Halogen-lead-cesium single-crystal optical fiber bundle and preparation method and application thereof

Abstract

The invention relates to a halogen-lead-cesium single-crystal optical fiber bundle and a preparation method and application thereof. The halogen-lead-cesium single-crystal optical fiber bundle is a set composed of a plurality of halogen-lead-cesium single-crystal optical fibers, the molecular formula of the halogen-lead-cesium single-crystal optical fibers is CsPbX3, X is I, Br or Cl, the diameter of the halogen-lead-cesium single-crystal optical fiber bundle is 10-30 microns, and the length-diameter ratio is larger than or equal to 500: 1. According to the method, a seeding growth mode is adopted for the first time, various halogen-lead-cesium single-crystal optical fiber bundles are obtained under the room temperature condition, the diameter of each optical fiber bundle is 10-30 microns, and the length-diameter ratio is larger than or equal to 500: 1. The halogen-lead-cesium single-crystal optical fiber bundle is formed by integrating dozens to hundreds of micro-nano optical fibers, the diameter fluctuation of the internal optical fibers is small, the surface is smooth, the quality of the optical fibers is high, and the halogen-lead-cesium single-crystal optical fiber bundle has a great length-diameter ratio, is large in flexibility and can be bent and coiled.

Description

Technical Field

[0001] The present invention relates to a lead halide cesium single crystal optical fiber bundle and a preparation method and application thereof, in particular to a delta-CsPbI3 single crystal optical fiber bundle and a solution growth method and application thereof, belonging to the technical field of lead-based metal halide semiconductor crystal materials. Background Art

[0002] Lead-based metal halide semiconductors have the advantages of easy solution growth, low material cost, high carrier transfer efficiency, large X-ray attenuation coefficient, high sunlight collection efficiency, adjustable band gap, and high luminescence efficiency. They are widely used in solar cells, X-ray detectors, light-emitting diodes, lasers and photocatalysis research.

[0003] Existing lead-based metal halide semiconductor crystal materials, due to their different structures, form a variety of crystalline shapes, such as bulk, thin films, and fibers. Compared to 3D and 2D crystals, one-dimensional lead-based metal halide fiber crystals have advantages such as low ion binding energy, long carrier diffusion length and lifetime, anisotropy, and flexibility. However, the diameter of a single fiber crystal is at the micro-nanometer level, and the response signal to an applied light field is weak. Considering the need to further improve the physical response of fiber crystals while maintaining the excellent optoelectronic properties of one-dimensional crystals, the preparation of single-crystal fiber bundles will greatly improve the energy conversion efficiency of one-dimensional crystals in optoelectronic devices such as light detection, lasers, and luminescence. Crystal fiber bundles have excellent flexibility and can be designed and prepared for wearable devices. They can also be used as new materials with excellent optoelectronic properties in advanced devices such as X-ray detectors, solar cell devices, and fiber lasers.

[0004] Current methods for preparing one-dimensional lead-based metal halides include hot injection, solvothermal, antisolvent vapor-assisted crystallization, chemical vapor deposition, template methods, solvent evaporation, and solution cooling. However, the growth of lead-based metal halide single crystal fiber bundles has not been reported. Existing methods for preparing one-dimensional lead-based metal halides each have shortcomings. For example, nanowire arrays prepared using templates have poor crystal uniformity and small crystal size. Template methods also require template preparation and subsequent removal.

[0005] Some existing one-dimensional metal halide crystals use spontaneous nucleation growth, and there is very little research on the use of seed crystal growth method to prepare micron-level optical fiber crystals. There has been no report on the controllable growth technology of lead halide cesium single crystal optical fiber bundles. Summary of the Invention

[0006] To address the shortcomings of the existing technology, the present invention provides a lead-halogen cesium single crystal optical fiber bundle and its preparation method and application. The resulting lead-halogen cesium single crystal optical fiber bundle is in a uniform single crystal state, has a smooth surface, a large aspect ratio, and good bending performance.

[0007] One of the purposes of the present invention is to provide a method for preparing lead halide cesium seed crystals.

[0008] The second object of the present invention is to provide a lead halide cesium single crystal optical fiber bundle

[0009] A third object of the present invention is to provide a method for preparing a lead halide cesium single crystal optical fiber bundle.

[0010] A fourth object of the present invention is to provide an application of a lead halide cesium single crystal optical fiber bundle.

[0011] The technical solutions of the present invention are as follows:

[0012] A method for preparing a lead halide cesium seed crystal comprises the following steps:

[0013] Cesium halide and lead halide are added to hydroiodic acid, and heated to dissolve at 30-40° C. for 4-8 hours to obtain a cesium lead halide solution; the cesium lead halide solution is filtered and naturally cooled to 15-20° C., and crystals are taken out from the solution to obtain cesium lead halide seed crystals.

[0014] Preferably according to the present invention, the cesium halide is cesium iodide, cesium bromide or cesium chloride; the lead halide is lead iodide, cesium bromide or lead chloride; and the molar ratio of the cesium halide to the lead halide is (1-1.1):(1-1.1).

[0015] Most preferably, the molar ratio of the cesium halide to the lead halide is 1:1.

[0016] Preferably, according to the present invention, the filtration is performed using a 0.22 μm polytetrafluoroethylene membrane.

[0017] A lead-cesium halide seed crystal is prepared according to the above method, and the lead-cesium halide seed crystal can be used to prepare a lead-cesium halide single crystal optical fiber bundle.

[0018] Preferably, according to the present invention, the diameter of the lead halide cesium seed crystal is 5 to 18 μm, and the aspect ratio is (20 to 70):1.

[0019] Further preferably, the diameter of the lead halide cesium seed crystal is 15 μm, and the aspect ratio is (40-60):1.

[0020] A cesium-lead-halogen single-crystal optical fiber bundle is a collection of several cesium-lead-halogen single-crystal optical fibers. The molecular formula of the cesium-lead-halogen single-crystal optical fibers is CsPbX3, wherein X is I, Br or Cl. The diameter of the cesium-lead-halogen single-crystal optical fiber bundle is 10 to 30 μm, and the length-to-diameter ratio is ≥500:1.

[0021] According to the preferred embodiment of the present invention, when X is I, the cesium lead halide single crystal fiber bundle is an iodine lead cesium single crystal fiber bundle, with a molecular formula of CsPbI3, a diameter of 10 to 30 μm, a length-to-diameter ratio of ≥500:1, a δ phase crystal structure, an orthorhombic crystal phase, mmm point group, and Pmnb space group. α=β=γ=90°.

[0022] According to the preferred embodiment of the present invention, when X is Br, the cesium lead halide single crystal fiber bundle is a cesium lead bromine single crystal fiber bundle, with a molecular formula of CsPbBr3, a diameter of 10 to 30 μm, a length-to-diameter ratio of ≥500:1, a δ phase crystal structure, an orthorhombic crystal phase, mmm point group, and Pmnb space group. α=β=γ=90° or Pnma space group α=β=γ=90°.

[0023] According to the preferred embodiment of the present invention, when X is Cl, the cesium lead halide single crystal fiber bundle is a cesium lead chlorine single crystal fiber bundle, with a molecular formula of CsPbCl3, a diameter of 10 to 30 μm, a length-to-diameter ratio of ≥500:1, a tetragonal crystal structure, a tetragonal crystal system, mmm point group, and Pmnb space group. α=β=γ=90°.

[0024] According to the present invention, the method for preparing the above-mentioned lead halide cesium single crystal optical fiber bundle comprises the following steps:

[0025] (1) adding cesium halide and lead halide to N,N-dimethylformamide (DMF), dissolving at 10-20° C. for 4-8 hours, and filtering to obtain a saturated solution of lead halide and cesium halide;

[0026] (2) After the lead halide cesium seed crystal is coated with glue and cut, it is seeded into the lead halide cesium saturated solution obtained in step (1), and grown in a closed state to obtain a lead halide cesium single crystal optical fiber bundle.

[0027] According to the preferred embodiment of the present invention, in step (1), the cesium halide is cesium iodide, cesium bromide or cesium chloride; the lead halide is lead iodide, cesium bromide or lead chloride; and the molar ratio of the cesium halide to the lead halide is (1 to 1.1): (1 to 1.1).

[0028] Most preferably, the molar ratio of the cesium halide to the lead halide is 1:1.

[0029] According to a preferred embodiment of the present invention, in step (1), the filtration is performed using a nylon filter membrane.

[0030] According to the preferred embodiment of the present invention, in step (2), the sealing state is: temperature 30-50° C., and relative humidity 10%-40%.

[0031] Further preferably, the sealing state is: temperature 25° C., and relative humidity of the environment is 20% to 30%.

[0032] Preferably, according to the present invention, in step (2), the growth rate of the lead halide cesium single crystal optical fiber bundle during the growth process is 0.1 to 0.5 μm / s.

[0033] The present invention also provides applications of lead-halogen cesium single crystal fiber bundles, and the applications of the lead-halogen cesium single crystal fiber bundles in the preparation of wearable devices, photovoltaic cells, light-emitting diodes, field-effect transistors, LED lighting, photochemical cells, lasers, or photodetectors; wherein the photodetectors include X-ray detectors, gamma-ray detectors, and ultraviolet detectors.

[0034] According to the present invention, the lead halide cesium single crystal optical fiber bundle is used in related imaging devices.

[0035] According to the present invention, the lead halide cesium single crystal optical fiber bundle is used in photocatalytic technology.

[0036] The technical features and beneficial effects of the present invention are as follows:

[0037] The present invention's use of HI solution as a solvent for preparing lead halide cesium seed crystals represents a significant technical contribution. The inventors unexpectedly discovered that seed crystals prepared using HI solution significantly improved the quality of the resulting crystal fiber bundles when seeded with DMF solution during subsequent crystal fiber bundle preparation, resulting in a uniform single crystal state. This finding is unprecedented in the field of iodine, lead halide cesium research. However, using conventional DMF solvent to prepare seed crystals and then seeding with DMF solution resulted in poor quality crystal fiber bundles that failed to meet application requirements. Related comparative experiments will be detailed in the specific embodiments.

[0038] The lead cesium halide crystal fiber bundle prepared by first preparing lead cesium halide seed crystals and then growing them by seeding has more uniform crystal quality and longer crystal length than the nanowire array prepared using a template in the prior art. At the same time, the preparation and removal of the template can be omitted, which is more cost-effective.

[0039] The present invention involves preparing lead-halide-cesium seed crystals and then growing them through seeded growth to produce lead-halide-cesium crystal fiber bundles. The innovation lies in the treatment of the seed crystals, allowing untreated seed crystals to grow into single fiber crystals after seeded growth. Furthermore, achieving single fiber bundle growth requires controlling appropriate solution growth conditions.

[0040] Based on the above technical features and experiments, the present invention has the following beneficial effects:

[0041] 1. This invention utilizes a seeded growth method for the first time to produce various lead-halogen cesium single-crystal optical fiber bundles at room temperature. The fiber bundles have diameters of 10 to 30 μm and length-to-diameter ratios of 500:1 or higher. These lead-halogen cesium single-crystal optical fiber bundles are composed of dozens to hundreds of micro-nano optical fibers. The fibers within the bundles exhibit minimal diameter fluctuations, smooth surfaces, high fiber quality, and a significant aspect ratio, resulting in high flexibility for bendability and coiling.

[0042] 2. The method for preparing a lead-halogen cesium single-crystal optical fiber bundle provided by the present invention utilizes a seeding growth method that achieves a high success rate and good repeatability in growing lead-halogen cesium single-crystal optical fiber bundles. After successful seeding, the length of the resulting lead-halogen cesium single-crystal optical fiber bundle depends on the fiber growth time. Under optimal growth conditions, the fiber growth rate can reach up to 0.3 μm / s, effectively overcoming the shortcomings of short crystals, uncontrollable diameter, and uneven quality. Furthermore, the single-crystal optical fiber growth method provided by the present invention is simple and easy to operate, and has great potential for promotion.

[0043] 3. The lead halide cesium single crystal optical fiber bundle provided by the present invention is highly flexible and bendable, and is suitable for the preparation of wearable devices, photovoltaic cells, light-emitting diodes, field-effect transistors, photocatalysis, LED lighting, photochemical cells, lasers, photodetectors (X-rays, γ-rays, ultraviolet rays) and related imaging devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 This is a photo of the seed growth of the iodine-lead-cesium single crystal optical fiber bundle prepared in Example 1.

[0045] Figure 2 This is an optical photograph after the growth of the iodine-lead-cesium single crystal optical fiber bundle in Example 1 is completed.

[0046] Figure 3 This is a comparison of the XRD pattern of the iodine-lead-cesium single crystal fiber bundle prepared in Example 1 and the yellow orthorhombic phase iodine-lead-cesium standard pattern.

[0047] Figure 4 This is an optical photograph of the iodine-lead-cesium seed crystal selected from the hydroiodic acid solution in Example 1.

[0048] Figure 5 This is a scanning electron microscope photograph of the iodine-lead-cesium single crystal optical fiber bundle prepared in Example 1.

[0049] Figure 6 This is the bending flexibility test result of the iodine-lead-cesium single crystal optical fiber bundle prepared in Example 1.

[0050] Figure 7 This is a scanning electron microscope photograph of a crystal bundle grown by selecting a seed crystal from the DMF solution in Comparative Example 1.

[0051] Figure 8This is an optical photograph of a crystal bundle grown by selecting a seed crystal from the DMF solution in Comparative Example 1.

[0052] Figure 9 This is a scanning electron microscope photograph of the crystal grown on the untreated seed crystal in Comparative Example 2. DETAILED DESCRIPTION

[0053] The present invention will be further described below by way of specific examples. It should be understood that these examples are only used to illustrate the present invention and are not intended to limit the scope of protection of the present invention.

[0054] The cesium iodide (CsI) and lead iodide (PbI2) used in the examples are microcrystalline powders (CsI purity is 99.9%, PbI2 purity is 99%), the concentration of N,N-dimethylformamide (DMF) solution is 99.5%, and the concentration of hydroiodic acid (HI) solution is 42%, all of which can be obtained commercially.

[0055] Example 1

[0056] A method for preparing an iodine-lead-cesium single crystal optical fiber bundle comprises the following steps:

[0057] (1) adding cesium iodide (CsI) and lead iodide (PbI2) to a hydroiodic acid solution, heating and dissolving at 35°C for 6 hours to obtain a 0.014M iodine-lead-cesium solution; filtering the iodine-lead-cesium solution through a 0.22 μm polytetrafluoroethylene membrane, and naturally cooling to 20°C after filtration, and taking out crystals from the solution to obtain iodine-lead-cesium seed crystals;

[0058] (2) Cesium iodide (CsI) and lead iodide (PbI2) were added to N,N-dimethylformamide, dissolved at 15°C for 4 h, and filtered through a 0.22 μm nylon membrane to obtain a saturated solution of 0.625 M iodine-lead-cesium solution;

[0059] (3) Selecting an iodine-lead-cesium seed crystal with a diameter of 15 μm and an aspect ratio of 40:1, coating the surface with glue, and after waiting for the glue to solidify, cutting the seed crystal and seeding it into the saturated lead-cesium halide solution obtained in step (2), growing it in a growth tank at a growth temperature of 40°C and an ambient relative humidity of 20% at a rate of 0.3 μm / s for 1 hour to obtain an iodine-lead-cesium single crystal optical fiber bundle.

[0060] The diameter of the iodine-lead-cesium single crystal optical fiber bundle prepared in this embodiment is 20 μm and the length is 1 mm.

[0061] The growth photos of the iodine-lead-cesium single crystal fiber bundle seeded into the supersaturated solution in this embodiment are shown in the figure. Figure 1 shown.

[0062] The optical photograph of the fiber bundle after the iodine-lead-cesium single crystal fiber seeding growth in this embodiment is as follows: Figure 2shown.

[0063] The XRD pattern of the iodine-lead-cesium single crystal fiber bundle in this embodiment is as follows: Figure 3 shown.

[0064] Depend on Figures 1 to 3 It can be seen that the orthogonal phase iodine-lead-cesium single crystal optical fiber bundle in this embodiment was successfully prepared.

[0065] The optical photograph of the iodine-lead-cesium seed crystal selected from the HI solution for seeding the iodine-lead-cesium single crystal optical fiber in this embodiment is shown in FIG. Figure 4 shown.

[0066] The scanning electron microscope photo of the iodine-lead-cesium single crystal fiber bundle prepared in this example is shown in FIG. Figure 5 shown.

[0067] Depend on Figure 5 It can be seen that the iodine-lead-cesium single crystal fiber bundle is composed of a collection of dozens to hundreds of micro-nano optical fibers, and has a flat and smooth surface, clear crystal edges and corners, and good crystal quality.

[0068] The bending test results of the iodine-lead-cesium single crystal fiber bundle prepared in this example are as follows: Figure 6 shown.

[0069] Depend on Figure 6 It can be seen that the iodine-lead-cesium single crystal fiber bundle is highly flexible, bendable, and has good bending performance.

[0070] Example 2

[0071] A method for preparing an iodine-lead-cesium single crystal optical fiber bundle is as described in Example 1, except that the crystal growth temperature is changed to 30°C.

[0072] The average growth rate of the iodine-lead-cesium single crystal optical fiber bundle prepared in this embodiment is 0.2 μm / s, the diameter is 20 μm, and the length is 0.7 mm after growing for 1 hour.

[0073] Example 3

[0074] A method for preparing an iodine-lead-cesium single crystal optical fiber bundle is as described in Example 1, except that the growth temperature is changed to 25°C.

[0075] The average growth rate of the iodine-lead-cesium single crystal optical fiber bundle prepared in this embodiment is 0.1 μm / s, the diameter is 20 μm, and the length is 0.3 mm after growing for 1 hour.

[0076] Example 4

[0077] A method for preparing an iodine-lead-cesium single crystal optical fiber bundle is as described in Example 1, except that the growth temperature is changed to 23°C.

[0078] The average growth rate of the iodine-lead-cesium single crystal optical fiber bundle prepared in this embodiment is 0.04 μm / s, the diameter is 20 μm, and the length is 0.2 mm after growing for 1 hour.

[0079] Comparative Example 1

[0080] A method for preparing an iodine-lead-cesium single crystal optical fiber bundle, wherein the specific steps are the same as those in Example 1, except that a DMF solution is used instead of a hydroiodic acid solution to prepare the seed crystal.

[0081] The scanning electron microscope photo of the iodine-lead-cesium single crystal optical fiber of the iodine-lead-cesium single crystal optical fiber bundle prepared in this comparative example is shown in FIG. Figure 7 As shown in the optical photograph Figure 8 shown.

[0082] Depend on Figure 7 and Figure 8 It can be seen that the iodine-lead-cesium single crystal optical fiber bundle grown in DMF solution after the seed crystal is selected from the DMF solution grows unevenly and the quality deteriorates significantly.

[0083] Comparative Example 2

[0084] A method for preparing an iodine-lead-cesium single crystal optical fiber bundle, the specific steps of which are the same as those of Example 1, except that the iodine-lead-cesium seed crystals in step (3) are not coated with glue and cut.

[0085] The scanning electron microscope photo of the iodine-lead-cesium single crystal optical fiber of the iodine-lead-cesium single crystal optical fiber bundle prepared in this comparative example is shown in FIG. Figure 9 shown.

[0086] Depend on Figure 9 It can be seen that the iodine-lead-cesium seed crystals that are not coated with glue and cut off cannot grow into crystal bundles after being planted.

[0087] Finally, it is necessary to further explain that the above embodiments are only further explanations of the present invention and should not be construed as limiting the scope of protection of the present invention. Non-substantial improvements and adjustments made by those skilled in the art based on the above content of the present invention fall within the scope of protection of the present invention.

Claims

1. A method for preparing lead halide cesium seed crystals, characterized in that: Here are the steps: Cesium halide and lead halide are added to hydroiodic acid, and heated to dissolve at 30-40° C. for 4-8 hours to obtain a cesium lead halide solution; the cesium lead halide solution is filtered and naturally cooled to 15-20° C., and crystals are taken out from the solution to obtain cesium lead halide seed crystals.

2. The preparation method according to claim 1, wherein The cesium halide is cesium iodide, cesium bromide or cesium chloride; the lead halide is lead iodide, cesium bromide or lead chloride; the molar ratio of the cesium halide to the lead halide is (1-1.1): (1-1.1); the filtration is performed using a 0.22 μm ultrafine water membrane; Further preferably, the molar ratio of the cesium halide to the lead halide is 1:

1.

3. A lead halide cesium seed crystal, characterized in that: It is prepared according to the method of claim 1.

4. The lead halide cesium seed crystal according to claim 3, wherein The diameter of the lead halide cesium seed crystal is 5 to 18 μm, and the aspect ratio is (20 to 70):1; Further preferably, the diameter of the lead halide cesium seed crystal is 15 μm, and the aspect ratio is (40-60):

1.

5. A lead halide cesium single crystal optical fiber bundle, characterized in that: The cesium halogen lead single crystal fiber bundle is a collection of several cesium halogen lead single crystal fibers. The molecular formula of the cesium halogen lead single crystal fibers is CsPbX3, wherein X is I, Br or Cl. The diameter of the cesium halogen lead single crystal fiber bundle is 10 to 30 μm, and the length-to-diameter ratio is ≥500:

1.

6. The lead halide cesium single crystal optical fiber bundle according to claim 1, wherein: When X is 1, the cesium lead halide single crystal fiber bundle is an iodine lead cesium single crystal fiber bundle, the molecular formula is CsPbI3, the crystal structure is δ phase, the crystal phase is orthorhombic system, mmm point group, Pmnb space group, α=β=γ=90°; When X is Br, the cesium lead halide single crystal fiber bundle is a cesium lead bromine single crystal fiber bundle, the molecular formula is CsPbBr3, the crystal structure is δ phase, the crystal phase is orthorhombic system, mmm point group, Pmnb space group, α=β=γ=90° or Pnma space group α=β=γ=90°; When X is Cl, the cesium lead halide single crystal fiber bundle is a cesium lead chlorine single crystal fiber bundle, the molecular formula is CsPbCl3, the crystal structure is tetragonal phase, the crystal phase is tetragonal system, mmm point group, Pmnb space group, α=β=γ=90°.

7. The method for preparing the lead halide cesium single crystal optical fiber bundle according to claim 5, characterized in that: The steps are as follows: (1) adding cesium halide and lead halide to N,N-dimethylformamide, dissolving at 10-20° C. for 4-8 hours, and filtering to obtain a saturated solution of lead halide and cesium halide; (2) After the lead halide cesium seed crystal is coated with glue and cut, it is seeded into the lead halide cesium saturated solution obtained in step (1), and grown in a sealed state to obtain a lead halide cesium single crystal optical fiber bundle.

8. The preparation method according to claim 7, wherein In step (1), the cesium halide is cesium iodide, cesium bromide or cesium chloride; the lead halide is lead iodide, cesium bromide or lead chloride; the molar ratio of the cesium halide to the lead halide is (1-1.1): (1-1.1); the filtration is performed using a nylon filter membrane; Further preferably, the molar ratio of the cesium halide to the lead halide is 1:

1.

9. The preparation method according to claim 7, wherein In step (2), the sealing state is: the temperature is 30-50° C., the relative humidity is 10%-40%; the growth rate of the lead halide cesium single crystal optical fiber bundle during the growth process is 0.1-0.5 μm / s; Further preferably, the sealing state is: temperature 25° C., and relative humidity of the environment is 20% to 30%.

10. The use of the lead halide cesium single crystal optical fiber bundle according to claim 5, characterized in that: The application of the lead halide cesium single crystal optical fiber bundle in the preparation of wearable devices, photovoltaic cells, light-emitting diodes, field-effect transistors, LED lighting, photochemical cells, lasers or photodetectors.

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