A micro-nano scale infrared light source based on a photonic crystal catalytic reaction and its applications

Abstract

The present invention relates to a micro-nano scale infrared light source based on a photonic crystal catalytic reaction and its application. The light source includes a micro reaction chamber, as well as a temperature control table, a substrate and a catalyst array that are sequentially arranged on the inner bottom surface of the micro reaction chamber. An infrared transparent glass is arranged in the area on the top surface of the micro reaction chamber that is directly opposite to the catalyst array. A mixed gas inlet and a mixed gas outlet are respectively arranged on both sides of the micro reaction chamber. When the nano catalyst array undergoes a catalytic reaction, it generates heat / absorbs heat and thus emits infrared light, and the catalyst array itself simultaneously serves as a photonic crystal to modulate the emission of infrared light. Compared with the prior art, the present invention can adjust the wavelength of the infrared light by adjusting the flow rate of the mixed gas. At the same time, through the customization of the photonic crystal structure, the emitted infrared light can be functionalized.

Description

Technical Field

[0001] The present invention belongs to the technical field of infrared light sources, and relates to a micro-nano scale infrared light source based on a photonic crystal catalytic reaction. Background Art

[0002] Infrared light sources have important application significance in key technologies such as medical diagnosis, biomolecular sensing, space communication, environmental monitoring, spectral imaging, and infrared countermeasures. One of the challenges of this technology is how to obtain infrared light with a wide spectrum and high power, especially light with a mid-infrared wavelength.

[0003] Infrared light sources can generally be sourced from lasers, diodes, and thermal radiation. The infrared light emitted by lasers and diodes has a limited wavelength band, and the infrared light emitted by thermal emitters has a wide wavelength band but is usually quasi-isotropic and has poor tunability. According to Planck's law, the wavelength and power of infrared radiation can be regulated by adjusting the temperature of the thermal emitter. Traditional methods usually heat the entire thermal radiator by electrothermal heating or use light with a specific wavelength to excite infrared light in a specific wavelength band. This not only places strict requirements on the bandgap of the target material, but also has a limited wavelength band for the emitted infrared light, etc. Summary of the Invention

[0004] The purpose of the present invention is to provide a micro-nano scale infrared light source based on a photonic crystal catalytic reaction.

[0005] The purpose of the present invention can be achieved by the following technical solutions:

[0006] A micro-nano scale infrared light source based on a photonic crystal catalytic reaction includes a micro reaction chamber, and a temperature control table, a substrate, and a catalyst array sequentially arranged on the inner bottom surface of the micro reaction chamber. An infrared transparent glass is arranged in the area on the top surface of the micro reaction chamber opposite to the catalyst array, and a mixed gas inlet and a mixed gas outlet are respectively arranged on both sides of the micro reaction chamber.

[0007] Further, the catalyst array is a photonic crystal array, which is formed by arranging a number of catalyst units in an array. Each catalyst unit is composed of an adiabatic layer and a catalytic layer longitudinally assembled from bottom to top on the substrate. The adiabatic layer can maximize the avoidance of heat generated / absorbed by the catalytic reaction from being conducted to the substrate, thereby maintaining the temperature of the catalytic layer. At the same time, the adiabatic layer has the function of supporting the catalytic layer and can improve and enhance the activity of the catalytic layer.

[0008] Furthermore, the catalytic layer is an N-layer structure, where N≥1; and when N≥2, the longitudinal structure of the catalytic layer is a periodic or non-periodic multi-layer structure.

[0009] Furthermore, each layer in the catalytic layer is independently selected from one or more composites of metals and their alloy compounds, oxides, transition metal chalcogenides, organic polymers, silicon, carbon nanotubes, graphene, etc. More specifically, the metal can be Pt, Pd, Rh, Au, Ag, Cu, Fe, Co, Ni, Al, Mn, etc., and the oxide can be Al2O3, SiO2, etc.

[0010] Furthermore, the thickness of the insulating layer is 5 nm to 500 μm; the longitudinal height of the catalytic layer is 1 nm to 200 μm. In addition, the radial dimension of the catalyst is the catalyst diameter.

[0011] Furthermore, the catalyst unit is circular or a polygon with M sides, where M ≥ 3. Here, the catalyst unit can be patterned into an array by using techniques such as electron beam lithography, ultraviolet lithography, hard mask method, 3D printing, etc. The catalytic layer can be prepared by methods such as physical vapor deposition, chemical vapor deposition, electrochemical deposition, solution synthesis, printing, etc.

[0012] Further, the mixed gas is used to undergo an exothermic or endothermic reaction under the catalysis of the catalyst array, and the mixed gas is a mixture of a reaction gas and air.

[0013] Furthermore, the reaction gas is hydrogen, methanol, ethanol, methane, etc.

[0014] Furthermore, the exothermic or endothermic reaction causes a temperature change from room temperature to above 600 °C, and the center wavelength of the released infrared rays is in the range of 3 to 10 μm. Adjusting the gas flow rate can adjust the temperature change and thus adjust the infrared wavelength.

[0015] Further, the photonic crystal structure of the catalyst array is a two-dimensional photonic crystal. By designing the material constituting the catalyst array and the periodic spacing in the x-y plane of the catalyst unit, the infrared light of a specific frequency can be converged and directionally emitted along the z direction. Specifically, the adjustment includes two aspects: 1. Different materials: The optical parameters of different materials are different, and the absorption and emission of light of different wavelengths are different; 2. The photonic crystal with a periodic structure of a specific spacing can filter or enhance light of a specific wavelength.

[0016] Further, the size of the micro reaction chamber is in centimeter scale; the substrate only needs to satisfy the function of carrying the catalyst, and it can be glass, etc.

[0017] Generally speaking, the micro-nano scale infrared light source based on the catalytic reaction of the photonic crystal array catalyst proposed by the present invention combines the catalyst with the photonic crystal structure. By adjusting the flow rate of the mixed gas, a catalytic reaction occurs on the catalyst to change the temperature of the catalyst itself, thereby emitting infrared light with adjustable wavelengths, and it can be used as an infrared point light source array at the micro-nano scale. The customization of the photonic crystal structure of the catalyst itself can modulate the infrared light functionality, such as directional emission. The infrared light source of the present invention is small, compact, and portable, and can expand more novel potential application scenarios.

[0018] Compared with the prior art, the present invention has the following advantages:

[0019] (1) The catalytic effect of the catalyst array of the present invention is better than that of the thin film, saving the amount of catalyst used.

[0020] (2) The infrared light of the present invention is emitted by the catalyst through catalytic reaction to adjust its own temperature, and the infrared wavelength range is wide and can be adjusted by the gas flow rate.

[0021] (3) The catalyst array of the present invention itself is a photonic crystal structure, which can achieve multi-functional modulation of the infrared light source, such as directional emission.

[0022] (4) The infrared light source realized by the catalyst of the present invention is at the micro-nano scale and has great potential application value in many fields. Description of the Drawings

[0023] Figure 1 It is a schematic diagram of the device of the micro-nano scale infrared light source based on the photonic crystal catalytic reaction of the present invention;

[0024] Figure 2 It is a process diagram of the Pt / Al2O3 catalyst array manufactured in Example 1.

[0025] Figure 3 It is a scanning electron microscope image of the Pt / Al2O3 catalyst array manufactured in Example 1.

[0026] Figure 4 It is the methanol conversion efficiency of the Pt / Al2O3 catalyst array and thin film manufactured in Example 2.

[0027] Figure 5 It is the temperature increase of the Pt / Al2O3 catalyst array and thin film catalyzed in Example 3.

[0028] Figure 6 It is the detection of the infrared emission wavelength of the Pt / Al2O3 thin film catalytic reaction manufactured in Example 3.

[0029] Figure 7Photonic crystal structure design (a) of the Pt / Si catalyst array fabricated for Example 4 and its simulation results (d) of infrared directional emission at 4.95 μm.

[0030] Reference numerals:

[0031] 1 - Mixed gas inlet; 2 - Micro reaction chamber; 3 - Temperature control table; 4 - Infrared transparent glass; 5 - Catalyst array; 6 - Substrate; 7 - Mixed gas outlet. Detailed implementation manners

[0032] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. This embodiment is implemented on the premise of the technical solution of the present invention, and the detailed implementation manners and specific operation processes are given, but the protection scope of the present invention is not limited to the following embodiments.

[0033] In the following embodiments, unless otherwise specified for functional components or processing technologies, it means that they are conventional components or structures adopted by those skilled in the art to achieve corresponding functions, or conventional technologies in the art.

[0034] First, the micro - nano scale infrared light source device used in each embodiment will be described below.

[0035] A micro - nano scale infrared light source based on a photonic crystal catalytic reaction provided by the present invention, the structure of which is shown in Figure 1 Figure, including a micro reaction chamber 2, and a temperature control table 3, a substrate 6, and a catalyst array 5 sequentially arranged on the inner bottom surface of the micro reaction chamber 2. An infrared transparent glass 4 is arranged in the area of the top surface of the micro reaction chamber 2 opposite to the catalyst array 5. A mixed gas inlet 1 and a mixed gas outlet 7 are respectively arranged on both sides of the micro reaction chamber 2; the catalyst array 5 is composed of a plurality of catalyst units arranged in an array, and each catalyst unit is composed of an adiabatic layer and a catalytic layer longitudinally assembled from bottom to top on the substrate 6. The function of the temperature control table 3 is to initiate the catalytic reaction.

[0036] The present invention will be described in more detail below based on the above - mentioned device using specific embodiments.

[0037] Example 1

[0038] An n - type Si (resistivity 1 - 10 Ω·cm) is used as the substrate, and the Si wafer is washed with absolute ethanol and deionized water in sequence and dried. A 120 - nm - thick polymethyl methacrylate (PMMA) is spin - coated on the silicon wafer. An array pattern ( Figure 2 i) is written on the PMMA using electron beam lithography technology. The pattern is a cylinder with a diameter of 50 nm, and the period in the plane is 150 nm. Then, it is developed ( Figure 2ii), Pattern the PMMA. Deposit 20 nm of Al2O3 (as an insulating layer) and 5 nm of Pt (as a catalytic layer) in sequence by magnetron sputtering as the catalyst ( Figure 2 iii), Finally, strip the PMMA. Figure 2 iv), Obtain sample P50-150. The scanning electron microscope structure of the obtained catalyst array is shown in Figure 3 .

[0039] Example 2

[0040] Using the same method as in Example 1, prepare cylinders with a diameter of 50 nm in a 1 mm × 1 mm area, and a catalyst array P50-100 with a period of 100 nm in the plane. The catalyst duty cycle is 19.6%. And prepare a 1 mm × 1 mm thin film (duty cycle 100%) as a control group. Place the catalyst in a micro-reaction chamber, and introduce a mixed gas of methanol and air. The flow rate of the mixed gas is 100 mL / min (that is, the air flow rate is 100 mL / min, and after passing through the methanol solution and flowing out, it is used as the mixed gas). When the heating temperature is 100 °C, the methanol conversion efficiency of the array catalyst exceeds that of the thin film (under the same conditions), reaching more than 70% ( Figure 4 ), demonstrating that the catalyst array has more excellent catalytic performance and can reduce the amount of catalyst used at the same time.

[0041] Example 3

[0042] Using the same method as in Example 2, prepare P30-60 (that is, the catalyst cylinder diameter is 30 nm and the period in the plane is 60 nm), P100-200 (that is, the catalyst cylinder diameter is 100 nm and the period in the plane is 200 nm), and P200-400 (that is, the catalyst cylinder diameter is 200 nm and the period in the plane is 400 nm) in a 1 mm × 1 mm area. The catalyst duty cycle is 19.6% for all. Introduce a mixed gas of methanol and air (flow rate 100 mL / min, the same as in Example 2 above), and set the heating temperature to 100 °C. The surface temperature of the catalyst rises, indicating that the catalytic reaction is an exothermic reaction, accompanied by a change in the infrared wavelength of thermal radiation. By adjusting the gas flow rate, the adjustment of the temperature rise can be achieved ( Figure 5 ). Taking the catalyst thin film in Example 2 as an example, when the methanol / air mixed gas flow rate is set to 100 mL / min, the experimental values of the infrared wavelength emission on the surface of the catalyst thin film are shown in Figure 6 .

[0043] Example 4

[0044] Select SiO2 as the substrate, and a bilayer material of 5 nm thick Pt and 70 nm thick Si as the catalyst array. The diameter of the array cylinder is 700 nm, and the unit structure design of the period is as shown in Figure 7a. The simulation results of infrared emission at 100 nm from its surface are shown in Figure 7 b (infrared wavelength of 4.95 μm), enabling vertically directional emission (directional selectivity) at a specific infrared wavelength (wavelength selectivity). In the figure, d is the radial size of the catalyst, and a and d are the spacing parameters of the periodic arrangement structure.

[0045] The above description of the embodiments is to enable those of ordinary skill in the art to understand and use the invention. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative efforts. Therefore, the present invention is not limited to the above embodiments, and the improvements and modifications made by those skilled in the art without departing from the scope of the present invention according to the disclosure of the present invention should be within the protection scope of the present invention.

Claims

1. A micro-nano scale infrared light source based on a photonic crystal catalytic reaction, characterized in that It includes a micro reaction chamber, and a temperature control table, a substrate and a catalyst array which are sequentially arranged on the inner bottom surface of the micro reaction chamber. An infrared transparent glass is arranged in the area on the top surface of the micro reaction chamber opposite to the catalyst array. A mixed gas inlet and a mixed gas outlet are respectively arranged on both sides of the micro reaction chamber; The substrate is SiO2, the catalyst array is a double-layer material of 5 nm thick Pt and 70 nm thick Si. The catalyst array is a periodic unit structure formed by arranging six catalyst units in an array in the x-y plane of the substrate. The diameter d of each catalyst unit is 700 nm, the distance r between the center of the catalyst array and the center point of each catalyst unit is r = 1.14×a / 3, and the distance a between the center points of adjacent two catalyst arrays is a = 3.5 μm; The micro-nano scale infrared light source can realize the vertical direction directional emission of infrared wavelength of 4.95 μm.

2. The micro-nano scale infrared light source based on a photonic crystal catalytic reaction according to claim 1, wherein The mixed gas fed through the mixed gas inlet is used to carry out an exothermic or endothermic reaction under the catalysis of the catalyst array. The mixed gas is a mixture of a reaction gas and air, and the reaction gas is hydrogen, methanol, ethanol or methane.

3. The micro-nano scale infrared light source based on the photonic crystal catalytic reaction according to claim 2, characterized in that, The exothermic or endothermic reaction that occurs causes the temperature change to be from room temperature to above 600 °C.

4. The application of a micro-nano scale infrared light source based on a photonic crystal catalytic reaction according to claim 1, characterized in that, During operation, by adjusting the gas flow rate fed through the mixed gas inlet, the temperature change is adjusted, and then the infrared wavelength is adjusted.

Images