Converting solar energy by to other forms of energy has attracted a lot of interest from academy to industry. However, the overall utilization efficiency of solar energy is inferior due to the limited effective solar spectrum range. Here, in order to utilize the broadband solar spectrum more efficiently, a novel hybrid absorber structure was proposed, which consists of a four-layer planar nanofilm with dual functions of heat absorption and photocatalysis. The average absorption in the visible range is larger than 0.95, and in the near-infrared spectral region, the average absorption is still larger than 0.85. The overall absorption of the absorber is over 0.86, while the thermal emittance is lower than 0.04, which can lead to remarkable thermal utilization efficiency. Moreover, the full range of the solar irradiance can be utilized by incorporating the photocatalytic TiO₂ layer into the absorber, which is active in the ultraviolet spectral range. In addition to the broadband spectral usage, the virtues of inexpensiveness and environmental friendliness make it a facile alternative to be applied in solar energy transformation.

Metamaterial absorbers show great promise for applications in optical manipulation, photodetection, solar energy harvesting, and photocatalysis. In this work, we present a twisted stacked metamaterial design that serves as a plasmonic perfect absorber with polarization selectivity. Leveraging effective energy localization, the metamaterial realizes a near-unity absorbance of up to 99.6% for right circularly polarized incidence and 97.2% for left circularly polarized incidence. At a longer wavelength in the visible range, the chiral metamaterial becomes more sensitive to the polarization state of the incident wave, retaining an ultrahigh absorption of light (~ 94%) for only a given polarization state, that is, light in this polarization state is effectively shielded. A giant circular dichroism signal of up to 7° can be simultaneously observed. Electromagnetic field and charge distribution simulations further reveal that the ultrahigh performance of the design is attributed to the interplay between cavity coupling, magnetic resonances, and plasmonic coupling. Besides switchable and tunable chirality, the plasmonic metamaterial presents a near-perfect absorption band with tunable operational wavelengths. We envision that the high-performance chiral gold metamaterial proposed here can serve as a good candidate for light trapping, chirality sensing, polarized light detection, and polarization-enhanced photocatalysis.

Engineering of semiconductor nanomaterials is critical to enhance the photoelectrochemical (PEC) performance for water splitting. However, semiconductors often show the low light absorption, slow charge transfer, and easy recombination of carriers, thus leading to the low catalytic efficiency. In this work, we show facile synthesis of ZnO@TiO₂ core–shell nanorods (NRs) arrays modified with Au nanoparticles (NPs) as the photoelectrode for PEC water splitting. Impressively, the obtained ZnO@TiO₂(15 nm)/Au(8 nm) array shows the maximum photocurrent density of 3.14 mA/cm² at 1.2 V vs. reversible hydrogen electrode (RHE), 2.6 times and 1.7 times higher than those obtained from ZnO NRs and ZnO@TiO₂(15 nm) arrays. The electric-field simulation and transient absorption spectroscopy show that the Au-decorated core–shell nanostructures have an enhanced hot electron generation and prolonged decay time, indicating effective charge transfer and recombination inhibition of carriers. This work provides an efficient preparation strategy for photoelectrodes as well as great potential for the large-scale development of this technology.