Broadband light absorbers are attractive for their applications in photodetection and photothermic conversion. Metal black absorbers are highly nanoscale porous deposits in the presence of inert gas and exhibit nanoscale structure. Silver nanoparticles have attracted intensive research interest because of their distinctive electrical and optical properties. Here, we fabricated a number of silver black films with nanoscale thicknesses under various gas ambient atmospheres (He and Ar). Our aim is to fabricate broadband absorbers with high absorption performance from the visible-to-mid-IR (MIR) spectral range and investigate their aging behaviors. The He-ambient silver black film exhibited average absorption coefficients of 3.17, 2.27, and 1.81 μm–1 in the visible, near-IR (NIR), and MIR ranges, respectively, with the highest value of 6.50 μm–1 at a wavelength of 357 nm. Those of the Ar-ambient film were 0.48, 0.51, and 0.443 μm–1 in visible, NIR, and MIR ranges, respectively. The absorption coefficients of the He-ambient film were much higher than those of the Ar-ambient film, which were very promising candidates as broadband absorbers. Moreover, metal black films suffered from aging phenomena because of their nanoscale porous structure. The long-term stability of the optical properties was worthy of attention for applications. Therefore, the room temperature aging behaviors of nanoscale-thick silver black films were investigated. Comparative analyses of the atomic content before/after aging demonstrated that the aging was attributed to crystallization, deliquescence, and oxidation. Comparative analyses of the absorption and photothermal response characteristics before/after aging were also performed. The results demonstrated that the nanoscale-thick silver black films possessed great absorption stability in the visible-to-MIR range and photothermal response stability, which can provide valuable reference for applications of broadband absorbers such as IR dynamic scene generation.

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The smart radiator device (SRD) with low solar absorption ( αs) and large infrared emittance modulation (Δ ɛ) is desirable to a spacecraft thermal control system. In this work, the SRD was fabricated through depositing the Ag/Al2O3/VO2 triple-layer film on the Si substrate by magnetron sputtering. The properties of the SRD devices were optimized by tuning the thickness of the VO2 layer, and a fantastic SRD device was acquired, which showed low αs, high Δ ɛ, and intense high-temperature infrared emittance ( ɛHT). For the device with a VO2 layer of 50 nm thickness, αs was as low as 29.7% and Δ ɛ reached 0.53 with ɛHT up to 0.87. The triple-layer film device shows great potential for applications in the spacecraft thermal control system.

VO2 is a promising candidate for smart energy-saving windows because of its unique thermochromism but suffers from a high transition temperature of 68 °C and poor thermochromic performance near room temperature. We fabricated a W-VO2/Cs0.32WO3 (CWO) composite flexible film, which shows a low transition temperature of 31.1 °C (W-VO2/CWO = 1:1) and much enhanced near-infrared shielding performance. The optimal W-VO2 + 0.5CWO reaches a desired near-infrared shielding efficiency of 76.34%. A model-house test under simulated solar irradiation further signifies the excellence of the W-VO2 + 0.5CWO composite flexible film under ambient conditions. The robust performance is attributed to the synergetic effects between W-VO2 and Cs0.32WO3, among which the former possesses a low MIT transition temperature and the latter possesses photo-thermal performance.