A method for preparing a Pb-based perovskite-polymer composite

Abstract

The application relates to a preparation method of a Pb-based perovskite-polymer composite material, and belongs to the field of radiation detection materials. The application aims to solve the problem that the existing blending method for preparing the Pb-based perovskite-polymer composite material needs to protect the perovskite crystals prepared in advance, and solve the problem that the existing in-situ growth method for preparing the Pb-based perovskite-polymer composite material has micropores, which affects the stability of the perovskite-polymer composite material. The preparation method is as follows: cesium acetate, lead bromide and polypropylene are mixed, then heated and stirred, and finally cooled to obtain the Pb-based perovskite-polymer composite material. The application is used for the preparation of the Pb-based perovskite-polymer composite material.

Description

Technical Field

[0001] This invention belongs to the field of radiation detection materials. Background Technology

[0002] Pb-based perovskite-polymer composites, as scintillator materials, have broad application prospects in radiation detection, security inspection, and industrial monitoring. Currently, the main synthesis methods for this material are blending and in-situ growth. The blending method involves preparing perovskite crystals in advance, then mixing them with a polymer, and preparing the perovskite-polymer composite material through spin coating or spinning. However, this method requires protective treatment of the pre-prepared perovskite crystals to prevent degradation in the air. The in-situ growth method involves solvent-induced polymer swelling, allowing the perovskite precursor solution to enter the polymer molecular chain. As the solvent evaporates, the perovskite precursor forms uniformly dispersed perovskite nanocrystals within the polymer. However, this method is affected by the solvent; when the solvent evaporates, it forms micropores in the polymer, thus affecting the stability of the perovskite-polymer composite material. Therefore, there are currently challenges in the preparation technology of Pb-based perovskite-polymer composites. Summary of the Invention

[0003] This invention aims to address the problem that existing blending methods for preparing Pb-based perovskite-polymer composites require protective treatment of the pre-prepared perovskite crystals, and to solve the problem that existing in-situ growth methods for preparing Pb-based perovskite-polymer composites have micropores that affect the stability of the perovskite-polymer composites. Therefore, this invention provides a method for preparing Pb-based perovskite-polymer composites.

[0004] A method for preparing a Pb-based perovskite-polymer composite material, comprising the following steps:

[0005] Cesium acetate, lead bromide and polypropylene were mixed, and then heated and stirred for 10 min to 120 min at a speed of 30 rpm to 90 rpm and a temperature of 160℃ to 230℃. Finally, the mixture was cooled to obtain a Pb-based perovskite-polymer composite material.

[0006] The molar ratio of cesium acetate to lead bromide is 1:(1-10).

[0007] The beneficial effects of this invention are:

[0008] This invention innovatively employs a readily industrializable, one-step, solvent-free method to encapsulate Pb-based perovskite nanocrystals into polypropylene, preparing a Pb-based perovskite-polymer composite material. This avoids the need for protective treatment of the perovskite crystals and the influence of solvents on the polymer material, problems encountered in other methods of preparing perovskite polymer composites. The method of this invention is not only technically simple to operate, but also maintains the non-porous structure of the prepared Pb-based perovskite-polymer composite material, exhibiting extremely high stability. It avoids the instability and deliquescence of Pb-based perovskite nanocrystals in air, while simultaneously imparting good mechanical properties and processability.

[0009] The molar ratio of cesium acetate to lead bromide described in this invention is 1:(1-10), which can better synthesize perovskite nanocrystals between polymer molecular chains. The reaction temperature of this invention is 160℃-230℃ to ensure that polypropylene melts without decomposing, while ensuring that cesium acetate and lead bromide reach the reaction temperature, so as to generate Pb-based perovskite nanocrystals between the molten polypropylene molecular chains. Attached Figure Description

[0010] Figure 1 X-ray diffraction pattern of the Pb-based perovskite-polymer composite material prepared in Example 1;

[0011] Figure 2 An X-ray optical photograph of the Pb-based perovskite-polymer composite material prepared in Example 1;

[0012] Figure 3 The X-ray fluorescence spectrum of the Pb-based perovskite-polymer composite material prepared in Example 1;

[0013] Figure 4 The image shows a scanning electron microscope (SEM) image of the Pb-based perovskite-polymer composite material prepared in Example 1.

[0014] Figure 5 The fluorescence image of the Pb-based perovskite-polymer composite material prepared in Example 1 under ultraviolet light after being soaked in water for one month;

[0015] Figure 6 The X-ray diffraction pattern of the Pb-based perovskite-polymer composite material prepared in Example 2;

[0016] Figure 7 An X-ray optical photograph of the Pb-based perovskite-polymer composite material prepared in Example 2;

[0017] Figure 8 The X-ray fluorescence spectrum of the Pb-based perovskite-polymer composite material prepared in Example 2;

[0018] Figure 9This is a scanning electron microscope image of the Pb-based perovskite-polymer composite material prepared in Example 2;

[0019] Figure 10 The image shows the fluorescence of the Pb-based perovskite-polymer composite material prepared in Example 2 after immersion in water for one month under a UV lamp. Detailed Implementation

[0020] Specific Implementation Method 1: This implementation method provides a method for preparing a Pb-based perovskite-polymer composite material, which is carried out according to the following steps:

[0021] Cesium acetate, lead bromide and polypropylene were mixed, and then heated and stirred for 10 min to 120 min at a speed of 30 rpm to 90 rpm and a temperature of 160℃ to 230℃. Finally, the mixture was cooled to obtain a Pb-based perovskite-polymer composite material.

[0022] The molar ratio of cesium acetate to lead bromide is 1:(1-10).

[0023] The beneficial effects of this embodiment are:

[0024] This embodiment innovatively employs a readily industrializable, one-step, solvent-free method to encapsulate Pb-based perovskite nanocrystals into polypropylene, preparing a Pb-based perovskite-polymer composite material. This avoids the need for protective treatment of the perovskite crystals and the influence of solvents on the polymer material, problems encountered in other methods of preparing perovskite polymer composites. This method is not only technically simple to operate but also maintains the non-porous structure of the prepared Pb-based perovskite-polymer composite material, exhibiting extremely high stability. It avoids the instability and deliquescence of Pb-based perovskite nanocrystals in air, while also imparting good mechanical properties and processability.

[0025] The molar ratio of cesium acetate to lead bromide described in this embodiment is 1:(1-10), which can better synthesize perovskite nanocrystals between polymer molecular chains. The reaction temperature of 160℃ to 230℃ in this embodiment is to melt the polypropylene without decomposing it, while ensuring that cesium acetate and lead bromide reach the reaction temperature, so as to generate Pb-based perovskite nanocrystals between the molten polypropylene molecular chains.

[0026] Specific Implementation Method Two: This implementation method differs from Specific Implementation Method One in that: cesium acetate, lead bromide, and polypropylene are mixed at a rotation speed of 30 rpm to 100 rpm for 5 min to 20 min. Everything else is the same as in Specific Implementation Method One.

[0027] Specific Implementation Method Three: This implementation method differs from Specific Implementation Method One or Two in that the total mass ratio of cesium acetate and lead bromide to polypropylene is 1:(10-30). Everything else is the same as in Specific Implementation Method One or Two.

[0028] Specific Implementation Method Four: This implementation method differs from Specific Implementation Methods One to Three in that the total mass ratio of cesium acetate and lead bromide to polypropylene is 1:(20-30). Everything else is the same as in Specific Implementation Methods One to Three.

[0029] Specific Implementation Method Five: This implementation method differs from Specific Implementation Methods One to Four in that the molar ratio of cesium acetate to lead bromide is 1:(4-10). Everything else is the same as in Specific Implementation Methods One to Four.

[0030] Specific Implementation Method Six: This implementation method differs from Specific Implementation Methods One to Five in that the molar ratio of cesium acetate to lead bromide is 1:(1-4). Everything else is the same as in Specific Implementation Methods One to Five.

[0031] Specific Implementation Method Seven: This implementation method differs from Specific Implementation Methods One to Six in that: under conditions of a rotation speed of 30 rpm to 90 rpm and a temperature of 160°C to 230°C, the mixture is heated and stirred for 10 min to 120 min using a torque rheometer. Everything else is the same as in Specific Implementation Methods One to Six.

[0032] Specific Implementation Method Eight: This implementation method differs from Specific Implementation Methods One to Seven in that: heating and stirring are performed for 10 to 50 minutes at a rotation speed of 60 rpm to 90 rpm and a temperature of 185°C to 195°C. Everything else is the same as in Specific Implementation Methods One to Seven.

[0033] Specific Implementation Method Nine: This implementation method differs from Specific Implementation Methods One to Eight in that: heating and stirring are performed for 10 to 50 minutes at a rotation speed of 30 to 60 rpm and a temperature of 185°C to 230°C. Everything else is the same as in Specific Implementation Methods One to Eight.

[0034] Specific Implementation Method Ten: This implementation method differs from Specific Implementation Methods One to Nine in that: under the conditions of a rotation speed of 30 rpm to 60 rpm and a temperature of 195°C to 230°C, heating and stirring are performed for 10 min to 50 min. Everything else is the same as Specific Implementation Methods One to Nine.

[0035] The beneficial effects of the present invention are verified using the following embodiments:

[0036] Example 1:

[0037] A method for preparing a Pb-based perovskite-polymer composite material, comprising the following steps:

[0038] Cesium acetate, lead bromide and polypropylene were mixed at a speed of 60 rpm for 10 min. Then, the mixture was heated and stirred for 10 min at a speed of 60 rpm and a temperature of 185 °C using a torque rheometer. Finally, the mixture was cooled to obtain a Pb-based perovskite-polymer composite material, namely CsPbBr3-polypropylene composite material.

[0039] The molar ratio of cesium acetate to lead bromide is 1:4; the total mass ratio of cesium acetate and lead bromide to the mass ratio of polypropylene is 1:20.

[0040] Figure 1 The figure shows the X-ray diffraction pattern of the Pb-based perovskite-polymer composite material prepared in Example 1. As can be seen from the figure, the sharp rays at 21.5°, 30° and 44° of the XRD pattern of the Pb-based perovskite-polypropylene composite material prepared in Example 1 match the monoclinic structure of CsPbBr3 (PDF#18-0364), proving that CsPbBr3 nanocrystals were successfully synthesized in the polypropylene matrix.

[0041] Figure 2 This is an X-ray optical photograph of the Pb-based perovskite-polymer composite material prepared in Example 1. It is clearly observed that the Pb-based perovskite-polypropylene composite material prepared in Example 1 exhibits good photoresponse under X-rays.

[0042] Figure 3 The figure shows the X-ray fluorescence spectrum of the Pb-based perovskite-polymer composite material prepared in Example 1. As can be seen from the figure, the CsPbBr3-polypropylene composite material prepared in Example 1 exhibits good photoluminescence under X-ray irradiation.

[0043] Figure 4 The image shows a scanning electron microscope (SEM) image of the Pb-based perovskite-polymer composite material prepared in Example 1. As can be seen from the image, the CsPbBr3 crystals in the CsPbBr3-polypropylene composite material prepared in Example 1 are well encapsulated by the polypropylene matrix, and no porous structure appears inside the material.

[0044] Figure 5 The image shows the fluorescence of the Pb-based perovskite-polymer composite material prepared in Example 1 under ultraviolet light after immersion in water for one month. As can be seen from the image, the CsPbBr3 crystals in the CsPbBr3-polypropylene composite material prepared in Example 1 are well coated by the polypropylene matrix, and the material exhibits good water stability.

[0045] Example 2: This example differs from Example 1 in that the torque rheometer temperature is set to 195℃. Everything else is the same as in Example 1.

[0046] Figure 6 The image shows the X-ray diffraction pattern of the Pb-based perovskite-polymer composite material prepared in Example 2. As can be seen from the figure, Example 2 successfully synthesized CsPbBr3 crystals in a polypropylene matrix.

[0047] Figure 7 This is an X-ray optical photograph of the Pb-based perovskite-polymer composite material prepared in Example 2. The figure clearly shows that the Pb-based perovskite-polypropylene composite material prepared in Example 2 exhibits good photoresponse under X-rays.

[0048] Figure 8 The figure shows the X-ray fluorescence spectrum of the Pb-based perovskite-polymer composite material prepared in Example 2. As can be seen from the figure, the CsPbBr3-polypropylene composite material prepared in Example 2 exhibits good photoluminescence under X-ray irradiation.

[0049] Figure 9 The image shows a scanning electron microscope (SEM) image of the Pb-based perovskite-polymer composite material prepared in Example 2. As can be seen from the image, the CsPbBr3 crystals in the CsPbBr3-polypropylene composite material prepared in Example 2 are well encapsulated by the polypropylene matrix, and no porous structure appears inside the material.

[0050] Figure 10 The image shows the fluorescence of the Pb-based perovskite-polymer composite material prepared in Example 2 after immersion in water for one month under a UV lamp. As can be seen from the image, the CsPbBr3 crystals in the CsPbBr3-polypropylene composite material prepared in Example 2 are well coated by the polypropylene matrix, and the material exhibits good water stability.

Claims

1. A method for preparing a Pb-based perovskite-polymer composite material, characterized in that... It is done in the following steps: Cesium acetate, lead bromide and polypropylene were mixed at a speed of 60 rpm for 10 min. Then, the mixture was heated and stirred for 10 min at a speed of 60 rpm and a temperature of 185℃~195℃ using a torque rheometer. Finally, the mixture was cooled to obtain a Pb-based perovskite-polymer composite material. The molar ratio of cesium acetate to lead bromide is 1:4; the total mass ratio of cesium acetate and lead bromide to the mass ratio of polypropylene is 1:20.

Images