We present a thin metasurface with large microwave absorptivity and low infrared emissivity simultaneously. By properly tuning the resonance peaks and impedance of the meta-atom, broadband microwave absorptivity greater than 90% from 8.2 to 16.0 GHz is achieved. In the meantime, owing to large coverage of periodic metal patches on the top surface, low infrared emissivity is exhibited in the infrared region (IR) of 8 µm–14 µm. The excellent agreement between numerical simulation and experimental result demonstrates the good performance of the proposed metasurface. Due to the usage of polymethacrylimide (PMI) and polyethylene terephthalate (PET) as the substrate, the metasurface is especially advantageous for the light weight, making it a favorite in real engineering applications.

Inorganic cesium lead halide perovskite nanowires (NWs) were synthesised by an in-plane selfassembly method. With the assistance of saturated solvent vapour, perovskite microparticles selfassembled into NWs. By stoichiometric adjustment of the halogen anion components in the NWs, their photoluminescence could be tuned to span the entire visible range. A detailed investigation of the lasing properties of the in-situ perovskite NWs and microplates revealed a lasing range of 420-560 nm, with typical thresholds of 18.8 μJ cm −2 for CsPbBr 3 NWs and 8.87 μJ cm −2 for CsPbBr x Cl 3−x microplates. The NWs exhibited robust stability under extended laser pumping in ambient atmosphere. IMPACT STATEMENT An in-plane self-assembly method was developed for high-quality CsPbX 3 nanowires preparation, and the NWs possessed robust lasing performance in the range of 420-560 nm.

much attention due to excitonic property in physics and devices. [18] Stability is the largest obstacle to hinder further development of HOIP materials and devices. [19][20][21] The soft-lattice nature of perovskite directly contributes to the excellent performances of the material by the large high-density defects toleration, [22] however, becomes a serious reason of degradation in turn. The degradation could be caused by internal factors, for example, lattice strain, [23] atomic vacancies, etc., [24] and also could be by external factors, such as light-illumination, [25,26] temperature, [27,28] humidity, [29,30] oxygen in ambient condition, etc. Considerable efforts are focusing on the internal factors of degradation from view of molecule design, for example, doping [23] and lattice-anchoring [31] to release internal strain, ligands engineering [24,32,33] for surface passivation, interfacial engineering to enhance moisture stability, [34] and even redox strategy [35] to recover materials. For external factors, an intuitive strategy is physically isolating perovskites from ambient environments, such as encapsulation with polymers, [36] silica, [37,38] or low penetrative 2D shields [39] such as graphene [40] and hexagonal boron nitride, etc. [41] Although the stability of 2D perovskite possesses some advantages in comparison with that of 3D counterpart due to the hydrophobic nature of organic ligands, there is an obvious yawning gap to commercial requirements. To date, the protocols were limited to improve the stability of 2D perovskites, such as deposition strategy to reduce crystal defects for optical stability, insulator selection for better hydrophobicity, [42] composite strategy with other monolayer materials, [40,41] supramolecular engineering, and so on. [43] It is known that carbon-fluorine is the strongest bond in organic chemistry. [44] The high polarity of carbon-fluorine directly affects the interfacial properties, chemical activity, dielectric constant, surface tension, and so on. One of the results is the hydrophobic interface, which can prevent the adsorption of water molecules on the surface. Additionally, they can passivate surfaces and serve as physiochemical barriers to reactive infiltrating species. In fact, some fluorinated organic compounds have been reported as surface passivation agent to improve the performances of perovskites. [45][46][47] However, researches about stabilizing optical properties by directly utilizing fluorinated organic-ligand as a 2D-HOIP insulating layer are rare. [48,49] In this work, in order to enhance the stabilities of 2D-HOIP, fluorinated cation (2-(4-fluorophenyl) ethylamine [F-PEA]) was chosen as the organic ligand to replace the phenyl ethylamine (PEA) in (PEA) 2 PbI 4 (PEPI), as the schematic diagram shown In this study, the interface of 2D hybrid organic-inorganic perovskites L 2 PbI 4 (here L stands for phenylethylamine, PEA) is engineered by fluorine substitution in its organic insulator layers, and the stability of the perovskite is investigated. For the ...

A black silicon structure with high-aspect-ratio surface spikes was designed and fabricated in vacuum, resulting in absorptance >90% over the range of 200–2500 nm. It is demonstrated that annealing, an essential step in the fabrication of semiconductor devices, has almost no effect on the infrared absorption of this material, while the infrared absorption of an identical structure fabricated in a SF6 drops dramatically after the annealing process. The characteristic of high infrared absorption and annealing-insensitivity is attributed to both the high-aspect-ratio structure and the phosphor-doped low impedance silicon. These results are important for the fabrication of highly efficient optoelectronic devices.

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