A cesium lead halide perovskite quantum dot glass optical fiber and its preparation method

Abstract

The present invention discloses a cesium lead halide perovskite quantum dot glass optical fiber and a preparation method thereof; in the present invention, the component elements of the perovskite quantum dots are added to a borosilicate glass system to generate Cs<supgt;+< / supgt>, Pb<supgt;2+< / supgt> and halogen ions, the reagents are adjusted according to the types of perovskite quantum dots required, and after sufficient grinding, high-temperature melting, and cooling and drawing, an optical fiber is obtained, and then through a heat treatment process, a glass optical fiber with uniform distribution of the size and density of perovskite quantum dots can be obtained; the preparation method of the present invention is simple, low in price, and the crystallization of quantum dots can be controlled, and the prepared optical fiber has a strong fluorescence peak and broadband tunability, and has application prospects in fiber lasers.

Description

Technical Field

[0001] The present invention relates to the fields of optical communication technology and nanomaterial preparation, and particularly relates to a cesium lead halide perovskite quantum dot glass optical fiber and a preparation method thereof. Background Art

[0002] In recent years, glass optical fibers have been widely studied due to their many advantages such as low loss, high bandwidth, and strong anti-interference ability, and have an irreplaceable position in the fields of optical communication, laser, sensing, and lighting.

[0003] Quantum dots are a type of low-dimensional semiconductor material with a lattice structure, and their size is at the nanometer level, usually in the range of a few nanometers to dozens of nanometers. Due to the quantum confinement effect caused by their extremely small size, quantum dots exhibit special optical, electrical, and magnetic properties. Among them, perovskite quantum dots have attracted much attention due to their excellent optoelectronic properties and broad application prospects. Perovskite refers to an oxide with the general molecular formula ABO 3 . Among them, the A position is usually occupied by metal ions with a larger radius, and the B position is occupied by metal ions with a smaller radius. In addition, other ions with similar radii or valences can also be embedded in this structure and maintain the crystal structure unchanged. Cesium lead halide perovskite quantum dots usually refer to semiconductor materials with the chemical formula CsPbX 3 (X = Cl, Br, I). In this structure, Cs + occupies the A position of perovskite, Pb 2+ occupies the B position of perovskite, and halogen elements (Cl - , Br - , I - ) occupy the O position of perovskite. Perovskite quantum dots have many advantages, such as high fluorescence quantum yield, narrow-band photoluminescence, and wide-wavelength absorption. In addition, by adjusting the type and proportion of halogen element X, luminescence covering the entire visible light range (400 - 750 nm) can be achieved under ultraviolet light excitation.

[0004] Currently, the research on quantum dot optical fibers mainly focuses on the near-infrared band, and the research on perovskite quantum dot glass optical fibers is less, which seriously restricts their further development. Based on this, the present invention has prepared CsPbCl x Br 3-x and CsPbBr x I 3-xPerovskite quantum dot glass optical fiber. Currently, there are mainly the following methods for preparing quantum dot glass optical fibers: The first is to prepare PbSe quantum dot glass optical fibers by the vertical drawing method of glass melt. This process is only used for the preparation of near-infrared PbSe quantum dot glass optical fibers and does not involve perovskite quantum dot optical fibers. The second is to prepare quantum dot glass optical fibers by the double crucible method. The quantum dot-doped core glass melt and the cladding glass melt without quantum dot components are respectively poured into the inner crucible and the outer crucible. After heating the crucibles to a certain temperature, the glass melts flow down together to form a precursor optical fiber, and then quantum dots are precipitated by annealing at different temperatures. This preparation process does not involve perovskite quantum dot glass optical fibers. The third is to prepare quantum dot glass optical fibers by the tube-rod method. A relatively stable silicate glass is selected as the core material. After heating it to softening, the optical fiber is drawn under the action of gravity, and then the optical fiber is annealed near the glass transition temperature to finally obtain the quantum dot glass optical fiber. This preparation process does not involve perovskite quantum dot glass optical fibers. The fourth is to prepare quantum dot glass optical fibers by the co-drawing method of tube-in-melt. This method first prepares a quantum dot-doped glass rod, which is used as the core glass after grinding and polishing; then the cladding glass without quantum dot components is prepared, and the core glass is inserted into the cladding glass to obtain the optical fiber preform, and then the preform is drawn in a drawing tower. This method has currently been used to prepare CsPbCl x Br 3-x and CsPbBr 3 perovskite quantum dot glass optical fiber, and the glass system is phosphate glass.

[0005] The present invention provides a method for preparing cesium lead halide perovskite quantum dot borosilicate glass optical fiber by the transverse drawing method of high-temperature melt, and realizes the tunability of the fluorescence wavelength of the optical fiber in the visible band by regulating the glass network structure, halogen components and heat treatment conditions. Summary of the Invention

[0006] The purpose of the present invention is to provide a cesium lead halide perovskite quantum dot glass optical fiber and a preparation method thereof. The present invention avoids the problem of uncontrollable crystallization of quantum dots in the process of preparing optical fibers in the prior art, and the method is simple, the raw materials are inexpensive, the size and density of quantum dots are controllable, and the emission wavelength covers the entire visible band.

[0007] The idea of the present invention is: First, the component elements of perovskite quantum dots are added to the borosilicate glass system to generate Cs + 、Pb 2+ and halogen ions. The reagents are adjusted according to the types of perovskite quantum dots required. After sufficient grinding, high-temperature melting, and cooling and drawing, the optical fiber is obtained, and then the glass optical fiber with uniform distribution of perovskite quantum dot size and density can be obtained through the heat treatment process.

[0008] The technical solution of the present invention is as follows:

[0009] A cesium lead halide perovskite quantum dot glass optical fiber is made from raw materials in the following mole percentages:

[0010] SiO 2 22 - 37%

[0011] B 2 O 3 23 - 38%

[0012] ZnO 15 - 25%

[0013] CaF 2 0 - 5%

[0014] Cs 2 CO 3 5 - 13%

[0015] PbCl 2 0 - 2%

[0016] NaCl 0 - 7%

[0017] PbBr 2 0 - 2%

[0018] NaBr 0 - 7%

[0019] PbI 2 0 - 2%

[0020] NaI 0 - 7%

[0021] Among them, PbCl 2 , PbBr 2 , PbI 2 are not all 0 at the same time, and NaCl, NaBr, and NaI are not all 0 at the same time;

[0022] The total of all raw materials is 100%.

[0023] The optical fiber described in the present invention is a doped CsPbCl x Br 3-x and / or CsPbBr x I 3-x (x = 0 - 3) perovskite quantum dot glass optical fiber, preferably made from raw materials in the following mole percentages:

[0024] SiO 2 25 - 34%

[0025] B 2 O 3 26 - 35%

[0026] ZnO 18 - 22%

[0027] CaF 2 0.5 - 1.5%

[0028] Cs 2 CO 3 5 - 9%

[0029] PbCl 2 0 - 1.6%

[0030] NaCl 0 - 6.8%

[0031] PbBr 2 0 - 1.6%

[0032] NaBr 0 - 6.8%

[0033] PbI 2 0 - 1.6%

[0034] NaI 0 - 6.8%

[0035] Among them, PbCl 2 , PbBr 2 , PbI 2 are not simultaneously 0, and NaCl, NaBr, and NaI are not simultaneously 0;

[0036] The total of all raw materials is 100%.

[0037] The preparation method of the cesium lead calcium halide perovskite quantum dot glass optical fiber described in the present invention is as follows:

[0038] (1) Grinding and mixing: Take each raw material according to the ratio, place it in an agate mortar, grind and mix evenly to obtain a mixed material;

[0039] Specifically, grind for 15 - 20 min;

[0040] When adjusting the type and proportion of halogen elements, it is necessary to change B 2 O 3 and SiO 2The molar percentage is used to obtain the optimal crystallization conditions (specifically refer to the embodiments of the present invention, which provide the optimal crystallization conditions for different perovskite quantum dot optical fibers);

[0041] (2) High-temperature melting: Pour the ground mixture into a sealed corundum crucible, and place it in a muffle furnace for melting to obtain a glass melt;

[0042] The melting temperature is 1100 - 1200 °C, and the melting time is 10 - 30 min. In this way, a uniformly mixed high-temperature glass melt can be obtained;

[0043] (3) Cooling and drawing: Wait for the glass melt to cool to a viscous state. At this time, place the corundum crucible horizontally on a high-temperature resistant platform, and draw a wire horizontally from the glass melt to obtain a glass optical fiber precursor;

[0044] When the glass melt cools to 650 - 850 °C, it becomes viscous, and at this time, the viscosity is moderate, which is conducive to horizontal wire drawing;

[0045] The specific operation of horizontal wire drawing is as follows: Insert the wire into the glass melt, ensure that one end of the wire is wrapped by the glass melt, and then draw it horizontally. A glass optical fiber precursor can be obtained between the wire and the crucible;

[0046] (4) Heat treatment: Place the glass optical fiber precursor in a quartz boat and place it in a vacuum tube furnace for heat treatment to precipitate perovskite quantum dots. After the tube furnace cools to room temperature, the cesium lead halide perovskite quantum dot glass optical fiber is obtained;

[0047] The temperature of heat treatment is 450 - 550 °C, and the time is 2 - 10 h.

[0048] The technical principle of the present invention is as follows:

[0049] In the raw material composition of the present invention, SiO 2 and B 2 O 3 are network formers, and their main function is to form a glass network structure. By adjusting the molar ratio of SiO 2 and B 2 O 3 , the crystallization of perovskite quantum dots can be promoted or inhibited, thereby affecting the luminescence performance of the glass optical fiber; ZnO is a network intermediate, which helps the synthesis of perovskite quantum dots and the uniform distribution of quantum dot sizes; CaF 2 is used to lower the glass transition temperature and thus promote the crystallization of perovskite quantum dot glass; Cs 2 CO 3 , PbCl 2 , NaCl, PbBr 2 and NaBr are used as CsPbCl x Br3-x Introducing body of quantum dots; Cs 2 CO 3 , PbBr 2 , NaBr, PbI 2 and NaI as the introducing body of CsPbBr x I 3-x quantum dots, the perovskite quantum dot optical fiber prepared using different raw materials can achieve luminescence in the wavelength range of 450 - 710 nm.

[0050] The key point of the present invention is that the crystallization of perovskite quantum dots in the glass optical fiber can be controlled and the distribution can be made uniform. During the fiber drawing process, transverse fiber drawing can avoid the deposition of quantum dots at the bottom of the optical fiber. In addition, since the glass melt is drawn into an extremely thin fiber, it is rapidly cooled, so that the quantum dots do not have time to crystallize, thereby reducing the uncontrollable crystallization of quantum dots. The size of the perovskite quantum dots can be controlled through the heat treatment process. The crystallization of glass at high temperature includes two stages: nucleation and growth. At an appropriate temperature, the higher the heat treatment temperature, the faster the growth rate of the crystal nuclei, and the larger the size of the perovskite quantum dots. The longer the heat treatment time, the larger the size of the perovskite quantum dots. Therefore, by adjusting the temperature and time of the heat treatment, perovskite quantum dots of different sizes can be obtained. According to the quantum size effect, perovskite quantum dot glass optical fibers with different emission wavelengths can be obtained.

[0051] Compared with the prior art, the beneficial effects of the present invention are mainly reflected in:

[0052] The method for preparing the cesium lead halide perovskite quantum dot glass optical fiber of the present invention is simple, inexpensive, and the crystallization of quantum dots can be controlled. The prepared optical fiber has a strong fluorescence peak and broadband tunability, and has application prospects in fiber lasers. Description of the Drawings

[0053] Figure 1 : Fluorescence emission spectrum of the CsPbCl 2 Br 1 quantum dot glass optical fiber of Example 1.

[0054] Figure 2 : Fluorescence emission spectrum of the CsPbCl 1 Br 2 quantum dot glass optical fiber of Example 2.

[0055] Figure 3 : Fluorescence emission spectrum of the CsPbBr 3 quantum dot glass optical fiber of Example 3.

[0056] Figure 4 : Fluorescence emission spectrum of the CsPbBr 1 I 2 quantum dot glass optical fiber of Example 4.

[0057] Figure 5 : CsPbI of Example 5 3 Fluorescence emission spectra of quantum dot glass fibers.

[0058] Figure 6 : Schematic diagram of the preparation process of the present invention. DETAILED DESCRIPTION

[0059] The present invention is further described below by means of specific embodiments, but the protection scope of the present invention is not limited thereto.

[0060] Embodiment 1:

[0061] According to the molar ratio of SiO 2 :B 2 O 3 :ZnO:CaF 2 :Cs 2 CO 3 :PbCl 2 :NaCl:PbBr 2 Weigh analytically pure SiO in a ratio of :NaBr=31:29:20:1:7:1.07:4.53:0.53:2.27 2 3.33g, B 2 O 3 3.61g, ZnO 2.91g, CaF 2 0.14g, Cs 2 CO 3 4.09 g, PbCl 2 0.53g, NaCl 0.47g, PbBr 2 The above chemical raw materials were ground thoroughly in a mortar, placed in a sealed corundum crucible and moved into a high-temperature muffle furnace, melted at 1200°C for 20 minutes to obtain a glass melt. After the melt cooled to 730°C with a moderate viscosity, an iron wire was inserted into the glass melt and quickly pulled out horizontally to obtain CsPbCl 2 Br 1 Quantum dot glass fiber precursors.

[0062] Then, the optical fiber precursor was placed in a quartz boat and moved into a vacuum tube furnace, where it was heated from room temperature to 470°C and heat treated for 8 hours to precipitate CsPbCl. 2 Br 1 Quantum dots, CsPbCl can be obtained when the heat treatment time is over and the tube furnace is cooled to room temperature 2 Br 1 Quantum dot glass optical fiber. The prepared optical fiber fluorescence emission spectrum is as follows Figure 1As shown, its central wavelength is 476nm and its full width at half maximum is 20nm.

[0063] Embodiment 2:

[0064] According to the molar ratio of SiO 2 :B 2 O 3 :ZnO:CaF 2 :Cs 2 CO 3 :PbCl 2 :NaCl:PbBr 2 Weigh analytically pure SiO in a ratio of :NaBr=30:30:20:1:7:0.53:2.27:1.07:4.53 2 3.33g, B 2 O 3 3.86g, ZnO 3.01g, CaF 2 0.14g, Cs 2 CO 3 4.22 g, PbCl 2 0.27g, NaCl 0.25g, PbBr 2 The above chemical raw materials were ground thoroughly in a mortar, placed in a sealed corundum crucible and moved into a high-temperature muffle furnace, melted at 1200°C for 20 minutes to obtain a glass melt. After the melt cooled to 730°C with a moderate viscosity, an iron wire was inserted into the glass melt and quickly pulled out horizontally to obtain CsPbCl 1 Br 2 Quantum dot glass fiber precursors.

[0065] Then, the optical fiber precursor was placed in a quartz boat and moved into a vacuum tube furnace, where it was heated from room temperature to 480°C and heat treated for 4 hours to precipitate CsPbCl. 1 Br 2 Quantum dots, CsPbCl can be obtained when the heat treatment time is over and the tube furnace is cooled to room temperature 1 Br 2 Quantum dot glass optical fiber. The prepared optical fiber fluorescence emission spectrum is as follows Figure 2 As shown, its central wavelength is 500nm and its full width at half maximum is 18nm.

[0066] Embodiment 3:

[0067] According to the molar ratio of SiO 2 :B 2 O 3 :ZnO:CaF 2 :Cs 2 CO 3 :PbBr2 Weigh analytically pure SiO 2 3.33g, B 2 O 3 3.86g, ZnO 3.01g, CaF 2 0.14g, Cs 2 CO 3 4.22 g, PbBr 2 1.09g, NaBr 1.29g. The above chemical raw materials were ground thoroughly in a mortar, placed in a sealed corundum crucible and moved into a high-temperature muffle furnace, melted at 1200℃ for 20min to obtain a glass melt, and after the melt cooled to 730℃ with moderate viscosity, an iron wire was inserted into the glass melt and quickly pulled out horizontally to obtain CsPbBr 3 Quantum dot glass fiber precursors.

[0068] Then, the optical fiber precursor was placed in a quartz boat and moved into a vacuum tube furnace, where it was heated from room temperature to 490°C and heat treated for 4 hours to precipitate CsPbBr. 3 Quantum dots, when the heat treatment time is over and the tube furnace is cooled to room temperature, CsPbBr 3 Quantum dot glass optical fiber. The prepared optical fiber fluorescence emission spectrum is as follows Figure 3 As shown, its central wavelength is 512nm and its full width at half maximum is 22nm.

[0069] Embodiment 4:

[0070] According to the molar ratio of SiO 2 :B 2 O 3 :ZnO:CaF 2 :Cs 2 CO 3 :PbBr 2 :NaBr:PbI 2 Weigh analytically pure SiO in a ratio of :NaI=26:34:20:1:7:0.53:2.27:1.07:4.53 2 2.86g, B 2 O 3 4.33g, ZnO 2.98g, CaF 2 0.14g, Cs 2 CO 3 4.17 g, PbBr 2 0.36, NaBr 0.43g, PbI 20.90 g of Cs₂CO₃, 1.24 g of NaI. After fully grinding the above chemical raw materials in a mortar, put them into a closed corundum crucible and transfer them into a high-temperature muffle furnace. Melt at 1200 °C for 20 min to obtain a glass melt. After the melt cools to a moderate viscosity at 730 °C, insert an iron wire into the glass melt and quickly pull it out horizontally to obtain CsPbBr 1 I 2 quantum dot glass fiber precursor.

[0071] Subsequently, put the fiber precursor into a quartz boat and transfer it into a vacuum tube furnace. Heat it from room temperature to 520 °C and heat-treat for 4 h. In this way, CsPbBr 1 I 2 quantum dots can be precipitated. When the heat treatment time ends and the tube furnace cools to room temperature, CsPbBr 1 I 2 quantum dot glass fiber can be obtained. The fluorescence emission spectrum of the prepared fiber is as Figure 4 shown, with a central wavelength of 624 nm and a full width at half maximum of 45 nm.

[0072] Example 5:

[0073] Weigh analytical pure SiO₂, B₂O₃, ZnO, CaF₂, Cs₂CO₃, PbI₂, and NaI according to the molar ratio of SiO₂:B₂O₃:ZnO:CaF₂:Cs₂CO₃:PbI₂:NaI = 25:35:20:1:7:1.6:6.8. Weigh 2.78 g of SiO₂, 2 B 2 O 3 ₃ of 4.51 g, 3.01 g of ZnO, 0.14 g of CaF₂, 2 Cs 2 ₂CO 3 ₃ of 4.22 g, 2 PbI 2 ₂ of 1.36 g, and 1.88 g of NaI. After fully grinding the above chemical raw materials in a mortar, put them into a closed corundum crucible and transfer them into a high-temperature muffle furnace. Melt at 1200 °C for 15 min to obtain a glass melt. After the melt cools to a moderate viscosity at 730 °C, insert an iron wire into the glass melt and quickly pull it out horizontally to obtain CsPbI 2 O 3 quantum dot glass fiber precursor. 2 Cs 2 ₂CO 3 ₃ of 4.22 g, 2 PbI 3 quantum dot glass fiber precursor.

[0074] Subsequently, put the fiber precursor into a quartz boat and transfer it into a vacuum tube furnace. Heat it from room temperature to 510 °C and heat-treat for 4 h. In this way, CsPbI 3 quantum dots can be precipitated. When the heat treatment time ends and the tube furnace cools to room temperature, CsPbI3 Quantum dot glass optical fiber. The fluorescence emission spectrum of the prepared optical fiber is as follows Figure 5 shown, with a central wavelength of 688 nm and a full width at half maximum of 35 nm.

Claims

1. A cesium lead halide perovskite quantum dot glass optical fiber, characterized in that: Made from the following raw materials in mole percentage: SiO2 22~37% <h2 style=";text-align:left;direction:ltr">B2O3<h2 style=";text-align:left;direction:ltr"> <h2 style=";text-align:left;direction:ltr"> 23~38% ZnO 15~25% CaF2 0~5% <h2 style=";text-align:left;direction:ltr">Cs2CO3<h2 style=";text-align:left;direction:ltr"> <h2 style=";text-align:left;direction:ltr"> 5~13% PbCl2 0~2% NaCl 0~7% PbBr2 0~2% NaBr 0~7% PbI2 0~2% NaI 0~7% Among them, PbCl2, PbBr2, and PbI2 are not 0 at the same time, and NaCl, NaBr, and NaI are not 0 at the same time; All raw materials total 100%; The preparation method of the cesium lead halide perovskite quantum dot glass optical fiber is as follows: (1) Grinding and mixing: taking the raw materials according to the proportion, grinding and mixing them in an agate mortar to obtain a mixture; (2) High-temperature melting: Pour the ground mixture into a sealed corundum crucible and place it in a muffle furnace for melting to obtain a glass melt; (3) Cooling and drawing: When the glass melt is cooled to a viscous state, the corundum crucible is placed horizontally on a high-temperature resistant platform, and a wire is drawn horizontally from the glass melt using an iron wire to obtain a glass optical fiber precursor; When the glass melt is cooled to 650-850℃, it becomes viscous, and the moderate viscosity is conducive to horizontal drawing; (4) Heat treatment: placing the glass fiber precursor in a quartz boat and placing it in a vacuum tube furnace for heat treatment to precipitate perovskite quantum dots, and then waiting for the tube furnace to cool to room temperature to obtain the cesium lead halide perovskite quantum dot glass fiber; The heat treatment temperature is 450~550℃ and the time is 2~10h.

2. The cesium lead halide perovskite quantum dot glass optical fiber according to claim 1, characterized in that: Made from the following raw materials in mole percentage: SiO2 25~34% <h2 style=";text-align:left;direction:ltr">B2O3<h2 style=";text-align:left;direction:ltr"> <h2 style=";text-align:left;direction:ltr"> 26~35% ZnO 18~22% CaF2 0.5~1.5% <h2 style=";text-align:left;direction:ltr">Cs2CO3<h2 style=";text-align:left;direction:ltr"> <h2 style=";text-align:left;direction:ltr"> 5~9% PbCl2 0~1.6% NaCl 0~6.8% PbBr2 0~1.6% NaBr 0~6.8% PbI2 0~1.6% NaI 0~6.8% Among them, PbCl2, PbBr2, and PbI2 are not 0 at the same time, and NaCl, NaBr, and NaI are not 0 at the same time; All raw materials add up to 100%.

3. The cesium lead halide perovskite quantum dot glass optical fiber according to any one of claims 1 or 2, characterized in that: Fiber doping with CsPbCl x Br 3-x and / or CsPbBr x I 3-x , x=0~3.

4. The cesium lead halide perovskite quantum dot glass optical fiber according to claim 1, characterized in that: In step (2) of the preparation method, the melting temperature is 1100-1200° C., and the melting time is 10-30 min.

5. The cesium lead halide perovskite quantum dot glass optical fiber according to claim 1, characterized in that: In step (3) of the preparation method, the operation of transverse wire drawing is as follows: insert the iron wire into the glass melt and ensure that one end of the iron wire is wrapped by the glass melt, and then pull it out transversely to obtain a glass optical fiber precursor between the iron wire and the crucible.

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