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Vanadium dioxide is a well-known phase-change material on account of its unique changes of optical property, which has seen a great increase in its implementation for the regulation of thermal radiance. However, the fabrication of VO2 needs strict conditions for its narrow sliver in the phase diagram. In this paper, in situ preparation of VO2 films by high-power impulse magnetron sputtering is proposed, in which ionized flux density is used to direct the crystal growth. Besides, the surface structure and thermochromic behaviors of the deposited films are studied in detail. Furthermore, simulations are carried out for the sake of optimizing the thickness of VO2 films with the largest emissivity modulation ability, and the experimental result reveals that their tuning range reaches up to 0.32. It is believed that our work will find wide applications not only in fundamental material science but also in thermal radiance regulation.

Alzheimer's disease (AD) is still an incurable neurodegenerative disease that causes dementia. AD changes the brain function that, over time, impairs memory and diminishes judgment and reasoning ability. Pathophysiology of AD is complex. Till now the cause of AD remains unknown, but risk factors include family history and genetic predisposition. The drugs previously approved for AD treatment do not modify the disease process and only provide symptomatic improvement. Over the past few decades, research has led to significant progress in the understanding of the disease, leading to several novel strategies that may modify the disease process. One of the major developments in this direction is the amyloid β (Aβ) aggregation. Small molecules could block the initial stages of Aβ aggregation, which could be the starting point for the design and development of new AD drugs in the near future. In this review we summarize the most promising small-molecule Aβ-aggregation inhibitors including natural compounds, novel small molecules, and also those are in clinical trials. Moreover, we briefly summarized some reported docking studies of small-molecule Aβ aggregation inhibitors. These will give us an idea about the chemical features required to design novel small molecules with anti-Aβ aggregation properties.

Metamaterial absorber/emitter is an important aspect of infrared radiation manipulation. In this paper, we proposed four simple switchable infrared metamaterial absorbers/emitters with Ag/VO 2 disks on the Ag plane employing triangle, square, hexagon, and circle unit cells. The spectral absorption peaks whose intensities are above 0.99 occur at ~4 μ m after structure optimization when VO 2 is in insulating state and disappear when VO 2 becomes metallic state. The simulated electromagnetic field reveals that the spectral absorption peaks are attributed to the excitation of magnetic polariton within the insulating VO 2 spacer layer, whose values exceed 1.59 orders of magnitude higher than the incident magnetic field. Longer resonant wavelength would be excited in square arrays because its configuration is a better carrier of charges at the same spans. For absorption stability, the absorbers/emitters with square and circular structures do not have any change with the polarization angles changing from 0° to 90°, due to the high rotational symmetric structure. And four absorbers/emitters reveal similar shifts and attenuations under different incident angles. We believed that the switchable absorber/emitter demonstrates promising applications in the sensing technology and adaptive infrared system.

The widespread use of the flexible infrared electrochromic device (IR-ED) fundamentally depends on not only the IR emissivity modulation ability of the functional layer but the component assembling structures. However, building integrated assembling structure for excellent flexibility and service life is an urgent but a challenging task due to exfoliation of the components of the traditional sandwich structure IR-ED during the use of bending and folding. Herein, we employed both sides of gold-plated nylon porous membrane as ion transport layer and electrode layer to construct highly-flexible monolithic integrated IR-ED. The dodecyl benzene sulfonate acid (DBSA)-doped PANI films were electrodeposited on the both side of gold-plated nylon porous membrane. Then the electrolyte was filled into the nylon porous membrane to successfully construct the highly-flexible monolithic integrated IR-ED. Compared with the traditional sandwich structure IR-ED, the unique configuration endows excellent IR electrochromic performance, ultra-high flexibility and structural stability. The monolithic integrated IR-ED can reversibly convert between colored state (dark green) and bleached state (golden yellow) upon the imposed external voltages, and the IR emission modulation of 0.43 and 0.40 is obtained at the wavelength ranges of 8–14 µm and 2.5–25 µm. The illustrated capabilities make the highly-flexible monolithic integrated IR EC device promising for thermoregulation related technologies and adaptive camouflage platforms.

Thermal radiation in the mid-infrared region profoundly affects human lives in various fields, including thermal management, imaging, sensing, camouflage, and thermography. Due to their fixed emissivities, radiance features of conventional materials are usually proportional to the quadruplicate of surface temperature, which set the limit, that one type of material can only present a single thermal function. Therefore, it is necessary and urgent to design materials for dynamic thermal radiation regulations to fulfill the demands of the age of intelligent machines. Recently, the ability of some smart materials to dynamically regulate thermal radiation has been evaluated. These materials are found to be competent enough for various commands, thereby, providing better alternatives and tremendously promoting the commercial potentials. In this review, the dynamic regulatory mechanisms and recent progress in the evaluation of these smart materials are summarized, including thermochromic materials, electrochromic materials, mechanically and humidity responsive materials, with the potential applications, insufficient problems, and possible strategies highlighted.

Si is one of the most important infrared optical materials. However, the high refraction index of Si in the infrared regions leads to large reflection losses, so increasing the infrared transmittance is of great significance to practical application. HfO2 film is widely investigated due to the high-k gate dielectric properties. And it also has excellent optical properties to be used as anti-reflection film for Si. In this study, doubled-sided HfO2 films (HfO2/Si/HfO2) were fabricated as anti-reflection coating on Si substrate to further enhance the infrared transmittance (99%). And the transmittance peak can be regulated by adjusting the thickness of HfO2 film. Besides, the deposition temperature had been optimized by using XRD, XPS, SEM, AFM, and optical measurements. The results indicate good crystallinity and flat surface for the samples. Furthermore, HfO2 films show surface hydrophobic properties, which can prevent water in the infrared application. These encouraging results show the HfO2 films have excellent application prospective for the infrared optical systems.

In this paper, the VO2 thermochromic film was in-situ prepared by High Power Impulse Magnetron Sputtering (HiPIMS). The discharge property of HiPIMS is regulated via the average power to optimize the optical performance of VO2 film. And the thermochromic ability characterized by △T2500 can exceed 55%. Besides, the phase transition temperature (e.g., ~42 °C) is much lower than 68 °C and with a narrow width of hysteresis loops (e.g., ~4 °C). Furthermore, the infrared radiation performance is studied by sputtering VO2 film on a polished Al foil. The emittance difference (△e) of the VO2 film achieves 0.12 at mid-infrared regions as temperature increases, which can be distinctly distinguished from the circumstance in the thermal images. The investigation comprehensively characterizes the VO2 film prepared by a rarely used method and demonstrates its possibility for infrared signaling and detection in industrial and military applications.