Four-mode infrared emission intelligent switching method based on double phase change materials and application of four-mode infrared emission intelligent switching method

Abstract

The invention discloses a four-mode infrared emission intelligent switching method based on a double-phase-change material and application of the four-mode infrared emission intelligent switching method, relates to the technical field of infrared radiation control, and aims at solving the problems that in the prior art, multi-mode switching is difficult to achieve, and compatibility is poor in a complex environment. The IST layer adopts a one-dimensional grating array structure; the two different thermally induced phase change materials are compounded, flexible switching of multiple different working modes can be achieved through cooperative phase change at different temperatures, multiple complex requirements are met, and compatibility to different complex environments is high; mode switching can be automatically changed according to temperature changes, continuous external energy input is not needed, and energy consumption is reduced; and the used non-volatile IST can keep a stable state in an environment of 630 DEG C or below, and can be used for extreme conditions such as thermal control of spacecrafts and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of infrared radiation control, and specifically to a four-mode infrared emission intelligent switching method based on dual-phase change materials and its application. Background Art

[0002] The thermal radiation control in the infrared band (3 - 14 μm) has important application values in fields such as thermal camouflage, infrared detection, thermal management, and radiative cooling. However, the requirements for thermal radiation characteristics in different application scenarios are often different, and traditional thermal radiation control technologies are difficult to meet multiple requirements simultaneously. For example, thermal camouflage requires low emissivity in the 3 - 5 μm and 8 - 14 μm bands, while radiative cooling requires high emissivity in the 8 - 14 μm band. Existing thermal radiation control technologies usually rely on a single phase change material, are difficult to achieve multi-mode switching, and have poor compatibility with complex environments. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to overcome the existing defects, and provide a four-mode infrared emission intelligent switching method based on dual-phase change materials and its application, which can effectively solve the problems in the background art.

[0004] To achieve the above object, the present invention first discloses a four-mode infrared emission intelligent switching method based on dual-phase change materials. The technical solution adopted is to use an intelligent infrared emitter, and the core functional unit components of the intelligent infrared emitter include a VO2 film layer, a Si dielectric layer, and an IST (In3SbTe2) layer; in the core functional unit components, the Si dielectric layer is located between the VO2 film layer and the IST layer; by compounding two different thermally induced phase change materials, phase change can occur within different temperature ranges, so as to achieve the effect of multi-mode switching and have compatibility with different environments.

[0005] When the temperature T < T0, neither the VO2 film layer nor the IST layer undergoes a phase change. The VO2 film layer is in a dielectric state, and the IST layer is in an amorphous state. The intelligent infrared emitter has a low emissivity in the 3 - 14 μm band and is suitable for thermal camouflage. This is Mode 1; T0 is the phase change temperature of the VO2 film layer, which is usually 68 °C without modification;

[0006] When the temperature T0 ≤ T ≤ T1 °C, the VO2 film layer undergoes a phase change and changes from a dielectric state to a metallic state, while the IST layer remains in an amorphous state. The intelligent infrared emitter has a high emissivity in the 8 - 14 μm band and is suitable for radiative cooling. This is Mode 2; T1 is the phase change temperature of the IST layer, which is usually 300 °C;

[0007] When the temperature T1 < T < T IST熔融When the temperature is at a certain level, the VO2 film layer is in the metallic state, the IST layer transforms into the crystalline state, and the intelligent infrared emitter has a low emissivity in the 3 - 5μm and 8 - 14μm bands and a high emissivity in the 5 - 8μm band, which is suitable for thermal management - compatible stealth. This is Mode Three;

[0008] When the temperature T drops below T0, the VO2 film layer reverts to the dielectric state, the IST layer remains in the crystalline state, and the intelligent infrared emitter has a low emissivity in the 3 - 14μm band, which is suitable for stable stealth. This is Mode Four;

[0009] When the temperature T ≥ T IST熔融 At this time, the VO2 film layer is in the metallic state, the IST layer transforms from the crystalline state to the amorphous state. Then, when the temperature T drops below T0, the VO2 film layer reverts to the dielectric state, and the IST layer remains in the amorphous state. At this point, it returns to Mode One.

[0010] As a preferred technical solution of the present invention, in the core functional component, the VO2 film layer is the bottom layer, the IST layer is the top layer, and the IST layer is a one - dimensional grating array structure. The one - dimensional grating array structure is simple and easy to process, and can be mass - produced using conventional photolithography or laser etching techniques, greatly reducing the preparation cost. Compared with the one - dimensional grating array structure, the two - dimensional grating array structure or disk structure has a more complex processing process and is more affected by processing errors. Moreover, the one - dimensional grating array structure can still maintain a stability of Δλ < 0.5nm in a 400°C working environment, which is an advantage that other structures are difficult to achieve.

[0011] As a preferred technical solution of the present invention, in the one - dimensional grating array structure of the IST layer, the grating period is 5μm, the grating width is 2μm (that is, the IST layer is a strip - shaped structure and is linearly array - distributed, and the distance between two adjacent IST strip - shaped structures is 3μm), the thickness of the IST layer is 100nm; the thickness of the VO2 film layer is 200nm; the thickness of the Si dielectric layer is 450nm.

[0012] As a preferred technical solution of the present invention, in the 8 - 14μm band, the emissivity of the intelligent infrared emitter in Mode Two is 0.73, and the emissivities in Mode One, Mode Three, and Mode Four are 0.02, 0.28, and 0.09 respectively.

[0013] As a preferred technical solution of the present invention, in the 3 - 5μm band, the emissivity of the intelligent infrared emitter in Mode One is 0.25. In Mode Two, the average emissivity in the 3 - 5μm band increases from the original 0.17 to 0.34. Entering Mode Three, the IST changes from amorphous to crystalline. Due to the strong reflection of the IST, the absorption peak in the 3 - 5μm band is suppressed, and the average emissivity also drops from 0.34 to 0.25. The emissivity in Mode Four is 0.19.

[0014] The above-mentioned four-mode infrared emission intelligent switching method based on dual-phase change materials can be applied to different fields such as infrared stealth, intelligent thermal control coatings, and heat dissipation modules of electronic devices. In the field of infrared stealth, the present invention can dynamically adapt to the temperature difference between day and night and the engine heating environment; in the field of intelligent thermal control coatings, the present invention can start Mode 2 (radiative cooling) in the sunlight area and switch to Mode 1 (thermal camouflage) in the shadow area; in the field of heat dissipation modules of electronic devices, the present invention can balance the heat dissipation requirements and infrared signal suppression.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: By compounding two different thermally induced phase change materials, the present invention can achieve flexible switching of multiple different working modes through the cooperative phase change at different temperatures, covering a variety of complex requirements and having high compatibility with different complex environments; and the switching of modes can be automatically changed according to temperature changes without continuous external energy input, reducing energy consumption.

[0016] Furthermore, the non-volatile IST used in the present invention can maintain a stable state in an environment below 630 °C and can be used in extreme conditions such as spacecraft thermal control.

[0017] Furthermore, the size of the IST layer is relatively large, and mass production can be achieved using conventional lithography technology, with low preparation costs. Description of the Drawings

[0018] Figure 1 It is a schematic structural diagram of the core functional unit component of the intelligent infrared emitter of the present invention;

[0019] Figure 2 It is a graph showing the relationship between the wavelength and refractive index change of VO2 of the present invention;

[0020] Figure 3 It is a graph showing the relationship between the wavelength and refractive index change of IST of the present invention;

[0021] Figure 4 It is a graph showing the relationship between the wavelength and refractive index change of Si of the present invention;

[0022] Figure 5 It is a graph showing the change relationship between the absorption spectrum and temperature of the intelligent infrared emitter of the present invention in Mode 1 and Mode 2;

[0023] Figure 6 It is a graph showing the change of the phase change response spectrum of the VO2 film layer of the present invention with temperature in Mode 1 and Mode 2;

[0024] Figure 7 It is a graph showing the change relationship between the absorption spectrum and temperature of the intelligent infrared emitter of the present invention in Mode 3 and Mode 4;

[0025] Figure 8It is the graph of the phase change response spectrum of the VO2 film layer of the present invention varying with temperature in Mode 3 and Mode 4;

[0026] Figure 9 (a) It is the absorption spectrum diagram of the intelligent infrared emitter of the present invention with the period length between 4.5 - 5.5 μm;

[0027] Figure 9 (b) It is the absorption spectrum diagram of the intelligent infrared emitter of the present invention with the grating length between 1.5 - 2.5 μm;

[0028] Figure 9 (c) It is the absorption spectrum diagram of the intelligent infrared emitter of the present invention with the silicon dielectric thickness between 0.35 - 0.55 μm;

[0029] Figure 9 (d) It is the absorption spectrum diagram of the intelligent infrared emitter of the present invention with the period length between 4.5 - 5.5 μm in Mode 3;

[0030] Figure 9 (e) It is the absorption spectrum diagram of the intelligent infrared emitter of the present invention with the grating length between 1.5 - 2.5 μm in Mode 3;

[0031] Figure 9 (f) It is the absorption spectrum diagram of the intelligent infrared emitter of the present invention with the silicon dielectric thickness between 0.35 - 0.55 μm in Mode 3;

[0032] Figure 10 (a) It is the absorption spectrum diagram of the intelligent infrared emitter of the present invention with different incident angles in the TE polarization state in Mode 2;

[0033] Figure 10 (b) It is the absorption spectrum diagram of the intelligent infrared emitter of the present invention with different incident angles in the TM polarization state in Mode 2;

[0034] Figure 10 (c) It is the absorption spectrum diagram of the intelligent infrared emitter of the present invention with different incident angles in the non - polarization state in Mode 2;

[0035] Figure 10 (d) It is the absorption spectrum diagram of the intelligent infrared emitter of the present invention with different incident angles in the TE polarization state in Mode 3;

[0036] Figure 10 (e) It is the absorption spectrum diagram of the intelligent infrared emitter of the present invention with different incident angles in the TM polarization state in Mode 3;

[0037] Figure 10 (f) It is the absorption spectrum diagram of the intelligent infrared emitter of the present invention with different incident angles in the non - polarization state in Mode 3;

[0038] Figure 11 Schematic diagram for the simulation control test of the intelligent infrared emitter of the present invention and the control group;

[0039] Figure 12 Comparison chart of the surface temperature changes of the intelligent infrared emitter of the present invention and the control group during the process of heating temperature rising from 80 °C to 400 °C;

[0040] Figure 13 Comparison chart of the simulated radiation intensity of the intelligent infrared emitter of the present invention and the control group in the 3-5 μm and 8-14 μm bands;

[0041] Figure 14 Comparison chart of the radiation intensity of the intelligent infrared emitter of the present invention and the control group at different temperatures. Detailed implementation manners

[0042] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0043] Embodiment 1

[0044] As Figure 1 shown, this embodiment discloses a four-mode infrared emission intelligent switching method based on dual-phase change materials. The technical solution adopted is to use an intelligent infrared emitter. The core functional components of the intelligent infrared emitter include a bottom VO2 film layer and a top IST layer, and a Si dielectric layer is provided therebetween; the top IST layer is a one-dimensional grating array structure, its grating period (P) is 5 μm, the grating width (W) is 2 μm, and the thickness (h1) of the IST layer is 100 nm; the thickness (h3) of the VO2 layer is 200 nm; the thickness (h2) of the Si dielectric layer is 450 nm; the absorption characteristics and electromagnetic distribution of the intelligent infrared emitter are numerically simulated through the radio frequency module (electromagnetic wave, frequency domain) in COMSOL Multiphysics.

[0045] As Figure 5 、 Figure 6 shown, when the temperature T < 68 °C, neither the VO2 film layer nor the IST layer undergoes a phase change. The VO2 layer is in a dielectric state, and the IST layer is in an amorphous state. The intelligent infrared emitter has a low emissivity in the 3-14 μm band and is suitable for thermal camouflage. This is Mode 1; in this mode (303K), the intelligent infrared emitter is almost completely in a low-radiation state. The dielectric state of VO2 and the amorphous state of IST make the emitter have a low absorption rate (high reflectivity) in the 3-14 μm band; average emissivity: ε3-5μm = 0.17, ε 8-14μm = 0.02; Application scenario: Suitable for thermal camouflage, enabling the target to blend in with the background environment under infrared detection;

[0046] When the temperature 68°C ≤ T ≤ 300°C, as Figure 2 shown, after the temperature reaches 68°C, the VO2 layer undergoes a phase change, transitioning from the dielectric state to the metallic state. The IST layer remains in the amorphous state. The intelligent infrared emitter has a high emissivity in the 8 - 14 μm band and is suitable for radiative cooling. This is Mode 2; In this mode (358K), with the metallization of VO2, three significant absorption peaks can be observed. The metallic state of VO2 and the Si dielectric layer form a Fabry - Perot resonator, exciting high absorption peaks in the 8 - 14 μm band; Average emissivity: ε 8-14μm = 0.73; Application scenario: Suitable for radiative cooling, dissipating heat in the form of infrared radiation to the environment through high emissivity;

[0047] As Figure 7 , Figure 8 shown, when the temperature 300°C < T < 630°C, the VO2 layer is in the metallic state. As Figure 3 shown, after the temperature reaches 300°C, the IST layer transforms into the crystalline state. The intelligent infrared emitter has a low emissivity in the 3 - 5 μm and 8 - 14 μm bands and a high emissivity in the 5 - 8 μm band, suitable for thermal management - compatible stealth. This is Mode 3; In this mode (573K), due to the strong reflectivity of the c - IST thin film, the absorption peaks in the 3 - 5 μm and 8 - 14 μm bands are suppressed, and the average emissivities decrease from 0.34 and 0.73 to 0.25 and 0.28 respectively, but still maintain a high emissivity (ε 5-8μm = 0.67) in the 5 - 8 μm band. Application scenario: Suitable for thermal management - compatible stealth in high - temperature environments, preventing the device from overheating and avoiding being detected by infrared detectors;

[0048] When the temperature T drops below 68°C, the VO2 layer returns to the dielectric state, and the IST layer remains in the crystalline state. The intelligent infrared emitter has a low emissivity in the 3 - 14 μm band, suitable for stable stealth. This is Mode 4; In this mode (303K), the strong absorption peak in the 5 - 8 μm band is also suppressed, and the average emissivity in this band decreases from 0.67 to 0.14, turning into a high - reflection state. The dielectric state of VO2 and the crystalline state of IST make the emitter have a low absorption rate (high reflectivity) in the 3 - 14 μm band; Average emissivity: ε 3-5μm = 0.19, ε 8-14μm = 0.09; Application scenario: Suitable for long - term stable camouflage, suitable for low - temperature environments or scenarios requiring long - term stealth.

[0049] When the temperature T ≥ 630 °C, the VO2 layer is in the metallic state, and the IST layer transforms from the crystalline state to the amorphous state. Then, when the temperature T drops below 68 °C, the VO2 layer returns to the dielectric state, and the IST layer remains amorphous. At this time, the mode one is returned.

[0050] As Figure 4 shown, during the whole process, the state of the silicon dielectric layer remains stable.

[0051] In order to verify the size of the core functional unit, as Figure 9 shown, the resonance wavelength is closely related to the states of VO2 and IST and the geometric size of the core functional unit. As Figure 9 (a) and Figure 9 (d) shown, with the increase of the structural period, the resonance wavelengths of mode two and mode three are slightly redshifted. When the grating width changes, mode two and mode three show different behavior patterns. It should be noted that since the IST thin film in mode two is amorphous, with the increase of the a-IST grating width, the absorption peak at 9.03 μm becomes wider Figure 9 (b)]. On the contrary, the IST thin film in mode three transforms into the crystalline state. Due to the strong reflection effect of the c-IST layer, the resonance intensity in the Si dielectric layer weakens. Therefore, with the increase of the grating width, the resonance peak at 6.46 μm gradually becomes narrower Figure 9 (e)]. In addition, with the increase of the Si dielectric layer thickness, the resonance wavelengths of the Si dielectric layer in mode two and mode three are both redshifted Figure 9 (c) and Figure 9 (f)]. Through Figure 9 the comparison results, it can be known that the optimal solution for the geometric size of the core functional unit is that the grating period (P) is 5 μm, the grating width (W) is 2 μm, the thickness (h1) of the IST layer is 100 nm; the thickness (h3) of the VO2 layer is 200 nm; and the thickness (h2) of the Si dielectric layer is 450 nm.

[0052] Figure 10 The polarization and incident angle dependence of the absorption spectrum are shown. Selecting a radiative cooling mode (mode two) and a thermal management compatible stealth mode (mode three), in the case of normal incidence (0°), the absorption spectra of mode two and mode three in the three polarization states are almost unchanged. With the increase of the incident angle, the absorption of TM polarization in mode two and mode three increases slowly, while the absorption of TE polarization gradually decreases. Generally speaking, the unpolarized wave shows an angle-insensitive characteristic within about 40°, and mode two and mode three show a similar trend, indicating that the thermal camouflage performance of the emitter is less affected by the angle and polarization, which is beneficial to its practical application.

[0053] To verify the beneficial effects of the present invention, the following simulation experiments were carried out: the surface temperature and radiation intensity of the intelligent infrared emitter were simulated, and the thermal simulation demonstrated the reduction of the surface temperature of the object and the thermal camouflage performance at different heating temperatures. For comparison, an ideal broadband low-emissivity surface was selected as the reference material (RM), as Figure 11 shown, the heating process of the intelligent infrared emitter and the RM (assuming the sample is deposited on a 2-mm-thick quartz substrate) on the heating plate was simulated. The surface temperature changes of the intelligent infrared emitter and the RM are shown in Figure 12 . For both samples, due to the emission of thermal energy, the surface temperature is lower than the heating temperature. When the heating temperature of the intelligent infrared emitter is lower than 300 °C, it can be found that the IST layer does not become crystalline, and the surface temperature of the intelligent infrared emitter is significantly lower than that of the RM, which is due to the high-emission mode in Mode II; as the temperature increases, the IST layer transforms into a crystalline state, and at a heating temperature of 400 °C, the surface temperature of the intelligent infrared emitter (350.5 °C) is 45.5 °C lower than that of the RM (396 °C), which is due to the radiative cooling of the intelligent infrared emitter in the non-atmospheric window (5-8 μm). In addition, an infrared (IR) camera captured the integrated thermal radiation signals in the 3-5-μm and 8-14-μm bands, which proved the effectiveness of infrared camouflage. As Figure 13 shown, as the heating temperature increases, the difference in radiation intensity becomes more significant. As the temperature increases, vanadium dioxide (VO2) gradually transforms from a dielectric state to a metallic state, entering the so-called Mode II. In Mode II, this material is an efficient radiative cooling mode, which helps to dissipate heat and minimize heat accumulation. When the heating temperature exceeds T>T IST = 300 °C, the intelligent switching thin film (IST thin film) transforms into a crystalline state, i.e., Mode III. In this state, the intelligent infrared emitter exhibits a low emissivity in the 3-5-μm and 8-14-μm bands, while exhibiting a high emissivity in the non-atmospheric window of 5-8 μm, thus facilitating heat dissipation. This characteristic enhances the thermal stability of the intelligent infrared emitter and makes it suitable for infrared camouflage applications. In addition, the crystalline intelligent switching layer (c-IST layer) acts as a strong reflection layer, suppressing the high-emission peaks at 3.36 μm and 9.03 μm. At a heating temperature of 400 °C, the radiation temperature of the intelligent infrared emitter in the 3-5-μm band is 261.3 °C, and the radiation temperature in the 8-14-μm band is 171.9 °C. Compared with 264.7 °C and 176.4 °C of the reference material (RM) ( Figure 14 ), these temperatures are 2.4 °C and 4.5 °C lower, respectively. The above results prove that the intelligent infrared emitter can selectively switch its mode under specific conditions and achieve the integration of an efficient radiative heat dissipation mode and a thermal management mode compatible with infrared stealth.

[0054] The stacking methods of the VO2 film layer, the Si dielectric layer, and the IST layer are all prior arts. Si is deposited on the VO2 film by electron beam evaporation coating, and the IST layer is attached to the Si dielectric layer through a lithography process.

[0055] In summary, the four-mode infrared emission intelligent switching method based on dual phase change materials provided by the present invention realizes the switching of four different thermal radiation modes by combining two phase change materials, VO2 and IST, and can adapt to various application scenarios. The emitter has the advantages of simple structure, low preparation cost, and no need for additional energy supply, and has broad application prospects.

[0056] Although the embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A four-mode infrared emission intelligent switching method based on dual-phase change materials, characterized in that: An intelligent infrared emitter is used, and the core functional unit components of the intelligent infrared emitter include a VO2 film layer, a Si dielectric layer, and an IST layer; the Si dielectric layer is located between the VO2 film layer and the IST layer; When the temperature T < T0, neither the VO2 film layer nor the IST layer undergoes a phase change. The VO2 film layer is in a dielectric state, and the IST layer is in an amorphous state. The intelligent infrared emitter has a low emissivity in the 3 - 14 μm band and is suitable for thermal camouflage. This is Mode 1; T0 is the phase change temperature of the VO2 film layer; When the temperature T0 ≤ T ≤ T1, the VO2 film layer undergoes a phase change, changing from a dielectric state to a metallic state, and the IST layer remains in an amorphous state. The intelligent infrared emitter has a high emissivity in the 8 - 14 μm band and is suitable for radiative cooling. This is Mode 2; T1 is the phase change temperature of the IST layer; When the temperature T1 < T < T IST熔融 At this time, the VO2 film layer is in the metallic state, the IST layer is transformed into the crystalline state, the intelligent infrared emitter has a low emissivity in the 3-5μm and 8-14μm bands and a high emissivity in the 5-8μm band, and is suitable for thermal management compatible stealth. This is Mode Three; When the temperature T drops below T0, the VO2 film layer returns to the dielectric state, the IST layer remains in the crystalline state, and the intelligent infrared emitter has a low emissivity in the 3-14 μm band, which is suitable for stable stealth. This is Mode Four; when the temperature T ≥ T IST熔融 When, the VO2 film layer is in the metallic state, the IST layer transforms from the crystalline state to the amorphous state. Then, when the temperature T drops below T0 again, the VO2 film layer returns to the dielectric state, and the IST layer remains in the amorphous state. At this time, it returns to Mode One.

2. The four-mode infrared emission intelligent switching method based on dual-phase change materials according to claim 1, wherein: In the core functional unit components, the VO2 film layer is the bottom layer, the IST layer is the top layer, and the IST layer is a one - dimensional grating array structure.

3. The four-mode infrared emission intelligent switching method based on dual-phase change materials according to claim 2, wherein: In the one - dimensional grating array structure of the IST layer, the grating period is 5 μm, the grating width is 2 μm, the thickness of the IST layer is 100 nm; the thickness of the VO2 film layer is 200 nm; the thickness of the Si dielectric layer is 450 nm.

4. The four-mode infrared emission intelligent switching method based on dual-phase change materials according to claim 1, characterized in that: In the 8 - 14 μm band, the emissivity of the intelligent infrared emitter in Mode 2 is 0.73, and the emissivities in Mode 1, Mode 3, and Mode 4 are 0.02, 0.28, and 0.09 respectively.

5. The four-mode infrared emission intelligent switching method based on dual-phase change materials according to claim 1, wherein: In the 3 - 5 μm band, the emissivity of the intelligent infrared emitter in Mode 1 is 0.25, in Mode 2 is 0.34, in Mode 3 is 0.25, and in Mode 4 is 0.

19.

6. Application of a four-mode infrared emission intelligent switching method, characterized in that: The four - mode infrared emission intelligent switching method based on dual - phase change materials according to claim 1 is applied to infrared stealth, intelligent thermal control coatings, and heat dissipation modules of electronic devices.

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