Fig. 1. Absorption mechanism of 3D self-assembly plasmonic photothermal metamaterials. (a) Absorption cross section of a single gold nanoparticle as a function of aspect ratio (short axis is 10 nm, long axis is 10, 20, 50 nm from top to bottom)^[52]; (b) schematic diagram of plasmon hybridization of multiple metal nanospheres^[53]; (c) normalized cross section of extinction of multiple alumina-coated gold nanospheres^[21]; (d) schematic diagram of preparation of plasmon tunable absorber^[52]; (e) schematic diagram of ideal plasmon absorber^[20]; (f)(g) experimental absorption curves of double-pass AAO template, gold-plated AAO template with pore diameter of 300 nm (Au/AAO) and gold-plated AAO template with pore diameter of 365 nm (Au/D-AAO)^[20]; (h)(i) simulation curves of Au/AAO absorptivity^[20]

Fig. 2. Blackbody radiation curves and different types of broad wavelength band spectra. (a) Blackbody radiation curves at temperatures of 5778 K (solid black line) and 298 K (dashed red line) and the corresponding solar spectrum and atmospheric radiation transmittance; (b) ideal spectrum for solar evaporation; (c) ideal spectra for radiative cooling without heat source (solid black line) and with heat source (dashed blue line); (d) ideal spectrum for spectral camouflage with heat dissipation function

Fig. 3. Schematic diagrams of solar interfacial water evaporation, absorption mechanism and broadband absorption curve. (a) Schematic diagram of Au/NPT for interfacial water evaporation^[22]; (b) schematic diagram of solar interfacial water evaporation^[20]; (c) cross-sectional diagrams of electric field distribution at different wavelengths (λ=500, 813, 1083, 2300 nm)^[20]; (d) schematic diagram of plasma-enhanced solar desalination process^[21]; (e) schematic diagram of i-Au/NPT for interfacial water evaporation^[22]; (f)(g) absorption/emission curves of Au/NPT and i-Au/NPT at 400‒2500 nm and 2.5‒18.0 μm, respectively, with the background showing the spectral distribution of the sun (orange) and blackbody radiation (purple) ^[22]

Fig. 4. Different types of self-assembly radiative cooling designs. (a) Radiative cooling film composed of silver film and SiO₂, in which the SiO₂ matrix contains SiO₂@Ag core-shell nanoparticles and Ag nanoparticles^[82]; (b) schematic diagram of a colored radiative cooling coating composed of PMMA resin as a matrix, submicron-sized Y₂O₃ particles as a solar light scatterer, and TiO₂@Ag core-shell nanoparticles as a colorant^[83]; (c) preparation process of TC-PDRC, including the preparation of gold nanoparticles by reducing HAuCl₄ with NaBH₄, the preparation of Au@SiO₂ core-shell nanoparticles, and the mixed cooling film formation^[84]; (d) three deep learning models, namely the RI model (red area), the VR model (blue area), and the PS model (green area), are used to inverse design StRC and SoRC^[85]

Fig. 5. Self-assembly system for realizing surface-enhanced Raman scattering. (a) Schematic diagram of APS integrating dual functions: plasma heating and spectral amplification^[25]; (b) peak intensity of Raman signal at 1150 cm^-1[90]; (c) schematic diagram of the AAO/MoS₂/Ag for detection of water pollutants^[91]

Fig. 6. Photocatalysis of different systems using photothermal metamaterials. (a) Schematic and energy of thermoelectric generation and its transfer to the molecule on the multimeric AuNP@AAO^[104]; (b) diffuse reflectance spectra of Co@dpAAO and Co/Al₂O₃, with the inset being the corresponding optical photographs^[105]; (c) relationship between the rate of O₂ generation and incident photon flux for different pore sizes of Au@AAO irradiated by a 523 nm light emitting diode^[107]

Fig. 7. Spectral camouflage achieved with photothermal metamaterials. (a) Optical photographs of tin-plated AAO templates at different reaming times^[110]; (b) spectral absorptivity/emissivity of c-UPA, radiation profiles of AM 1.5G and 1500 K blackbody^[111]; (c) schematic diagram of the camouflage structures in visible and infrared bands^[112]; (d) demonstration of camouflage in visible and infrared bands^[112]