Solar blind filter and preparation method and application thereof

Abstract

The application provides a solar blind filter and a preparation method and application thereof. The solar blind filter comprises a first filter and a second filter which are stacked, the first filter comprises an ultraviolet transmission layer and an ultraviolet 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 comprises inorganic semiconductor quantum dots. The solar blind filter provided by the application has a relatively thin 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 blindness filter and a preparation method and application thereof. Background Art

[0002] Currently, there are numerous methods for detecting partial discharge (PD) in the insulation performance of high-voltage electrical equipment. Infrared detection is the primary method suitable for online monitoring and dynamic inspections of power transmission and transformation equipment. Because infrared detection measures infrared radiation emitted by equipment due to surface temperature changes caused by PD, it suffers from detection lag and is susceptible to interference from factors such as rain and snow. Relying on manual evaluation and evaluation is prone to false detections, missed detections, low defect detection rates, and significant resource consumption for defect screening. Ultraviolet imagers, as instruments for detecting corona discharge and other issues during live operation, can early detect insulation hazards or damage, significantly reducing equipment failure rates and ensuring the safe operation of power systems. UV imaging, without requiring power outages, provides a relatively safe, intuitive, rapid, and accurate assessment of PD on the external insulation of high-voltage electrical equipment. Its high sensitivity and the absence of direct contact with the equipment allow for the integration of UV imaging with drones and online monitoring equipment to collect essential data on the operating status of the external insulation of high-voltage electrical equipment. Leveraging technologies such as big data-based artificial intelligence recognition promises to promptly and accurately identify equipment defects and hidden dangers, leading to its widespread application.

[0003] In UV imaging or detection technology, solar-blind UV light (wavelength range of 240nm-290nm) has become a key research area in UV detection due to its unique spectral properties and strong resistance to interference from sunlight. As a core component of UV detection, solar-blind filters have a direct impact on the sensitivity and stability of the entire system. Currently, solar-blind filters on the market primarily come in two types: interference and absorptive. Interference filters, requiring hundreds of layers of dielectric coating, often have low in-band transmittance (maximum transmittance of around 10%). Furthermore, these filters are highly sensitive to angle of view, making it difficult to achieve full solar-blind performance for UV detection. Absorptive filters, while unaffected by angle of view and possessing strong absorption, are relatively thick (typically greater than 30mm), and their complex and costly manufacturing processes hinder their widespread adoption. Summary of the Invention

[0004] Based on this, the present application provides a solar blinding filter with relatively thin thickness, excellent selectivity and high transmittance, as well as a preparation method and application thereof.

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

[0006] A first optical filter and a second optical filter are stacked, wherein the first optical filter includes a stacked ultraviolet transmitting layer and an ultraviolet absorbing layer, and the second optical filter includes a visible light absorbing 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 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 optionally 2 nm to 10 nm;

[0015] (3) The visible light absorbing layer includes 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 provided 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-blinding filter to solar-blinding ultraviolet light is ≥20%, and the wavelength of the solar-blinding ultraviolet light is 240nm~290nm.

[0021] A 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 transmitting layer and an ultraviolet absorbing layer which are stacked, and the second optical filter comprises a visible light absorbing 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 absorbing layer includes:

[0025] Depositing the sol containing the inorganic semiconductor quantum dots on one side of the ultraviolet transmitting layer by a spin coating process or a sputtering process, and preparing the ultraviolet absorbing layer after annealing;

[0026] Optionally, the spin coating process has a spin coating rate of 2000 rpm to 3000 rpm;

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

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

[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 the remaining 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] Figure 1 Schematic diagram of a solar blind filter according to one embodiment of the present application.

[0032] Figure 2 Schematic diagram of a solar blind filter according to one embodiment of the present application.

[0033] Figure 3 Spectral characteristic curve diagram of a solar blind filter according to one embodiment of the present application.

[0034] Figure 4 Spectral characteristic curve diagram of a solar blind filter according to one embodiment of the present application.

[0035] Figure 5 Spectral characteristic curve diagram of a solar blind filter according to one embodiment of the present application.

[0036] Reference numerals: 10 first optical filter; 20 second optical filter; 110 ultraviolet transmitting layer; 120 ultraviolet absorbing layer; 130 protective layer; 200 visible light absorbing layer.

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

[0038] To facilitate understanding of the present application, the present application will be described in more detail below. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, the purpose of providing these embodiments is to provide a more thorough and comprehensive understanding of the disclosure of the present application.

[0039] For simplicity, this application only explicitly discloses certain numerical ranges. However, any lower limit may be combined with any upper limit to form an unspecified range; and any lower limit may be combined with other lower limits to form an unspecified range, and similarly, any upper limit may be combined with any other upper limit to form an unspecified range. In addition, although not explicitly stated, each point or individual value between the endpoints of a range is included in the range. Thus, each point or individual value may serve as its own lower limit or upper limit and be combined with any other point or individual value, or with other lower limits or upper limits, to form an unspecified range.

[0040] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly 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 stated, the term "and / or" used herein includes any and all combinations of one or more related listed items, "above" and "below" are inclusive of the number, and the meaning of "multiple" in "one or more" is more than two.

[0041] As used herein, when referring to a numerical interval (i.e., a numerical range), unless otherwise specified, the distribution of the optional numerical values ​​within the numerical interval is deemed to be continuous and includes the two numerical endpoints of the numerical interval (i.e., the minimum and maximum values), as well as every numerical value between the two numerical endpoints. Unless otherwise specified, when a numerical interval refers only to integers within the numerical interval, it includes the two endpoint integers of the numerical range, as well as every integer between the two endpoints, which is equivalent to directly listing every integer. When multiple numerical ranges are provided to describe a feature or characteristic, 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 subranges included therein. The "numerical value" in the numerical interval can be any quantitative value, such as a number, percentage, ratio, etc. "Numerical interval" allows for a broad range of numerical interval types including percentage intervals, ratio intervals, and ratio intervals.

[0042] In this document, if a method flow involves multiple steps, unless otherwise specified herein, there is no strict order restriction on the execution of these steps, and they can be performed in an order other than the order described. Moreover, any step can include multiple sub-steps or multiple stages, and these sub-steps or stages do not necessarily need to be completed at the same time, but can be performed at different times, and their execution order does not necessarily need to be sequential, but can be performed in rotation, alternation, or simultaneously with other steps or parts of sub-steps or stages of other steps.

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

[0044] In the first aspect, the present application provides a solar blind filter, see Figure 1 Examples include:

[0045] A first optical filter 10 and a second optical filter 20 are stacked, wherein the first optical filter 10 includes a UV-transmitting layer 110 and a UV-absorbing layer 120, and the second optical filter 20 includes a visible light-absorbing layer 200;

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

[0047] The solar-blind filter provided in this application includes the above-mentioned structure. After light enters the first filter, the ultraviolet-transmitting layer has high transmittance and low absorptivity for ultraviolet light. Thus, the majority of the ultraviolet light passing through the ultraviolet-transmitting layer enters the ultraviolet-absorbing layer. The ultraviolet-absorbing layer, due to the introduction of inorganic semiconductor quantum dots, can utilize the band gap of the inorganic semiconductor to cover the solar-blind ultraviolet band in the incident light. Simultaneously, the size effect of the quantum dots is used to precisely control light selectivity, resulting in the ultraviolet-absorbing layer having excellent selectivity for incident light, high transmittance for the solar-blind ultraviolet band, and excellent cutoff performance for visible and near-ultraviolet light. The second filter can effectively absorb the visible light fluorescence generated by the excited inorganic semiconductor quantum dots. Thus, the combination of the first and second filters can achieve high transmittance for the solar-blind ultraviolet band and deep absorption for the remaining bands, effectively improving the signal-to-noise ratio of a detector using the solar-blind filter.

[0048] It should be noted that in the solar 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 second filter has an absorption depth of 400 nm to 100 nm, and an absorption intensity of no less than 10 OD (Optical Density). This allows the second filter to effectively filter out visible light fluorescence generated by the excited inorganic semiconductor quantum dots, thereby improving the selectivity of the solar-blind filter and its transmittance in the solar-blind ultraviolet band.

[0051] In some embodiments, the band gap of the inorganic semiconductor quantum dots is ≥3.4 eV, and can be 3.5 eV to 6.2 eV. For example, the band gap of the inorganic semiconductor quantum dots can be 3.4 eV, 3.6 eV, 3.8 eV, 4 eV, 4.2 eV, 4.4 eV, 4.6 V, 4.8 eV, 5 eV, 5.2 eV, 5.4 eV, 5.6 eV, 5.8 eV, 6 eV, 6.2 eV, 6.4 eV, 6.6 V, 6.8 eV, 7.0 eV, or within a range consisting of any of the above values. In this way, the band gap of the inorganic semiconductor quantum dots 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 high absorption of 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. This allows the inorganic semiconductor quantum dots to have a wide band gap, which effectively absorbs visible light and near-ultraviolet light while providing high transmittance to solar-blinding ultraviolet light.

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

[0054] In some embodiments, the ZnO matrix doped quantum dots include ZnO doped 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 UV absorbing layer is between 5 nm and 105 nm. For example, the thickness of the UV absorbing layer can be 5 nm, 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 105 nm, or within a range of any of the above values; optionally, the thickness can be between 10 nm and 100 nm. This allows the UV absorbing layer to control its light absorption intensity. A relatively large thickness can easily reduce transmittance; a relatively small thickness can result in relatively low light absorption intensity.

[0057] In some embodiments, the average particle size of the inorganic semiconductor quantum dots is between 0.5 nm and 15 nm. For example, the average particle size of the inorganic semiconductor quantum dots can be 0.5 nm, 2 nm, 3 nm, 4 nm, 5 nm, 6 nm, 7 nm, 8 nm, 9 nm, 10 nm, 15 nm, or within a range comprised of any of the above values; optionally, it can be between 2 nm and 10 nm. By controlling the average particle size of the inorganic semiconductor quantum dots, the selectivity of the ultraviolet absorption layer for light can be precisely controlled, resulting in a high transmittance of the ultraviolet absorption layer for solar-blinding ultraviolet light and excellent cutoff performance for visible light and near-ultraviolet light. This can improve the environmental adaptability of the solar-blinding filter and extend its service life.

[0058] As an example, the average particle size of inorganic semiconductor quantum dots can be measured with reference to GB / T 19077-2016 Particle Size Distribution Laser Diffraction Method 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 UV-transmitting layer comprises one or more of quartz glass, sapphire, and magnesium fluoride. This allows the UV-transmitting layer to have high UV transmittance and low UV absorptivity, thereby reducing UV absorption and allowing most of the UV light passing through the UV-transmitting layer to enter the UV-absorbing layer.

[0060] In some embodiments, the visible light absorbing layer comprises ultraviolet glass, which can 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 second filter has a thickness of 3 mm to 10 mm. For example, the second filter can have a thickness of 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, or any range thereof. This can further enhance the second filter's ability to absorb fluorescence generated by inorganic semiconductor quantum dots.

[0063] In some embodiments, see Figure 2 In the example of FIG, the first optical filter 10 further includes a protective layer 130, and the protective layer 130 is provided 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 SiO 2 and Al 2 O 3 .

[0065] In some embodiments, the protective layer has a thickness of 10 nm to 100 nm. For example, the protective layer can have a thickness of 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, or any range thereof. This allows the solar-blinding filter to have both high mechanical strength and thermal stability and high transmittance to solar-blinding 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 240 nm to 290 nm.

[0067] Therefore, the solar blind filter provided by the present application is relatively thin, has excellent ultraviolet light selectivity and high transmittance, and has good thermal stability and mechanical strength. It 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 transmitting layer and an ultraviolet absorbing layer, and the second filter includes a visible light absorbing layer; the ultraviolet absorbing layer is arranged between the ultraviolet transmitting layer and the second filter, and the ultraviolet absorbing layer contains inorganic semiconductor quantum dots.

[0070] The solar-blind filter prepared using the preparation method of the present application comprises the aforementioned structure. After light enters the first filter, the UV-transmitting layer exhibits high transmittance and low absorptivity for UV light. Consequently, the majority of the UV light passing through the UV-transmitting layer enters the UV-absorbing layer. The UV-absorbing layer, incorporating inorganic semiconductor quantum dots, utilizes the band gap of the inorganic semiconductor to cover the solar-blind UV band of the incident light. Simultaneously, the size effect of the quantum dots is utilized to precisely control light selectivity, resulting in the UV-absorbing layer exhibiting excellent selectivity for incident light, high transmittance for the solar-blind UV band, and excellent cutoff performance for visible and near-ultraviolet light. The second filter effectively absorbs the visible light fluorescence generated by the excited inorganic semiconductor quantum dots. The combination of the first and second filters achieves high transmittance for the solar-blind UV band and deep absorption for the remaining wavelengths, effectively improving the signal-to-noise ratio of detectors using the solar-blind filter.

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

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

[0073] In step S100 , annealing can make the deposited inorganic semiconductor quantum dot film layer denser and have better adsorption properties with the ultraviolet transparent layer.

[0074] In some embodiments, the spin coating process is performed at a spin coating rate of 2000 rpm to 3000 rpm. For example, the spin coating rate can be 2000 rpm, 2200 rpm, 2400 rpm, 2600 rpm, 2800 rpm, 3000 rpm, or any range thereof. This can result in a more uniform film layer of the deposited inorganic semiconductor quantum dots and 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 hour to 2 hours. This can further improve the density of the deposited inorganic semiconductor quantum dot film.

[0076] In summary, this application utilizes a spin coating or sputtering process to prepare the UV absorbing layer. By precisely controlling parameters such as the spin coating rate, UV absorbing layer thickness, and annealing temperature and time, the filter performance can be optimized. Consequently, the preparation method proposed in this application is simple, reduces production costs, improves production efficiency, and facilitates large-scale application.

[0077] In some embodiments, the inorganic semiconductor quantum dots are prepared using a 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 metal salt-containing solution 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, thereby stably encapsulating the surface of the inorganic semiconductor quantum dots and preventing quantum dot agglomeration and devitrification.

[0085] In a third aspect, the present application also 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 reverse side of the present application in an ultraviolet detector.

[0086] Example

[0087] The following are specific examples, which describe the present disclosure in more detail. These examples are intended for illustrative purposes only, as various modifications and variations within the scope of the present disclosure will be apparent to those skilled in the art. Unless otherwise stated, all parts, percentages, and ratios reported in the following examples are by 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. The instruments used in the examples are also commercially available.

[0088] Example 1

[0089] (1) ZnO quantum dots

[0090] 0.2 g of zinc acetate dihydrate was dissolved in 60 mL of ethanol, placed under a 240 W ultrasonic environment for 50 minutes, 1 mL of polyethylene glycol (PEG) was added, and the solution was placed under a 240 W ultrasonic environment for 40 minutes; 0.04 g of lithium hydroxide solution was titrated into the zinc acetate solution, ultrasonically reacted at 240 W for 30 minutes, 1 mL of oleic acid was added, and the solution was allowed to stand for 5 minutes; the resulting 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 hours 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 a 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 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 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 to use as a UV transparent layer.

[0095] (4) UV absorption layer

[0096] The ZnO quantum dot sol was coated on the surface of quartz by spin coating, and rotated at 3000 rpm for 1 hour, and then annealed at 500°C for 2 hours to obtain a UV 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] Reference Figure 2 The structure is as follows: the first filter and the ultraviolet glass serving 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 (99.99% purity) 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 mixture 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 mixture was placed in a 240W ultrasonic environment for 40 minutes; the resulting 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 4.5 eV~4.9 eV).

[0104] (2) Sol containing Ga2O3 quantum dots

[0105] 2 g of Ga2O3 quantum dots modified with a 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 transparent layer.

[0108] (4) UV absorption layer

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

[0110] (5) Protective layer

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

[0112] (6) Solar blind filter

[0113] Reference Figure 2The structure is as follows: the first filter and the ultraviolet glass serving 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 conditions are regulated 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 regulated 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 regulated 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 conditions are regulated 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 regulated 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 regulated 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 regulated so that the thickness of the ultraviolet absorption layer is 105 nm.

[0130] Example 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 (band gap of 0.7 eV to 1.0 eV) is used instead of ZnO quantum dots to prepare the sol, and the average particle size of the PbSe quantum dots and the ZnO quantum dots is the same.

[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 blinding 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, a comparison of Examples 1-12 with Comparative Example 1 shows that the first filter in Comparative Example 1, made of ZnO, fails to transmit solar-blinding ultraviolet light. In contrast, the first filters in Examples 1-12, made of inorganic semiconductor quantum dots, exhibit high transmittance for solar-blinding ultraviolet light and good cutoff performance for visible and near-ultraviolet light. A comparison of Examples 1-12 with Comparative Example 2 shows that, after omitting the second filter, Comparative Example 2 exhibits high transmittance for solar-blinding ultraviolet light, but poor cutoff performance for visible and near-ultraviolet light.

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

[0146] In addition, from Figures 3-5 It can also be seen 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, thus having a good cut-off performance.

[0147] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned 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-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art could make various modifications and improvements without departing from the spirit of the present application, all of which fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

Claims

1. A solar blindness filter, characterized in that: include: A first optical filter and a second optical filter are stacked, wherein the first optical filter includes a stacked ultraviolet transmitting layer and an ultraviolet absorbing layer, and the second optical filter includes a visible light absorbing layer; The ultraviolet absorption layer is provided between the ultraviolet transmission layer and the second filter, the ultraviolet absorption layer comprises inorganic semiconductor quantum dots, and the band gap of the inorganic semiconductor quantum dots is ≥3.4 eV; 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 of the day-blind ultraviolet band and deep absorption of the remaining bands can be achieved.

2. The solar blind filter according to claim 1, characterized in that The band gap of the inorganic semiconductor quantum dots is 3.5 eV to 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.

4. The solar blind filter according to claim 3, characterized in that: One or more of the following conditions are met: (1) The ZnO matrix doped quantum dots include ZnO doped Mg quantum dots; (2) The Ga2O3 matrix doped quantum dots include one or both of Ga2O3 doped Si quantum dots and Ga2O3 doped Sn quantum dots.

5. 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; (2) The average particle size of the inorganic semiconductor quantum dots is 0.5 nm to 15 nm; (3) The visible light absorbing layer includes ultraviolet glass; (4) The thickness of the second filter is 3 mm to 10 mm.

6. The solar blind filter according to claim 5, characterized in that: One or more of the following conditions are met: (1) The thickness of the ultraviolet absorption layer is 10 nm to 100 nm; (2) The average particle size of the inorganic semiconductor quantum dots is 2 nm to 10 nm.

7. The solar blind filter according to claim 1 or 2, characterized in that: The first filter further includes a protective layer, which is arranged between the ultraviolet absorption layer and the second filter.

8. The solar blind filter according to claim 7, characterized in that: One or more of the following conditions are met: (1) The protective layer contains one or both of SiO2 and Al2O3; (2) The thickness of the protective layer is 10 nm to 100 nm.

9. The solar blind filter according to claim 1 or 2, characterized in that: 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.

10. A method for preparing a solar blindness 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 transmitting layer and an ultraviolet absorbing layer which are stacked, and the second optical filter comprises a visible light absorbing layer; The ultraviolet absorption layer is provided between the ultraviolet transmission layer and the second filter, the ultraviolet absorption layer comprises inorganic semiconductor quantum dots, and the band gap of the inorganic semiconductor quantum dots is ≥3.4 eV; 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 of the day-blind ultraviolet band and deep absorption of the remaining bands can be achieved.

11. The preparation method according to claim 10, characterized in that: The preparation method of the ultraviolet absorption layer comprises: The sol containing the inorganic semiconductor quantum dots is deposited on one side of the ultraviolet transmission layer by a spin coating process or a sputtering process, and the ultraviolet absorption layer is prepared after annealing.

12. The preparation method according to claim 11, characterized in that One or more of the following conditions are met: (1) The spin coating process has a spin coating rate of 2000 rpm to 3000 rpm; (2) 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.

13. The preparation method according to any one of claims 10 to 12, characterized in that The inorganic semiconductor quantum dots are prepared by ultrasonic chemical method.

14. Use of the solar-blind filter according to any one of claims 1 to 9 or the solar-blind filter prepared by the preparation method according to any one of claims 10 to 13 in an ultraviolet detector.

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