Wang Wenhao, Wang Hanbin, Yu Peng, Sun Kai, Tong Xin, Lin Feng, Wu Cuo, You Yimin, Xie Wuze, Li Yunpeng, Yuan Chenzhi, Govorov Alexander O, Muskens Otto L, Xu Hongxing, Sun Song, Wang Zhiming
Opt Express. 2021 Oct 11;29(21):33456-33466. doi: 10.1364/OE.439546.
Strong absorption of the full spectrum of sunlight at high temperatures is desired for photothermal devices and thermophotovoltaics. Here, we experimentally demonstrate a thin-film broadband absorber consisting of a vanadium nitride (VN) film and a SiO anti-reflective layer. Owing to the intrinsic high loss of VN, the fabricated absorber exhibits high absorption over 90% in the wide range of 400-1360 nm. To further enhance the near-infrared absorption, we also propose a metamaterial absorber by depositing patterned VN square patches on the thin-film absorber. An average absorption of 90.4% over the range of 400-2500 nm is achieved due to the excitation of broad electric dipole resonance. Both thin-film and metamaterial absorbers are demonstrated to possess excellent incident angle tolerances (up to 60°) and superior thermal stability at 800 ℃. The proposed refractory VN absorbers may be potentially used for solar energy harvesting, thermal emission, and photodetection.
对于光热器件和热光伏而言，在高温下对太阳光全光谱的强吸收是十分必要的。在此，我们通过实验展示了一种由氮化钒（VN）薄膜和SiO抗反射层组成的薄膜宽带吸收器。由于VN固有的高损耗，所制备的吸收器在400 - 1360 nm的宽范围内呈现出超过90%的高吸收率。为了进一步增强近红外吸收，我们还提出了一种超材料吸收器，即在薄膜吸收器上沉积图案化的VN方形贴片。由于宽电偶极子共振的激发，在400 - 2500 nm范围内实现了90.4%的平均吸收率。薄膜吸收器和超材料吸收器均被证明具有出色的入射角耐受性（高达60°）以及在800℃时的卓越热稳定性。所提出的难熔VN吸收器可能潜在地用于太阳能收集、热发射和光电探测。
