In this study, we designed a novel ultra-wideband (UWB) absorber and numerically analyzed it to demonstrate that its light absorptivity was greater than 90% in the wavelength range of visible light and near-infrared (405-1505 nm). The structure of proposed novel UWB absorber consisted of four layers of films, including silica, titanium, magnesium fluoride, and aluminium, and the upper silica and titanium layers had rectangular cubes in them. For that, the excitations of propagating surface plasmon resonance (PSPR), local surface plasmon resonance (LSPR), and the resonance of Fabry-Perot (FP) cavity were generated at the same time and combined to reach the effect of perfect absorption and ultra-wideband. The proposed absorber had an average absorptivity of 95.14% in the wavelength range of 405 ∼ 1505 nm when the light was under normal incidence. In addition, the UWB absorber was large incident angle insensitive and polarization-independent. The absorber proposed in the paper had great prospects in the fields of thermal electronic equipment, solar power generation, and perfect cloaking.

The selective broadband absorption of solar radiation plays a crucial role in applying solar energy. However, despite being a decade‐old technology, the rapid and precise designs of selective absorbers spanning from the solar spectrum to the infrared region remain a significant challenge. This work develops a high‐performance design paradigm that combines deep learning and multi‐objective double annealing algorithms to optimize multilayer nanostructures for maximizing solar spectral absorption and minimum infrared radiation. Based on deep learning design, we experimentally fabricate the designed absorber and demonstrate its photothermal effect under sunlight. The absorber exhibits exceptional absorption in the solar spectrum (calculated/measured = 0.98/0.94) and low average emissivity in the infrared region (calculated/measured = 0.08/0.19). This absorber has the potential to result in annual energy savings of up to 1743 kW h/m ² in areas with abundant solar radiation resources. Our study opens a powerful design method to study solar‐thermal energy harvesting and manipulation, which will facilitate for their broad applications in other engineering applications.

Passive power generation has recently stimulated interest in thermoelectric generators (TEGs) using the radiative cooling mechanism. However, the limited and unstable temperature difference across the TEGs significantly degrades the output performance. In this study, an ultra-broadband solar absorber with a planar film structure is introduced as the hot side of the TEG to increase the temperature difference by utilizing solar heating. This device not only enhances the generation of electrical power but also realizes all-day uninterrupted electrical output due to the stable temperature difference between the cold and hot sides of the TEG. Outdoor experiments show the self-powered TEG obtains maximum temperature differences of 12.67 °C, 1.06 °C, and 5.08 °C during sunny daytime, clear nighttime, and cloudy daytime, respectively, and generates output voltages of 166.2 mV, 14.7 mV, and 95 mV, respectively. Simultaneously, the corresponding output powers of 879.25 mW/m², 3.85 mW/m², and 287.27 mW/m² are produced, achieving 24-hour uninterrupted passive power generation. These findings propose a novel strategy to combine solar heating and outer space cooling by a selective absorber/emitter to generate all-day continuous electricity for unsupervised small devices.

We theoretically proposed an ultra-broadband infrared light absorber and demonstrated that a high absorption could be obtained in the range of ultra-broadband infrared light using the iron thin layers. The simulation results showed that the proposed absorber could achieve a close-to-unity absorption rate across a wide infrared spectral range, and that the average absorption rate would reach 90.6% over the range of 1.4-11.4μm. The high absorption rate resulted from the excitation of strong localized surface plasmon resonance in the iron layers and the superposition of different resonance frequencies. Numerical analysis results demonstrated that our proposed absorber had a broader efficient absorption range than most previously reported broadband infrared light absorbers.

The absorption and reflection of electromagnetic waves by various particles in the earth’s atmosphere allow the passage of only certain electromagnetic wavelengths to reach the ground, called Earth’s atmosphere transparent window. In this study, perfect absorption was theoretically obtained in the range of near- and mid-infrared earth’s atmospheric transparency window using a simple absorber with metal-dielectric-metal structure. The numerical simulations showed the average absorption to reach 96.2% at wavelengths from 2000 to 6000 nm. Also, the broadband absorption was noticed and attributed to combined physical mechanisms, such as anti-reflection effect, localized surface plasmon polariton, propagating surface plasmon polarization, Fabry–Pérot cavity and slow light mode. Meanwhile, the proposed absorber displayed simple-structure, low-cost, wide-angle, and polarization-independent. In sum, the proposed absorber might be useful for future applications related to atmospheric transparency window, such as remote sensing, energy harvesting, infrared detection, and stray light elimination.

Here, we have theoretically proposed an ideal structure of selective solar absorber with multilayer planar films, which can absorb the incident light throughout the entire solar spectrum (300–2500 nm) and over a wide angular range, whatever the polarization angle of 0°~90°. The efficiency of the proposed absorber is proven by the Finite-Difference Time Domain (FDTD) simulation. The average absorption rate over the solar spectrum is up to 96.6%. The planar design is extremely easy to fabricate and modify, and this structure does not require lithographic processes to finish the absorbers. Improvements of the solar absorber on the basis of planar multilayer-film structures is attributed to multiple asymmetric highly lossy Fabry–Perot resonators. Because of having many virtues, such as using different refractory and non-noble metals, having angle and polarization independence, and having ideal absorption for entire solar spectrum, our proposed absorbers are promising candidates for practical industrial production of the solar-energy harvesting.