specific choice of the reactive gas, the deposition of colorless transparent as well as blue films of different composition is possible. The optical transmittance in the visible spectral range was up to 75% for as-deposited oxygen-rich layers. Additionally, hydrogen-doped tungsten oxide samples were grown. Superior electrochromic switching was observed for H + -doped layers, probably by some kind of preconditioning. This resulted in a value for the standardized optical coloration efficiency of 26.5 cm 2 /C. [ABSTRACT FROM AUTHOR]

Highlights: MXene/WO3−x composite film with excellent electrochromic performances was fabricated for the first time. The addition of MXene is an effective strategy for simultaneously enhancing electron and ion transport behaviors in the electrochromic layer. The kinetics of ion diffusion in electrochromic devices are studied in depth based on both experiment and simulation. Electrochromic technology plays a significant role in energy conservation, while its performance is greatly limited by the transport behavior of ions and electrons. Hence, an electrochromic system with overall excellent performances still need to be explored. Initially motivated by the high ionic and electronic conductivity of transition metal carbide or nitride (MXene), we design a feasible procedure to synthesize the MXene/WO3−x composite electrochromic film. The consequently boosted electrochromic performances prove that the addition of MXene is an effective strategy for simultaneously enhancing electrons and ions transport behavior in electrochromic layer. The MXene/WO3−x electrochromic device exhibits enhanced transmittance modulation and coloration efficiency (60.4%, 69.1 cm2 C−1), higher diffusion coefficient of Li+ and excellent cycling stability (200 cycles) over the pure WO3−x device. Meanwhile, numerical stimulation theoretically explores the mechanism and kinetics of the lithium ion diffusion, and proves the spatial and time distributions of higher Li+ concentration in MXene/WO3−x composite electrochromic layer. Both experiments and theoretical data reveal that the addition of MXene is effective to promote the transport kinetics of ions and electrons simultaneously and thus realizing a high-performance electrochromic device. This work opens new avenues for electrochromic materials design and deepens the study of kinetics mechanism of ion diffusion in electrochromic devices. [ABSTRACT FROM AUTHOR]

Poly-3-thiopheneboronic acid was synthesized by electrochemical polymerization from 3-thienylboronic acid dissolved in the mixture of boron trifluoride diethyl etherate and acetonitrile. Cyclic voltammetry during electropolymerization shows oxidative and reductive peaks growing in each next cycle. An investigation by scanning electron microscopy displayed the polymer layer like a highly flexible film of 110 nm thick with grains of 60–120 nm in size. Strong negative solvatochromic effect was observed. Optical spectra of poly-3-thienylboronic acid at different potentials and pH were studied. Potential cycling leads to a well reversible electrochromic effect. At pH 7.4, the increase of potential leads to the decrease in the absorption band at 480 nm and to the rise in the absorption band at 810 nm with an isosbestic point at 585 nm. Spectroelectrochemical behavior of poly-3-thienylboronic acid and polythiophene was compared. Binding of sorbitol at fixed electrode potential leads to an increase in the absorbance in the shortwave band and to the decrease in the longwave band; the effect depends on the electrode potential and pH. Perspectives of application of poly-3-thienylboronic acid as new chemosensitive material are discussed. [ABSTRACT FROM AUTHOR]

In the present investigation, a series of molybdenum-doped bismuth selenide (MoxBi(2−x)Se3) (x = 0.01 to 0.05) thin films have been deposited by simple and low-cost arrested precipitation technique (APT) onto substrate for the first time. The deposition has been carried out from aqueous alkaline bath using nonhazardous triethanolamine as a complexing agent at low temperature. The deposited thin films have been characterized to study optical, structural, morphological, compositional, electrical, and photoelectrochemical properties by using UV–Vis, XRD, SEM, AFM, TEM, SAED, EDS, XPS, EC, TEP, and PEC techniques. In the series of MoxBi(2−x)Se3 thin films, properties were altered with increase in molybdenum content. Optical absorption study shows red shift of absorbance in visible region and reflected in bandgap energy, which decreases from 1.48 to 1.30 eV. The SEM images show granular surface morphology without any cracks and increases in particle size with Mo content in film. The AFM analysis shown average roughness of the film which is 4.79 nm/µm2. TEM analysis gives agglomerated and granular morphology of the material. The SAED pattern gives excellent agreement with XRD results. EDS and XPS analysis confirms the presence of Mo, Bi, and Se elements with + 4, + 3, and − 2 oxidation states, respectively. From electrical conductivity measurements, activation energy was calculated and it decreases from 0.9565 to 0.1162 eV with increase in Mo content. Electrical conductivity increases with temperature indicates semiconducting nature of the films. TEP measurement shows negative Seebeck coefficient which confirms n-type semiconductor property. The PEC power conversion efficiency increases from 0.042 to 0.456% with increase in Mo content. [ABSTRACT FROM AUTHOR]

Microwave-assisted methods are facile synthetic routes for the synthesis of nanoparticles. Cu2O nanoaggregates (Cu2O NA) were synthesized using Bauhinia purpurea (B. purpurea) leaf extract via microwave method. The incorporation of Cu2O NA in β-cyclodextrin generated Cu2O-β-CD nanocomposite (Cu2O-β-CD NC). The structure and morphology of the Cu2O-β-CD NC were investigated using characterization techniques like Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and atomic force microscopy. The crystallines Cu2O NA and Cu2O-β-CD NC have size 30.65 and 19.73 nm, respectively. The Cu2O-β-CD NC revealed excellent catalytic activities for the reduction of nitro aromatic compounds in the presence of NaBH4. Gold electrode modified with Cu2O-β-CD NC is effective for the sensing levofloxacin. The electrocatalytic performance of the modified electrode was optimized, and the limit of detection was found to be 6.93 nM. The synergistic effect between the semiconductor Cu2O nanoaggregates and high adsorption capability of β-CD provided a better platform for the fast degradation of 4-nitrophenol and enhanced sensitivity for the determination of levofloxacin. [ABSTRACT FROM AUTHOR]

Amorphous dielectric WO3 films with a surface roughness from 4 to 5 nm have been grown by room-temperature pulsed laser deposition on quartz and c-sapphire substrates using metallic targets. We have examined the effect of the nature of the substrates and the oxygen pressure during the growth process on the transmission spectrum of the WO3 films in the range from 400 to 2000 nm. The parameters of the films have been shown to depend on the oxygen pressure during the growth process. Raising the oxygen pressure from 20 to 60 mTorr during the film growth process increases the transmission of the WO3 films from 40 to 75% in the visible and UV spectral regions and from 10 to 70% in the IR. With increasing oxygen pressure during film growth, the band gap of the WO3 films increases from 3.01 to 3.34 eV in the case of sapphire substrates and from 2.95 to 3.42 eV in the case of quartz substrates, being only slightly dependent on the nature of the substrate. Using a WO3 film grown at room temperature, we have fabricated the first thin-film liquid-electrolyte electrochromic cell. Its transmission in the spectral range from 300 to 900 nm drops by 30% at an applied voltage of 2.5 V, with a coloration time on the order of 2 min. [ABSTRACT FROM AUTHOR]

LiFePO4 thin films are grown by pulsed laser deposition technique in relation to deposition parameters. Different characterizations such as XRD, SEM, Raman, and electrochemical studies are undertaken on the prepared samples. Structural phase of the deposited thin film expresses the orthorhombic Pnma olivine. LiFePO4 thin films grown on Pyrex glass substrate have harsh surface with a few dispatches of grains, whereas the thin films deposited on ITO-coated glass substrate have demonstrated exceptionally fine and uniform particles without dispatches of grains. Raman peaks are situated at 1237.7 and 1416 cm−1. From the conductivity studies, the conductivity has been raised for the Pyrex glass up to 1.1 × 10−4 S cm−1 at 373 K, whereas in case of ITO-coated glass, the conductivity has been enhanced up to 1.6 × 10−4 S cm−1 at 373 K. The transmission spectra change CC from obscurity state to free state from 15 to 83% at around 39 cm2 C−1. CV of LiFePO4 thin film on ITO-coated glass substrate has exhibited the anodic and cathodic peaks at 3.2 and 3.19 V. These outcomes demonstrate that the determination of a suitable substrate is significant for creating the film terminal with the high rate limit, particularly in considering the utilization of microbatteries. [ABSTRACT FROM AUTHOR]

Afterglow luminescent probes with high signal-to-background ratio show promise for in vivo imaging; however, such probes that can be selectively delivered into target sites and switch on afterglow luminescence remain limited. We optimize an organic electrochromic material and integrate it into near-infrared (NIR) photosensitizer (silicon 2,3-naphthalocyanine bis(trihexylsilyloxide) and (poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene]) containing nanoparticles, developing an H2S-activatable NIR afterglow probe (F12+-ANP). F12+-ANP displays a fast reaction rate (1563 ± 141 M−1 s−1) and large afterglow turn-on ratio (~122-fold) toward H2S, enabling high-sensitivity and -specificity measurement of H2S concentration in bloods from healthy persons, hepatic or colorectal cancer patients. We further construct a hepatic-tumor-targeting and H2S-activatable afterglow probe (F12+-ANP-Gal) for noninvasive, real-time imaging of tiny subcutaneous HepG2 tumors (<3 mm in diameter) and orthotopic liver tumors in mice. Strikingly, F12+-ANP-Gal accurately delineates tumor margins in excised hepatic cancer specimens, which may facilitate intraoperative guidance of hepatic cancer surgery. Afterglow imaging probes are of interest for in vivo imaging due to high signal-to-background ratios. Here, the authors report on an afterglow nanoparticle which is activated by hydrogen sulphide and demonstrate the measurement of hydrogen sulphide levels and the labelling of hepatic cancer specimens in vivo. [ABSTRACT FROM AUTHOR]

Intercalation-based inorganic materials that change their colours upon ion insertion/extraction lay an important foundation for existing electrochromic technology. However, using only such inorganic electrochromic materials, it is very difficult to achieve the utmost goal of full-colour tunability for future electrochromic technology mainly due to the absence of structural flexibility. Herein, we demonstrate an ultracompact asymmetric Fabry-Perot (F-P) nanocavity-type electrochromic device formed by using partially reflective metal tungsten as the current collector and reflector layer simultaneously; this approach enables fairly close matching of the reflections at both interfaces of the WO3 thin layer in device form, inducing a strong interference. Such an interference-enhanced device that is optically manipulated at the nanoscale displays various structural colours before coloration and, further, can change to other colours including blue, red, and yellow by changing the optical indexes (n, k) of the tungsten oxide layer through ion insertion. Electrochromic devices are generally not capable of tuning more than one color. Here, the authors use Fabry-Perot nanocavities to create electrochromic devices with a wide color tuning range and vibrant color. [ABSTRACT FROM AUTHOR]

A fluorescent pentamer 5QnQnPV with one phenyl central donor group surrounded by four quinoline acceptor groups set in a quadrupolar A-π-A-π-D-π-A-π-A electronic structure was synthesized. This compound is an organic semiconductor and shows a wide band fluorescence emission that spans from the blue to the red region with a maximum peak centered at 509 nm. In addition, its HOMO (− 5.4 eV)/LUMO (− 3.5 eV) energy values, determined by cyclic voltammetry, optical gap EgOpt of 2.18 and theoretical DT-DFT studies indicated a potential for OLED fabrication. When such device was made with a ITO/PEDOT:PSS/5QnQnPV/Al configuration it displayed a maximum electroluminescent response at 860 nm. The structural and physical characterization of this compound was performed using 1H and 13C Nuclear Magnetic Resonance, Fourier Transformed Infrared Spectroscopy, Mass Spectroscopy and Atomic Force Microscopy. [ABSTRACT FROM AUTHOR]

The poly(3,4-ethylenedioxythiophene-co-3-phenylthiophene) (P(EDOT-co-3PT)) and poly(3,4-ethylenedioxythiophene-co-3-(4-fluorophenyl)thiophene) (P(EDOT-co-FPT)) were electropolymerized with the application of 1.62 V and 1.95 V, respectively. Unpublished spectroelectrochemical and electrochromic properties of the conjugated copolymers with monomer ratio of 1:1 were investigated. A potential range of − 1.0 to 2.0 V was found to be suitable for the device operation between blue to purple (P(EDOT-co-3PT)) and (P(EDOT-co-FPT)). The maximum transmittance difference (Δ% T) was determined to be 8.24 and 10.37%, and the time differences between oxidation and reduction were 2.14 and 2.94 s. The copolymers showed lower band gap energies than their original homopolymers (~ 1.4 eV). [ABSTRACT FROM AUTHOR]

Zn-Ti-O composite thin film prepared on FTO by sol-gel technique is discovered presenting electrochromic behavior in electrolytes with Li+ ion (LiClO4) and K+ (KCl) as well. The observed EC colored/bleached switching is electrolyte dependent which is blue-green/transparent in LiClO4 and gray-blue/transparent in KCl, respectively. Accordantly, the respective most optical modulation (ΔT) between colored and bleached states is ~ 32% (710 nm) in LiClO4 and ~ 37% (600 nm) in KCl. The finding of appreciable steady EC durability with appealing visual optical contrast (ΔT) in conventionally fabricated Zn-Ti-O thin film using with bigger/heavier K+ electrolyte helps expanding the applicable components in EC device. [ABSTRACT FROM AUTHOR]

Methods of preparation of single-crystal 4-N,N-dimethylamino-4′-N′-methyl stilbazolium tosylate (DAST) films with a thickness of several micrometers, designed for electro-optic modulation, have been analyzed. Thin-film single crystals have been obtained, the shape and absorption spectrum of which confirm their crystal structure of the "red" DAST crystal form. Homogeneous luminescence in the polarization-contrast regime indicates their single crystallinity and uniform orientation. These materials are designed for intracavity modulation of laser radiation. [ABSTRACT FROM AUTHOR]

The kinetics of coloration in thin hydrogenated vanadium pentoxide films under the internal electrochromic effect is studied alongside with the influence of their hydrogenation by means of plasma-immersion ion implantation on this process. The variant of uniform implantation and the nonuniform case when a film is partially subjected to ion treatment are considered. Based on the experiments on measuring the electrochromically colored surface area growth rate and the passing current, it has been revealed that the electrochromic effect becomes much stronger in the nonuniform variant, when the cathode is placed on the nonhydrogenated part of a film, and the anode is located on its hydrogenated part. [ABSTRACT FROM AUTHOR]