Organic-inorganic hybrid metal halide glass optical fiber and preparation method and application thereof

Abstract

The invention discloses an organic-inorganic hybrid metal halide glass optical fiber as well as a preparation method and application thereof. The organic-inorganic hybrid metal halide glass optical fiber provided by the invention comprises a core layer and a cladding layer, the preparation raw material of the core layer comprises an organic-inorganic hybrid metal halide; the refractive index of the core layer is greater than that of the cladding layer; the melting point of the core layer is lower than that of the cladding layer. According to the invention, the organic-inorganic hybrid metal halide is adopted to prepare the glass optical fiber with the core-cladding structure, so that the glass optical fiber has good flexibility, a small bending radius can be realized, and the optical loss under the small bending radius is low; based on the characteristics of high transmittance, high luminous efficiency, high glass forming ability and low melting point of the organic-inorganic hybrid metal halide, the preparation of the optical fiber at a relatively low temperature can be ensured, the energy consumption is effectively reduced, and the glass optical fiber with good forming performance and adjustable luminous performance is obtained and has potential application value in the optical fields of optical transmission, sensing, illumination, laser and the like.

Description

Technical Field

[0001] The present invention belongs to the field of optoelectronic technology, and particularly relates to an organic-inorganic hybrid metal halide glass optical fiber and its preparation method and application. Background Art

[0002] Optical fibers use photons as the medium for transmitting information and are widely used in photonic devices and information communication. The advantages they can offer include: higher transmission speed, higher memory density, and lower power consumption, etc., effectively alleviating the physical limitations imposed by Moore's Law. Silica glass and polymers are two important optical fiber materials. Due to its excellent light transmittance, mature manufacturing process, and extremely low propagation loss, silica glass remains an indispensable transmission medium in the fields of optical information processing, sensing, and communication. However, the processing of silica glass requires high-temperature conditions of 1700 - 2000 °C, and it is also very difficult to chemically modify it. In addition, due to its inherent brittleness, multilayer encapsulation and anti-bending protection measures are required in practical applications. In contrast, polymers have also become important materials in the field of optical fibers due to their low cost, easy processing, and excellent flexibility, etc. However, polymer-based optical fibers still face many challenges, including high transmission loss, poor low-temperature stability, and sensitivity to ultraviolet irradiation. Different from passive optical fibers that only transmit light, active optical fibers expand their functions through embedded light-emitting centers and optical amplification mechanisms. This fundamental difference highlights the key requirements for the next-generation waveguide media, namely the synergistic integration of three basic properties: ultra-low optical loss, mechanical flexibility for reconfigurable photonics, and dual-mode operation that supports self-luminous (active) and externally coupled (passive) photon management.

[0003] In the past few decades, researchers have devoted a great deal of effort to the development and optimization of single-crystal optical waveguides due to their excellent luminescent properties and small fiber diameters. Such materials are promising for optical signal gain and optical waveguide transmission in complex photonic integrated circuits. However, previously reported active single-crystal waveguide materials have some limitations, including high losses, complex synthesis processes, and low yields. Meanwhile, preliminary studies on quantum dots and fiber systems were reported as early as 2005. The optical properties of quantum dots are reflected in their absorption, radiation, and scattering properties. Population inversion can be achieved through stimulated absorption, stimulated emission, spontaneous emission, and non-radiative transitions of quantum dots. Therefore, gain in optical communication and laser applications has been achieved through quantum dot-doped fibers. In the process of doping quantum dots, the chemical vapor deposition method (MCVD) is the most traditional and stable process, and this technology has now been widely used in fiber preparation. The preparation process mainly involves first using a high-purity silica tube as a substrate, and then alternately depositing quantum dots and pure silica layers to prepare a preform. Subsequently, quantum dot-doped fibers are prepared through the fiber drawing process. At the same time, quantum dots can also be doped in polymers. Due to their small size, quantum dots doped in polymer fibers do not cause too much optical loss to the fibers. Compared with polymer fibers, quantum dot-doped polymer fibers do not require additional light sources and coupling structures, making integrated photonic devices more compact. Electrospinning and direct drawing are the main methods for preparing quantum dot-doped polymer fibers. In addition, by dissolving quantum dots in a solution with a refractive index similar to that of the cladding and placing a glass capillary in the solution to utilize the capillary action of the glass capillary, quantum dot-doped liquid-core fibers can be obtained. Although quantum dots exhibit excellent optical properties, they must be dispersed in a transparent medium to achieve the function of an optical waveguide. Currently, how to prevent problems such as agglomeration of quantum dots during doping in the medium remains an urgent and unsolved problem.

[0004] Among the materials currently used for active fibers, although silica glass fibers have the characteristic of low transmission loss, their preparation requires high temperatures (1700 - 2000 °C), and they are highly brittle and have a large bending radius; polymer fibers have good flexibility but high optical losses and poor stability. Existing active fiber materials (such as quantum dot-doped fibers) have problems such as complex synthesis and easy agglomeration. Fiber systems based on crystals are still restricted by anisotropic growth kinetics (crystallization time exceeding 72 hours), losses caused by interface defects, and poor environmental stability - these challenges are essentially related to their ordered lattice structures. Therefore, there is an urgent need for a new type of fiber material with low preparation temperature, high flexibility, low optical loss, and adjustable luminescence. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide an organic-inorganic hybrid metal halide glass optical fiber with low preparation temperature, low optical loss, mechanical flexibility for reconfigurable photonics, and dual-mode operation supporting self-luminous (active) and externally coupled (passive) photon management.

[0006] To solve the above technical problem, a first aspect of the present invention provides an organic-inorganic hybrid metal halide glass optical fiber, comprising a core layer and a cladding layer coated outside the core layer; the preparation raw materials of the core layer include organic-inorganic hybrid metal halides; the refractive index of the core layer is greater than that of the cladding layer; the melting point of the core layer is lower than that of the cladding layer.

[0007] Preferably, the refractive index of the organic-inorganic hybrid metal halide glass > 1.35. For example, it can be any value among 1.36, 1.5, 1.6, 1.7, 1.8, 2.0, 2.2 or 2.5 or a range value between any two of them.

[0008] Preferably, the melting point of the organic-inorganic hybrid metal halide ≤ 250 °C. For example, it can be any value among 50 °C, 60 °C, 80 °C, 100 °C, 150 °C, 200 °C or 250 °C or a range value between any two of them.

[0009] Preferably, the decomposition temperature of the organic-inorganic hybrid metal halide is greater than the melting point.

[0010] Preferably, the structural formula of the organic-inorganic hybrid metal halide is AMX; where A is an organic cation, M is a metal cation, and X is a halogen anion.

[0011] Preferably, the organic cation includes at least one of quaternary phosphonium organic cations or their derivatives, quaternary ammonium organic cations or their derivatives, and guanidine organic cations or their derivatives; more preferably, the organic cation includes at least one of quaternary phosphonium organic cations, quaternary ammonium organic cations or guanidine organic cations.

[0012] Preferably, the metal cation includes at least one of manganese, lead, antimony, copper, iron, cobalt, nickel, zinc, tin or indium ions.

[0013] Preferably, the halogen anion includes Cl - , Br - or I - and at least one of them.

[0014] Preferably, the preparation method of the organic-inorganic hybrid metal halide includes a solvent evaporation method and a cooling crystallization method.

[0015] Preferably, the solvent evaporation method is as follows: dissolve the raw materials in an organic solvent, and crystals will precipitate after the solvent evaporates. The evaporation temperature is 20 to 100 °C, and the evaporation time is 1 to 48 hours.

[0016] Preferably, the cooling crystallization method is as follows: dissolve the raw materials in an organic solvent, heat it and then cool it to precipitate crystals. The heating temperature is 50 to 150 °C, the heating time is 1 to 12 hours, and the cooling time is 1 to 12 hours.

[0017] Preferably, the cladding is a transparent dielectric material; more preferably, the transparent dielectric material includes at least one of quartz capillary, fluorinated ethylene propylene (FEP), perfluoroalkoxy alkane (PFA), polytetrafluoroethylene (PTFE), polycarbonate (PC), polystyrene (PS), polyethylene terephthalate (PET), or polymethyl methacrylate (PMMA).

[0018] Preferably, the melting point of the transparent dielectric material is higher than that of the core layer.

[0019] Preferably, the diameter of the core layer is 10 to 2000 μm. For example, it can be any value among 10 μm, 50 μm, 100 μm, 300 μm, 500 μm, 700 μm, 1000 μm, 1200 μm, 1500 μm, or 2000 μm or the range value between any two of them.

[0020] Preferably, the outer diameter of the cladding is 30 to 3000 μm. For example, it can be any value among 30 μm, 100 μm, 300 μm, 500 μm, 700 μm, 1000 μm, 1200 μm, 1500 μm, 2000 μm, or 3000 μm or the range value between any two of them.

[0021] Preferably, the length of the glass optical fiber is 1 to 100 cm. For example, it can be any value among 1 cm, 5 cm, 10 cm, 20 cm, 40 cm, 60 cm, 80 cm, 90 cm, or 100 cm or the range value between any two of them.

[0022] Preferably, the bending radius of the organic-inorganic hybrid metal halide glass optical fiber ≥ 0.8 mm. For example, it can be any value among 0.8 mm, 0.9 mm, 1 mm, 2 mm, 3 mm, 5 mm, 10 mm, 50 mm, 100 mm or the range value between any two of them.

[0023] Preferably, the bending loss rate of the organic-inorganic hybrid metal halide glass optical fiber at a bending radius of 0.8 mm ≤ 20%.

[0024] Preferably, the optical loss coefficient of the organic-inorganic hybrid metal halide glass optical fiber under the condition of 450 nm is ≤ 2 dB / cm.

[0025] The second aspect of the present invention provides a method for preparing the organic-inorganic hybrid metal halide glass optical fiber described in the first aspect of the present invention, including the following steps: melting the preparation raw materials of the core layer and filling them into the cladding to obtain the organic-inorganic hybrid metal halide glass optical fiber.

[0026] Preferably, the preparation method specifically includes the following steps: melting the preparation raw materials of the core layer; taking a hollow tube as the cladding, bringing the hollow tube into contact with the melted preparation raw materials of the core layer; and sealingly connecting the hollow tube to a vacuum device, adjusting the pressure inside the hollow tube through the vacuum device, and using the pressure difference to make the melted preparation raw materials of the core layer fill the hollow tube, and then cooling and forming to obtain the organic-inorganic hybrid metal halide glass optical fiber.

[0027] Preferably, the temperature for melting the preparation raw materials of the core layer is 100 - 300 °C. For example, it can be any value among 100 °C, 200 °C or 300 °C or the range value between any two of them.

[0028] In some embodiments of the present invention, the method for preparing the organic-inorganic hybrid metal halide glass optical fiber includes the following steps:

[0029] S1: Prepare AMX crystals according to the structural formula of the organic-inorganic hybrid metal halide;

[0030] S2: Heat the AMX crystals to a molten state at 100 - 300 °C until no bubbles are generated;

[0031] S3: Place the melt and the transparent medium hollow tube in a constructed constant temperature zone; avoid the rapid quenching of the melt of the organic-inorganic hybrid metal halide and solidification in the tube;

[0032] S4: Fill the melt into the transparent medium hollow tube and cool and form to obtain the organic-inorganic hybrid metal halide glass optical fiber.

[0033] Specifically, step S4 is: sealingly connecting the hollow tube to a vacuum device (such as a vacuum pump), adjusting the pressure inside the hollow tube through the vacuum device, and using the pressure difference to make the melted preparation raw materials of the core layer fill the hollow tube, and cooling and forming to obtain the organic-inorganic hybrid metal halide glass optical fiber.

[0034] The third aspect of the present invention provides an application of the organic-inorganic hybrid metal halide glass optical fiber described in the first aspect of the present invention in information transmission, sensing, imaging, lighting, laser or anti-counterfeiting.

[0035] Specifically, the information transmission can be optical information transmission; the sensing can be optical sensing; the imaging can be X-ray detection imaging; the illumination can be solid-state illumination, especially light-emitting diode illumination; the anti-counterfeiting can be luminescent anti-counterfeiting; and so on.

[0036] The beneficial effects of the present invention are as follows: The present invention prepares a glass optical fiber with a core-cladding structure using an organic-inorganic hybrid metal halide, which has good flexibility, can achieve a small bending radius, and has low optical loss at a small bending radius; based on the characteristics of high transmittance, high luminous efficiency, high glass-forming ability, and low melting point of the organic-inorganic hybrid metal halide, by adjusting the refractive index and melting point of the core layer, it is possible to ensure the preparation of the optical fiber at a lower temperature, effectively reduce energy consumption, and obtain a glass optical fiber with good forming performance and adjustable luminous performance.

[0037] Specifically, compared with the prior art, the present invention has the following advantages:

[0038] 1. The present invention selects an organic-inorganic hybrid metal halide that can achieve a stable melt as the core layer of the optical fiber. Its decomposition temperature is higher than the melting point, and it can remain stable in the melt state, with a small viscosity and fluidity; further, a glass optical fiber with a core-cladding structure is obtained by using a transparent dielectric hollow tube (such as quartz capillary tube, FEP, PFA, PMMA, PTFE, PET, PC, PS, etc.) as the cladding of the optical fiber. The obtained glass optical fiber has the advantages of high luminous efficiency, high transmittance, good flexibility, few defects inside the optical fiber, low optical loss, and adjustable luminous performance.

[0039] 2. The present invention proposes to use a filling method to prepare an organic-inorganic hybrid metal halide glass optical fiber. Due to the low melting point of the metal halide, the glass optical fiber can be prepared at a low temperature (such as ≤300 °C), and it has excellent bending performance. This method has universality and scalability. At the same time, based on the adjustable characteristics of metal ions, active optical fibers with different color emissions can be realized. By constructing a unified temperature zone during the optical fiber preparation process, the situation where the organic-inorganic hybrid metal halide melt rapidly quenches and solidifies in the tube is effectively avoided.

[0040] 3. The glass optical fiber of the present invention has high transmittance and high luminous efficiency, and is a good material for active optical fibers, which can broaden the material system of active optical fibers; moreover, the preparation temperature of the present invention is low and the bending radius is small, which can solve the problems of high-temperature preparation and large bending radius required for quartz optical fibers. The organic-inorganic hybrid metal halide glass optical fiber provided by the present invention has good application effects in the fields of information transmission, imaging, measurement, anti-counterfeiting, or illumination. Description of the Drawings

[0041] Figure 1 Differential scanning calorimetry diagram of the (HTPP)2SbBr5 crystal for Example 1.

[0042] Figure 2 The ultraviolet-visible transmission spectrum and refractive index curve of the (HTPP)2SbBr5 glass of Example 1.

[0043] Figure 3 Schematic diagram of the preparation process of the glass fiber of Example 1.

[0044] Figure 4 Micrograph of the (HTPP)2SbBr5 glass fiber of Example 1.

[0045] Figure 5 Optical loss coefficient of the (HTPP)2SbBr5 glass fiber of Example 1 under 450 nm laser excitation.

[0046] Figure 6 Bending photograph and bending loss test diagram of the (HTPP)2SbBr5 glass fiber with an inner diameter of 100 μm in Example 1.

[0047] Figure 7 Micrograph of the (HTPP)2PbBr4 glass fiber of Example 2.

[0048] Figure 8 Photographs of the (HTPP)2SbBr5 glass fiber of Example 1 and the (HTPP)2MnBr4 glass fiber of Example 3 for information anti-counterfeiting encryption. Detailed implementation manners

[0049] The content of the present invention will be further described in detail through specific examples below. Similarly, it should be understood that the following examples are only used to further illustrate the present invention and cannot be construed as limiting the protection scope of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the principles described in the present invention fall within the protection scope of the present invention. The specific process parameters and the like in the following examples are also only an example within a suitable range, that is, those skilled in the art can make selections within a suitable range through the description in this article, rather than being limited to the specific data in the following examples. The raw materials, reagents or devices used in the following examples and comparative examples can be obtained from conventional commercial channels or can be obtained by existing known methods without special instructions.

[0050] Example 1

[0051] A kind of (HTPP)2SbBr5 glass fiber, and the specific preparation steps are as follows:

[0052] 1) Mix hexyltriphenylphosphonium bromide (HTPPBr, CAS: 4762-26-9) and antimony tribromide (SbBr3, CAS: 7789-61-9) in a certain amount of anhydrous methanol solution according to a molar mass ratio of 2:1, and stir to obtain a clear precursor solution. Place the solution in a room-temperature environment and slowly evaporate it for 1-2 days to obtain (HTPP)2SbBr5 crystals.

[0053] Figure 1 is the differential scanning calorimetry analysis result of (HTPP)2SbBr5 crystals, with a heating rate of 10 °C / minute: the T of (HTPP)2SbBr5 m = 114.3 °C, T g = 35.0 °C, T g / T m is 0.79, showing excellent glass-forming ability.

[0054] 2) Grind and mix hexyltriphenylphosphonium bromide and antimony tribromide evenly according to a molar mass ratio of 2:1, and put them into a muffle furnace preheated to 230 °C for firing to completely melt the raw materials to form a homogeneous melt. Then let the melt cool naturally to room temperature to obtain (HTPP)2SbBr5 glass.

[0055] Use a 2×2 cm 2 square silica gel mold to prepare (HTPP)2SbBr5 glass into a square glass with a thickness of 1 mm, and conduct ultraviolet-visible transmission spectroscopy tests and ellipsometry tests to obtain the Figure 2 ultraviolet-visible transmission spectrum and refractive index curve of (HTPP)2SbBr5 glass as shown. Among them, (a) is the ultraviolet-visible transmission spectrum, and (b) is the refractive index curve. From Figure 2 (a) it can be seen that this glass material has a transmittance of >80% in the range of 500-1000 nm; from Figure 2 (b) it can be seen that the refractive index of this glass material is 1.67 at 730 nm, which is higher than the refractive index of commercial soluble polytetrafluoroethylene PFA (1.35). The refractive index difference between the core material and the cladding material provides a basis for the design of the fiber core-cladding structure.

[0056] 3) Place the (HTPP)2SbBr5 glass in a special high-temperature-resistant glass container and place it on a heating stage set at 230 °C for melting. Select PFA hollow tubes with inner diameters of 100 μm, 300 μm, 500 μm, 800 μm, and 1000 μm respectively as the fiber cladding material and seal-connect them to the vacuum pump tube. Construct a constant-temperature region through an annular heating jacket to ensure that the glass container and the PFA hollow tube are in the same temperature range. Under the action of the vacuum pump, fill the PFA hollow tube with the (HTPP)2SbBr5 glass melt. Subsequently, take out the PFA tube and let it cool naturally at room temperature to finally obtain the (HTPP)2SbBr5 glass fiber with a core-cladding structure. The schematic diagram of the preparation process is shown in Figure 3 , where n1 refers to the refractive index of the (HTPP)2SbBr5 glass (core layer), n2 refers to the refractive index of the PFA hollow tube (cladding), and n1 > n2; θ max refers to the light incident angle.

[0057] The length of the prepared optical fiber is 40 cm, and the preparation of longer optical fibers can be achieved by improving the size of the heating jacket. Figure 4 is the microscope photo of the prepared (HTPP)2SbBr5 glass fiber. Among them, (a1) is the overall photo of the glass fiber made of the PFA hollow tube with an inner diameter of 100 μm, and it can be seen that the outer diameter of the cladding of the glass fiber is 300 μm; (a2) is the photo of the inner core of the glass fiber made of the PFA hollow tube with an inner diameter of 100 μm, and it can be seen that the inner core diameter of the glass fiber is 100 μm; (b1) is the overall photo of the glass fiber made of the PFA hollow tube with an inner diameter of 300 μm, and it can be seen that the outer diameter of the cladding of the glass fiber is 600 μm; (b2) is the photo of the inner core of the glass fiber made of the PFA hollow tube with an inner diameter of 300 μm, and it can be seen that the inner core diameter of the glass fiber is 300 μm; (c1) is the overall photo of the glass fiber made of the PFA hollow tube with an inner diameter of 500 μm, and it can be seen that the outer diameter of the cladding of the glass fiber is 1600 μm; (c2) is the photo of the inner core of the glass fiber made of the PFA hollow tube with an inner diameter of 500 μm, and it can be seen that the inner core diameter of the glass fiber is 500 μm; (d1) is the overall photo of the glass fiber made of the PFA hollow tube with an inner diameter of 800 μm, and it can be seen that the outer diameter of the cladding of the glass fiber is 1600 μm; (d2) is the photo of the inner core of the glass fiber made of the PFA hollow tube with an inner diameter of 800 μm, and it can be seen that the inner core diameter of the glass fiber is 800 μm. From Figure 4 it can be seen that there are no defects such as bubbles and cracks inside the optical fiber, indicating that the method of this embodiment can prepare high-quality optical fibers.

[0058] Test the optical loss coefficient of the (HTPP)2SbBr5 glass fiber under 450 nm laser excitation by the truncation method. The test results are as Figure 5As shown in the figure. Starting from Figure 5 It can be seen that when the inner diameter is 1000 μm, the lowest optical loss coefficient of the glass fiber is 0.16 dB / cm; when the inner diameter is 800 μm, the lowest optical loss coefficient of the glass fiber is 0.63 dB / cm; when the inner diameter is 500 μm, the lowest optical loss coefficient of the glass fiber is 0.74 dB / cm; when the inner diameter is 300 μm, the lowest optical loss coefficient of the glass fiber is 0.49 dB / cm; when the inner diameter is 100 μm, the lowest optical loss coefficient of the glass fiber is 1.09 dB / cm.

[0059] Figure 6 Figure 6 is a bending photograph and bending loss test diagram of (HTPP)2SbBr5 glass fiber with an inner diameter of 100 μm. Among them, (a) is a photograph of the glass fiber with a bending radius of 0.8 mm, and (b) is a bending loss test diagram of the glass fiber with different bending radii. Starting from Figure 6 As can be seen from (a) in Figure 6, no visible microcracks will occur in the glass fiber with a bending radius of 0.8 mm, showing excellent flexibility; starting from Figure 6 As can be seen from (b) in Figure 6, as the bending radius becomes smaller, the bending loss of the glass fiber increases, but at a bending radius of 0.8 mm, the bending loss of the glass fiber still remains below 10%, that is, the glass fiber has only a very small bending loss even at a bending radius of 0.8 mm.

[0060] Example 2

[0061] A kind of (HTPP)2PbBr4 glass fiber, the specific preparation steps are as follows:

[0062] 1) Mix hexyltriphenylphosphonium bromide (HTPPBr, CAS: 4762-26-9) and lead bromide (PbBr2, CAS: 10031-22-8) in a glass beaker according to a molar mass ratio of 2:1. Place the beaker in a muffle furnace at 230 °C to melt it into a uniform melt, and then let the melt cool naturally to room temperature to obtain (HTPP)2PbBr4 glass.

[0063] 2) Place (HTPP)2PbBr4 glass in a special high-temperature-resistant glass container and place it on a heating table set at a temperature of 230 °C for melting. Select PFA hollow tubes with inner diameters of 100, 300, 500, and 800 μm respectively as the fiber cladding material, and seal them to the vacuum pump tube. Construct a constant temperature area through an annular heating jacket to ensure that the glass container and the PFA hollow tube are in the same temperature range. Under the action of a vacuum pump, fill the PFA hollow tube with (HTPP)2PbBr4 glass melt. Subsequently, take out the PFA tube and let it cool naturally at room temperature to finally obtain (HTPP)2PbBr4 glass fiber with a core-cladding structure.

[0064] Figure 7 are the microscope photos of the prepared (HTPP)2PbBr4 glass optical fibers. Among them, (a1) is the overall photo of the glass optical fiber made of a PFA hollow tube with an inner diameter of 100 μm. It can be seen that the outer diameter of the cladding of the glass optical fiber is 300 μm; (a2) is the photo of the core of the glass optical fiber made of a PFA hollow tube with an inner diameter of 100 μm. It can be seen that the core diameter of the glass optical fiber is 100 μm; (b1) is the overall photo of the glass optical fiber made of a PFA hollow tube with an inner diameter of 300 μm. It can be seen that the outer diameter of the cladding of the glass optical fiber is 600 μm; (b2) is the photo of the core of the glass optical fiber made of a PFA hollow tube with an inner diameter of 300 μm. It can be seen that the core diameter of the glass optical fiber is 300 μm; (c1) is the overall photo of the glass optical fiber made of a PFA hollow tube with an inner diameter of 500 μm. It can be seen that the outer diameter of the cladding of the glass optical fiber is 1600 μm; (c2) is the photo of the core of the glass optical fiber made of a PFA hollow tube with an inner diameter of 500 μm. It can be seen that the core diameter of the glass optical fiber is 500 μm; (d1) is the overall photo of the glass optical fiber made of a PFA hollow tube with an inner diameter of 800 μm. It can be seen that the outer diameter of the cladding of the glass optical fiber is 1600 μm; (d2) is the photo of the core of the glass optical fiber made of a PFA hollow tube with an inner diameter of 800 μm. It can be seen that the core diameter of the glass optical fiber is 800 μm. It can be seen from Figure 7 the figure that there are no defects such as air bubbles and cracks inside the optical fiber, indicating that the method of this embodiment can prepare high-quality optical fibers.

[0065] Example 3

[0066] A kind of (HTPP)2MnBr4 glass optical fiber, and the specific preparation steps are as follows:

[0067] 1) Mix hexyltriphenylphosphonium bromide (HTPPBr, CAS: 4762-26-9) and manganese(II) bromide tetrahydrate (MnBr2·4H2O, CAS: 10031-20-6) in a glass beaker according to a molar mass ratio of 2:1. Place the beaker in a muffle furnace at 230 °C to melt into a uniform melt, and then let the melt cool naturally to room temperature to obtain (HTPP)2MnBr4 glass.

[0068] 2) Place (HTPP)2MnBr4 glass in a special high-temperature-resistant glass container and place it on a heating table set at 230 °C for melting. Select a PFA hollow tube with an inner diameter of 100 μm as the fiber cladding material and seal it to the vacuum pump tube. Construct a constant-temperature region through an annular heating jacket to ensure that the glass container and the PFA hollow tube are in the same temperature range. Under the action of a vacuum pump, fill the PFA hollow tube with (HTPP)2MnBr4 glass melt. Subsequently, take out the PFA tube and let it cool naturally at room temperature to finally obtain (HTPP)2MnBr4 glass optical fiber with a core-cladding structure.

[0069] Application Example

[0070] The application of glass optical fiber in anti-counterfeiting encryption is as follows:

[0071] Take the (HTPP)2SbBr5 glass optical fiber prepared in Example 1 and the (HTPP)2MnBr4 glass optical fiber prepared in Example 3 with an inner diameter of 100 μm and embed them into a cardboard substrate respectively. Among them, the (HTPP)2MnBr4 glass optical fiber forms the pattern of "SYSU", and the (HTPP)2SbBr5 glass optical fiber forms the pattern of "2024". Under the excitation of 365 nm ultraviolet light, when the above patterns are imaged through the visible light and near-infrared spectral channels, a wavelength-dependent spatial emission pattern is presented. Figure 8 Photos of the (HTPP)2SbBr5 glass optical fiber of Example 1 and the (HTPP)2MnBr4 glass optical fiber of Example 3 used for information anti-counterfeiting encryption. From Figure 8 It can be seen that by using a visible light camera and a near-infrared camera, it is possible to record the optical images of the luminescent fiber braided patterns with different luminescent properties under ultraviolet light. The pattern of "SYSU" formed by the (HTPP)2MnBr4 optical fiber is imaged by the visible light camera, and the pattern of "2024" formed by the (HTPP)2SbBr5 optical fiber is imaged by the near-infrared camera, indicating that the glass optical fiber provided by the embodiments of the present invention has the effect of dual-mode information encryption.

[0072] In the embodiments of the present invention, an organic-inorganic hybrid metal halide capable of achieving a stable melt is selected as the core layer of the optical fiber. Its decomposition temperature is higher than the melting point, and it can remain stable in the molten state, with a small viscosity and fluidity. Further, a transparent dielectric hollow tube (such as PFA, PMMA, PTFE, etc.) is used as the cladding of the optical fiber to obtain a core-clad structured glass optical fiber. The obtained glass optical fiber has the advantages of high luminous efficiency, high transmittance (transmittance > 80% at a wavelength of 500 - 1000 nm), good flexibility (bending loss still remains below 10% at a bending radius of 0.8 mm), few defects inside the optical fiber (no bubbles, cracks), low optical loss (the optical loss coefficient of an optical fiber with an inner diameter of 1000 μm is as low as 0.16 dB / cm), and adjustable luminous performance.

[0073] Moreover, in the embodiments of the present invention, the organic-inorganic hybrid metal halide glass optical fiber is prepared by the filling method. Due to the low melting point characteristic of the metal halide, the glass optical fiber can be prepared at a low temperature (such as ≤ 300 °C), and it has excellent bending performance. This method has generality and scalability. At the same time, based on the adjustable characteristic of metal ions, active optical fibers with different color emissions can be realized. By constructing a unified temperature zone during the optical fiber preparation process, the situation that the organic-inorganic hybrid metal halide melt rapidly quenches and solidifies in the tube is effectively avoided.

[0074] The glass optical fiber provided in the embodiments of the present invention has high transmittance and high luminous efficiency, and is a good material for active optical fibers, which can broaden the material system of active optical fibers. Moreover, the preparation temperature of the embodiments of the present invention is low and the bending radius is small, which can solve the problems that quartz optical fibers require high-temperature preparation and large bending radii. The organic-inorganic hybrid metal halide glass optical fiber provided in the embodiments of the present invention has good application effects in information transmission, sensing, imaging, lighting, lasers, or anti-counterfeiting.

[0075] In summary, the present invention uses an organic-inorganic hybrid metal halide to prepare a core-clad structured glass optical fiber, which has good flexibility, can achieve a small bending radius, and has low optical loss at a small bending radius. Based on the characteristics of high transmittance, high luminous efficiency, high glass-forming ability, and low melting point of the organic-inorganic hybrid metal halide, by adjusting the refractive index and melting point of the core layer, it is possible to ensure the preparation of the optical fiber at a lower temperature, effectively reduce energy consumption, and obtain a glass optical fiber with good forming performance and adjustable luminous performance.

Claims

1. An organic-inorganic hybrid metal halide glass optical fiber, characterized in that, It includes a core layer and a cladding layer coated outside the core layer; the raw materials for preparing the core layer include organic-inorganic hybrid metal halides; the refractive index of the core layer is greater than that of the cladding layer; the melting point of the core layer is lower than that of the cladding layer.

2. The organic-inorganic hybrid metal halide glass optical fiber according to claim 1, wherein The refractive index of the organic-inorganic hybrid metal halide > 1.35; and / or, the melting point of the organic-inorganic hybrid metal halide ≤ 250 °C; and / or, the decomposition temperature of the organic-inorganic hybrid metal halide is greater than the melting point.

3. The organic-inorganic hybrid metal halide glass optical fiber according to claim 1, characterized in that, The structural formula of the organic-inorganic hybrid metal halide is AMX; wherein, A is an organic cation, M is a metal cation, and X is a halogen anion.

4. The organic-inorganic hybrid metal halide glass optical fiber according to claim 3, characterized in that, The organic cation includes at least one of quaternary phosphonium organic cations or their derivatives, quaternary ammonium organic cations or their derivatives, and guanidine organic cations or their derivatives; and / or, the metal cation includes at least one of manganese, lead, antimony, copper, iron, cobalt, nickel, zinc, tin or indium ions; and / or, the halogen anion includes Cl - , Br - or I - and at least one of them.

5. The organic-inorganic hybrid metal halide glass optical fiber according to claim 1, characterized in that, The material of the cladding layer is a transparent dielectric material.

6. The organic-inorganic hybrid metal halide glass optical fiber according to claim 5, characterized in that, The transparent dielectric material includes at least one of quartz capillary tubes, perfluoro(ethylene-propylene), soluble polytetrafluoroethylene, polytetrafluoroethylene, polycarbonate, polystyrene, polyethylene terephthalate or polymethyl methacrylate.

7. The organic-inorganic hybrid metal halide glass optical fiber according to claim 1, wherein The diameter of the core layer is 10 - 2000 μm; and / or, the outer diameter of the cladding layer is 30 - 3000 μm.

8. A method for preparing an organic-inorganic hybrid metal halide glass optical fiber according to any one of claims 1 to 7, characterized in that, It includes the following steps: Melt the raw materials for preparing the core layer and fill them into the cladding layer to obtain the organic-inorganic hybrid metal halide glass optical fiber.

9. The preparation method according to claim 8, wherein The preparation method specifically includes the following steps: melt the raw materials for preparing the core layer; take a hollow tube as the cladding layer, make the hollow tube contact with the molten raw materials of the core layer; and seal the hollow tube and a vacuum device, adjust the pressure inside the hollow tube through the vacuum device, and use the pressure difference to make the molten raw materials of the core layer fill the hollow tube, and then cool and form to obtain the organic-inorganic hybrid metal halide glass optical fiber.

10. Application of an organic-inorganic hybrid metal halide glass optical fiber as described in any one of claims 1 - 7 in information transmission, sensing, imaging, lighting, laser or anti-counterfeiting.

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