Preparation method of casting-wire drawing integrated perovskite nanocrystalline glass optical fiber

Abstract

The invention belongs to the technical field of gain optical fiber preparation, and particularly relates to a preparation method of a casting-wire drawing integrated perovskite nanocrystalline glass optical fiber. The method comprises the following steps: melting a fiber core glass raw material into a fiber core glass melt; heating a cladding glass tube to a softening wire drawing temperature, and pouring the fiber core glass melt to form a preform; carrying out wire drawing treatment on the preform, and drawing to obtain a precursor optical fiber; and carrying out annealing treatment on the precursor optical fiber to obtain the perovskite nanocrystalline glass optical fiber. The preparation method is simple in process, high in controllability and wide in applicability, rapid devitrification during optical fiber drawing in a traditional process is avoided, interface reaction in the optical fiber is reduced, the perovskite nanocrystalline glass optical fiber which is good in light transmission performance and high in luminous efficiency is prepared, and a new way is developed for preparing the low-loss nanocrystalline functional optical fiber.

Description

Technical Field

[0001] The present invention belongs to the technical field of gain optical fiber preparation, and more specifically relates to a method for preparing a casting-drawing integrated perovskite nanocrystalline glass optical fiber. Background Art

[0002] Fiber lasers have broad application prospects in a wide range of fields, including marine submarine communications, information storage, biomedicine, industrial processing, and display lighting. Currently, visible fiber lasers face technical bottlenecks in output power, failing to meet practical application requirements. The research and development of high-power visible lasers is of vital importance. The main factors influencing fiber laser performance include the pump source, resonator, and gain fiber. The performance of the gain fiber plays a crucial role in improving the output characteristics of the fiber laser and is currently the most significant factor restricting the development of visible fiber lasers. On the one hand, the luminescence performance of the gain fiber directly affects the laser's output wavelength and conversion efficiency. On the other hand, the thermodynamic properties of the gain fiber significantly influence the fiber laser's stability, laser damage threshold, and output power. Therefore, developing a gain fiber with high luminescence efficiency is crucial to improving the conversion efficiency of visible fiber lasers and breaking through the output power bottleneck.

[0003] Currently, the gain fibers used for visible lasers are primarily rare-earth ion-doped fluoride fibers. Based on the rare-earth ion luminescence mechanism, they can be divided into upconversion fibers and downconversion fibers. Upconversion fiber lasers utilize near-infrared (980nm) semiconductor laser pumping to achieve high-energy visible-band laser output through a two-photon or multiphoton process. The intrinsic efficiency of upconversion luminescence from rare-earth ions is generally low, resulting in low gain efficiency for upconversion fibers. Downconversion fiber lasers utilize blue (405nm) semiconductor lasers as pump sources to achieve longer-wavelength visible laser output. Due to the relatively small absorption cross-section of rare-earth ions for blue light, the fiber's gain efficiency is low, making it difficult to significantly increase the laser output power. Limited by the low gain efficiency of rare-earth-doped fibers, visible fiber lasers have so far struggled to exceed 10W for extended periods of time. Therefore, there is an urgent need to develop new visible laser gain fibers to achieve breakthroughs in luminescence efficiency.

[0004] Due to their perfect crystal structure, perovskite materials have a visible-band luminescence efficiency far exceeding that of rare-earth-doped materials, making them ultra-efficient optical gain materials in the visible band. In recent years, perovskite crystal materials have been widely used in the field of visible lasers, and perovskite visible lasers are a major research hotspot both domestically and internationally. Visible laser output in multiple bands with ultra-low pump thresholds has been achieved in devices composed of perovskite nanowires, nanosheets, nanospheres, and thin films. Despite this, there have been no reports of perovskite fiber lasers to date, primarily due to limitations in perovskite fiber preparation technology. When perovskite fibers are prepared using the traditional tube-and-rod method, violent crystallization occurs, leading to rapid crystal growth, a sharp increase in fiber loss, and severe luminescence quenching, making it difficult to achieve fiber laser output. Therefore, how to prepare a perovskite nanocrystal glass fiber capable of fiber laser output has become a difficult problem that technicians in this field urgently need to overcome. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for preparing a casting-drawing integrated perovskite nanocrystal glass optical fiber, so as to overcome the defects and limitations of the traditional tube-rod method in the preparation of perovskite optical fibers, and to achieve the successful preparation of low-loss gain optical fibers containing perovskite nanocrystals.

[0006] To achieve the above object, the present invention provides the following solutions:

[0007] One of the technical solutions of the present invention is to provide a method for preparing a casting-drawing integrated perovskite nanocrystalline glass optical fiber, comprising the following steps:

[0008] melting the core glass raw material into a core glass melt;

[0009] After heating the cladding glass tube to a softening drawing temperature, pouring the core glass melt into the tube to form a preform;

[0010] Drawing the preform into a precursor optical fiber;

[0011] The precursor optical fiber is annealed to obtain the perovskite nanocrystal glass optical fiber.

[0012] Furthermore, in terms of molar percentage, the core glass raw materials include: SiO2 20-46%, AX36-44%, ZnO 4-6%, SrCO3 3-7%, NaY 3-9%, Cs2CO3 6-8%, PbO 1-3% and Al2O31-3%;

[0013] Wherein, the AX is one of B2O3, P2O5 and GeO2; and the NaY is at least one of NaCl, NaBr and NaI.

[0014] Optionally, the molar ratio of NaY to PbO in the core glass raw material is 3:1.

[0015] Furthermore, the cladding glass tube is made of K9 glass, high borosilicate glass or soda-lime-silica glass.

[0016] Furthermore, the melting step includes: heating the core glass raw material to 1050-1250° C., keeping the temperature for 30-90 minutes, and then reducing the temperature by 100° C. to obtain the core glass melt.

[0017] Furthermore, the softening drawing temperature is 10-30° C. higher than the temperature of the core glass melt.

[0018] Furthermore, the speed of the wire drawing process is 10-20 m / s.

[0019] Furthermore, the annealing treatment is performed at a temperature of 500-540° C. and for a time of 5-10 hours.

[0020] After annealing treatment, perovskite nanocrystals are precipitated in the optical fiber core. The perovskite nanocrystals are CsPbCl3, CsPbBr3, CsPbI3, CsPbCl x Br 3-x 、CsPbI x Br 3-x Any one of , where x<3.

[0021] The second technical solution of the present invention is to provide a perovskite nanocrystalline glass optical fiber, which is prepared by the above-mentioned preparation method.

[0022] Furthermore, the core glass of the perovskite nanocrystalline glass optical fiber is perovskite-doped borosilicate glass, phosphosilicate glass or germanate glass.

[0023] The third technical solution of the present invention is to provide an application of the above-mentioned perovskite nanocrystalline glass optical fiber in a high-power visible fiber laser.

[0024] The present invention discloses the following technical effects:

[0025] The process of the present invention is simple, highly controllable, and widely applicable. It avoids the rapid crystallization during optical fiber drawing in traditional processes, reduces interfacial reactions in the optical fiber, and prepares perovskite nanocrystalline glass optical fibers with good light transmission performance and high-efficiency luminescence, opening up a new path for the preparation of low-loss nanocrystalline functional optical fibers.

[0026] The perovskite nanocrystal glass optical fiber prepared by the present invention can improve the gain efficiency in the visible band, is suitable for high-power visible fiber lasers, and can solve the bottleneck problem of low output power of current visible fiber lasers.

[0027] The present invention adopts a pouring-drawing integrated method to prepare perovskite nanocrystal glass optical fiber. This method is different from the traditional tube-and-rod method and the fused core method. The present method is to pour the core glass melt directly into the cladding glass tube, and the two are drawn together into a precursor optical fiber, and then the optical fiber is annealed to prepare the perovskite nanocrystal glass optical fiber. The core glass is in a molten state, has a large internal energy, and is not easy to crystallize. Rapid drawing causes the glass diameter to quickly become thinner, and heat dissipation becomes faster. It can effectively avoid the large amount of crystallization during the traditional tube-and-rod method of preparing optical fiber, and the prepared optical fiber loss is low. In addition, the core glass already in a molten state is poured into the cladding glass tube and immediately drawn, which greatly reduces the contact time between the core glass and the cladding glass, reduces interfacial reaction and element diffusion, and further reduces optical fiber loss.

[0028] The perovskite nanocrystalline glass optical fiber prepared by the method of the present invention not only has low transmission loss, but also has high-efficiency visible band luminescence, which provides favorable conditions for obtaining high-efficiency visible laser output. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The accompanying drawings, which constitute part of the present invention, are provided to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are provided to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0030] Figure 1 Schematic diagram of the process flow for preparing perovskite nanocrystalline glass optical fiber according to an embodiment of the present invention.

[0031] Figure 2 These are the emission spectrum and cross-sectional micrograph of the perovskite nanocrystal glass optical fiber prepared in Example 1, wherein the inset is a cross-sectional micrograph.

[0032] Figure 3 This is the XRD pattern of the perovskite nanocrystal glass optical fiber prepared in Example 1.

[0033] Figure 4 This is a diagram of the luminescence quantum yield of the perovskite nanocrystal glass optical fiber prepared in Example 1. DETAILED DESCRIPTION

[0034] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0035] It should be understood that the terms described herein are intended only to describe particular embodiments and are not intended to limit the present invention. In addition, for numerical ranges herein, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. The intermediate value within any stated value or stated range, and each smaller range between any other stated value or intermediate value within the stated range, is also encompassed within the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded within the scope.

[0036] Unless otherwise indicated, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein may also be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of any conflict with any incorporated document, the contents of this specification shall prevail.

[0037] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments described herein without departing from the scope or spirit of the invention. Other embodiments will be apparent to those skilled in the art from the description of the invention. The description and examples are intended to be illustrative only.

[0038] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0039] Unless otherwise specified, the raw materials and reagents involved in the specific embodiments of the present invention are all commercially available products, and the purchase channels do not affect the realization of the technical effects.

[0040] Unless otherwise specified, the room temperature and normal temperature involved in the specific embodiments of the present invention are both 20-30°C.

[0041] Unless otherwise specified, "%" in the raw materials of the present invention refers to molar percentage.

[0042] It should be pointed out that the matters not described in detail in the present invention are conventional operating means in this field and are not the focus of the present invention.

[0043] Example 1

[0044] The preparation steps of perovskite nanocrystal glass optical fiber include:

[0045] S1. Process soda-lime-silica glass into a cylindrical glass tube with an inner diameter of 5.0 mm, an outer diameter of 40 mm, and a length of 100 mm, and polish the inner and outer surfaces to a mirror finish to serve as the cladding glass tube;

[0046] S2. After mixing the core glass raw materials, grind them in an agate mortar for 15 minutes to mix them thoroughly. Then pour the mixed materials into a platinum pointed crucible, cover it, and place it in a high-temperature electric furnace. Slowly heat it to 1250°C and keep it warm for 60 minutes. Then reduce the temperature to 1150°C and keep it warm to obtain a uniform core glass melt.

[0047] The ratio of the core glass raw materials is (in mole percentage): SiO2 40%, GeO2 31%, ZnO6%, SrCO35%, NaBr 6%, Cs2CO3 7%, PbO 2% and Al2O3 3%;

[0048] S3. Fix the cladding glass tube on a drawing tower and slowly heat it to 1170°C. Draw the lower end of the cladding glass tube into a tapered shape, seal the glass tube, and slowly pour the core glass melt into the cladding glass hole along the wall of the cladding glass tube until the cladding glass tube is filled with the core glass melt to form a preform.

[0049] S4. The preform rod is quickly drawn at 1170°C to draw the cladding and the core into an optical fiber together. The drawing speed of the drawing tower is adjusted to 12m / s, and the outer diameter of the optical fiber is adjusted to 125 microns. It is then placed in a precision annealing furnace and heat-treated at 510°C for 10 hours to uniformly precipitate CsPbBr3 perovskite nanocrystals in the optical fiber core to prepare perovskite nanocrystal glass optical fiber with good light transmittance and high luminescence efficiency.

[0050] Example 2

[0051] The preparation steps of perovskite nanocrystal glass optical fiber include:

[0052] S1. Process high borosilicate glass into a cylindrical glass tube with an inner diameter of 5.0 mm, an outer diameter of 40 mm, and a length of 100 mm, and polish the inner and outer surfaces to a mirror finish to serve as the cladding glass tube;

[0053] S2. After mixing the core glass raw materials, grind them in an agate mortar for 15 minutes to mix them thoroughly. Then pour the mixed materials into a platinum pointed crucible, cover it, and place it in a high-temperature electric furnace. Slowly heat it to 1200°C and keep it warm for 60 minutes. Then reduce the temperature to 1100°C and keep it warm to obtain a uniform core glass melt.

[0054] The ratio of the core glass raw materials is (in mole percentage): SiO2 36%, B2O3 36%, ZnO 6%, SrCO3 5%, NaBr 2%, NaI 4%, Cs2CO3 6%, PbO 2% and Al2O3 3%;

[0055] S3. Fix the cladding glass tube on a drawing tower and slowly heat it to 1120°C. Draw the lower end of the cladding glass tube into a tapered shape, seal the glass tube, and slowly pour the core glass melt into the cladding glass hole along the wall of the cladding glass tube until the cladding glass tube is filled with the core glass melt to form a preform.

[0056] S4. The preform rod is quickly drawn at 1120℃ to draw the cladding and core into optical fiber together. The drawing speed of the drawing tower is adjusted to 12m / s, and the outer diameter of the optical fiber is adjusted to 125 microns. It is then placed in a precision annealing furnace and heat treated at 540℃ for 10 hours to uniformly precipitate CsPbBr in the optical fiber core. 1.2 I 1.8 Perovskite nanocrystals are used to prepare perovskite nanocrystal glass optical fibers with good light transmittance and high luminescence efficiency.

[0057] Example 3

[0058] The preparation steps of perovskite nanocrystal glass optical fiber include:

[0059] S1. Process K9 glass into a cylindrical glass tube with an inner diameter of 5.0 mm, an outer diameter of 40 mm, and a length of 100 mm. Polish the inner and outer surfaces to a mirror finish to serve as the cladding glass tube.

[0060] S2. After mixing the core glass raw materials, grind them in an agate mortar for 15 minutes to mix them thoroughly. Then pour the mixed materials into a platinum pointed crucible, cover it, and place it in a high-temperature electric furnace. Slowly heat it to 1050°C and keep it at that temperature for 60 minutes. Then reduce the temperature to 950°C and keep it at that temperature to obtain a uniform core glass melt.

[0061] The ratio of the core glass raw materials is (in mole percentage): SiO2 37%, P2O5 34%, ZnO 6%, SrCO3 5%, NaBr 4%, NaI 2%, Cs2CO3 7%, PbO 2% and Al2O3 3%;

[0062] S3. Fix the cladding glass tube on a drawing tower and slowly heat it to 970°C. Draw the lower end of the cladding glass tube into a cone shape, seal the glass tube, and slowly pour the core glass melt into the cladding glass hole along the wall of the cladding glass tube until the cladding glass tube is filled with the core glass melt to form a preform.

[0063] S4. The preform rod is quickly drawn at 970℃ to draw the cladding and core into optical fiber together. The drawing speed of the drawing tower is adjusted to 12m / s, and the outer diameter of the optical fiber is adjusted to 125 microns. It is then placed in a precision annealing furnace and heat treated at 500℃ for 10 hours to uniformly precipitate CsPbBr in the optical fiber core. 1.8 Cl 1.2Perovskite nanocrystals are used to prepare perovskite nanocrystal glass optical fibers with good light transmittance and high luminescence efficiency.

[0064] Test example

[0065] Figure 1 Schematic diagram of the process flow for preparing perovskite nanocrystalline glass optical fiber according to an embodiment of the present invention.

[0066] Figure 2 The emission spectrum and cross-sectional micrograph of the perovskite nanocrystal glass fiber prepared in Example 1 are shown, with the inset showing a cross-sectional micrograph. As can be seen from the figure, after heat treatment, the fiber has excellent light transmission. Under excitation by a 405nm laser, green light emission with a central wavelength of 515nm and a spectral half-wavewidth of 20nm is observed, corresponding to the luminescence of the CsPbBr3 perovskite.

[0067] Figure 3 This is the XRD pattern of the perovskite nanocrystal glass optical fiber prepared in Example 1. As can be seen from the figure, it corresponds to the diffraction pattern of CsPbBr3 perovskite, proving that perovskite nanocrystals have precipitated in the optical fiber.

[0068] Figure 4 This is a graph showing the quantum yield of the perovskite nanocrystal glass optical fiber prepared in Example 1. As can be seen from the graph, under 405nm blue light excitation, the quantum efficiency of the optical fiber is as high as 87.3%.

[0069] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0070] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing a casting-drawing integrated perovskite nanocrystalline glass optical fiber, characterized in that the steps include: melting the core glass raw material into a core glass melt; After heating the cladding glass tube to a softening drawing temperature, pouring the core glass melt into the tube to form a preform; Drawing the preform into a precursor optical fiber; The precursor optical fiber is annealed to obtain the perovskite nanocrystal glass optical fiber.

2. The preparation method according to claim 1, wherein In terms of molar percentage, the core glass raw materials include: SiO2 20-46%, AX 36-44%, ZnO 4-6%, SrCO3 3-7%, NaY 3-9%, Cs2CO3 6-8%, PbO 1-3% and Al2O3 1-3%; Wherein, the AX is one of B2O3, P2O5 and GeO2; and the NaY is at least one of NaCl, NaBr and NaI.

3. The preparation method according to claim 2, wherein The molar ratio of NaY to PbO in the core glass raw material is 3:

1.

4. The preparation method according to claim 1, wherein The cladding glass tube is made of K9 glass, high borosilicate glass or soda-lime-silica glass.

5. The preparation method according to claim 1, wherein The melting step includes: heating the core glass raw material to 1050-1250° C., keeping the temperature for 30-90 minutes, and then reducing the temperature by 100° C. to obtain the core glass melt.

6. The preparation method according to claim 1, wherein The softening drawing temperature is 10-30° C. higher than the temperature of the core glass melt.

7. The preparation method according to claim 1, wherein The speed of the wire drawing process is 10-20 m / s.

8. The preparation method according to claim 1, wherein The annealing treatment is performed at a temperature of 500-540° C. and for a time of 5-10 hours.

9. A perovskite nanocrystal glass optical fiber, characterized in that: The perovskite nanocrystalline glass optical fiber is prepared by the preparation method according to any one of claims 1 to 8.

10. Use of the perovskite nanocrystal glass optical fiber according to claim 9 in a high-power visible fiber laser.

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