Fig. 1. (a), (c) Schematics of the ATRD and the ATMRD. (b) Working diagram of the ideal temperature-adaptive radiative cooling. (d) Surface pattern dimensions and cross-sectional diagram of designed ATMRD. (e), (f) Comparison of simulated solar absorptance and thermal emissivity between ATRD and ATMRD. The blue line represents low temperature, and the red line represents high temperature.

Fig. 2. (a), (b) Simulated solar absorptance spectra for ATMRD Lx‐Gy samples with x=1, 2, 4, 6, 8, and 10μm and y=0.5, 1, 2, and 3μm. Here, the dotted and solid lines represent the I and M states of VO2, respectively. The dark line represents the solar absorptance spectra of ATRD. The simulated solar absorptance as a function of feature size L along with gap size G at temperatures of (c) 25°C and (d) 90°C. Note that signed solid lines and dashed lines represent simulation results for square and circular patterns, respectively. The size of the symbol indicates the variation of the feature size.

Fig. 3. (a)–(g) Simulated emissivity spectra at different L and G for ATMRD with square array structure. (h) ε value and (i) Δε as a function of L at different G. Note that the dotted and solid lines in panels (a)–(g) represent the insulator and metal states of VO2, respectively. The solid lines and dashed lines in panel (i) represent the simulation results for square and circular patterns, respectively.

Fig. 4. (a) Photograph of ATMRD L4-G1, and the middle colored area is the micro–nanostructure. (b) Cross-sectional SEM image and EDS mappings of ATMRD. (c) SEM morphology of the ATMRD’s top view with different L and G.

Fig. 5. (a) XRD pattern of the ATMRD. (b) Raman spectrum at room temperature for VO2 films. (c) UV-VIS-NIR transmittance spectra at 20°C and 90°C of VO2 film deposited on a sapphire substrate for reference. (d) Temperature-dependent transmittance of the VO2 film at a wavelength of 2500 nm. The inset shows the corresponding d(T%)/dT−T curves in the heating cycle using Lorentz function fitting.

Fig. 6. Thermal emissivity spectra at different temperatures, emittance-dependent temperature during heating and cooling, and solar absorptance at low and high temperatures for (a), (e), (i) ATRD, (b), (f), (j) ATMRD L4-G1, (c), (g), (k) ATMRD L6-G1, and (d), (h), (l) ATMRD L8-G1, respectively.

Fig. 7. (a) Comparison of the thermal emittance. (b) Comparison of emittance tunability between ATMRD Lx-Gy and ATRD. (c) Comparison of solar absorptance between ATMRD Lx-Gy and ATRD at different temperatures. (d) Optimal performance of ATMRD L4-G1. (e) Comparison of the emittance performance with previous reports.^3–5" target="_self" style="display: inline;">^–5,20–24" target="_self" style="display: inline;">^{–24,38–48}" target="_self" style="display: inline;">^–48

Fig. 8. (a) Schematic of a simulated solar heating test and (c) IR thermal emittance test, and the θ represents different detection angles. (b) Temperature tracking of diverse samples under simulated solar heating. (d) Thermal IR imaging of vertical incidence under different temperatures for Al flake, commercial 3M tape, and different ATMRDs. (e) Thermal IR imaging of the ATMRD L4-G1 at different detection angles at 90°C.

Fig. 9. (a) Schematic diagram of simulated ATMRD using FDTD, the x–z plane at y=0μm. (b) Equivalent LC circuit model for MP excitation when VO2 is in the metallic phase. Electromagnetic field distribution of the x–z cross section of one array cell at different wavelengths in the VO2 metallic phase. (c) ATRD. (d)–(h) ATMRD L4-G1. (i) ATMRD L8-G1. (j), (k) ATMRD L10-G1. Note that the contour color indicates the magnetic field strength, expressed as |H|2, and the black arrows represent the electric field vectors. The white arrow indicates the current loop of the equivalent LC circuit.