More-Chevalier Joris, Martan Jiří, Repän Taavi, Duprey Sylvain, Hruška Petr, Novotný Michal, Honnerová Petra, Kejzlar Jan, Labbé Christophe, Poupon Morgane, Prokop Dejan, Nikitin Daniil, Portier Xavier, Fitl Přemysl, Cardin Julien, Jaaniso Raivo, Lančok Ján
Institute of Physics, Czech Academy of Sciences, Na Slovance 2, 182 21 Prague 8, Czech Republic.
Department of Physics and Measurements, University of Chemistry and Technology Prague, Technická 5, 166 28 Prague 6, Czech Republic.
Langmuir. 2025 Feb 18;41(6):3832-3842. doi: 10.1021/acs.langmuir.4c03838. Epub 2025 Jan 1.
Black aluminum is a material characterized by high surface porosity due to columnar growth and exhibits unique optical properties that make it attractive for applications such as light trapping, infrared detection, and passive thermal radiation cooling. In this study, we correlate the structural and optical properties of black aluminum by comparing it with conventional reflective aluminum layers. These layers of varying thicknesses were deposited on fused silica substrates, and their optical properties were analyzed. COMSOL simulations, supported by experimental data, reveal that black aluminum's structure leads to a significant reduction in visible light reflectivity and an increase in emissivity in the near- and mid-infrared ranges. This enhanced emissivity is partly due to the presence of aluminum nitride (AlN) grain boundaries and an oxidized surface layer. Optically, black aluminum differs significantly from reflective aluminum by presenting a reflectivity below 5% in visible wavelength and an average emissivity of approximately 0.4-0.5 from 1.2 to 20 μm. Thermally, it possesses approximately ten times lower thermal conductivity and doubles the volumetric heat capacity. These differences are attributed to its porous structure, nanoscale crystallites, and the presence of aluminum nitrides and oxides within the material.
黑色铝是一种由于柱状生长而具有高表面孔隙率的材料，并且展现出独特的光学特性，这使其在诸如光捕获、红外探测和被动热辐射冷却等应用中具有吸引力。在本研究中，我们通过将黑色铝与传统反射铝层进行比较，来关联其结构和光学特性。将不同厚度的这些层沉积在熔融石英衬底上，并对其光学特性进行分析。由实验数据支持的COMSOL模拟表明，黑色铝的结构导致可见光反射率显著降低，并且在近红外和中红外范围内发射率增加。这种增强的发射率部分归因于氮化铝（AlN）晶界和氧化表面层的存在。在光学上，黑色铝与反射铝有显著差异，在可见光波长下反射率低于5%，在1.2至20μm范围内平均发射率约为0.4 - 0.5。在热学上，它的热导率大约低十倍，体积热容量增加一倍。这些差异归因于其多孔结构、纳米级微晶以及材料中存在的氮化铝和氧化物。
