Room temperature phase pyroelectric material and method of making same

Abstract

This invention discloses a room-temperature phase pyroelectric material and its preparation method, relating to the field of pyroelectric material technology, with the chemical formula C4H. 14 N₂OPbCl₄ is prepared as follows: 2-Dimethylaminoethylamine is cooled and stirred in an ice-water bath, then hydrogen peroxide solution is added dropwise while stirring. After the reaction, the resulting reaction solution is vacuum dried to obtain the nitrogen oxide of 2-dimethylaminoethylamine. The nitrogen oxide of 2-dimethylaminoethylamine and lead chloride are added to a concentrated hydrochloric acid solution, heated in an oil bath, and stirred to obtain a pyroelectric material. The pyroelectric material of this invention has a perovskite structure and undergoes a reversible phase transition reaction at a phase transition temperature of 27°C. During the phase transition, a current is generated at the polar axis of the crystal. The phase transition temperature at room temperature allows the pyroelectric material to operate within a relatively stable temperature range, providing reliable energy collection performance and showing great application value in waste heat utilization, self-sustaining systems, and other fields.

Description

Technical Field

[0001] This invention relates to the field of pyroelectric materials technology, and in particular to a room temperature phase pyroelectric material and its preparation method. Background Technology

[0002] Room temperature pyroelectric materials are of great significance in energy harvesting. They exhibit the characteristic of achieving pyroelectric effect at room temperature, providing a new approach for efficient energy conversion.

[0003] Pyroelectric materials can convert minute temperature changes in the surrounding environment into electrical energy, making them a promising candidate for waste heat utilization. By integrating these materials into devices or systems, waste heat generated in industrial processes, mechanical motion, or other systems can be effectively utilized and converted into electrical energy, thereby improving energy efficiency.

[0004] The energy conversion properties of pyroelectric materials make them a key component of self-sustaining energy systems. These materials can capture minute temperature changes from the surrounding environment, providing a reliable, autonomous power source for wireless sensors, low-power electronic devices, or other remotely controlled devices, reducing reliance on traditional batteries.

[0005] Compared to some other energy harvesting technologies, pyroelectric materials can typically achieve energy conversion without external excitation. This gives them a unique advantage in certain special environments or scenarios where a continuous external energy input cannot be provided.

[0006] Currently, most pyroelectric materials are either high-temperature or low-temperature pyroelectric, limiting their applications and hindering widespread use. The phase transition temperature of pyroelectric materials at room temperature means they can achieve efficient energy conversion amidst temperature fluctuations in the natural environment. This allows these materials to fully utilize their pyroelectric effect under common room temperature conditions, thereby improving energy conversion efficiency. Since room temperature is the typical temperature range for daily life and most industrial applications, the phase transition temperature of pyroelectric materials matching room temperature makes them more practical. Therefore, developing a room-temperature phase pyroelectric material is of great significance. Summary of the Invention

[0007] Based on the technical problems existing in the background technology, the present invention proposes a room temperature phase pyroelectric material and its preparation method. The material has a perovskite structure and undergoes a reversible phase transition reaction at a phase transition temperature of 27°C.

[0008] This invention proposes a room-temperature phase pyroelectric material with the chemical formula C4H. 14 N2OPbCl4.

[0009] Furthermore, the Curie temperature of the pyroelectric material is 27°C;

[0010] When the temperature is less than 27°C, the pyroelectric material belongs to the monoclinic crystal system, space group Cc.

[0011] When the temperature is greater than 27°C, the pyroelectric material belongs to the monoclinic crystal system C2 / C space group.

[0012] The preparation method of the above-mentioned room-temperature phase pyroelectric material proposed in this invention includes the following steps:

[0013] 1) Cool 2-dimethylaminoethylamine in an ice-water bath with stirring, then add hydrogen peroxide solution dropwise and stir to react;

[0014] 2) After the reaction in step 1) is completed, the reaction solution is dried under vacuum to obtain the nitrogen oxide of 2-dimethylaminoethylamine;

[0015] 3) The nitrogen oxide of 2-dimethylaminoethylamine and lead chloride were added to a concentrated hydrochloric acid solution, heated in an oil bath, and stirred to react, thus obtaining a pyroelectric material.

[0016] Further, in step 1), 2-dimethylaminoethylamine is cooled by stirring in an ice-water bath for 20-30 minutes.

[0017] Further, in step 1), the mass-to-volume ratio of 2-dimethylaminoethylamine to hydrogen peroxide solution (g / ml) is 1:11-13, and the mass percentage concentration of the hydrogen peroxide solution is 30%.

[0018] Furthermore, in step 1), the reaction is stirred for 46-50 hours.

[0019] Furthermore, in step 3), the oil bath heating temperature is 75-85℃, and the reaction is stirred for 2-4 hours.

[0020] Further, in step 3), the mass-to-volume ratio (g / g / mL) of the nitrogen oxide of 2-dimethylaminoethylamine, lead chloride, and concentrated hydrochloric acid is 4:5:180-240, and the mass percentage concentration of the concentrated hydrochloric acid solution is 36%.

[0021] Compared with the prior art, the beneficial effects of this application are mainly reflected in the following aspects:

[0022] 1. The pyroelectric material of this invention has a perovskite structure, which undergoes a reversible phase transition reaction at a phase transition temperature of 27°C. During the phase transition, an electric current is generated at the polar axis of the crystal. The phase transition temperature at room temperature allows the pyroelectric material to operate within a relatively stable temperature range, providing reliable energy harvesting performance. Compared to materials that require extreme high or low temperature conditions, room temperature operating conditions are easier to achieve, reducing the engineering complexity and stability challenges of the material.

[0023] 2. The pyroelectric material of this invention has significant application value in waste heat utilization and self-sustaining systems. It can convert changes in ambient temperature into electrical energy, effectively solving the problem of waste heat waste and improving the sustainable use of energy. Compared with traditional energy harvesting technologies, the pyroelectric material in this system can achieve energy conversion without external excitation or high-temperature conditions. This makes it highly suitable for special environments or scenarios where continuous external energy input cannot be provided.

[0024] 3. The method for preparing pyroelectric materials in this invention is easy to operate and test.

[0025] The phase transition temperature advantage of the pyroelectric material of this invention at room temperature makes it easier to achieve efficient energy conversion in various practical applications, thus showing broad application potential in energy harvesting and related fields. Attached Figure Description

[0026] Figure 1 This is the low-temperature single-crystal structure of the room-temperature phase pyroelectric material in the embodiments of the present invention;

[0027] Figure 2 This is the high-temperature single-crystal structure of the room-temperature phase pyroelectric material in the embodiments of the present invention;

[0028] Figure 3 This is the XRD pattern of the room-temperature phase pyroelectric material in the embodiments of the present invention;

[0029] Figure 4 This is a pyroelectric coefficient diagram of the room temperature phase pyroelectric material in the embodiment of the present invention, wherein curve a is the temperature-polarization intensity curve and curve b is the temperature-electric charge curve. Detailed Implementation

[0030] The technical solution of the present invention will now be described in detail through specific embodiments.

[0031] Example 1

[0032] This invention provides a perovskite material with room-temperature pyroelectric phase transition properties, the chemical composition of which is C4H. 14 N2OPbCl4. This material has a pyroelectric phase transition temperature of 27°C, is in the room temperature phase, and can be used for energy harvesting in many applications.

[0033] The preparation method of the above-mentioned room-temperature phase pyroelectric material includes the following steps:

[0034] 1) Add 4.4 g of 2-dimethylaminoethylamine to a round-bottom flask and place it in an ice-water bath, stirring for 20 minutes; then add 50 mL of 30% hydrogen peroxide solution dropwise and stir the reaction for 48 hours.

[0035] 2) The reaction solution obtained after the reaction was completed was dried under vacuum to obtain 4.5g of oily liquid, which was confirmed by nuclear magnetic resonance to be the nitrogen oxide of 2-dimethylaminoethylamine;

[0036] 3) Take 400 mg of nitrogen oxide of 2-dimethylaminoethylamine and 500 mg of lead chloride and add them to a round-bottom flask. Add 20 mL of concentrated hydrochloric acid solution, heat in an oil bath to 80 °C, and stir for 3 h to obtain the pyroelectric material.

[0037] The pyroelectric material prepared in Example 1 was tested. Figure 1 This refers to the low-temperature phase packing mode of low-temperature pyroelectric materials, and the cell parameters and molecular arrangement at different temperatures; Figure 2 This refers to the high-temperature phase packing mode of high-temperature pyroelectric materials, including cell parameters and molecular arrangement at different temperatures; Figure 3 The PXRD pattern obtained from the experimental test of the pyroelectric material shows that the high-temperature phase pyroelectric perovskite material is a homogeneous phase.

[0038] The room-temperature pyroelectric perovskite material prepared in Example 1 was analyzed. High-quality, appropriately sized single crystals were selected under a polarized light microscope, and analyzed using a Bruker CD6000 variable-temperature X-ray single-crystal diffractometer at temperatures of 102 K and 333 K with a molybdenum target. The X-ray diffraction structure of the single crystal was determined. The OLEX2 software with the SHELXTL97 package was used for single-crystal structure analysis and refinement. Specific crystal structure data for this compound are shown in Table 1.

[0039] Table 1. Crystallographic parameters of the room-temperature phase pyroelectric material prepared in Example 1

[0040]

[0041]

[0042]

[0043] The pyroelectric coefficient of the pyroelectric material prepared in Example 1 was tested, such as... Figure 4 As shown, it rapidly enters the phase transition stage at 27°C.

[0044] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A room-temperature phase pyroelectric material, characterized in that, Its chemical formula is C4H 14 N2OPbCl4, The pyroelectric material has a perovskite structure and a Curie temperature of 27°C. When the temperature is below 27°C, the pyroelectric material belongs to the monoclinic crystal system. Cc Space group, When the temperature is above 27°C, the pyroelectric material belongs to the monoclinic crystal system. C2 / C Space group; The crystallographic parameters of the pyroelectric material are as follows: 。 2. The method for preparing room-temperature phase pyroelectric materials as described in claim 1, characterized in that, Includes the following steps: 1) Cool 2-dimethylaminoethylamine in an ice-water bath with stirring, then add hydrogen peroxide solution dropwise and stir to react; 2) After the reaction in step 1) is completed, the reaction solution is dried under vacuum to obtain the nitrogen oxide of 2-dimethylaminoethylamine; 3) The nitrogen oxide of 2-dimethylaminoethylamine and lead chloride were added to a concentrated hydrochloric acid solution, heated in an oil bath, and stirred to react, thus obtaining a pyroelectric material.

3. The method for preparing room-temperature phase pyroelectric materials according to claim 2, characterized in that, In step 1), 2-dimethylaminoethylamine is cooled by stirring in an ice-water bath for 20-30 minutes.

4. The method for preparing room-temperature phase pyroelectric materials according to claim 2, characterized in that, In step 1), the mass-to-volume ratio of 2-dimethylaminoethylamine to hydrogen peroxide solution (g / ml) is 1:11-13, and the mass percentage concentration of the hydrogen peroxide solution is 30%.

5. The method for preparing room-temperature phase pyroelectric materials according to claim 2, characterized in that, In step 1), the reaction is stirred for 46-50 hours.

6. The method for preparing room-temperature phase pyroelectric materials according to claim 2, characterized in that, In step 3), the oil bath heating temperature is 75-85℃, and the reaction is stirred for 2-4 hours.

7. The method for preparing room-temperature phase pyroelectric materials according to claim 2, characterized in that, In step 3), the mass-to-volume ratio (g / g / mL) of the nitrogen oxide of 2-dimethylaminoethylamine, lead chloride, and concentrated hydrochloric acid is 4:5:180-240, and the mass percentage concentration of the concentrated hydrochloric acid solution is 36%.

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