Perovskite nanocrystal glass optical filter, preparation method thereof and optical element

Abstract

The application provides a perovskite nanocrystal glass filter and a preparation method and an optical element thereof. The perovskite nanocrystal glass filter comprises the following components in percentage by mass: Bi2O3: 50-80%; B2O3: 8-25%; La2O3: 1-10%; Al2O3: 0-3%; Na2SO4: 0-1%; and the perovskite nanocrystal glass filter further comprises Cs2O, PbBr2, NaCl and NaBr. The perovskite nanocrystal glass filter has the characteristics of low production cost, controllable cutoff in the working wavelength (450-490 nm) region, high transmittance in the transmission region, good chemical stability, superior optical performance and durability.

Description

TECHNICAL FIELD

[0001] The present application relates to a perovskite nanocrystal glass filter and a preparation method thereof and an optical element, and belongs to the technical field of glass filters. BACKGROUND

[0002] The filter is a commonly used functional component in optical devices, which is used to selectively filter out light of a specific wavelength. The filter is widely used in medical equipment, optical instruments, photography and video shooting, etc. The traditional filter is usually made by glass coating, but they have the limitations of high cost and short service life.

[0003] In the glass filter, the glass transmission region of the transition metal ion and rare earth ion colorant filter has excess absorption peaks and poor steepness; the glass of the metal colloid colorant filter uses noble metal salt, resulting in high cost and low cutoff degree. These two types of glasses are only suitable for cases where the filtering performance is not high, therefore, a new type of filter technology needs to be developed to overcome these problems. SUMMARY

[0004] Problems to be solved by the application

[0005] In view of the problems existing in the prior art, such as low cutoff degree and poor steepness of the existing glass filter, one of the main purposes of the present application is to provide a perovskite nanocrystal glass filter. The melting point of the perovskite nanocrystal glass filter of the present application is relatively low, which greatly reduces the melting temperature and reduces the cost of raw materials, thereby saving the production cost.

[0006] In addition, the perovskite nanocrystal glass filter of the present application also reduces the volatilization of halide to form quantum dots, and significantly improves the cutoff steepness of the glass filter, realizes controllable cutoff in the working wavelength (450-490nm) region, and has high transmittance in the transmission region. Moreover, the perovskite nanocrystal glass filter of the present application has good chemical stability, which can meet the requirements of industry development on glass performance.

[0007] Further, the present application also provides a preparation method of the perovskite nanocrystal filter glass, which is simple and easy to operate, and the raw materials are easy to obtain, which is suitable for mass production.

[0008] Solution for solving the problem

[0009] The present application first provides a perovskite nanocrystal glass filter, which comprises the following components in mass percentage:

[0010] Bi2O3: 50-80%;

[0011] B2O3: 8-25%;

[0012] La2O3: 1-10%;

[0013] Al2O3: 0-3%;

[0014] Na2SO4: 0-1%;

[0015] Further, the perovskite nanocrystal glass filter further comprises Cs2O, PbBr2, NaCl and NaBr.

[0016] The perovskite nanocrystal glass filter according to the present application, wherein the content of Cs2O is 8-18% by mass, the content of PbBr2 is 5-15% by mass, the content of NaCl is 1-3% by mass, and the content of NaBr is 1-3% by mass.

[0017] The perovskite nanocrystal glass filter according to the present application, wherein the sum of the contents of Cs2O, PbBr2, NaCl and NaBr, Cs2O+PbBr2+NaCl+NaBr, is 10-30% by mass; and / or,

[0018] The mass ratio of Cs2O to PbBr2 is 0.7-0.8:1, or the mass ratio of Cs2O to PbBr2 is 1.5-1.8:1.

[0019] The perovskite nanocrystal glass filter according to the present application, wherein when the thickness of the perovskite nanocrystal glass filter is 2 mm, the cut-off wavelength is 450 nm or more; and / or,

[0020] When the thickness of the perovskite nanocrystal glass filter is 2 mm, the transmittance in the 520-550 nm wavelength band is 65% or more, the transmittance in the 550-630 nm wavelength band is 70% or more, and the transmittance in the 630-800 nm wavelength band is 79% or more.

[0021] The perovskite nanocrystal glass filter according to the present application, wherein the acid resistance of the perovskite nanocrystal glass filter is grade 2 or grade 1, and the water resistance of the perovskite nanocrystal glass filter is grade 2 or grade 1.

[0022] The present application also provides a preparation method of the perovskite nanocrystal glass filter according to the present application, wherein the preparation method comprises the following steps:

[0023] Mixing the component raw materials of the perovskite nanocrystal glass filter to obtain a mixture;

[0024] After melting, shaping and annealing the mixture, a bismuthate precursor glass is obtained.

[0025] The bismuthate precursor glass is heat treated to obtain a perovskite nanocrystal glass optical filter.

[0026] According to the preparation method, the melting comprises melting the mixture in a melting furnace and then homogenizing to obtain molten glass.

[0027] Preferably, the homogenizing is performed under gradient stirring; more preferably, the gradient stirring comprises a combination of two or more of 4-12 hours at a rotation speed of 40 rpm, 4-12 hours at a rotation speed of 30 rpm, 1-3 hours at a rotation speed of 20 rpm, and 1-3 hours at a rotation speed of 10 rpm.

[0028] Further preferably, the melting temperature is 900-950 DEG C, and the homogenizing temperature is 1000-1050 DEG C.

[0029] According to the preparation method, the forming comprises forming by pouring or pouring and dripping; preferably, the molten glass is cooled to 800-850 DEG C and then poured or poured and dripped; and / or,

[0030] The annealing temperature is 280-350 DEG C, and the annealing time is 5-8 hours.

[0031] According to the preparation method, the heat treatment comprises nucleating and crystallizing the bismuthate precursor glass in a crystallization furnace.

[0032] Preferably, the nucleating temperature is 350-380 DEG C, and the nucleating time is 2-10 hours; and / or, the crystallizing temperature is 400-460 DEG C, and the crystallizing time is 6-24 hours.

[0033] The application further provides an optical element comprising the perovskite nanocrystal glass optical filter.

[0034] Effects of the application

[0035] The perovskite nanocrystal glass optical filter has low production cost, controllable cutoff in the working wavelength (450-490 nm) region, high transmittance in the transmission region, good chemical stability, superior optical performance and durability.

[0036] Further, the preparation method of the perovskite nanocrystal glass optical filter is simple and easy to implement, raw materials are easy to obtain, the production cost is low, the melting temperature is low, and the method is suitable for mass production. BRIEF DESCRIPTION OF DRAWINGS

[0037] Figure 1The spectral transmittance graph (a) and the X-ray diffraction spectrum (b) of the perovskite nanocrystal glass filter glass of Example 1 of the present application are shown;

[0038] Figure 2 The spectral transmittance graph (a) and the X-ray diffraction spectrum (b) of the perovskite nanocrystal glass filter glass of Example 2 of the present application are shown;

[0039] Figure 3 The spectral transmittance graph (a) and the X-ray diffraction spectrum (b) of the perovskite nanocrystal glass filter glass of Example 3 of the present application are shown;

[0040] Figure 4 The spectral transmittance graph (a) and the X-ray diffraction spectrum (b) of the perovskite nanocrystal glass filter glass of Example 4 of the present application are shown;

[0041] Figure 5 The spectral transmittance graph (a) and the X-ray diffraction spectrum (b) of the perovskite nanocrystal glass filter glass of Example 5 of the present application are shown;

[0042] Figure 6 The spectral transmittance graph (a) and the X-ray diffraction spectrum (b) of the perovskite nanocrystal glass filter glass of Example 6 of the present application are shown. DETAILED DESCRIPTION

[0043] Various illustrative embodiments, features and aspects of the present application are described below in detail. The word "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any implementation described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other implementations.

[0044] In addition, numerous specific details are set forth in the following description in order to provide a thorough understanding of the present application. Those skilled in the art will understand, however, that the present application can be practiced without certain specific details being presented. In other instances, well-known methods, procedures, components, and steps have not been described in detail as they are not pertinent to the subject matter of the present application.

[0045] Unless otherwise indicated, units used in the present specification are international standard units, and the numerical values, numerical value ranges appearing in the present application should be understood as including systematic errors that are inevitable in industrial production.

[0046] In the present specification, the meaning of "may" includes both the meaning of performing a certain process and the meaning of not performing a certain process.

[0047] In this specification, reference to "some specific / preferred embodiments", "other specific / preferred embodiments", "embodiments", etc. means that a particular feature (e.g. a characteristic, structure, property, and / or characteristic) described in relation to the embodiment is included in at least one embodiment described herein, and can or can not be present in other embodiments. In addition, it should be understood that the described features can be combined in any suitable manner in the various embodiments.

[0048] In this specification, a numerical range expressed using "numerical value A ~ numerical value B" means a range including the end point numerical values A, B.

[0049] "Does not contain" "0%" described herein means that the compound, element, etc. is not intentionally added as a raw material to the glass of the present application, but as a raw material and / or equipment for producing the glass, there can be some impurities or components that are not intentionally added, and a small amount or trace amount is contained in the final glass, and such a case is also within the scope of protection of the present application.

[0050] <First aspect>

[0051] A first aspect of the present application provides a perovskite nanocrystal glass filter mainly including the following components in mass percentage:

[0052] Bi2O3: 50 ~ 80%;

[0053] B2O3: 8 ~ 25%;

[0054] La2O3: 1 ~ 10%;

[0055] Al2O3: 0 ~ 3%;

[0056] Na2SO4: 0 ~ 1%;

[0057] In addition, the perovskite nanocrystal glass filter further contains Cs2O, PbBr2, NaCl, and NaBr.

[0058] The composition of the perovskite nanocrystal glass filter of the present application will be described in detail below. It should be noted that the present application will form a bismuthate precursor glass in advance before forming the perovskite nanocrystal glass filter.

[0059] Through a suitable composition and introduction amount, the perovskite nanocrystals that can be precipitated in the perovskite nanocrystal glass filter of the present application include CsPbBr a Cl 3-a (0 < a ≤ 3), and Cs4PbBr b Cl 6-b(0<b≤6) quantum dots. The excellent performance of perovskite nanocrystals on bismuthate precursor glass substrate is utilized, which has superior optical performance and durability. The present application can selectively filter light of different wavelengths in the 450-490 nm region by controlling the composition and size of perovskite nanocrystals.

[0060] The present application utilizes the quantum confinement effect of perovskite quantum dots to form perovskite nanocrystal glass filters. When the geometric radius of a semiconductor crystal material gradually decreases to less than the exciton Bohr radius of its bulk material, the energy levels of its valence and conduction bands will change from continuous to discrete distribution. The smaller the size of the quantum dot, the greater the influence of quantum confinement effect on the photo-generated electrons and holes, thereby increasing the energy level gap. Specifically, the energy of the quantum dot to absorb and emit photons increases with the decrease of the size of the quantum dot, and the absorption spectrum cutoff wavelength position gradually blue shifts. By adjusting the amount of raw materials introduced, the perovskite nanocrystals that can be precipitated in the bismuthate precursor glass have CsPbBr a Cl 3-a (0<a≤3) and Cs4PbBr b Cl 6-b (0<b≤6).

[0061] Bi2O3 is a network former in the bismuthate precursor glass system of the present application. When the content of Bi2O3 is 50-80%, Bi2O3 begins to exist in the form of [BiO6] octahedron in the glass network structure. With the increase of Bi2O3 content, Bi2O3 enters the network structure as a network former, making the glass structure loose, reducing the viscosity of the glass, lowering the transition temperature of the glass, and increasing the thermal expansion coefficient. The bismuthate precursor glass of the present application can be melted at a lower temperature without crystallization, reducing the volatilization of halide to form quantum dots, and greatly improving the performance of the glass. Therefore, the content of Bi2O3 in the present application is 50-80% by mass, for example: 52%, 55%, 58%, 60%, 62%, 65%, 68%, 70%, 72%, 75%, 78%, etc.

[0062] B2O3 is a network former in glass, and the introduction of B2O3 network former in bismuthate precursor glass can improve the glass forming and stability. By using B2O3, the anti-crystallization of the pre-formed bismuthate precursor glass of the present application can be enhanced. In addition, B2O3 can also improve the phonon energy of the bismuthate precursor glass and reduce its infrared transmittance. Therefore, the content of B2O3 in the present application is 8-25% by mass, for example: 10%, 12%, 14%, 16%, 18%, 20%, 22%, 24%, etc.

[0063] La2O3 is an out-of-network body in bismuthate precursor glass, La2O3 can form stable compounds with other elements in bismuthate precursor glass, thereby preventing it from being oxidized or reduced, and improving the chemical stability of bismuthate precursor glass. Therefore, adding appropriate La2O3 in bismuthate precursor glass can improve its performance. In the present application, the content of La2O3 is 1-10% by mass, for example, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, etc.

[0064] Al2O3 plays a role of network intermediate in bismuthate precursor glass. Al2O3 can be connected with the glass framework, making the glass structure more compact, and improving the chemical stability, mechanical properties and thermal stability of bismuthate precursor glass. However, when the content of Al2O3 is too high, it will increase the difficulty of melting of bismuthate precursor glass, which is not conducive to the formation of quantum dots. Therefore, in the present application, the content of Al2O3 is controlled to be 0-3% by mass, for example: 0.2%, 0.5%, 0.8%, 1%, 1.2%, 1.5%, 1.8%, 2%, 2.2%, 2.5%, 2.8%, etc.

[0065] Na2SO4 plays a role of clarifying agent in glass manufacturing process, which can remove bubbles in molten glass and provide sodium ions required for the production of bismuthate precursor glass. In the present application, the content of Na2SO4 is 0-1% by mass, for example, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, etc.

[0066] The above glass composition is mainly used for forming bismuthate precursor glass. The present application uses bismuthate precursor glass as the matrix, which has the advantages of low phonon energy, high refractive index, strong corrosion resistance, relatively good chemical stability, and low raw material cost. Therefore, the bismuth borate precursor glass with low melting point is selected, which greatly saves the production cost and makes the product have great advantages in the market.

[0067] Cs2O, PbBr2, NaCl and NaBr are quantum dot components in the glass of the present application. By using Cs2O, PbBr2, NaCl and NaBr, different types of quantum dots can be formed, i.e. perovskite nanocrystals, including CsPbBr a Cl 3-a (0<a≤3) and Cs4PbBr b Cl 6-b (0<b≤6). Perovskite nanocrystals CsPbBr a Cl 3-a (0<a≤3) and Cs4PbBr b Cl 6-bThe quantum dot with 0<b≤6 has strong exciton absorption, sharp short-wave cutoff characteristics, and high transmittance in the transmission region without extra absorption peaks.

[0068] Specifically, in the present application, the content of Cs2O is 8-18% by mass, for example, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, etc.; the content of PbBr2 is 5-15%, for example: 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, etc.; the content of NaCl is 1-3%, for example, 1.2%, 1.4%, 1.6%, 1.8%, 2%, 2.2%, 2.4%, 2.6%, 2.8%, etc.; the content of NaBr is 1-3%, for example, 1.2%, 1.4%, 1.6%, 1.8%, 2%, 2.2%, 2.4%, 2.6%, 2.8%, etc. When the content of Cs2O is 8-18%, the content of PbBr2 is 5-15%, the content of NaCl is 1-3%, and the content of NaBr is 1-3%, the quantum dot required by the present application can be obtained.

[0069] In some specific embodiments, when the mass ratio of Cs2O to PbBr2 is 0.6-1.8:1, by adjusting the ratio of NaCl to NaBr, Cs4PbBr b Cl 6-b (0<b≤6) quantum dot or CsPbBr a Cl 3-a (0<a≤3) quantum dot. Specifically, when the mass ratio of Cs2O to PbBr2 is 0.7-0.8:1, for example, 0.71:1, 0.72:1, 0.73:1, 0.74:1, 0.75:1, 0.76:1, 0.77:1, 0.78:1, 0.79:1, etc., by adjusting the ratio of NaCl to NaBr, CsPbBr a Cl 3-a (0<a≤3) quantum dot is formed. When the mass ratio of Cs2O to PbBr2 is 1.5-1.8:1, for example, 1.52:1, 1.55:1, 1.58:1, 1.6:1, 1.62:1, 1.65:1, 1.68:1, 1.7:1, 1.72:1, 1.75:1, 1.78:1, etc., by adjusting the ratio of NaCl to NaBr, Cs4PbBr b Cl 6-b (0<b≤6) quantum dot is formed.

[0070] In the present application, the sum of the contents of Cs2O, PbBr2, NaCl and NaBr, Cs2O+PbBr2+NaCl+NaBr, is 10-30% by mass, for example, 12%, 15%, 18%, 20%, 22%, 25%, 28%, etc. When the sum of the contents of Cs2O, PbBr2, NaCl and NaBr, Cs2O+PbBr2+NaCl+NaBr, is 10-30%, it can further facilitate the formation of the desired perovskite nanocrystals.

[0071] The perovskite nanocrystal glass filter described in the present application has high transmittance in the transmission region, no extra absorption peak and steep cutoff characteristics. When the thickness of the perovskite nanocrystal filter glass is 2 mm, the cutoff wavelength of the perovskite nanocrystal glass of the present application is 450-490 nm.

[0072] When the thickness of the perovskite nanocrystal filter glass is 2 mm, the transmittance in the 520-550 nm wavelength band is 65% or more, the transmittance in the 550-630 nm wavelength band is 70% or more, and the transmittance in the 630-800 nm wavelength band is 79% or more.

[0073] Further, the acid resistance of the perovskite nanocrystal glass filter of the present application is grade 2 or grade 1; the water resistance of the perovskite nanocrystal glass filter of the present application is grade 2 or grade 1

[0074] <Second aspect>

[0075] The second aspect of the present application provides a method for preparing a perovskite nanocrystal glass filter, comprising the following steps:

[0076] Mixing the raw materials of the perovskite nanocrystal glass filter to obtain a mixture;

[0077] After melting, shaping and annealing the mixture, a bismuthate precursor glass is obtained;

[0078] After heat treatment of the bismuthate precursor glass, a perovskite nanocrystal glass filter is obtained.

[0079] In the present application, the raw materials of the perovskite nanocrystal glass filter can include one or more combinations of carbonates, phosphates, nitrates, sulfates, hydroxides, oxides, chlorides, bromides, and elements.

[0080] In some specific embodiments, the melting includes melting the mixture in a melting furnace and then homogenizing to obtain a molten glass, and then removing the molten glass from the melting furnace.

[0081] In the present application, the melting step comprises adding the mixture into a melting furnace, melting and homogenizing in a closed melting furnace to form molten glass.

[0082] Specifically, in the present application, the melting temperature is 900-950℃, which can melt the mixture from powder state to form glass liquid state.

[0083] In some specific embodiments, the homogenization is carried out under gradient stirring, which can ensure that the glass raw materials are completely melted and mixed uniformly, so that the bubbles and stripes of the final perovskite nanocrystal glass filter meet the use requirements.

[0084] Specifically, the gradient stirring comprises two or more combinations of 4-12h at a rotation speed of 40rpm, 4-12h at a rotation speed of 30rpm, 1-3h at a rotation speed of 20rpm, and 1-3h at a rotation speed of 10rpm. When using the above two or more combinations, the glass raw materials can be completely melted and mixed uniformly.

[0085] Further, in the present application, the homogenization temperature is 1000-1050℃. The homogenization is more excellent in terms of exhaust, so the temperature is higher than the melting temperature. When the temperature rises to the homogenization temperature, the stirrer can be moved down to 10-20mm from the bottom of the crucible, which is beneficial to realize gradient stirring.

[0086] The type of stirrer is not particularly limited in the present application and can be selected as needed. Preferably, it can include a reinforced platinum stirrer and the like.

[0087] Since the melting and homogenization temperatures of the bismuthate precursor glass are both low, the volatilization of halogen elements is greatly reduced, and energy is saved. Using a reinforced platinum stirrer to stir the glass liquid greatly improves the uniformity of the glass and also solves the problems of micro-bubbles and stripes in the glass.

[0088] In some specific embodiments, for forming, the present application is not particularly limited, and generally the molten glass is poured or poured into a mold for forming, preferably the molten glass is cooled to 800-850℃ before being poured or poured into a mold for forming, thereby obtaining a formed body, more preferably, the pouring method is used for forming to reduce the generation of stripes.

[0089] In some specific embodiments, the present application eliminates internal stress in the glass by annealing. Specifically, the annealing temperature is 280-350℃; and / or, the annealing time is 5-8h.

[0090] In some specific embodiments, the heat treatment comprises nucleation and crystallization of the bismuthate precursor glass in a crystallization furnace. Nucleation is mainly to make the bismuthate precursor glass nucleate to form crystals, and crystallization is to make the crystals grow. Through nucleation and crystallization, the desired perovskite nanocrystal glass filter can be obtained.

[0091] In some specific embodiments, the nucleation temperature is 350-380°C, the nucleation time is 2-10h; and / or, the crystallization temperature is 400-460°C, the crystallization time is 6-24h. In addition, the temperature field uniformity of the crystallization furnace is ±2°C.

[0092] The present application uses a bismuthate precursor glass matrix with a lower melting point, and the subsequent heat treatment temperature for forming a perovskite nanocrystal glass filter is significantly reduced, thereby improving the production efficiency and reducing the cost.

[0093] <Third aspect>

[0094] The third aspect of the present application also provides an optical element comprising the perovskite nanocrystal glass filter according to the present application. In the present application, the optical element can comprise a glass element and a glass preform.

[0095] Specifically, the glass preform can be manufactured using a means such as grinding processing, or a means such as re-hot press forming, precision press forming, etc. That is, the glass preform can be manufactured by mechanically processing the glass such as grinding and polishing, or by re-hot press forming a preform blank for press forming made of glass, and then grinding processing, or by precision press forming a preform blank manufactured by grinding processing. It should be noted that the means for preparing the glass preform is not limited to the above means.

[0096] Examples

[0097] The embodiments of the present application will be described in detail below with reference to examples, but those skilled in the art will understand that the following examples are only for illustration of the present application, and should not be regarded as limiting the scope of the present application. If no specific conditions are specified in the examples, the conventional conditions or the conditions recommended by the manufacturer are used. If no manufacturer of the reagent or instrument is specified, it is a conventional product that can be obtained by purchase.

[0098] Example 1

[0099] Take the corresponding raw materials according to the content of each component of the set perovskite nanocrystal glass and mix them evenly. The raw materials include: 52.87 wt% of Bi2O3, 12.95 wt% of B2O3, 5.53 wt% of La2O3, 0.9 wt% of Al2O3, 0.04 wt% of Na2SO4, 15.27 wt% of Cs2O, 9.46 wt% of PbBr2, 1.60 wt% of NaCl, and 1.38 wt% of NaBr. After mixing the raw materials of each component evenly, add them to a closed and covered melting furnace. Specifically, feed and melt at 930 °C, and raise the temperature to 1030 °C to homogenize the glass liquid. When the temperature rises to the homogenization temperature, stir down with a strengthened platinum stirrer to a distance of 10 - 20 mm from the bottom of the crucible. Then carry out gradient stirring, specifically at a rotation speed of 20 rpm for 1 h, at a rotation speed of 40 rpm for 12 h, and at a rotation speed of 20 rpm for 1 h to form molten glass; form the molten glass into a mold by pouring at 850 °C to obtain a formed body; place the formed body in an annealing furnace at a temperature of 320 °C for annealing for 6 hours to obtain a bismuthate precursor glass; place the bismuthate precursor glass in a crystallization furnace for crystallization and nucleation. The temperature field uniformity of the crystallization furnace is between ±2 °C. Specifically, keep the temperature at 380 °C for 5 h to nucleate the glass, and then continue to raise the temperature to 450 °C and keep it for 18 h for crystallization to grow the crystals and obtain perovskite nanocrystal glass.

[0100] After testing, as Figure 1 shown, the crystal type precipitated from the perovskite nanocrystal glass is hexagonal phase, with Cs4PbBr b Cl 6-b (0 < b ≤ 6) quantum dots. The cut-off wavelength of the glass is 487 nm, and the transmittance is more than 90% at wavelengths between 630 and 800 nm; the perovskite nanocrystal glass can be used for filters in the wavelength range of 450 nm - 490 nm.

[0101] Example 2

[0102] Take the corresponding raw materials according to the component contents of the set perovskite nanocrystal glass and mix them evenly. The raw materials include: 52.76 wt% of Bi2O3, 12.93 wt% of B2O3, 5.52 wt% of La2O3, 0.9 wt% of Al2O3, 0.04 wt% of Na2SO4, 15.24 wt% of Cs2O, 9.43 wt% of PbBr2, 1.80 wt% of NaCl, and 1.38 wt% of NaBr. After mixing the raw materials of each component evenly, add them to a closed and covered melting furnace. Specifically, feed and melt at 930 °C, and raise the temperature to 1030 °C to homogenize the glass liquid. When the temperature rises to the homogenization temperature, stir down with a strengthened platinum stirrer to a distance of 10 - 20 mm from the bottom of the crucible. Then perform gradient stirring, specifically stir at a rotation speed of 20 rpm for 1 h, at a rotation speed of 40 rpm for 12 h, and at a rotation speed of 20 rpm for 1 h to form molten glass; form the molten glass into a mold by pouring at 850 °C to obtain a formed body; place the formed body in an annealing furnace at 320 °C for annealing for 6 hours to obtain a bismuthate precursor glass; place the bismuthate precursor glass in a crystallization furnace for crystallization and nucleation. The temperature field uniformity of the crystallization furnace is between ±2 °C. Specifically, keep it at 380 °C for 5 h to nucleate the glass, and then continue to raise the temperature to 450 °C and keep it for 18 h for crystallization to grow the crystals and obtain perovskite nanocrystal glass.

[0103] After testing, as Figure 2 shown, the crystal type precipitated from the perovskite nanocrystal glass is hexagonal phase, with Cs4PbBr b Cl 6-b (0 < b ≤ 6) quantum dots. The cut-off wavelength of the glass is 480 nm; the perovskite nanocrystal glass can be used for a filter in the wavelength range of 450 nm - 490 nm.

[0104] Example 3

[0105] Take the corresponding raw materials according to the component contents of the set perovskite nanocrystal glass and mix them evenly. The raw materials include: 52.66 wt% Bi2O3, 12.9 wt% B2O3, 5.5 wt% La2O3, 0.9 wt% Al2O3, 0.04 wt% Na2SO4, 15.2 wt% Cs2O, 9.42 wt% PbBr2, 2.0 wt% NaCl, and 1.38 wt% NaBr. After mixing the raw materials of each component evenly, add them to a closed and covered melting furnace. Specifically, feed and melt at 930 °C, and raise the temperature to 1030 °C to homogenize the glass liquid. When the temperature rises to the homogenization temperature, stir down with a strengthened platinum stirrer to a distance of 10 - 20 mm from the bottom of the crucible. Then perform gradient stirring, specifically, stir at a speed of 20 rpm for 1 h, at a speed of 40 rpm for 12 h, and at a speed of 20 rpm for 1 h to form molten glass; form the molten glass into a mold by pouring at 850 °C to obtain a formed body; place the formed body in an annealing furnace at 320 °C for annealing for 6 hours to obtain a bismuthate precursor glass; place the bismuthate precursor glass in a crystallization furnace for crystallization and nucleation. The temperature field uniformity of the crystallization furnace is between ±2 °C. Specifically, keep the temperature at 380 °C for 5 h to nucleate the glass, and then continue to raise the temperature to 450 °C and keep it for 18 h for crystallization to grow the crystals and obtain perovskite nanocrystal glass.

[0106] After testing, as Figure 3 shown, the crystal type precipitated from the perovskite nanocrystal glass is hexagonal phase, with Cs4PbBr b Cl 6-b (0 < b ≤ 6) quantum dots, and the cut-off wavelength of the glass is 468 nm; the perovskite nanocrystal glass can be used for filters in the wavelength range of 450 nm - 490 nm.

[0107] Example 4

[0108] Take corresponding raw materials according to the component contents of the set perovskite nanocrystal glass and mix them evenly. The raw materials include: 52.55 wt% of Bi2O3, 12.87 wt% of B2O3, 5.49 wt% of La2O3, 0.9 wt% of Al2O3, 0.04 wt% of Na2SO4, 15.18 wt% of Cs2O, 9.4 wt% of PbBr2, 2.2 wt% of NaCl, and 1.37 wt% of NaBr. After mixing the raw materials of each component evenly, add them to a closed and covered melting furnace. Specifically, charge and melt at 930 °C, and raise the temperature to 1030 °C to homogenize the glass liquid. When the temperature rises to the homogenization temperature, stir down with a strengthened platinum stirrer to a distance of 10 - 20 mm from the bottom of the crucible. Then perform gradient stirring, specifically, stir at a speed of 20 rpm for 1 h, at a speed of 40 rpm for 12 h, and at a speed of 20 rpm for 1 h to form molten glass; form the molten glass into a mold by pouring at 850 °C to obtain a formed body; place the formed body in an annealing furnace at 320 °C for annealing for 6 hours to obtain a bismuthate precursor glass; place the bismuthate precursor glass in a crystallization furnace for crystallization and nucleation. The temperature field uniformity of the crystallization furnace is between ±2 °C. Specifically, keep it at 380 °C for 5 h to nucleate the glass, and then continue to raise the temperature to 450 °C and keep it for 18 h for crystallization to grow the crystals and obtain perovskite nanocrystal glass.

[0109] After testing, as Figure 4 shown, the crystal type precipitated from the perovskite nanocrystal glass is hexagonal phase, with Cs4PbBr b Cl 6-b (0 < b ≤ 6) quantum dots, and the cut-off wavelength of the glass is 459 nm; the perovskite nanocrystal glass can be used for filters in the wavelength range of 450 nm - 490 nm.

[0110] Example 5

[0111] The components of the perovskite nanocrystal glass are mixed according to the set content of each component, and the raw materials are mixed uniformly, including: 55.29wt% Bi2O3, 13.55wt% B2O3, 5.78wt% La2O3, 0.94wt% Al2O3, 0.04wt% Na2SO4, 9.04wt% Cs2O, 11.79wt% PbBr2, 1.90wt% NaCl, 1.67wt% NaBr. After the components are mixed uniformly according to the proportion, they are added into a closed and capped melting furnace, and the glass liquid is homogenized at 930℃ and then heated to 1030℃. When the temperature rises to the homogenization temperature, the reinforced platinum stirrer is stirred to 10-20mm from the bottom of the crucible. Then gradient stirring is carried out, specifically at a speed of 20rpm for 1h, at a speed of 40rpm for 12h, and at a speed of 20rpm for 1h, to form a molten glass; the molten glass is formed into a shaped body by leaching at 850℃ in a mold; the shaped body is placed in an annealing furnace at a temperature of 320℃ for annealing for 6 hours to obtain a bismuthate precursor glass; the bismuthate precursor glass is placed in a crystallization furnace for crystallization and nucleation, and the temperature field uniformity of the crystallization furnace is ±2℃; specifically, the glass is nucleated at 380℃ for 5h, and then crystallized at 450℃ for 18h to grow crystals, to obtain a perovskite nanocrystal glass.

[0112] As shown in FIG. 1, the type of crystal precipitated from the perovskite nanocrystal glass is cubic phase, and the CsPbBr Figure 5 As shown in FIG. 1, the type of crystal precipitated from the perovskite nanocrystal glass is cubic phase, and the CsPbBr a Cl 3-a (0<a≤3) quantum dots, and the cutoff wavelength of the glass is 490nm; the perovskite nanocrystal glass can be used for optical filters in the wavelength range of 450nm-490nm.

[0113] Example 6

[0114] The components of the perovskite nanocrystal glass are mixed according to the set content of each component, and the raw materials are mixed uniformly, the raw materials include: 55.51wt% of Bi2O3, 13.60wt% of B2O3, 5.80wt% of La2O3, 0.94wt% of Al2O3, 0.04wt% of Na2SO4, 9.08wt% of Cs2O, 11.85wt% of PbBr2, 1.50wt% of NaCl, 1.68wt% of NaBr. After the components are mixed uniformly according to the proportion, they are added into a closed and capped melting furnace, and the glass liquid is homogenized at 1030℃ after the specific charging and melting at 930℃. When the temperature rises to the homogenization temperature, the reinforced platinum stirrer is stirred to 10-20mm away from the bottom of the crucible. Then gradient stirring is carried out, specifically, stirring at 20rpm for 1h, stirring at 40rpm for 12h, and stirring at 20rpm for 1h, to form a molten glass; the molten glass is formed into a shaped body in a mold at 850℃ by means of leakage; the shaped body is placed in an annealing furnace at a temperature of 320℃ for annealing for 6 hours to obtain a bismuthate precursor glass; the bismuthate precursor glass is placed in a crystallization furnace for crystallization and nucleation, the temperature field uniformity of the crystallization furnace is ±2℃, specifically, the glass is nucleated at 380℃ for 5h, and then the temperature is continuously raised to 450℃ for 18h for crystallization, so that the crystal grows, and a perovskite nanocrystal glass is obtained.

[0115] As shown in FIG. 1, the type of crystal precipitated from the perovskite nanocrystal glass is cubic phase, and the CsPbBr Figure 6 As shown in FIG. 1, the type of crystal precipitated from the perovskite nanocrystal glass is cubic phase, and the CsPbBr a Cl 3-a (0<a≤3) quantum dots, and the cutoff wavelength of the glass is 470nm; the perovskite nanocrystal glass can be used for an optical filter in the wavelength range of 450nm-490nm.

[0116] Performance test

[0117] 1. Transmittance

[0118] The transmittance curve of the glass sample in the wavelength range of 200nm-800nm is tested by using a spectrometer according to the test method of GB / T7962.12-2010, and the transmittance of the glass sample in the present application refers to the lowest transmittance in the corresponding wavelength range, and the test results are shown in FIG. 2 and Table 1. Figures 1-6

[0119] 2. Cutoff wavelength

[0120] The wavelength obtained by drawing a tangent line at the point where the transmittance sharply drops to zero on the transmittance curve is called the cutoff wavelength, and the test results are shown in FIG. 3 and Table 1. Figures 1-6

[0121] 3. X-ray diffraction spectrum​​

[0122] The perovskite nanocrystal glass filter of Examples 1-6 was taken, and when powder X-ray diffraction method was used with CuK α The X-ray diffraction pattern of the perovskite nanocrystal glass filter was analyzed under the irradiation experimental conditions, and the results are shown in Figure 1 and Table 1. Figures 1-6

[0123] 4. Water resistance stability

[0124] The water resistance stability (R C ) of the glass (surface method) was tested according to the method specified in GB / T 7962.15-2010. The water resistance stability in the present application is sometimes referred to as water resistance or water stability. The results are shown in Table 1.

[0125] 5. Acid resistance stability

[0126] The acid resistance stability (R A ) of the glass (surface method) was tested according to the method specified in GB / T 7962.14-2010. The results are shown in Table 1.

[0127] Table 1. Test results

[0128]

[0129] As can be seen from Table 1, the crystal type of the perovskite nanocrystal glass filter of Examples 1-4 of the present application is hexagonal phase, and has Cs4PbBr b Cl 6-b (0<b≤6) quantum dots. The crystal type of the perovskite nanocrystal glass filter of Examples 5-6 is cubic phase, and has CsPbBr a Cl 3-a (0<a≤3) quantum dots. When the thickness of the perovskite nanocrystal glass filter is 2 mm, the cut-off wavelength of Examples 1-6 is all above 450 nm; and the transmittance of the perovskite nanocrystal glass filter at a thickness of 520-550 nm is above 65%, at 550-630 nm is above 70%, and at 630-800 nm is above 79%. In addition, the acid stability of the perovskite nanocrystal glass filter of Examples 1-6 is level 2, and the water stability is level 2.

[0130] It should be noted that although the technical solutions of the present application are described with specific examples, those skilled in the art can understand that the present application should not be limited thereto.

[0131] ​Having described various embodiments of the application, it is to be understood that the above description is meant to be illustrative only and not exhaustive, and is not limited to the disclosed embodiments. Many modifications and variations will be apparent to those of ordinary skill in the art, without departing from the scope and spirit of the described embodiments. The choice of words in this document is intended to best explain the principles of the embodiments, the practical application, or technical improvement over the existing technology, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A perovskite nanocrystalline glass filter, characterized in that, It comprises the following components by mass percentage: Bi2O3: 50~75%; B2O3: 8~25%; La2O3: 1~10%; Al2O3: 0.2~3%; Na2SO4: 0.04~1%; Furthermore, the perovskite nanocrystalline glass filter also contains Cs2O, PbBr2, NaCl, and NaBr; By mass percentage, the content of Cs2O is 8-18%, the content of PbBr2 is 5-15%, the content of NaCl is 1-3%, and the content of NaBr is 1-3%. The perovskite nanocrystals that can be precipitated in the perovskite nanocrystalline glass filter include CsPbBr. a Cl 3-a or Cs4PbBr b Cl 6-b Quantum dots, where 0 <a≤3,0<b≤6。 2. The perovskite nanocrystalline glass filter according to claim 1, characterized in that, The total content of Cs₂O, PbBr₂, NaCl, and NaBr (Cs₂O + PbBr₂ + NaCl + NaBr) is 15-30% by mass percentage; and / or, The mass ratio of Cs2O to PbBr2 is 0.7~0.8:1, or the mass ratio of Cs2O to PbBr2 is 1.5~1.8:

1.

3. The perovskite nanocrystalline glass filter according to claim 1 or 2, characterized in that, When the thickness of the perovskite nanocrystalline glass filter is 2 mm, its cutoff wavelength is above 450 nm; and / or, When the thickness of the perovskite nanocrystalline glass filter is 2 mm, the transmittance is above 65% in the 520~550 nm band, above 70% in the 550~630 nm band, and above 79% in the 630~800 nm band.

4. The perovskite nanocrystalline glass filter according to claim 1 or 2, characterized in that, The perovskite nanocrystalline glass filter has an acid resistance stability of level 2 or level 1; the perovskite nanocrystalline glass filter has a water resistance stability of level 2 or level 1.

5. A method for preparing a perovskite nanocrystalline glass filter according to any one of claims 1 to 4, characterized in that, The preparation method includes the following steps: The raw materials of the perovskite nanocrystalline glass filter are mixed to obtain a mixture; The mixture is melted, shaped and annealed to obtain bismuthate precursor glass; The bismuthate precursor glass was heat-treated to obtain a perovskite nanocrystalline glass filter.

6. The preparation method according to claim 5, characterized in that, The smelting process includes melting the mixture in a smelting furnace and then homogenizing it to obtain molten glass.

7. The preparation method according to claim 6, characterized in that, The homogenization was carried out under gradient stirring conditions.

8. The preparation method according to claim 7, characterized in that, The gradient stirring includes two or more combinations of the following: stirring at 40 rpm for 4-12 hours, stirring at 30 rpm for 4-12 hours, stirring at 20 rpm for 1-3 hours, and stirring at 10 rpm for 1-3 hours.

9. The preparation method according to claim 8, characterized in that, The melting temperature is 900~950℃, and the homogenization temperature is 1000~1050℃.

10. The preparation method according to any one of claims 6 to 9, characterized in that, The molding includes molding by casting or pouring; and / or, The annealing temperature is 280~350℃; the annealing time is 5~8h.

11. The preparation method according to claim 10, characterized in that, After the molten glass is cooled to 800~850℃, it is then poured or cast into shape.

12. The preparation method according to any one of claims 5 to 9, characterized in that, The heat treatment includes nucleation and crystallization of the bismuthate precursor glass in a crystallization furnace.

13. The preparation method according to claim 12, characterized in that, The nucleation temperature is 350~380℃, and the nucleation time is 2~10h; and / or, the crystallization temperature is 400~460℃, and the crystallization time is 6~24h.

14. An optical element, characterized in that, Including the perovskite nanocrystalline glass filter according to any one of claims 1 to 4.

Images