Lithium-Ion-Assisted Ultrafast Charging Double-Electrode Smart Windows with Energy Storage and Display Applications

Optical Phenomena in Molecule-Based Magnetic Materials

Since the last century, we have witnessed the development of molecular magnetism which deals with magnetic materials based on molecular species, i.e., organic radicals and metal complexes. Among them, the broadest attention was devoted to molecule-based ferro-/ferrimagnets, spin transition materials, including those exploring electron transfer, molecular nanomagnets, such as single-molecule magnets (SMMs), molecular qubits, and stimuli-responsive magnetic materials. Their physical properties open the application horizons in sensors, data storage, spintronics, and quantum computation. It was found that various optical phenomena, such as thermochromism, photoswitching of magnetic and optical characteristics, luminescence, nonlinear optical and chiroptical effects, as well as optical responsivity to external stimuli, can be implemented into molecule-based magnetic materials. Moreover, the fruitful interactions of these optical effects with magnetism in molecule-based materials can provide new physical cross-effects and multifunctionality, enriching the applications in optical, electronic, and magnetic devices. This Review aims to show the scope of optical phenomena generated in molecule-based magnetic materials, including the recent advances in such areas as high-temperature photomagnetism, optical thermometry utilizing SMMs, optical addressability of molecular qubits, magneto-chiral dichroism, and opto-magneto-electric multifunctionality. These findings are discussed in the context of the types of optical phenomena accessible for various classes of molecule-based magnetic materials.

On-demand engineerable visible spectrum by fine control of electrochemical reactions

Tunability of optical performance is one of the key technologies for adaptive optoelectronic applications, such as camouflage clothing, displays, and infrared shielding. High-precision spectral tunability is of great importance for some special applications with on-demand adaptability but remains challenging. Here we demonstrate a galvanostatic control strategy to achieve this goal, relying on the finding of the quantitative correlation between optical properties and electrochemical reactions within materials. An electrochromic electro-optical efficiency index is established to optically fingerprint and precisely identify electrochemical redox reactions in the electrochromic device. Consequently, the charge-transfer process during galvanostatic electrochemical reaction can be quantitatively regulated, permitting precise control over the final optical performance and on-demand adaptability of electrochromic devices as evidenced by an ultralow deviation of <3.0%. These findings not only provide opportunities for future adaptive optoelectronic applications with strict demand on precise spectral tunability but also will promote in situ quantitative research in a wide range of spectroelectrochemistry, electrochemical energy storage, electrocatalysis, and material chemistry.

In-situ synthesized V2CTx MXene-based immune tag for the electrochemical detection of Interleukin 6 (IL-6) from breast cancer cells

Interleukin-6 (IL-6) is a proinflammatory cytokine with a critical role in immune regulation and treatment of many diseases, including breast cancer. Herein, we developed a novel V2CTx MXene-based immunosensor for rapid and accurate IL-6 detection. The chosen substrate was V2CTx, a 2-dimensional (2D) MXene nanomaterial with excellent electronic properties. Prussian blue (Fe4[Fe(CN)6]3), used for its electrochemical properties, and spindle-shaped gold nanoparticles (Au SSNPs), used to combine with antibodies, were in-situ synthesized on the surface of the MXene. The in-situ synthesis ensures a firm chemical connection compared to other tags formed by a less stable physical absorption. Inspired by a sandwich ELISA test, the modified V2CTx tag was captured by the electrode surface with cysteamine to detect the analyte, IL-6, after being attached with a capture antibody (cAb). Benefiting from an increased surface area, an enhanced charge transfer rate, and a firm connection of the tag, this biosensor exhibited excellent analytical performance. The high sensitivity, high selectivity, and wide detection range covering the IL-6 level of both healthy individuals and breast cancer patients were obtained to meet clinical demands. Herein, this V2CTx MXene-based immunosensor is a potential therapeutic and diagnostic point-of-care alternative to routine ELISA IL-6 detection methods.

Temperature-Dependent Electrochromic Devices for Energy-Saving Dual-Mode Displays

Electrochromic (EC) devices show promising prospects with the increasing demand for energy-efficient and sustainable technologies. Multifunctionality integration is an inevitable characteristic for EC devices to adapt to changing environments. Herein, a dual-mode temperature-dependent EC device is demonstrated for the first time. Combined with the transparent PVA/EG-ZnCl₂ organohydrogel electrolyte, the devices exhibit good EC performances over a wide temperature range (-40 to 40 °C). The evolutions of ion/electron transport kinetics-related indicators with temperature are further explored and simulated to reveal the mechanism of the temperature dependence of EC devices. Significantly, the optimized tungsten oxide-based EC device shows high performances at the extremely low temperature of -40 °C with a large transmittance modulation (80.8% @660 nm) and outstanding optical memory effects (97.3% retention of the initial transmittance modulation after 32 h) without electrical energy consumption. Furthermore, with a perovskite quantum dot photoluminescence film serving as the backlight, the device can switch display modes between emissive and reflective to realize its functionality in bright or dark conditions. This work provides a broad application prospect for EC devices in diverse environments of light (bright/dark) and temperature (hot/cold).

Self-Driven Electrochromic Window System Cu/WOx-Al3+/GR with Dynamic Optical Modulation and Static Graph Display Functions

Electrochromic devices with unique advantages of electrical/optical bistability are highly desired for energy-saving and information storage applications. Here, we put forward a self-driven Al-ion electrochromic system, which utilizes WO_x films, Cu foil, and graphite rod as electrochromic optical modulation and graph display electrodes, coloration potential supplying electrodes, and bleaching potential supplying electrodes, respectively. The inactive Cu electrode can not only realize the effective Al³⁺ cation intercalation into electrochromic WO_x electrodes but also eliminate the problem of metal anode consumption. The electrochromic WO_x electrodes cycled in Al³⁺ aqueous media exhibit a wide potential window (∼1.5 V), high coloration efficiency (36.0 cm²/C), and super-long-term cycle stability (>2000 cycles). The dynamic optical modulation and static graph display function can be achieved independently only by switching the electrode connection mode, thus bringing more features to this electrochromic system. For a large-area electrochromic system (10 × 10 cm²), the absolute transmittance value in its color-neutral state can reach about 41% (27%) at 633 nm (780 nm) by connecting the Cu and WO_x electrodes for 140 s. The original transparent state can be readily recovered by replacing the Cu foil with the graphite rod. This work throws light on next-generation electrochromic applications for optical/thermal modulation, privacy protection, and information display.