Abstract An optically selective stack based on molybdenum oxide nanometric layers (Mo/MoOx/Mo/MoO3/Al2O3) was designed using SCOUT reflectance simulations and fabricated using balanced magnetron sputtering for applications in solar thermal systems. The material properties were experimentally optimised by varying the process parameters namely: target power, gas flow rates, and deposition time. In the stack, the bottommost Mo metal layer is used to improve adhesion, reduce diffusion while acting as an infrared reflector, the MoOx layer of the tandem stack acts as the primary light absorbing layer, and the topmost MoO3 + Al2O3 layers act as anti-reflection layers. The individual layers of the optical stack exhibited an amorphous structure as confirmed using X-ray diffraction. The existence of lower oxidation states (+4, +5) of molybdenum in the MoOx layer was revealed by X-ray photoelectron spectroscopy. The stack achieved a high absorptance in the solar spectrum region (α = 0.969) and a low thermal emissivity in the infrared region (e = 0.15 at 82 °C) at optimal process parameters. The oxidation resistance and thermal stability were evaluated by annealing the samples in vacuum up to 500 °C.

中文翻译：

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具有 Al2O3 钝化层的纳米级 MoOx 多层中增强的光热转换

摘要 基于氧化钼纳米层 (Mo/MoOx/Mo/MoO3/Al2O3) 的光学选择性堆叠使用 SCOUT 反射率模拟设计，并使用平衡磁控溅射制造，用于太阳能热系统。通过改变工艺参数，即目标功率、气体流速和沉积时间，对材料特性进行了实验优化。在堆叠中，最底部的 Mo 金属层用于提高附着力，减少扩散，同时充当红外反射器，串联堆叠的 MoOx 层充当主要光吸收层，而最顶部的 MoO3 + Al2O3 层充当抗反射层。反射层。如使用 X 射线衍射所证实的，光学叠层的各个层表现出无定形结构。低氧化态的存在（+4，通过 X 射线光电子能谱揭示了 MoOx 层中 +5) 的钼。在最佳工艺参数下，该堆栈在太阳光谱区域 (α = 0.969) 中实现了高吸收率，在红外区域 (e = 0.15 在 82 °C) 中实现了低热发射率。通过在高达 500 °C 的真空中对样品进行退火来评估抗氧化性和热稳定性。