Tantalum hafnium carbide (Ta4HfC5) powders were synthesized by solvothermal treatment and carbothermal reduction reactions from an inorganic hybrid. Tantalum pentachloride, hafnium chloride, and phenolic resin were used as the sources of tantalum, hafnium, and carbon, respectively. Pyrolysis of the complexes at 1000°C/1 h initiated the carbothermal reduction to result in multiplex phases including tantalum carbide and hafnium oxide which after heat treatment at 1400°C–1600°C transformed to single‐phase solid solution Ta4HfC5 by solid solution reaction. The mean crystallite size of Ta4HfC5 particles was less than 80 nm, and the composition of Ta, Hf, and C elements was near stoichiometric and homogeneously distributed in the powder samples. XRD pattern for Ta4HfC5 powders was analyzed.
The compatible stealth functionality in the infrared (IR) and radar wave bands is the most important research topic in the field of stealth material technology. Here, a new hybrid metasurface (HMS) for infrared-multiband radar stealth-compatible materials was proposed and studied. Two specifically designed metasurface layers that can control the infrared emission and microwave absorption were combined to realize radar and IR bi-stealth. The simulated and experimental results show that the HMS has five strong absorption peaks at f 1 = 6.35, f 2 = 8.38, f 3 = 12.10, f 4 = 15.37 and f 5 = 18.05 GHz. In addition, the emissivity of the proposed HMS is less than 0.32 from 3 to 14 µm and shows low emissivity characteristics in the infrared band. These results demonstrate that the proposal has practical application to multispectral stealth technology. INDEX TERMS Metasurfaces, infrared-radar stealth-compatible, low emission.
Power conversion efficiency (PCE)
is one of the important factors in influencing the overall performance
of dye-sensitized solar cells (DSSCs), and precise prediction of PCE
is a feasible strategy for preparing highly efficient DSSCs devices.
In this work, we designed a series of phenothiazine-based organic
dyes by introducing different π-spacers including the 4-isopropyl-4H-dithieno[3,2-b:2′,3′-d]pyrrole (DTP) and 2,7-dihydronaphtho[1,2-d:5,6-d′]diimidazole (NDI) to tune their photovoltaic
properties. The present studies reveal that the PCE value of the DTP-based
dye is estimated to be 8.55%, in excellent agreement with the experimentally
available value (8.19%) observed in the reported analogue. In comparison
to DTP, the strong electron-deficiency NDI group induces a remarkable
red-shifting of maximum absorption band, broadening the optical absorption
into the near-infrared region. As a consequence, the NDI-based dye
achieves an impressive PCE value of 15.51%, which is expected to be
a potential organic dye applied in DSSCs.
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