The demand for green and sustainable energy-saving technologies has extensively promoted the development of refrigeration technology. Radiative cooling is emerging as a cutting-edge technology, attracting widespread attention for its unique working principle.1^–7 Compared with other refrigeration technologies,8^–11 radiative cooling can efficiently reduce the object’s temperature without external power sources or refrigerants, eliminating the limitations of traditional refrigeration methods and achieving more flexible and efficient energy utilization.

Passive radiative cooling relies on the emission of heat from terrestrial objects to the 3K outer space through the thermal infrared transparency window (∼8 to 14μm), commonly referred to as the “atmospheric window.” To effectively dissipate heat, materials for passive radiative cooling are typically designed with minimal solar absorptance (αsol) in the wavelength range of 0.3 to 2.5μm and maximal thermal emittance (ε) within the atmospheric window. Such a property has been realized in various materials such as herbs,1^,12 paints,13^–15 fabrics,16^–18 and ceramics.7^,19 However, the emissivity of these schemes remains static and is usually designed for daytime radiative cooling, which will cause unnecessary overcooling due to continuous heat dissipation when the object’s temperature is lower than desired. Very recently, emittance-adaptive devices have been developed to achieve dynamic thermal regulation. A promising solution is employing thermochromic phase-change materials to switch automatically between radiative cooling and heat-retaining modes, effectively addressing the well-known overcooling problem of daytime passive radiative cooling.3^,5^,20^,21 Typically, a vanadium dioxide (VO2) radiative cooling system in the form of a Fabry–Perot (F–P) resonant cavity achieves self-switching in thermal radiation, providing a promising design for dynamic radiative cooling.22^,23 However, the inherent contradiction between desired high emissivity and low solar absorptance remains a notable limitation in such radiative devices. The emittance and solar absorptance are sensitively dependent on the structure of the devices and the thickness of VO2.24 Usually, achieving a high emittance comes at the expense of solar absorptance and vice versa, leading to limited upgradability. Recently, it has been demonstrated that patterned micro–nano-structures with subwavelength dimensions for the VO2 surface induce plasmonic resonances, effectively boosting the absorption of electromagnetic waves.25^–28 Some preliminary designs have also proposed to overcome the mutual constraints of VO2-based F–P resonator radiative devices.29^–32 Although this solution is highly desirable, existing efforts are either purely theoretical simulations or are limited by fabrication technology due to too small or complex micro–nano-structures requiring high-precision etching technology. In addition, the relationship between the size of micro–nano-structure and performance (e.g., αsol and ε) has not yet been comprehensively evaluated and verified by experiment.

In this work, we designed and prepared a temperature-adaptive metasurface radiative cooling device (ATMRD). The ATMRD is a simple sandwich structure consisting of silver (Ag), hafnium oxide (HfO2), and patterned VO2. Through optical simulation and experimental verification, the size range of the optimal VO2 micro-structure that achieves synergy between solar absorptance and emittance was clarified. Based on the results of simulation optimization, the ATMRD with the best VO2 microstructure was fabricated using sample mask-filling engineering. The prepared ATMRD exhibited excellent radiative cooling and solar reflectivity performance, automatically switching the atmospheric window ε from 0.13 to 0.85 when the surface temperature exceeds a pre-set transition temperature; meanwhile, achieving a satisfactory αsol of 27.71% at 20°C (or 35.44% at 90°C). The potential applications were further evaluated using simulated solar heating tests and infrared (IR) thermography. This scheme represents a significant advancement in balancing conflicting requirements to enhance radiative cooling performance. Simultaneously, the adoption of a simple and cost-effective micro–nano-preparation technology offers a practical solution for the fabrication of micro-nanostructures.

Figure 1(a) illustrates a typical temperature-adaptive radiative device (ATRD) based on the F–P resonator. A highly reflective metal layer is placed at the bottom, followed by a middle layer of highly IR transparent material and a continuous VO2 film covers the top. In the insulating (I) state of VO2 at T<TMIT (metal–insulator transition temperature), VO2 allows high transmission of IR light, and incident IR light is reflected by the bottom metal layer, achieving a low IR absorption. The heat inside the object cannot radiate away, preventing the overcooling phenomenon. By contrast, the ATRD becomes highly absorptant to IR light when VO2 switches to the metal (M) state at T>TMIT. The absorption is further amplified in the atmospheric window through a design of a 1/4 wavelength cavity.3 According to Kirchhoff’s law, the IR absorptance (A) equals emittance (ε) for IR opaque materials.33 Hence, the emittance achieves a temperature-adaptive switch in the atmospheric window from low to high (or high to low) depending on the I–M phase transition of VO2, as illustrated in Fig. 1(b).

Here, the reflective layer uses an Ag metal with the highest reflection compared with other common metals [Figs. S1(a) and S1(b) in the Supplementary Material], which will contribute to achieving a high solar reflection [Fig. S1(c) in the Supplementary Material]. HfO2 is selected as the dielectric layer due to its high IR transparency at a broad bandwidth.34 The simulated optimal emittance tunability (Δε=0.66) can be achieved in ATRD by optimizing the thickness of the HfO2 and VO2 layer (Fig. S2 in the Supplementary Material), whereas the αsol is 33.48% at low temperature [the dotted horizontal line in Fig. 2(h)] and 43.51% at high temperature [the dotted horizontal line in Fig. 2(i)]. High solar absorptance, especially at high temperatures, will cause the object’s temperature to increase and weaken the radiation heat dissipation ability to a certain extent during daytime.

Aiming at the goal of achieving low αsol and high ε, we employ a periodic array pattern to replace the continuous VO2 film, as depicted in Figs. 1(c) and 1(d), namely, constructing an ATMRD. The incorporation of VO2 metasurface can obviously reduce αsol and enhance ε through rational structural design to tune the resonant frequency to the atmospheric window, as shown in Figs. 1(e) and 1(f). The resonant frequency of the metasurface strongly depends on the structure parameters of the top metallic patterns,35 including geometric shape, arrangement period (P), feature size (L), and gap (G) with the relation P=L+G, as shown in Fig. 1(c). We create simple squares and circular patterns to consider the effects of L and G on αsol and ε. For convenience, the samples with different L and G for squares and circular patterns are labeled as Lx-Gy and Dx-Gy, respectively, where x represents the variation of L or D from 1 to 10μm, and y represents the G ranging from 0.5 to 3μm. The simulated solar absorptance results for ATMRD with a square array structure are presented in Figs. 2(a) and 2(b) and Fig. S3 in the Supplementary Material. The amplitude of the solar absorptance curve for all samples gradually weakens as G increases at a fixed L or L decreases at fixed G. The same trend is found in ATMRD with a circular array structure shown in Fig. S4 in the Supplementary Material, indicating that αsol significantly depends on the coverage area of VO2 in ATMRD. The integration results in Figs. 2(c) and 2(d) using Eq. (1) (see Sec. 4.2) suggest a proportional relationship between αsol and the coverage area of VO2: the larger the VO2 coverage area, the stronger αsol.

Figures 3(a)–3(g) show the simulated emissivity spectra of ATMRD with the square patterns of different L and G in the frequency range from 2.5 to 20μm. Compared with the emissivity spectra of ATRD, additional peaks are induced by the periodic VO2 patterns besides the 1/4nλ resonant absorption peak. Variations in feature size L and gap G significantly impact the intensity and position of the emittance peak as VO2 is in the metallic phase. When L is fixed, both the emissivity intensity and bandwidth increase as G becomes narrower. As L increases at fixed G, the intensity of the enhanced emissivity peak gradually decreases, whereas the long wave absorption edge shifts toward a longer wavelength, as shown in Fig. 3(g). A comparison is carried out for different L or G in the same period P (P=L+G), as shown in Fig. S5 in the Supplementary Material. It is found that the emissivity intensity and bandwidth obviously increase as L increases, or G decreases at fixed P when VO2 is in the metallic phase. The thermal emittances (ε) at different L and G are calculated with Eq. (2) (presented in Sec. 4.2) by referencing the blackbody radiation spectra and exhibited in Fig. 3(h). At low temperatures, the thermal emittance (εL) of ATMRD is lower than that of ATRD, which is more beneficial in preventing the overcooling of objects at low temperatures. As the feature size L increases in ATMRD, the εL slightly increases due to the increased area of VO2. In comparison, the emittance at high temperature (εH) is significantly enhanced. The εH of ATMRD increases rapidly with increasing L as L≤4 and reaches the maximum value at L=4 for the G0.5 and G1 ATMRDs, followed by a slight decline with a further increase in L. As L≥4, the εH of G1 and G0.5 surpasses that of ATRD. However, the εH of ATMRD with a larger gap (G>1) is lower than that of ATRD. The emittance tunability (Δε) of ATMRD outperforms ATRD over a broader pattern range when L>2 and G≤1, with the peak value located at L=4, as shown in Fig. 3(i). The results of ATMRD with a circular array structure (Fig. S6 in the Supplementary Material) also revealed consistent regularity, with slightly lower Δε than square patterns [Fig. 3(i)] because the rounded corners of circular patterns increase the gap G. The above results indicate that the appropriate values of feature size and gap (or period) are crucial to achieving emittance enhancement.

Based on the above simulated results, we selected three representative feature sizes (L=4, 6, and 8μm) and three gap values (G=1, 2, and 3μm) to fabricate ATMRD using a simple mask-filling engineering. The experimental section describes the fabrication process in detail. Figure 4(a) exhibits a photograph of the ATMRD. It presents a rainbow spectrum under visible light due to the structural color induced by the micro–nanostructure.36 The cross-sectional scanning electron microscopy (SEM) image and energy dispersive spectroscopy (EDS) mapping of the ATMRD in Fig. 4(b) exhibit good adhesion among different layers, providing a fundamental guarantee for the device’s performance. The thickness of the Ag, HfO2, and VO2 layers is 100, 800, and 50 nm, respectively. Figure 4(c) shows the SEM morphology of the ATMRD’s top view. All samples present well-designed geometries over the range of feature sizes L from 4 to 8μm and G from 1 to 3μm, attributed to advanced photolithography and magnetron sputtering deposition technology. This method can significantly reduce manufacturing costs and achieve scale preparation compared with electron beam lithography.

Figures 5(a) and 5(b) show the X-ray diffractometer (XRD) and Raman results of ATMRD films for phase identification. The XRD pattern in Fig. 5(a) primarily exhibits the crystalline structure of HfO2, along with diffraction peaks of Ag. No other impurities are observed. The Raman results in Fig. 5(b) confirm the existence of the M1-phase VO2 film.37 In addition, the VO2 film reveals an excellent IR switch from high transmittance and high reflectance at TMIT=68°C, as shown in Figs. 5(c) and 5(d).

The emissivity spectra of ATMRD are detected under different temperatures, as depicted in Figs. 6(a)–6(d). The emissivity of the devices changes significantly from low to high values with the increase in temperature. The ATRD exhibits strong absorption for wavelengths larger than 4μm, with an emissivity peak at ∼8μm when heated to 90°C [Fig. 6(a)], corresponding to the blackbody radiation peak. For ATMRD at 90°C, the peak intensity of L4-G1 and L6-G1 devices is significantly enhanced and almost reaches 100% [Figs. 6(b) and 6(c)], whereas L8-G1 shows a slight decrease in peak intensity [Fig. 6(d)]. The increasing L causes the peak to shift toward longer wavelengths, as indicated in Figs. 6(b)–6(d) and Fig. 7(a). The temperature-dependent thermal emittances are obtained from Figs. 6(a)–6(d) using Eq. (2), intuitively evaluating the Δε, as shown in Figs. 6(e)–6(h). A rapid switch from εL to εH is observed when the temperature exceeds TMIT. The εH values for L4-G1, L6-G1, and L8-G1 are 0.85, 0.89, and 0.84, respectively, representing a more than 13% improvement over ATRD’s value of 0.75. As the temperature gradually declines, the εH can maintain over a broad temperature range and then switch to εL at ∼50°C due to a typical hysteresis effect of VO2 phase transition, contributing to more effective heat dissipation at high temperatures. However, the thermal emissivity gradually decreases as G broadens from 1 to 3μm at a fixed L, as shown in Fig. S7 in the Supplementary Material. Only Lx-G1 achieves significantly improved emittance compared with ATRD, as indicated in Fig. 7(b), which is consistent with the simulated results. The Δε of ATMRD-L4-G1 (Δε=0.72) is enhanced by 20% compared with the ATRD (Δε=0.6).

Figures 6(i)–6(m) and Fig. S8 in the Supplementary Material present the measured solar absorptance spectra at low and high temperatures. The relationship of solar absorptance, feature size, and gap size at 20°C and 90°C is illustrated in Fig. 7(c), respectively. Solar absorptance at low temperatures shows a noticeable decline in ATMRD compared with ATRD (35.25%). When ATMRD switches to the εH state, solar absorptance rises slightly but remains significantly lower than ATRD’s (46.55%). Solar absorptance of the L4-G1 is 27.71% at low temperatures and rises to 35.44% at high temperatures. ATMRDs with more significant gaps achieve smaller solar absorptance but lower emissivity. Hence, the ATMRD L4-G1 achieves optimal performance with αsol=27.71% at 20°C (αsol=35.44% at 90°C) and εH=0.85 (Δε=0.72), as shown in Fig. 7(d). Figure 7(e) compares the emittance performance of dynamic radiation cooling devices reported in recent years. The performance of the radiative cooling device designed in this work is better than most literature results, affirming the viability of the design scheme and preparation method presented in this study.

We carried out verification experiments to evaluate the practical application potential of ATMRD devices. A solar simulator was employed to conduct a preliminary test of the sunlight reflection capability; the schematic diagram is shown in Fig. 8(a). The 3M tape (ε=0.96), silicon (Si) wafer (ε=0.5), and aluminum (Al) sheet (ε=0.1) are selected as reference samples. The results in Fig. 8(b) show that the temperature of ATRD quickly rises and then gradually levels off to 37°C within 120 s, but the temperature is much lower than that of the 3M tape (53°C) and Si wafer (44°C). The ATMRD presents a lower temperature than the ATRD, and the temperature further declines toward that of the Al sheet with decreasing L. The temperature of ATMRD L4-G1 is only 33°C, slightly higher than that of the Al sheet (28°C). Such a low solar absorptance significantly reduces solar radiation interference to the cooling device.

The emittance switching of ATMRD, along with two reference samples, was examined by IR imaging with a thermal IR camera, as shown in Fig. 8(c). One reference sample is an Al sheet, which features a consistently low thermal emittance of 0.10, and the other is the commercial 3M tape, possessing a steady high thermal emittance of 0.96, pasted over the Al2O3 substrate used in ATMRD. Compared with the two references, the ATMRD shows a significant thermal radiation change over the VO2 phase transition [Fig. 8(d)]. Before the phase transition, the thermal radiation of ATMRD is consistent with that of the Al sheet and then switches to a high emittance state after the phase transition. Moreover, the emittance exhibits weak dependence on the detection angle, as displayed in Fig. 8(e). The result demonstrates that the ATMRD has excellent solar reflectance and considerable heat dissipation.

To elucidate the underlying mechanism responsible for the metasurface-enhanced absorption based on the F–P resonant cavity, electromagnetic field distributions in the x–z cross section of one array cell [Fig. 9(a)] were investigated for ATMRDs with different feature size L with VO2 in the metal phase. Coupled with the F–P resonances in ATRD [Fig. 9(c)], the multimode polariton resonances are excited in ATMRD, as shown in Figs. 9(d)–9(k) and Figs. S9–S11 in the Supplementary Material, producing the corresponding sharp peaks in the emissivity spectra in Fig. 3. The results show that the polariton resonance strongly depends on the structural parameters of feature size and gap size or period of the metasurface.

The surface plasmon polariton (SPP) resonance emerges on the surface of the VO2 units when the feature size L (or period P) matches the wavelength of the incident wave. For ATMRD L4-G1, the SPP resonance occurs at ∼5μm due to the strong electric polarization above the VO2 units in Fig. 9(d). For L6-G1, L8-G1, and L10-G1, the SPP resonance appears at 7, 9, and 11μm, respectively, as shown in Figs. S10C and S11E in the Supplementary Material and Fig. 9(k).

As the incident wavelength λ>P, the electric polarization in the HfO2 medium between the metallic VO2 and the Ag substrate gradually increases, as characterized by the polarized electric field vectors, which indicate electric current loops in Figs. 9(e)–9(g). The alternatively polarized electric field induces strong localized magnetic polaritons (MPs).47 The electromagnetic polariton resonances can be understood by employing an equivalent inductor–capacitor (LC) circuit model.48 The sandwiched HfO2 spacer serves as a capacitor (C), whereas the top metallic VO2 microstructure and the bottom Ag substrate function as inductors (Lk+Lm), as illustrated in Fig. 9(b), forming a resonant LC circuit. The LC circuit induces the magnetic field and develops magnetic dipoles according to Lenz’s law.49 Eventually, the localized strong magnetic field is induced at the resonance frequency of the magnetic and electric dipoles, where the total impedance equals zero.35 In other words, the MP resonance is excited at the resonance frequency, resulting in an enhanced absorption effect. At 6.8μm, an intense MP resonance centers below the gaps of VO2 units of L4-G1 in Fig. 9(e). As the wavelength of incident light becomes longer, the induced electric polarization period also changes for a longer period of time. The strong polariton resonances occur at ∼9.2 and ∼12.5μm, with the enhanced magnetic response centering below the VO2 units, as shown in Figs. 9(f) and 9(g). Further increasing the incident wavelength, the polarization becomes weak. Hence, the emissivity spectrum experiences gradual suppression at a longer wavelength.

For λ<P, the polarized electric field period is smaller than the feature size L. Figures 9(i) and 9(j) indicate two localized SPP resonances on one VO2 unit for L8-G1 and L10-G1. This is because two periodic polarization electric fields are formed on the surface of each metallic VO2 unit when λ is half of P, thus exciting two localized SPP resonances. Meanwhile, the multiple MP resonances can also be excited between VO2 layers and Ag layers at resonant frequencies. However, the polarization strength gradually weakens as the λ becomes much smaller than P. Therefore, the metastructure loses its effects, as λ is much smaller than P.

We have successfully designed and fabricated the temperature-adaptive metasurface radiative device—ATMRD by sample mask-filling engineering. The fabrication of a VO2 metasurface resolves the issue of balancing high emittance and low solar absorptance. The metasurface stimulates the localized polariton resonances as VO2 in the metallic state, enhancing the absorption of electromagnetic radiation in the thermal IR and declining αsol through reducing the area of VO2. The fabricated ATMRD L4-G1 demonstrates the ability to switch the atmospheric window thermal emittance from 0.13 to 0.85 over the VO2 phase transition. Meanwhile, it achieves a commendable αsol of 27.71%. The simulation-based analysis reveals the relationship between the structural parameters of the metasurface and performance, providing a guide for the design of metasurface radiative cooling devices. The solar absorptance is directly proportional to the coverage area of VO2, independent of the pattern shape. However, in terms of emissivity, the structural parameters (feature size and gap size or period) of the metasurface play a pivotal role in triggering the polariton resonances of different manners at specific frequencies. Reduced pattern gaps facilitate the enhancement of IR absorption, whereas the feature sizes of 4 and 6μm perform the optimal thermal emittance because they can ultimately excite the polariton resonances in the thermal IR range.

Radiative cooling devices featuring a triple-layer film structure of Ag/HfO2/VO2 were fabricated on a c-Al2O3 substrate using magnetron sputtering. Initially, a reflective layer of Ag was deposited on the substrate using a high-purity Ag target. Subsequently, an 800-nm HfO2 layer was deposited utilizing a ceramic target. For ATRD, a 50-nm-thick layer of vanadium is directly deposited on the top of the HfO2 layer using a high-purity metal vanadium target at room temperature. The vanadium film underwent thermal treatment to transform into the VO2 M1 phase using a rapid annealing furnace (RTP-500, Beijing East-star Research Office of Applied Physics, Beijing, China). For ATMRD, the VO2 microstructure was fabricated through mask-filling engineering, as illustrated in Fig. S12 in the Supplementary Material.

The pre-prepared Ag/HfO2 device underwent plasma cleaning initially to remove surface contaminants. Photoresist (L300, Seoul, Republic of Korea) was spin-coated on the HfO2 layer at a speed of 4000 r/min, and the patterned potholes on the HfO2 layer were achieved through exposure in a photolithography machine. Subsequently, pure vanadium was deposited into the patterned potholes, and the photoresist mask, along with excess vanadium, was eliminated through immersion and ultrasonic delamination in an acetone solution. Following this step, the patterned vanadium microstructure underwent additional thermal treatment to transform the VO2 (M) phase, thereby producing the final ATMRD.

The morphology was observed by field emission scanning electron microscopy (FE-SEM, Hitachi S-4800, Tokyo, Japan). The phase structure of the films was measured utilizing an XRD (Rigaku SmartLab SE, Tokyo, Japan) and a Raman spectrometer (Horiba LabRAM HR Evolution, Paris, France) equipped with a 532-nm laser. An ultraviolet–visible–near-IR spectrophotometer (UV-VIS-NIR, Agilent UV3600, Santa Clara, California, United States) fitted with an integrating sphere measured the transmittance and reflectivity from 300 to 2500 nm at different temperatures using a homemade heating table. Thermal spectral reflectance was characterized by a Fourier transform IR spectrometer (Nicolet iS50, Madison, Wisconsin, United States) equipped with mid-IR IntegratIR spheres (PIKE Technologies, Inc., Madison, Wisconsin, United States) and mercury cadmium telluride (MCT) detectors over the ∼2 to 18μm wavelength range at 12-deg angle of incidence. According to Kirchhoff’s law of radiation, in a state of thermodynamic equilibrium, the spectral emittance ε(λ,T) equals the spectral absorptance A(λ,T).33 As a radiative cooling device comprises a thick Ag layer, the transmittance (T) in the solar and thermal IR wavelength ranges was considered zero. Thus, its thermal spectral emittance in this range was computed as ε(λ,T)=A(λ,T)=1−R(λ,T).

The solar absorptance (αsol) and thermal emittance (ε) can be calculated from the corresponding spectral data using the following equations: αsol=∫0.3μm2.5μmA(λ)ϕsol(λ)dλ∫0.3μm2.5μmϕsol(λ)dλ,(1)ε(T)=∫8μm14μmB(λ,T)(1−R(λ,T))dλ∫8μm14μmB(λ,T)dλ,(2)where A(λ) is the spectral absorptance at corresponding wavelength λ. ϕsol(λ) is the solar irradiance spectrum for an air mass of 1.5 corresponding to the sun standing 37 deg above the horizon. R(λ,T) is the reflectance at wavelength λ and temperature T. B(λ,T) is the spectral intensity of blackbody emission at the desired temperature given by Planck’s law. By calculating the performance at high and low temperatures, the emittance tunability (Δε) can be obtained: Δε=εH−εL.

The solar heating simulation test was carried out using a solar simulator (PLS-SXE300, Beijing Perfectlight Technology Co., Ltd., Beijing, China), and a temperature recorder fitted with a Pt temperature sensor recorded the temperatures. Before measuring each type of material surface, the shutter of the solar simulator remained closed, and the sample was first stabilized at room temperature. Then, the shutter was opened, and the surface temperature was recorded as a function of time. Thermal IR images were captured by an FLIR A310 infrared camera (IR camera) working at a 7.5- to 14-μm wavelength. To minimize reflections in the surrounding environment, the experiments were conducted in an open, outdoor environment. Before testing, the IR camera was calibrated using a thermocouple and 3M tape (a commercial product with a constant emittance of 0.96) as a reference to ensure that the displayed surface temperature matches the reference sample’s actual temperature. The sample was heated using a heating stage, and the IR camera recorded video images at a fixed detection angle.

We used finite-difference time-domain (FDTD, Ansys Lumerical, Canonsburg, Pennsylvania, United States) modeling for numerical simulations of the radiative cooling device. A three-dimensional unit cell model was established, including the VO2 submicrometer square or circle, HfO2 layer, and Ag substrate. The materials’ optical properties were obtained from Ref. 24 for VO2 and Ref. 34 for HfO2. The optical properties of Ag employed in the simulation were calculated from Palik’s handbook.50 The simulation region had a size of x×y×z referring to the period of the P micrometer disks. The perfect matching layer boundary conditions were applied along the propagation of electromagnetic waves (z direction), and periodic boundary conditions were applied along the x direction and y direction. A broadband linearly polarized plane wave was directed toward the unit cell from above the structure at normal incidence. Positioned above the plane wave source was a frequency–domain power monitor designed to capture the reflected waves. The simulation exclusively focuses on the transverse magnetic (TM) wave, where metamaterial particles are excited by the y component of the magnetic field. Due to the symmetry of the considered patterns, the reflectance remains consistent for both transverse electric and TM waves. All simulations detailed in this paper are conducted within a three-dimensional computational domain, employing a nonuniform structured mesh with a minimum mesh size of 1 nm.35

Junlin Yang is a PhD candidate at the Beijing Institute of Technology, under the supervision of professor Jingbo Li. His research primarily focuses on the structure and performance regulation of thermochromic phase change materials and the design of radiative thermal control devices.

Haibo Jin is a professor at the Beijing Institute of Technology. His main research interests focus on functional materials and energy storage and conversion, with a primary emphasis on key materials and technologies for secondary batteries and hydrogen energy development. He has published over 100 papers, which have been cited more than 10,000 times, and holds 15 authorized invention patents. He was once selected as one of the “top 1% highly cited Chinese authors” by a journal of the Royal Society of Chemistry.

Jingbo Li is a professor at the Beijing Institute of Technology. His research focuses on novel electromagnetic functional materials, multi-field regulation, and device design and fabrication, with a primary emphasis on key materials and technologies for broadband intelligent electromagnetic modulation and the development of energy-saving windows. He has led and completed more than 10 major projects, published over 100 papers, held 12 national invention patents, and edited 2 textbooks.

Biographies of the other authors are not available.