Three-dimensional germanium-based halide perovskite ferroelectric material, preparation method and application thereof

Abstract

This application discloses a three-dimensional germanium-based halide perovskite ferroelectric material, its preparation method, and its applications, belonging to the field of materials science. The molecular formula of the three-dimensional germanium-based halide perovskite ferroelectric material is (CH7N2)GeI3. This three-dimensional germanium-based halide perovskite ferroelectric material is lead-free, has a high Curie temperature, and a low coercive field; moreover, this material can be prepared by a solution cooling method, which has mild reaction conditions, is simple and easy to implement, and is inexpensive; due to its strong X-ray absorption and long carrier migration lifetime, it has bright application prospects in fields such as X-ray detection.

Description

Technical Field

[0001] This application relates to a three-dimensional germanium-based halide perovskite ferroelectric material, its preparation method, and its application, belonging to the field of materials. Background Technology

[0002] Halide perovskites have attracted widespread attention from researchers due to their excellent physicochemical properties, and they have broad application prospects in optoelectronic devices such as lasers, sensors, solar cells, and photodetectors. Particularly ferroelectric halide perovskite materials exhibit high dielectric constants, strong polarization effects, and low operating voltages, making them promising for ferroelectric memories and sensors. Their advantage lies in their non-volatility, meaning that once information is written to them, the material retains the written state even without an external power source.

[0003] In recent years, germanium-based (Ge) hybrid perovskites have gained attention due to their low toxicity and stronger polarizability. 2 The increasingly diverse structures and properties associated with lone-pair electrons have attracted widespread attention from researchers. In particular, Ge... 2+ 4s 2 The strong stereochemical expression of lone pairs of electrons leads to large octahedral distortions, resulting in strong second harmonics and large polarization in germanium-based perovskites. Compared to traditional lead-based perovskites, germanium-based perovskites not only reduce the environmental and health risks associated with lead but also improve electron mobility. Germanium-based three-dimensional perovskite ferroelectric materials offer superior electrical and optical properties, along with lower electron losses, making them suitable for high-efficiency energy conversion and optoelectronic devices. Therefore, exploring the ferroelectricity of three-dimensional halide perovskites based on three-dimensional germanium-based perovskite ferroelectric materials has significant scientific research value and broad application prospects in X-ray detection devices. Summary of the Invention

[0004] This invention provides a three-dimensional germanium-based halide perovskite ferroelectric material, its preparation method, and its application in X-ray detection. The three-dimensional germanium-based halide perovskite ferroelectric material of this invention is lead-free, has a high Curie temperature, and a low coercive field. Furthermore, this material can be prepared using a solution cooling method, which is mild, simple, and inexpensive. Due to its strong X-ray absorption and long carrier migration lifetime, it has promising application prospects in fields such as X-ray detection.

[0005] According to the first aspect of this application, a three-dimensional germanium-based halide perovskite ferroelectric material is provided. By replacing the common lead element with germanium, a material with excellent ferroelectric properties and thermal stability is prepared. This achieves a dual improvement in ferroelectric properties and thermal stability, particularly by reducing the coercive field. It maintains a high ferroelectric response even at high temperatures. With better thermal stability, it can maintain long-term performance stability under extreme conditions (such as high temperatures), making it suitable for a wider range of electronic device applications, such as X-ray detectors.

[0006] A three-dimensional germanium-based halide perovskite ferroelectric material, wherein the molecular formula of the three-dimensional germanium-based halide perovskite ferroelectric material is (CH7N2)GeI3.

[0007] Optionally, the three-dimensional germanium-based halide perovskite ferroelectric material belongs to the monoclinic crystal system at room temperature, with space group Cc and cell parameters of . α=90°, β=129.12°, γ=90°.

[0008] Furthermore, the three-dimensional germanium-based halide perovskite ferroelectric material undergoes a ferroelectric-paraelectric phase transition at 421 K.

[0009] The hysteresis loop measured by the Sawyer-Tower circuit method indicates that the three-dimensional germanium-based halide perovskite ferroelectric material (CH7N2)GeI3 exhibits ferroelectric properties in the ferroelectric phase, with a polarization intensity of approximately 0.35 μC / cm. 2 The coercive field is as low as 0.8 kV / cm.

[0010] According to a second aspect of this application, a method for preparing a three-dimensional germanium-based halide perovskite ferroelectric material is provided.

[0011] The preparation method of the above-mentioned three-dimensional germanium-based halide perovskite ferroelectric material includes:

[0012] (1) Add GeO2 to a mixed solution of hydroiodic acid and hypophosphoric acid, stir and heat to 90-110℃, and then continue stirring for 30-60 minutes;

[0013] (2) Then add methylhydrazine sulfate and continue heating and stirring until a clear solution is obtained.

[0014] (3) Finally, after cooling to room temperature, the three-dimensional germanium-based halide perovskite ferroelectric material is obtained.

[0015] Optionally, the ratio of GeO2, hydroiodic acid, and hypophosphite is 2 mmol: 5-10 ml: 2-4 ml.

[0016] Optionally, the molar ratio of GeO2 to methylhydrazine sulfate is 1:1-2.

[0017] Optionally, the weight percentage of HI in hydroiodic acid is 55-58%;

[0018] The weight percentage of H3PO2 in hypophosphorous acid is 50-55%.

[0019] Optionally, the cooling rate is 0.5-2℃ / day.

[0020] The above-described application of three-dimensional germanium-based halide perovskite ferroelectric materials in the fabrication of X-ray detectors.

[0021] The above-described three-dimensional germanium-based halide perovskite ferroelectric materials are used in X-ray detection.

[0022] The beneficial effects that this application can produce include:

[0023] The three-dimensional germanium-based halide perovskite ferroelectric material, its preparation method, and its applications provided in this application are lead-free, have a high Curie temperature, and a low coercive field. Moreover, this material can be prepared by a solution cooling method, which has mild reaction conditions, is simple and easy to implement, and is inexpensive. Due to its advantages such as strong X-ray absorption and long carrier migration lifetime, it has a bright application prospect in fields such as X-ray detection. Attached Figure Description

[0024] Figure 1 This is a room-temperature crystal photograph of the three-dimensional germanium-based halide perovskite ferroelectric material of this invention.

[0025] Figure 2 This is a schematic diagram of the ferroelectric phase structure of the three-dimensional germanium-based halide perovskite ferroelectric material of the present invention.

[0026] Figure 3 This is the differential scanning calorimetry test curve of the three-dimensional germanium-based halide perovskite ferroelectric material of the present invention.

[0027] Figure 4 It is the nonlinear frequency harmonic signal of the three-dimensional germanium-based halide perovskite ferroelectric material of this invention.

[0028] Figure 5 This is the hysteresis loop of the three-dimensional germanium-based halide perovskite ferroelectric material of the present invention.

[0029] Figure 6 The present invention describes the X-ray response performance of the three-dimensional germanium-based halide perovskite ferroelectric material under 0V and 10V bias voltages. Detailed Implementation

[0030] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.

[0031] Unless otherwise specified, all raw materials used in the embodiments of this application were purchased through commercial channels.

[0032] Unless otherwise specified, all test methods are standard and all instrument settings are those recommended by the manufacturer.

[0033] The analysis method in the embodiments of this application is as follows:

[0034] The instrument used for crystallographic data analysis was an X-ray single-crystal diffractometer, Agilent Technologies, Bruker D8, with a Mo target X-ray source.

[0035] The instrument used for hysteresis loop analysis was a ferroelectric analyzer, Radiant Premier II, manufactured by Texas Instruments International Ltd., under room temperature conditions.

[0036] The differential scanning calorimetry curve analysis was performed using a differential scanning calorimeter, NETZSCH DSC 3500, manufactured by Netzsch GmbH, Germany, under conditions of 320K-440K.

[0037] The instrument used for nonlinear frequency doubling signal analysis was an Nd:YAG laser from the Anhui Institute of Optics and Precision Instruments, under room temperature conditions.

[0038] The instrument used for X-ray response performance analysis was a miniature X-ray tube system, Ametek Ltd., Mini-X2, under room temperature conditions.

[0039] Example 1

[0040] A method for synthesizing a three-dimensional germanium-based halide perovskite ferroelectric material, comprising the following sequential steps:

[0041] (1) Add GeO2 to a mixed solution of hydroiodic acid and hypophosphoric acid, stir and heat to 100°C, and then continue stirring for 30 minutes;

[0042] (2) Then add methylhydrazine sulfate and continue heating and stirring until a clear solution is obtained.

[0043] (3) Finally, after cooling to room temperature, the three-dimensional germanium-based halide perovskite ferroelectric material is obtained.

[0044] The weight percentage of HI in hydroiodic acid is 57%.

[0045] The weight percentage of H3PO2 in hypophosphorous acid is 50%.

[0046] The amounts of GeO2, hydroiodic acid, and hypophosphite used are 2 mmol of GeO2, 5 ml of hydroiodic acid, and 2 ml of hypophosphite.

[0047] The dosage of both GeO2 and methylhydrazine sulfate is 2 mmol.

[0048] The clarified solution obtained in step (2) was cooled from 70°C to 25°C at a rate of 1°C / day to obtain bulk three-dimensional germanium-based halide perovskite ferroelectric materials, such as... Figure 1 As shown.

[0049] This three-dimensional germanium-based halide perovskite ferroelectric material, such as Figure 2 As shown, at room temperature, it is a ferroelectric phase, monoclinic crystal system, space group Cc, with cell parameters of... α = 90°, β = 129.12°, γ = 90°. A Ge atom is surrounded by six I atoms, linked together to form a highly distorted [GeI6]. 4- Octahedron, each [GeI6] 4- Octahedrons are connected by common corners to form an inorganic framework, and methylhydrazine atoms are located in the pores of the octahedron connections, forming a typical three-dimensional perovskite.

[0050] Its phase transition temperature was determined by differential scanning calorimetry (DSC), such as Figure 3 As shown, the compound underwent a ferroelectric-paraelectric structural transformation at 421 K.

[0051] A second-order nonlinear signal (SHG) test was performed on the three-dimensional germanium-based halide perovskite ferroelectric (CH7N2)GeI3 obtained in Example 1, such as... Figure 4 As shown, this material exhibits a strong second-order nonlinear signal at room temperature, approximately 0.5 times that of the standard sample potassium dihydrogen phosphate (KDP), indicating its great application potential in fields such as nonlinear optics.

[0052] The hysteresis loop of the three-dimensional germanium-based halide perovskite ferroelectric material (CH7N2)GeI3 obtained in Example 1 was tested, and the results were as follows: Figure 5 As shown, the saturation polarization intensity at room temperature is approximately 0.35 μC / cm. 2 The coercive field is as low as 0.8 kV / cm.

[0053] X-ray radiation detection experiments were conducted on the three-dimensional germanium-based halide perovskite ferroelectric material (CH7N2)GeI3 obtained in Example 1. Radiation response tests were performed using an Ag target X-ray source. Figure 6 As shown. The sensitivities are 250 μCy when the bias voltage is 0V and 10V, respectively. -1 cm -2 and 453μCGy -1 cm -2 It exhibits excellent self-driven radiation response performance. This indicates its great application potential in fields such as radiation detection devices.

[0054] The above description is merely a few embodiments of this application and is not intended to limit this application in any way. Although this application discloses preferred embodiments as described above, it is not intended to limit this application. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solution of this application using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A three-dimensional germanium-based halide perovskite ferroelectric material, characterized in that, The molecular formula of the three-dimensional germanium-based halide perovskite ferroelectric material is (CH7N2)GeI3.

2. The three-dimensional germanium-based halide perovskite ferroelectric material according to claim 1, characterized in that, The three-dimensional germanium-based halide perovskite ferroelectric material belongs to the monoclinic crystal system at room temperature, with space group Cc and cell parameters of . α=90°, β=129.12°, γ=90°.

3. The method for preparing the three-dimensional germanium-based halide perovskite ferroelectric material according to claim 1 or 2, characterized in that, include: (1) Add GeO2 to a mixed solution of hydroiodic acid and hypophosphoric acid, stir and heat to 90-110℃, and then continue stirring for 30-60 minutes; (2) Then add methylhydrazine sulfate and continue heating and stirring until a clear solution is obtained. (3) Finally, after cooling to room temperature, the three-dimensional germanium-based halide perovskite ferroelectric material is obtained.

4. The preparation method according to claim 3, characterized in that, The ratio of GeO2, hydroiodic acid, and hypophosphite is 2 mmol: 5-10 ml: 2-4 ml.

5. The preparation method according to claim 3, characterized in that, The molar ratio of GeO2 to methylhydrazine sulfate is 1:1-2.

6. The preparation method according to claim 3, characterized in that, The weight percentage of HI in hydroiodic acid is 55-58%. The weight percentage of H3PO2 in hypophosphorous acid is 50-55%.

7. The preparation method according to claim 3, characterized in that, The cooling rate is 0.5-2℃ / day.

8. The application of the three-dimensional germanium-based halide perovskite ferroelectric material according to claim 1 or 2 in the preparation of X-ray detector devices.

9. The application of the three-dimensional germanium-based halide perovskite ferroelectric material as described in claim 1 or 2 in X-ray detection.

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