Solar blind optical filter and preparation method and application thereof

Abstract

The invention provides a solar blind optical filter and a preparation method and application thereof, the solar blind optical filter comprises a first optical filter and a second optical filter which are laminated, the first optical filter comprises an ultraviolet transmission layer and an ultraviolet absorption layer which are laminated, and the second optical filter comprises a visible light absorption layer; the ultraviolet absorption layer is arranged between the ultraviolet transmission layer and the second optical filter, and the ultraviolet absorption layer comprises inorganic semiconductor quantum dots. The solar blind optical filter provided by the invention is relatively thin in thickness, and has excellent selectivity and high transmittance.

Description

Technical Field

[0001] The present application relates to the field of optoelectronic technology, and in particular to a solar blind filter and a preparation method and application thereof. Background Art

[0002] At present, there are many methods for partial discharge detection of insulation performance of high-voltage electrical equipment, and the main infrared detection method suitable for online monitoring and dynamic inspection of power transmission and transformation equipment. Since the infrared detection method is to detect infrared radiation when the surface temperature changes due to partial discharge of the equipment, there is a detection lag and it is easily affected by rain and snow. The detection evaluation that relies on manual experience is prone to false detection and missed detection, low defect detection rate, and large consumption of manpower and material resources for defect identification. As an instrument for live detection of corona, etc., the ultraviolet imager can detect the existing insulation hidden dangers or damage early, which is of great significance for reducing the equipment failure rate and ensuring the safe operation of the power system. The ultraviolet imaging method does not require power outage, and can reflect the partial discharge of the external insulation of high-voltage electrical equipment in a relatively safe, intuitive, fast and accurate manner. It has high detection sensitivity and does not require direct contact with the equipment. The integrated application of ultraviolet imaging method with drones, online monitoring equipment, etc. can realize the basic data collection of the external insulation operation status of high-voltage electrical equipment for power transmission and transformation. The use of technologies such as artificial intelligence recognition based on big data is expected to timely and accurately discover equipment defects and hidden dangers, so it has been widely used.

[0003] In ultraviolet imaging or detection technology, solar-blind ultraviolet light (wavelength range of 240nm~290nm) has strong anti-interference ability to sunlight due to its special spectral characteristics, and has become an important research direction in the field of ultraviolet detection. As one of the core components of ultraviolet detection, the performance of solar-blind filters directly affects the sensitivity and stability of the entire system. At present, the solar-blind filters on the market are mainly in two forms: interference type and absorption type. Among them, interference filters, because they need to be plated with hundreds of layers of dielectric films, often have low in-band transmittance (the maximum transmittance can only reach about 10%). At the same time, this type of filter is easily affected by the angle, and it is difficult to achieve full solar-blind characteristics of ultraviolet detection. Absorption filters are not affected by angles and have deep absorption intensity, but they are thicker in size (usually thicker than 30mm), and the preparation process is complex and costly, making it difficult to achieve large-scale promotion and application. Summary of the invention

[0004] Based on this, the present application provides a solar-blind filter that is relatively thin, has excellent selectivity and high transmittance, and a preparation method and application thereof.

[0005] The first aspect of the present application provides a solar blind filter, comprising:

[0006] A first filter and a second filter are stacked, wherein the first filter comprises a UV transmission layer and a UV absorption layer which are stacked, and the second filter comprises a visible light absorption layer;

[0007] The ultraviolet absorption layer is arranged between the ultraviolet transmission layer and the second filter, and the ultraviolet absorption layer includes inorganic semiconductor quantum dots.

[0008] In some embodiments of the present application, the band gap of the inorganic semiconductor quantum dots is ≥3.4 eV, and can be optionally 3.5 eV~6.2 eV.

[0009] In some embodiments of the present application, the inorganic semiconductor quantum dots include one or more of ZnO quantum dots, Ga2O3 quantum dots, ZnO matrix doped quantum dots, and Ga2O3 matrix doped quantum dots;

[0010] Optionally, the ZnO matrix doped quantum dots include ZnO doped with Mg quantum dots;

[0011] Optionally, the Ga2O3 matrix-doped quantum dots include one or both of Ga2O3 doped Si quantum dots and Ga2O3 doped Sn quantum dots.

[0012] In some embodiments of the present application, one or more of the following conditions are met:

[0013] (1) The thickness of the ultraviolet absorption layer is 5 nm to 105 nm, and can be optionally 10 nm to 100 nm;

[0014] (2) The average particle size of the inorganic semiconductor quantum dots is 0.5 nm to 15 nm, and can be 2 nm to 10 nm;

[0015] (3) The visible light absorbing layer comprises ultraviolet glass;

[0016] (4) The thickness of the second filter is 3 mm to 10 mm.

[0017] In some embodiments of the present application, the first filter further includes a protective layer, and the protective layer is disposed between the ultraviolet absorption layer and the second filter;

[0018] Optionally, the protective layer comprises one or both of SiO2 and Al2O3;

[0019] Optionally, the protective layer has a thickness of 10 nm to 100 nm.

[0020] In some embodiments of the present application, the transmittance of the solar-blind filter to solar-blind ultraviolet light is ≥20%, and the wavelength of the solar-blind ultraviolet light is 240nm~290nm.

[0021] The second aspect of the present application provides a method for preparing a solar blind filter, comprising:

[0022] Forming a first optical filter and a second optical filter which are stacked, wherein the first optical filter comprises an ultraviolet transmission layer and an ultraviolet absorption layer which are stacked, and the second optical filter comprises a visible light absorption layer;

[0023] The ultraviolet absorption layer is arranged between the ultraviolet transmission layer and the second filter, and the ultraviolet absorption layer includes inorganic semiconductor quantum dots.

[0024] In some embodiments of the present application, the method for preparing the ultraviolet absorption layer includes:

[0025] Using a spin coating process or a sputtering process, a sol containing the inorganic semiconductor quantum dots is deposited on one side of the ultraviolet transmission layer, and the ultraviolet absorption layer is prepared after annealing;

[0026] Optionally, the spin coating rate of the spin coating process is 2000rpm~3000rpm;

[0027] Optionally, when the spin coating process is adopted, the annealing temperature is 450° C. to 600° C., and the annealing time is 1 h to 2 h.

[0028] In some embodiments of the present application, the inorganic semiconductor quantum dots are prepared by ultrasonic chemistry.

[0029] The third aspect of the present application provides an application of the solar-blind filter according to the first aspect of the present application or the solar-blind filter prepared according to the preparation method described in the second aspect in an ultraviolet detector.

[0030] The solar-blind filter provided in the present application can achieve high transmittance of the solar-blind ultraviolet band and deep absorption of other bands through the cooperation of the first filter and the second filter. It has excellent ultraviolet light selectivity and high transmittance, which can effectively improve the signal-to-noise ratio of the detector using the solar-blind filter. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] FIG. 1 is a schematic diagram of a solar-blind filter according to an embodiment of the present application.

[0032] FIG. 2 is a schematic diagram of a solar-blind filter according to an embodiment of the present application.

[0033] FIG. 3 is a graph showing the spectral characteristics of a solar-blind filter according to an embodiment of the present application.

[0034] FIG. 4 is a graph showing the spectral characteristics of a solar-blind filter according to an embodiment of the present application.

[0035] Figure 5This is a spectral characteristic curve diagram of a solar-blind filter according to an embodiment of the present application.

[0036] Reference numerals: 10 first optical filter; 20 second optical filter; 110 ultraviolet transmission layer; 120 ultraviolet absorption layer; 130 protection layer; 200 visible light absorption layer.

[0037] In FIG. 3 and FIG. 4 , the horizontal axis is wavelength in nm, and the vertical axis is transmittance. DETAILED DESCRIPTION

[0038] In order to facilitate understanding of the present application, the present application will be described more comprehensively below. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present application more thorough and comprehensive.

[0039] For simplicity, this application only explicitly discloses some numerical ranges. However, any lower limit can be combined with any upper limit to form an unclearly recorded range; and any lower limit can be combined with other lower limits to form an unclearly recorded range, and any upper limit can be combined with any other upper limit to form an unclearly recorded range. In addition, although not clearly recorded, each point or single value between the range endpoints is included in the range. Thus, each point or single value can be combined with any other point or single value as its own lower limit or upper limit or with other lower limits or upper limits to form an unclearly recorded range.

[0040] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application. It should be noted that, unless otherwise specified, the term "and / or" used herein includes any and all combinations of one or more related listed items, and "above" and "below" are inclusive of the number, and the meaning of "multiple" in "one or more" is more than two.

[0041] Herein, when it comes to a numerical interval (i.e., a numerical range), unless otherwise specified, the distribution of the optional numerical values ​​within the numerical interval is considered to be continuous and includes the two numerical endpoints (i.e., the minimum and maximum values) of the numerical interval, and each numerical value between the two numerical endpoints. Unless otherwise specified, when a numerical interval only refers to integers within the numerical interval, including the two endpoint integers of the numerical range, and each integer between the two endpoints, is equivalent to directly listing each integer. When multiple numerical ranges are provided to describe features or characteristics, these numerical ranges can be combined. In other words, unless otherwise specified, the numerical ranges disclosed herein should be understood to include any and all sub-ranges included therein. The "numerical value" in the numerical interval can be any quantitative value, such as a number, a percentage, a ratio, etc. "Numerical interval" allows broadly including numerical interval types such as percentage intervals, ratio intervals, and ratio intervals.

[0042] In this article, if there are multiple steps involved in the method flow, unless there is a clear different description in this article, there is no strict order restriction for the execution of these steps, and they can be executed in other orders than described. Moreover, any step can include multiple sub-steps or multiple stages, and these sub-steps or stages are not necessarily executed at the same time, but can be executed at different times, and their execution order is not necessarily sequential, but can be executed in turn, alternating or simultaneously with other steps or parts of sub-steps or stages of other steps.

[0043] The above application content of the present application is not intended to describe each disclosed embodiment or each implementation in the present application. The following description more specifically illustrates exemplary embodiments. In many places throughout the application, guidance is provided by a series of examples, which can be used in various combinations. In each example, enumeration is only used as a representative group and should not be interpreted as exhaustive.

[0044] In a first aspect, the present application provides a solar blind filter, referring to the example of FIG1 , which comprises:

[0045] A first optical filter 10 and a second optical filter 20 are stacked, wherein the first optical filter 10 includes an ultraviolet transmission layer 110 and an ultraviolet absorption layer 120 which are stacked, and the second optical filter 20 includes a visible light absorption layer 200;

[0046] The ultraviolet absorption layer 120 is disposed between the ultraviolet transmission layer 110 and the second filter 20 , and the ultraviolet absorption layer 120 includes inorganic semiconductor quantum dots.

[0047] The solar-blind filter provided by the present application includes the above structure. After the light is incident on the first filter, the ultraviolet transmission layer has a high transmittance and a low absorptivity for the ultraviolet light, so that most of the ultraviolet light passing through the ultraviolet transmission layer can be incident on the ultraviolet absorption layer. Since the ultraviolet absorption layer introduces inorganic semiconductor quantum dots, the band gap of the inorganic semiconductor can be used to cover the solar-blind ultraviolet band in the incident light, and the size effect of the quantum dots can be used to accurately control the selectivity of light, so that the ultraviolet absorption layer has excellent selectivity for the incident light, and has a high transmittance for the solar-blind ultraviolet band, and has excellent cutoff performance for visible light and near-ultraviolet light. The second filter can effectively absorb the visible light fluorescence generated by the excitation of the inorganic semiconductor quantum dots. In this way, through the cooperation of the first filter and the second filter, high transmittance for the solar-blind ultraviolet band and deep absorption for the remaining bands can be achieved, so that the signal-to-noise ratio of the detector using the solar-blind filter can be effectively improved.

[0048] It should be noted that in the day-blind filter of the present application, when the ultraviolet absorption layer is arranged between the ultraviolet transmission layer and the second filter, the ultraviolet absorption layer may be adjacent to the ultraviolet transmission layer and the second filter respectively, or other components may be arranged between the ultraviolet absorption layer and the ultraviolet transmission layer and / or between the ultraviolet absorption layer and the second filter.

[0049] It should be noted that the day-blind ultraviolet band described in this application refers to ultraviolet light with a wavelength of 240nm~290nm; the visible light has a wavelength of 380nm~780nm; and the near-ultraviolet light has a wavelength of 315nm~400nm.

[0050] In some embodiments, the absorption depth of the second filter to light is 400nm~100nm, and the absorption intensity to light is not less than 10OD (Optical Density). In this way, the second filter can effectively filter out the visible light fluorescence generated by the excitation of inorganic semiconductor quantum dots, and improve the selectivity of the solar-blind filter to light and the transmittance to the solar-blind ultraviolet band.

[0051] In some embodiments, the band gap of the inorganic semiconductor quantum dot is ≥3.4eV, and can be 3.5eV~6.2eV; for example, the band gap of the inorganic semiconductor quantum dot can be 3.4eV, 3.6eV, 3.8eV, 4eV, 4.2eV, 4.4eV, 4.6V, 4.8eV, 5eV, 5.2eV, 5.4eV, 5.6eV, 5.8eV, 6eV, 6.2eV, 6.4eV, 6.6V, 6.8eV, 7.0eV or in the range of any of the above values. In this way, the band gap of the inorganic semiconductor quantum dot can cover the solar-blind ultraviolet band, so that the ultraviolet absorption layer and the solar-blind filter have high transmittance to solar-blind ultraviolet light, and have high absorption to visible light and near-ultraviolet light.

[0052] In some embodiments, the inorganic semiconductor quantum dots include one or more of ZnO quantum dots, Ga2O3 quantum dots, ZnO matrix doped quantum dots, and Ga2O3 matrix doped quantum dots. In this way, the inorganic semiconductor quantum dots can have a wider band gap, and the band gap can effectively absorb visible light and near-ultraviolet light, while having a higher transmittance to solar-blind ultraviolet light.

[0053] It can be understood that ZnO matrix-doped quantum dots refer to quantum dots that are doped with ZnO as the matrix; Ga2O3 matrix-doped quantum dots refer to quantum dots that are doped with Ga2O3 as the matrix.

[0054] In some embodiments, the ZnO matrix doped quantum dots include ZnO doped with Mg quantum dots.

[0055] In some embodiments, the Ga2O3 matrix-doped quantum dots include one or both of Ga2O3 doped Si quantum dots and Ga2O3 doped Sn quantum dots.

[0056] In some embodiments, the thickness of the ultraviolet absorption layer is 5nm to 105nm. For example, the thickness of the ultraviolet absorption layer can be 5nm, 10nm, 20nm, 30nm, 40nm, 50nm, 60nm, 70nm, 80nm, 90nm, 100nm, 105nm or in the range of any of the above values; it can be selected from 10nm to 100nm. In this way, the absorption intensity of the ultraviolet absorption layer to light can be controlled. If the thickness is relatively large, the transmittance is easily reduced; if the thickness is relatively small, the absorption intensity to light will be relatively small.

[0057] In some embodiments, the average particle size of the inorganic semiconductor quantum dots is 0.5nm~15nm. For example, the average particle size of the inorganic semiconductor quantum dots can be 0.5nm, 2nm, 3nm, 4nm, 5nm, 6nm, 7nm, 8nm, 9nm, 10nm, 15nm or within the range of any of the above values; it can be selected as 2nm~10nm. By controlling the average particle size of the inorganic semiconductor quantum dots, the selectivity of the ultraviolet absorption layer to light can be accurately controlled, so that the ultraviolet absorption layer has a higher transmittance to solar-blind ultraviolet light, and has excellent cutoff performance for visible light and near-ultraviolet light, thereby improving the environmental adaptability of the solar-blind filter and extending its service life.

[0058] As an example, the average particle size of the inorganic semiconductor quantum dots can be measured with reference to the particle size distribution laser diffraction method in GB / T 19077-2016, using a laser particle size analyzer, such as the Mastersizer 2000E laser particle size analyzer from Malvern Instruments Ltd., UK.

[0059] In some embodiments, the ultraviolet transmission layer comprises one or more of quartz glass, sapphire and magnesium fluoride. In this way, the ultraviolet transmission layer can have high transmittance and low absorptivity for ultraviolet light, reduce the absorption of ultraviolet light, and make most of the ultraviolet light passing through the ultraviolet transmission layer enter the ultraviolet absorption layer.

[0060] In some embodiments, the visible light absorbing layer includes ultraviolet glass, so as to effectively absorb the fluorescence generated by the inorganic semiconductor quantum dots.

[0061] In some embodiments, the UV glass comprises silicon dioxide, a boron oxide compound, and a sodium oxide compound.

[0062] In some embodiments, the thickness of the second filter is 3 mm to 10 mm. For example, the thickness of the second filter can be 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, or any range thereof. In this way, the absorption of the fluorescence generated by the inorganic semiconductor quantum dots by the second filter can be further improved.

[0063] In some embodiments, referring to the example of Fig. 2, the first optical filter 10 further includes a protective layer 130, and the protective layer 130 is disposed between the ultraviolet absorption layer 120 and the second optical filter 20. The provision of the protective layer is conducive to improving the mechanical strength and thermal stability of the solar blind filter.

[0064] In some embodiments, the protective layer comprises one or both of SiO2 and Al2O3.

[0065] In some embodiments, the thickness of the protective layer is 10 nm to 100 nm. For example, the thickness of the protective layer can be 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, or within the range of any of the above values. In this way, the solar blind filter can have higher mechanical strength and thermal stability, and also have higher transmittance to solar blind ultraviolet light.

[0066] In some embodiments, the transmittance of the solar-blinding filter to solar-blinding ultraviolet light is ≥20%, and the wavelength of the solar-blinding ultraviolet light is 240nm~290nm.

[0067] Therefore, the solar-blind filter provided in the present application is relatively thin, has excellent ultraviolet light selectivity and high transmittance, and also has good thermal stability and mechanical strength, and can be widely used in fields such as power corona detection, forest fire detection, and missile tail flame warning.

[0068] In a second aspect, the present application provides a method for preparing a solar blindness filter, which can be used to prepare the solar blindness filter of the first aspect of the present application, and may include the following steps:

[0069] Step S10, forming a first filter and a second filter that are stacked, wherein the first filter includes a stacked ultraviolet transmission layer and an ultraviolet absorption layer, and the second filter includes a visible light absorption layer; the ultraviolet absorption layer is arranged between the ultraviolet transmission layer and the second filter, and the ultraviolet absorption layer contains inorganic semiconductor quantum dots.

[0070] The solar-blind filter prepared by the preparation method of the present application includes the above structure. After the light is incident on the first filter, the ultraviolet transmission layer has a high transmittance and a low absorptivity for the ultraviolet light, so that most of the ultraviolet light passing through the ultraviolet transmission layer can be incident on the ultraviolet absorption layer. Since the ultraviolet absorption layer introduces inorganic semiconductor quantum dots, the band gap of the inorganic semiconductor can be used to cover the solar-blind ultraviolet band in the incident light, and the selectivity of the light can be accurately controlled by the size effect of the quantum dots, so that the ultraviolet absorption layer has excellent selectivity for the incident light, and has a high transmittance for the solar-blind ultraviolet band, and has excellent cutoff performance for visible light and near-ultraviolet light. The second filter can effectively absorb the visible light fluorescence generated by the excitation of the inorganic semiconductor quantum dots. In this way, through the cooperation of the first filter and the second filter, high transmittance for the solar-blind ultraviolet band and deep absorption for the remaining bands can be achieved, so that the signal-to-noise ratio of the detector using the solar-blind filter can be effectively improved.

[0071] In some embodiments, the method for preparing the ultraviolet absorption layer may include the following steps:

[0072] Step S100: using a spin coating process or a sputtering process, depositing the sol containing the inorganic semiconductor quantum dots on one side of the ultraviolet transmission layer, and preparing the ultraviolet absorption layer after annealing.

[0073] In step S100, annealing can make the film layer of the deposited inorganic semiconductor quantum dots more dense and have better adsorption properties with the ultraviolet transmission layer.

[0074] In some embodiments, the spin coating process has a spin coating rate of 2000 rpm to 3000 rpm. For example, the spin coating rate may be 2000 rpm, 2200 rpm, 2400 rpm, 2600 rpm, 2800 rpm, 3000 rpm or any range thereof. In this way, the film layer of the inorganic semiconductor quantum dots formed by deposition may be more uniform and have better adhesion to the UV-transmitting layer.

[0075] In some embodiments, when the spin coating process is used, the annealing temperature is 450° C. to 600° C., and the annealing time is 1 h to 2 h. In this way, the density of the inorganic semiconductor quantum dot film formed by deposition can be further improved.

[0076] In summary, the present application adopts a spin coating process or a sputtering process to prepare the ultraviolet absorption layer, and the performance of the filter can be optimized by accurately controlling the spin coating rate, the thickness of the ultraviolet absorption layer, and the annealing temperature and time. Therefore, the preparation method proposed in the present application is simple in process, can reduce production costs, improve production efficiency, and is conducive to large-scale promotion and application.

[0077] In some embodiments, the inorganic semiconductor quantum dots are prepared by sonochemical method.

[0078] In some embodiments, the method for preparing inorganic semiconductor quantum dots using ultrasonic chemistry may include the following steps:

[0079] Step S200, subjecting the solution containing the metal salt to a first ultrasonic treatment;

[0080] Step S210, adding a hydroxide-containing solution to the solution after the first ultrasonic treatment, and performing a second ultrasonic treatment;

[0081] Step S220, washing and centrifuging the solution after the second ultrasonic treatment to obtain inorganic semiconductor quanta.

[0082] In some embodiments, a surface modifier may be added in step S200 or step S210. By wrapping the inorganic semiconductor quantum dots with the surface modifier, the quantum dots can be evenly dispersed to avoid agglomeration. At the same time, it can also protect them from the influence of moisture, oxygen or other substances in the environment, making them more stable.

[0083] In some embodiments, the protective layer can be prepared by thermal evaporation or sputtering.

[0084] In some embodiments, the surface modifier includes a polymer modifier, such as polyethylene glycol. The polymer modifier can form a chemical bond with the inorganic semiconductor quantum dots, and can be stably wrapped on the surface of the inorganic semiconductor quantum dots through the chemical bond, thereby preventing the quantum dots from agglomerating and causing devitrification.

[0085] In a third aspect, the present application also provides an application of a solar-blind filter according to the first aspect of the present application or a solar-blind filter prepared according to the preparation method described on the second reverse side of the present application in an ultraviolet detector.

[0086] Example

[0087] The following are specific examples, which more specifically describe the contents disclosed in this application, and these examples are only for illustrative purposes, because it is obvious to those skilled in the art that various modifications and variations are made within the scope of the disclosure of this application. Unless otherwise stated, all parts, percentages, and ratios reported in the following examples are based on weight, and all reagents used in the examples are commercially available or synthesized according to conventional methods and can be used directly without further processing, and the instruments used in the examples are commercially available.

[0088] Example 1

[0089] (1) ZnO quantum dots

[0090] 0.2 g zinc acetate dihydrate was dissolved in 60 mL ethanol, placed under 240 W ultrasonic environment for 50 min, 1 mL polyethylene glycol (PEG) was added, and placed under 240 W ultrasonic environment for 40 min; 0.04 g lithium hydroxide solution was titrated into the zinc acetate solution, ultrasonically reacted at 240 W for 30 min, 1 mL oleic acid was added and allowed to stand for 5 min; the obtained solution was centrifuged and washed three times with a 1:5 mixed solution of n-hexane and ethanol, and then dried at 60 ° C for 2 h to obtain ZnO quantum dots (band gap of 3.5 eV~4.0 eV).

[0091] (2) Sol containing ZnO quantum dots

[0092] 2 g of ZnO quantum dots modified with high molecular weight polymer PEG were dissolved in 20 g of chloroform, and magnetic stirring was performed at 60° C. for 2 h to completely dissolve the ZnO quantum dots, thereby obtaining a sol containing ZnO quantum dots.

[0093] (3) UV-transmitting layer

[0094] Use a special quartz cleaner to clean the quartz and ultrasonicate it for 30 minutes to ensure that the quartz surface is clean. The water used in the whole process is deionized water. After cleaning, blow it dry with nitrogen and use it as a UV transmission layer for standby use.

[0095] (4) UV absorption layer

[0096] The sol containing ZnO quantum dots was coated on the surface of quartz by spin coating, and was rotated at 3000 rpm for 1 hour, and then annealed at 500°C for 2 hours to obtain an ultraviolet absorption layer.

[0097] (5) Protective layer

[0098] A 10 nm thick SiO2 protective layer is deposited on the surface of the ultraviolet absorption layer by thermal evaporation to prepare the first filter.

[0099] (6) Solar Blind Filter

[0100] 2 , the first filter and the ultraviolet glass as the second filter are encapsulated in a blackened aluminum housing, with the first filter being the light incident surface, to prepare a solar blind filter.

[0101] Example 2

[0102] (1) Ga2O3 quantum dots

[0103] 0.1 mL of liquid metal gallium (purity 99.99%) was added to 20 mL of hydrochloric acid solution (pH = 1.5), and placed in a 240W ultrasonic environment for 30 minutes; insoluble particles were removed by centrifugation, 0.1 mL of 50 mmol / L hydrogen peroxide solution was added, and the solution was placed in a 240W ultrasonic environment for 40 minutes; the reaction solution was dialyzed for 10 hours; 1 mL of polyethylene glycol (PEG) was added, and the solution was placed in a 240W ultrasonic environment for 40 minutes; the obtained solution was washed three times by centrifugation with a 1:5 mixed solution of n-hexane and ethanol, and then dried at 60°C for 2 hours to obtain Ga2O3 quantum dots (band gap of 4.5eV~4.9eV).

[0104] (2) Sol containing Ga2O3 quantum dots

[0105] 2 g of Ga2O3 quantum dots modified with high molecular weight polymer PEG were dissolved in 20 g of chloroform and stirred with a magnetic stirrer at 60°C for 2 h to completely dissolve the dots, thereby obtaining a sol containing Ga2O3 quantum dots.

[0106] (3) Base cleaning

[0107] Use a special sapphire cleaner to clean the sapphire, and ultrasonicate for 30 minutes to ensure that the sapphire surface is clean. The water used in the whole process is deionized water. After cleaning, blow it dry with nitrogen to use as a UV transmission layer for later use.

[0108] (4) UV absorption layer

[0109] The sol containing Ga2O3 quantum dots was coated on the surface of sapphire by spin coating, and was spun at 2000 rpm for 1 hour, and then annealed at 600°C for 2 hours to obtain an ultraviolet absorption layer.

[0110] (5) Protective layer

[0111] A 15 nm thick Al2O3 protective film layer is plated on the surface of the ultraviolet absorption layer by magnetron sputtering to prepare the first filter.

[0112] (6) Solar Blind Filter

[0113] 2 , the first filter and the ultraviolet glass as the second filter are encapsulated in a blackened aluminum housing, with the first filter being the light incident surface, to prepare a solar blind filter.

[0114] Example 3

[0115] The preparation process is similar to that of Example 1, with the main difference being that in step (1), the ultrasonic power condition is adjusted so that the average particle size of the ZnO quantum dots is 2 nm.

[0116] Example 4

[0117] The preparation process is similar to that of Example 1, with the main difference being that in step (1), the ultrasonic power condition is adjusted so that the average particle size of the ZnO quantum dots is 10 nm.

[0118] Example 5

[0119] The preparation process is similar to that of Example 1, with the main difference being that in step (1), the ultrasonic power condition is adjusted so that the average particle size of the ZnO quantum dots is 0.5 nm.

[0120] Example 6

[0121] The preparation process is similar to that of Example 1, with the main difference being that in step (1), the ultrasonic power condition is adjusted so that the average particle size of the ZnO quantum dots is 15 nm.

[0122] Example 7

[0123] The preparation process is similar to that of Example 1, with the main difference being that in step (4), the spin coating time is adjusted so that the thickness of the ultraviolet absorption layer is 10 nm.

[0124] Example 8

[0125] The preparation process is similar to that of Example 1, with the main difference being that in step (4), the spin coating time is adjusted so that the thickness of the ultraviolet absorption layer is 100 nm.

[0126] Example 9

[0127] The preparation process is similar to that of Example 1, with the main difference being that in step (4), the spin coating time is regulated so that the thickness of the ultraviolet absorption layer is 5 nm.

[0128] Example 10

[0129] The preparation process is similar to that of Example 1, with the main difference being that in step (4), the spin coating time is adjusted so that the thickness of the ultraviolet absorption layer is 105 nm.

[0130] Embodiment 11

[0131] The preparation process is similar to that of Example 1, with the main difference being that step (1) is omitted and in step (2), an equal mass of PbSe quantum dots (with a band gap of 0.7 eV to 1.0 eV) is used to replace ZnO quantum dots to prepare the sol, and the average particle size of the PbSe quantum dots is the same as that of the ZnO quantum dots.

[0132] Example 12

[0133] The preparation process is similar to that of Example 1, with the main difference being that step (1) is omitted and in step (2), an equal mass of CsPbCl3 quantum dots (band gap of 6.5 eV~7.0 eV) is used instead of ZnO quantum dots to prepare the sol, and the average particle size of the CsPbCl3 quantum dots and the ZnO quantum dots is the same.

[0134] Comparative Example 1

[0135] The preparation method is similar to that of Example 1, with the main difference being that step (1) is omitted and in step (2), an equal mass of ZnO is used instead of ZnO quantum dots to prepare the sol.

[0136] Comparative Example 2

[0137] The preparation method is similar to that of Example 1, with the main difference being that in step (6), the second filter is removed.

[0138] The solar blind filters prepared in Examples 1 to 12 and Comparative Examples 1 to 2 were subjected to relevant performance tests, and the test results are shown in Table 1 below.

[0139] Among them, the test conditions or test standards for each performance test item are as follows:

[0140] (1) Test of transmittance and out-of-band cutoff depth for solar-blind ultraviolet light

[0141] Use a spectrum analyzer (such as Yokogawa AQ6374) to test the peak transmittance of the solar-blind filter to solar-blind ultraviolet light and the minimum out-of-band cutoff depth.

[0142] Table 1

[0143]

[0144] In Table 1, when comparing Examples 1 to 12 with Comparative Example 1, it can be seen that when Comparative Example 1 uses ZnO to prepare the first filter, it cannot transmit day-blinding ultraviolet light; while Examples 1 to 12 use inorganic semiconductor quantum dots to prepare the first filter, but have a higher transmittance for day-blinding ultraviolet light, and have good cutoff performance for visible light and near-ultraviolet light. When comparing Examples 1 to 12 with Comparative Example 2, it can be seen that after Comparative Example 2 omits the second filter, although it has a higher transmittance for day-blinding ultraviolet light, it has poor cutoff performance for visible light and near-ultraviolet light.

[0145] In addition, by comparing Examples 1, 3 to 6, it can be seen that when the average particle size of the ZnO quantum dots is 2nm to 10nm, the transmittance of the day-blinding ultraviolet light can exceed 25%, and the cutoff performance of visible light and near-ultraviolet light can exceed 5.0OD. By comparing Examples 1, 7 to 10, it can be seen that when the thickness of the ultraviolet absorption layer is 10nm to 100nm, the transmittance of the day-blinding ultraviolet light can exceed 20%, and the cutoff performance of visible light and near-ultraviolet light can exceed 5.0OD. By comparing Example 1 with Examples 11 to 12, it can be seen that when the band gap of the inorganic semiconductor quantum dots is not between 3.5eV and 6.2eV, the transmittance of the day-blinding ultraviolet light will decrease to a certain extent.

[0146] In addition, it can also be seen from Figures 3 to 5 that the solar-blind filter of the present application has a high transmittance to solar-blind ultraviolet light, and can deeply absorb visible light and near-ultraviolet light, and thus has a good cutoff performance.

[0147] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0148] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims.

Claims

1. A solar blind filter, characterized in that: include: A first filter and a second filter are stacked, wherein the first filter comprises a UV transmission layer and a UV absorption layer which are stacked, and the second filter comprises a visible light absorption layer; The ultraviolet absorption layer is arranged between the ultraviolet transmission layer and the second filter, and the ultraviolet absorption layer includes inorganic semiconductor quantum dots.

2. The solar blind filter according to claim 1, characterized in that: The band gap of the inorganic semiconductor quantum dots is ≥3.4 eV, and can be selected to be 3.5 eV~6.2 eV.

3. The solar blind filter according to claim 1 or 2, characterized in that: The inorganic semiconductor quantum dots include one or more of ZnO quantum dots, Ga2O3 quantum dots, ZnO matrix doped quantum dots and Ga2O3 matrix doped quantum dots; Optionally, the ZnO matrix doped quantum dots include ZnO doped with Mg quantum dots; Optionally, the Ga2O3 matrix-doped quantum dots include one or both of Ga2O3 doped Si quantum dots and Ga2O3 doped Sn quantum dots.

4. The solar blind filter according to claim 1 or 2, characterized in that: Meet one or more of the following conditions: (1) The thickness of the ultraviolet absorption layer is 5 nm to 105 nm, and can be optionally 10 nm to 100 nm; (2) The average particle size of the inorganic semiconductor quantum dots is 0.5 nm to 15 nm, and can be 2 nm to 10 nm; (3) The visible light absorbing layer comprises ultraviolet glass; (4) The thickness of the second filter is 3 mm to 10 mm.

5. The solar blind filter according to any one of claims 1 to 4, characterized in that: The first filter further comprises a protective layer, and the protective layer is arranged between the ultraviolet absorption layer and the second filter; Optionally, the protective layer comprises one or both of SiO2 and Al2O3; Optionally, the protective layer has a thickness of 10 nm to 100 nm.

6. The solar blind filter according to claim 1 or 2, characterized in that: The transmittance of the solar-blind filter to solar-blind ultraviolet light is ≥20%, and the wavelength of the solar-blind ultraviolet light is 240nm~290nm.

7. A method for preparing a solar blind filter, characterized in that: include: Forming a first optical filter and a second optical filter which are stacked, wherein the first optical filter comprises an ultraviolet transmission layer and an ultraviolet absorption layer which are stacked, and the second optical filter comprises a visible light absorption layer; The ultraviolet absorption layer is arranged between the ultraviolet transmission layer and the second filter, and the ultraviolet absorption layer includes inorganic semiconductor quantum dots.

8. The preparation method according to claim 7, characterized in that: The preparation method of the ultraviolet absorption layer comprises: Using a spin coating process or a sputtering process, a sol containing the inorganic semiconductor quantum dots is deposited on one side of the ultraviolet transmission layer, and the ultraviolet absorption layer is prepared after annealing; Optionally, the spin coating rate of the spin coating process is 2000rpm~3000rpm; Optionally, when the spin coating process is adopted, the annealing temperature is 450° C. to 600° C., and the annealing time is 1 h to 2 h.

9. The preparation method according to claim 7 or 8, characterized in that: The inorganic semiconductor quantum dots are prepared by ultrasonic chemical method.

10. Use of the solar-blind filter according to any one of claims 1 to 6 or the solar-blind filter prepared by the preparation method according to any one of claims 7 to 9 in an ultraviolet detector.

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