Novel viologen-based organic-inorganic hybrid photoconductive material, preparation method and application

Abstract

The present invention discloses the preparation and application of a novel viologen-based organic-inorganic hybrid photoconductive material, which belongs to the field of photoelectric material preparation and application. The present invention includes the following contents: (1) preparing an organic-inorganic hybrid material C14N4H22Pb2I8 by a solution method; (2) characterizing the crystal structure of the compound by x-ray diffraction; (3) bonding a single crystal to a silver wire with a diameter of 125 microns with silver conductive glue, and placing it in a shielding box, and studying the photoconductive properties of the compound under dark and light conditions. The method of the present invention can be used to prepare a crystalline material with photoelectric properties, and the material shows good application prospects in photoelectric devices such as light-controlled switches.

Description

Technical Field

[0001] The present invention belongs to the technical field of photoelectric materials, and in particular relates to a novel viologen-based organic-inorganic hybrid photoconductive material, a preparation method and application thereof. Background Art

[0002] Energy storage technology is an essential link in the development of new energy systems and one of the key technologies for achieving the national dual-carbon strategic goals. In recent years, with the research on energy storage optoelectronic devices such as photovoltaic power generation, people have conducted extensive research on optoelectronic materials with tunable conductivity properties. Organic-inorganic hybrid materials have the advantages of controllable structure and stable performance, and have received widespread attention in the field of photoelectric conversion. Viologen-based compounds are a class of organic compounds with the function of gaining and losing electrons, which can be used in photochromism, liquid flow batteries and other fields. However, there is a lack of research on organic-inorganic hybrid materials constructed based on viologen compounds in terms of photoconductivity. The present invention uses ethylamine viologen as a ligand, constructs a one-dimensional iodine lead chain through the induction of positive charge and amino group, forms an organic-inorganic hybrid material, and studies its photoconductivity properties. The constructed material exhibits excellent photoelectric properties. Summary of the invention

[0003] In view of the above problems, the present invention provides a new type of viologen-based organic-inorganic hybrid photoconductive material, preparation method and application, and studies its photoconductive properties, laying a foundation for future research on the application of viologen-based organic-inorganic hybrid photoelectric devices.

[0004] One of the purposes of the present invention is to provide a novel viologen-based organic-inorganic hybrid photoconductive material, wherein the novel viologen-based organic-inorganic hybrid photoconductive material is formed by inducing the construction of a one-dimensional iodine-lead chain using a positively charged ethylamine viologen as a template to form an organic-inorganic hybrid photoconductive material; the molecular formula of the novel viologen-based organic-inorganic hybrid photoconductive material is: C 14 N4H 22 Pb2I8.

[0005] Furthermore, the IV curves of the organic-inorganic hybrid photoconductive material in the directions parallel to the a-axis (∥a) and parallel to the b-axis (∥b) show a linear relationship, exhibiting the electrical properties of the crystal; the organic-inorganic hybrid photoconductive material shows a good linear relationship in both directions under light and darkness, and is an ohmic element; under light conditions, the conductivity of the organic-inorganic hybrid photoconductive material in the directions parallel to the a-axis (∥a) and parallel to the b-axis (∥b) is significantly increased compared to that in the dark, so that it exhibits different photoconductive properties under light and darkness.

[0006] (1)C 14 N4H 22 Structural characterization of Pb2I8

[0007] C 14 N4H 22 The single crystal data of Pb2I8 were obtained using a Rigaku R-AXIS SPIDER single crystal X-ray diffractometer with Mo / Kα radiation. The crystal structure was determined at room temperature. The crystal structure was solved by SHELXTL-2014 and OLEX-2 programs.

[0008] C 14 N4H 22 The X-ray powder diffraction data of Pb2I8 were obtained by using a Bruker D8 Advance X-ray diffractometer using CuKα rays (λ=0.15418 nm). A certain amount of dry compound was ground into powder in an agate mortar and then pressed into tablets. The diffraction data with a diffraction angle between 5-60° were collected at room temperature.

[0009] (2)C 14 N4H 22 Characterization of properties of Pb2I8

[0010] C 14 N4H 22 The infrared spectrum data of Pb2I8 was obtained by KBr pellet method and tested by Bruker Tensor27 FTIR spectrophotometer. The background correction experiment used spectrally pure KBr as blank experiment. 14 N4H 22 Pb2I8 was added to the dried KBr and ground and mixed evenly. An appropriate amount of the mixed sample was pressed into a tableting mold to form a translucent tablet. The 4000-500cm -1 The data is in the wavelength range.

[0011] C 14 N4H 22 The solid UV-Vis data of Pb2I8 was obtained by U-3010 UV-Vis spectrophotometer. An appropriate amount of ground C 14 N4H 22 Pb2I8, use BaSO4 white plate for baseline calibration, then test to get C 14 N4H 22 UV-Vis absorption spectrum of Pb2I8.

[0012] The second object of the present invention is to provide a method for preparing the novel viologen-based organic-inorganic hybrid photoconductive material, comprising the following steps:

[0013] (1) Synthesis of ethylamine viologen compounds

[0014] 4,4-Bipyridine (30 mmol) and 2-iodoethylamine hydroiodide (60 mmol to 120 mmol) were mixed and dissolved in acetonitrile (50 ml), and then heated under reflux and stirred at 50° C. for 48 h. After cooling, a khaki powder was obtained.

[0015] (2) Purification of ethylamine viologen compounds

[0016] The khaki powder obtained in (1) is washed with cold methanol and dried. Subsequently, the obtained solid powder is dissolved with about 10 ml of water. The remaining small amount of undissolved solid powder can be heated to dissolve it. Then, the ethylamine viologen aqueous solution is added dropwise to the cold methanol until all the yellow powder is precipitated. The mixture is filtered and dried under vacuum to obtain a pure ethylamine viologen compound (C 14 N4H 22 I4), yield: 40%.

[0017] (3) Viologen-based organic-inorganic hybrid material C 14 N4H 22 Preparation of Pb2I8

[0018] a. Lead iodide and ethylamine viologen compound were added to a hydroiodic acid aqueous solution (55wt%, 20ml) in sequence, and a hypophosphorous acid aqueous solution (50wt%, 2ml) was added to inhibit the decomposition of hydroiodic acid during the reaction. Subsequently, the mixed solution was heated and stirred until the lead iodide and ethylamine viologen compound were completely dissolved and the solution became a clear solution.

[0019] b. The clear solution was heated and reacted for 2 h to complete the reaction, and then slowly cooled to gradually precipitate brown rectangular crystals, which were washed with a non-polar solvent, vacuum filtered, and dried at 40 °C to obtain C 14 N4H 22 Pb2I8 crystal. Elemental analysis measured values ​​(%, theoretical value): C10.13 (10.03), N3.21 (3.34), H1.137 (1.312).

[0020] Preferably, the amount of lead iodide and ethylamine viologen compound used in step a is (0.5 mol to 1.5 mol): 0.5 mol.

[0021] Preferably, the heating temperature of the mixed solution in steps a and b is 120°C to 160°C.

[0022] Preferably, the cooling rate in step b is 5°C / h to 20°C / h.

[0023] Preferably, the non-polar solution in step b is acetone, ether, ethylene dichloride, etc., to avoid C 14 N4H 22Pb2I8 crystals may be decomposed in polar detergents. The optimal solvent is acetone and the number of washings is 3 to 5 times.

[0024] The third object of the present invention is to provide an application of the novel viologen-based organic-inorganic hybrid photoconductive material in the optoelectronic field.

[0025] The novel viologen-based organic-inorganic hybrid photoconductive material C 14 N4H 22 Application research of anisotropic photoconductivity of Pb2I8:

[0026] (1) In order to characterize the correspondence between the macroscopic orientation of the single crystal and the microscopic crystal axis direction, we 14 N4H 22 When collecting single crystal X-ray diffraction data of Pb2I8, index processing was performed. It can be seen that for C 14 N4H 22 For Pb2I8 single crystal, the a-axis direction (the direction in which the iodine-lead chain extends) corresponds to the direction of the longest side of its single crystal macroscopic body.

[0027] (2) Single crystal conductivity test uses homemade equipment and methods. The specific steps are:

[0028] a. Select brown crystals with regular shape, certain macroscopic size and good crystallinity;

[0029] b. Under a microscope, use silver conductive glue to bond the single crystal to a silver wire with a diameter of 125 microns, and let it stand to ensure that the single crystal and the silver wire are firmly bonded;

[0030] c. Place the bonded single crystal in a shielding box and use a digital source meter (Keithley 2400) to measure the C 14 N4H 22 Pb2I8 crystals were subjected to linear voltammetry tests in different directions and at different temperatures. We collected C 14 N4H 22 Linear voltammetric curves of Pb2I8 in the direction parallel to the a-axis (∥a) and the direction parallel to the b-axis (∥b) in the temperature range of 30°C to 110°C. The IV curves of the compound in both directions show a good linear relationship, and with the increase of temperature, the conductivity in different directions increases significantly, showing the electrical properties of a semiconductor.

[0031] (3) To further explore the potential application of the prepared viologen-based organic-inorganic hybrid materials as photoelectric responsive devices, we characterized compound C 14 N4H 22 The photoelectric properties of Pb2I8 were characterized by characterizing the photoconductivity of single crystals under light and dark conditions. The specific steps are:

[0032] a. Open a small hole on the top of the shielding box as a light-transmitting hole;

[0033] b. Place the sample directly below the light-transmitting hole in the shielding box. 14 N4H 22 Pb2I8 samples were subjected to linear voltammetry tests under light and dark conditions. We collected compound C 14 N4H 22 Linear voltammetric curves of Pb2I8 under illumination and darkness in the direction parallel to the a-axis (∥a) and the b-axis (∥b). Under illumination and darkness, the current-voltage characteristics of the compound in both directions show a good linear relationship, and it is an ohmic element. Under illumination, the conductivity of the compound is significantly increased compared to that in darkness, so that it exhibits different photoconductivity characteristics under illumination and darkness, and has good application value in the field of light-controlled switches.

[0034] Preferably, in step a, the diameter of the small holes on the shielding wire is 2 cm to 8 cm, which can provide sufficient light intensity to the sample without affecting the shielding effect of the shielding box against external interference, thereby achieving an optimal testing environment.

[0035] Preferably, in step b, the light source is a full-spectrum xenon lamp with a light density of 250 mW cm -2 , the distance between the light source and the sample is 10cm to 20cm to achieve the best light intensity effect.

[0036] Beneficial Effects

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] (1) Large-sized brown single crystal C was prepared by solution method and adjusting the reactant ratio, reaction temperature, reaction time, cooling rate and other conditions during the synthesis process. 14 N4H 22 Pb2I8;

[0039] (2) The crystal structure of the compound was characterized and analyzed by X-ray diffraction. Its structure is composed of a one-dimensional iodine-lead chain and an electron-deficient ethylamine viologen cation. The electron-deficient viologen cation has the function of gaining and losing electrons, which enhances the electron transfer ability between adjacent iodine-lead chains, making the compound exhibit multi-directional anisotropic conductivity.

[0040] (3) The light absorption properties of the compound were characterized by UV-visible spectrophotometry. The addition of the viologen cation with a conjugated structure made the compound show better light absorption properties in the visible light range (300-700nm). Compared with yellow lead iodide, the addition of the viologen cation made compound C 14 N4H 22The band gap width of Pb2I8 is reduced to 1.91eV, showing excellent semiconductor properties and good application prospects in the field of optoelectronic devices such as solar cells;

[0041] (4) The single crystal was bonded to a silver wire with a diameter of 125 μm using silver conductive glue and placed in a shielding box to study the photoconductivity properties of the compound under dark and light conditions. 14 N4H 22 Pb2I8 is parallel to the a-axis (∥a) or the b-axis (∥b). 14 N4H 22 The conductivity of Pb2I8 under illumination is significantly higher than that of the compound in the dark. It exhibits different photoconductivity properties under illumination and in the dark, and has good application value in the field of optoelectronic devices such as light-controlled switches. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 is the synthetic reaction formula of the ethylamine viologen compound C14N4H22I4 of the present invention;

[0043] Figure 2 For the present invention C 14 N4H 22 Crystal structure diagram of Pb2I8;

[0044] Figure 3 For the present invention C 14 N4H 22 Powder X-ray diffraction pattern of Pb2I8;

[0045] Figure 4 For the present invention C 14 N4H 22 Infrared spectrum data of Pb2I8;

[0046] Figure 5 For the present invention C 14 N4H 22 UV-Vis absorption spectrum and energy gap diagram of Pb2I8;

[0047] Figure 6 For the present invention C 14 N4H 22 Schematic diagram of the crystal axis direction of Pb2I8;

[0048] Figure 7 For the present invention C 14 N4H 22 Linear voltammetric curves of Pb2I8 at different temperatures in the direction parallel to the a-axis (∥a);

[0049] Figure 8 For the present invention C 14 N4H22 Linear voltammetric curves of Pb2I8 at different temperatures in the direction parallel to the b axis (∥b);

[0050] Fig. 9 For the present invention C 14 N4H 22 Photoconductivity test of Pb2I8 under illumination and in darkness in the direction parallel to the a-axis (∥a);

[0051] Fig.10 For the present invention C 14 N4H 22 Photoconductivity test of Pb2I8 under illumination and darkness in the direction parallel to the b axis (∥b); DETAILED DESCRIPTION

[0052] The following will be combined with the embodiments and Figure 1-10 The embodiments of the present invention are described in detail. The following examples are only used to illustrate the present invention and should not be considered to limit the scope of the present invention.

[0053] Example 1

[0054] A novel viologen-based organic-inorganic hybrid photoconductive material, wherein the novel viologen-based organic-inorganic hybrid photoconductive material is formed by inducing the construction of a one-dimensional iodine-lead chain using a positively charged ethylamine viologen as a template to form an organic-inorganic hybrid photoconductive material, and the molecular formula of the novel viologen-based organic-inorganic hybrid photoconductive material is: C 14 N4H 22 Pb2I8.

[0055] (1)C 14 N4H 22 Structural characterization of Pb2I8 compounds

[0056] C 14 N4H 22 The single crystal data of Pb2I8 compounds were obtained using a Rigaku R-AXIS SPIDER single crystal X-ray diffractometer with Mo / Kα radiation. The crystal structure was determined at room temperature. The crystal structure was solved by SHELXTL-2014 and OLEX-2 programs. Table 1 shows compound C 14 N4H 22 Pb2I8 crystal data. Figure 2 Compound C 14 N4H 22 Crystal structure diagram of Pb2I8.

[0057] Table 1 Compound C 14 N4H 22 Crystallographic data of Pb2I8

[0058]

[0059] Compound C 14 N4H 22 The X-ray powder diffraction data of Pb2I8 was obtained by using a Bruker D8 Advance X-ray diffractometer with Cu Kα radiation (λ = 0.15418 nm). A certain amount of dry compound was ground into powder in an agate mortar, then pressed into tablets, and the diffraction data was collected at room temperature with a diffraction angle between 5-60°. Figure 3 As shown, the experimental data spectrum is highly consistent with the data spectrum simulated by single crystal structure, indicating that compound C 14 N4H 22 The crystallinity of Pb2I8 is higher, showing a purer crystal phase.

[0060] (2)C 14 N4H 22 Characterization of the properties of Pb2I8 compounds

[0061] Compound C 14 N4H 22 The infrared spectrum data of Pb2I8 was obtained by KBr tablet method and tested by Bruker Tensor27FTIR spectrophotometer. The background correction experiment used spectrally pure KBr as blank experiment. 14 N4H 22 Pb2I8 was added to the dried KBr and ground into powder and mixed evenly. An appropriate amount of the mixed sample was pressed into a tablet pressing mold to form a translucent tablet. The 4000-400cm -1 The data is in the wavelength range. Figure 4 Compound C is shown 14 N4H 22 Infrared spectrum data of Pb2I8, 3038cm -1 The peak is attributed to the CH stretching vibration peak on the pyridine ring, 1483 cm -1 , 1546cm -1 The peak is attributed to the characteristic peak of C=N and C=C stretching vibration in the pyridine ring, 815cm -1 It can be attributed to the NH bending vibration peak, and the infrared measurement data is consistent with the single crystal analysis results.

[0062] Compound C 14 N4H 22 Solid UV-Vis data of Pb2I8 was obtained by U-3010 UV-Vis spectrophotometer. An appropriate amount of ground compound C was placed in the solid UV sample cell. 14 N4H 22Pb2I8, using BaSO4 white plate for baseline calibration, then tested in the wavelength range of 300-700nm to obtain compound C 14 N4H 22 UV-Vis absorption spectrum of Pb2I8. Figure 5 Compound C is shown 14 N4H 22 UV-visible absorption spectrum and energy gap diagram of Pb2I8. It can be seen from the figure that the compound has good light absorption performance. The addition of viologen cations with conjugated structure widens the light absorption range of the compound to 700nm, showing good light absorption performance. Compared with yellow lead iodide, the addition of viologen cations makes compound C 14 N4H 22 The band gap width of Pb2I8 is reduced to 1.91eV, showing excellent semiconductor properties and showing good application prospects in optoelectronic devices such as solar cells.

[0063] Example 2

[0064] The preparation method of the novel viologen-based organic-inorganic hybrid photoconductive material comprises the following steps:

[0065] (1) Synthesis of ethylamine viologen compounds

[0066] 4,4-Bipyridine (30 mmol) and 2-iodoethylamine hydroiodide (120 mmol) were mixed and dissolved in acetonitrile (50 ml), and then heated under reflux and stirred at 50° C. for 48 h. After cooling, a khaki powder was obtained. Figure 1 The ethylamine viologen compound C of the present invention 14 N4H 22 The synthetic reaction formula of I4.

[0067] (2) Purification of ethylamine viologen compounds

[0068] The khaki powder obtained in (1) was washed with cold methanol and dried. Subsequently, the obtained powder was dissolved with about 10 ml of water. The remaining small amount of undissolved solid powder was heated to dissolve it. Then, the ethylamine viologen aqueous solution was added dropwise to the cold methanol until all the yellow powder was precipitated. After filtering, vacuum drying was performed to obtain the pure ethylamine viologen compound (C 14 N4H 22 I4), yield: 40%.

[0069] (3) Viologen-based organic-inorganic hybrid material C 14 N4H 22 Preparation of Pb2I8

[0070] a. Lead iodide and ethylamine viologen compound were added to hydroiodic acid aqueous solution (55wt%, 20ml) in sequence, and hypophosphorous acid aqueous solution (50wt%, 2ml) was added to inhibit the decomposition of hydroiodic acid during the reaction. Subsequently, the mixed solution was heated and stirred until the lead iodide and the like were completely dissolved and the solution became a clear solution.

[0071] b. The clear solution was heated and reacted for 2 h to complete the reaction, and then slowly cooled to gradually precipitate brown rectangular crystals, which were washed with a non-polar solvent, vacuum filtered, and dried at 40 °C to obtain C 14 N4H 22 Pb2I8 crystal. Elemental analysis measured values ​​(%, theoretical value): C10.13 (10.03), N3.21 (3.34), H1.137 (1.312).

[0072] In step a, the dosage of lead iodide and ethylamine viologen compound is 1.0 mol:0.5 mol.

[0073] The heating temperature of the mixed solution in steps a and b is 140°C.

[0074] The cooling rate in step b is 10°C / h.

[0075] The non-polar solution in step b is acetone, and the washing times are 4 times.

[0076] Example 3

[0077] Application of the above-mentioned novel viologen-based organic-inorganic hybrid photoconductive material in the optoelectronic field.

[0078] The novel viologen-based organic-inorganic hybrid photoconductive material C 14 N4H 22 Photoconductive application research of Pb2I8:

[0079] (1) In order to characterize the correspondence between the macroscopic orientation of the single crystal and the microscopic crystal axis direction, we 14 N4H 22 When collecting single crystal X-ray diffraction data of Pb2I8, index processing was performed. 14 N4H 22 For Pb2I8 single crystal, the a-axis direction (the direction in which the iodine-lead chain extends) corresponds to the direction of the longest side of its single crystal macroscopic body. Figure 6 C 14 N4H 22 Schematic diagram of the crystal axis direction of Pb2I8.

[0080] (2) After determining the crystal axis direction, we collected C 14 N4H 22Linear voltammetric curve of Pb2I8 in the direction parallel to the a-axis (∥a) and the direction parallel to the b-axis (∥b) in the temperature range of 30℃ to 110℃. The single crystal conductivity test uses homemade equipment and methods. The specific steps are:

[0081] a. Select brown crystals with regular shape, certain size and good crystallinity;

[0082] b. Under a microscope, use silver conductive glue to bond the single crystal to a silver wire with a diameter of 125 microns, and let it stand to ensure that the single crystal and the silver wire are firmly bonded;

[0083] c. Place the bonded single crystal in a shielding box and use a digital source meter (Keithley 2400) to measure the C 14 N4H 22 Linear voltammetry tests were performed on Pb2I8 crystals in different directions and at different temperatures.

[0084] Figure 7 and Figure 8 Shown is C 14 N4H 22 Linear voltammetric curves of Pb2I8 in the direction parallel to the a-axis (∥a) and the b-axis (∥b) in the temperature range of 30°C to 110°C and the calculated activation energy. Within the test range, compound C 14 N4H 22 The IV curves of Pb2I8 in two directions show a good linear relationship, and the device exhibits the electrical properties of an ohmic element. Moreover, as the temperature increases, the conductivity in different directions increases significantly, showing the electrical properties of a semiconductor. Compound C 14 N4H 22 The activation energies of Pb2I8 in the directions parallel to the a-axis (∥a) and parallel to the b-axis (∥b) are 0.46eV and 0.43eV, respectively, showing anisotropic conductivity characteristics.

[0085] (3) To further explore the potential application of the prepared viologen-based organic-inorganic hybrid materials as photoelectric responsive devices, we characterized compound C 14 N4H 22 The photoelectric properties of Pb2I8 were characterized by characterizing the photoconductivity of single crystals under light and dark conditions. The specific steps are:

[0086] a. Open a small hole on the top of the shielding box as a light-transmitting hole;

[0087] b. Place the sample directly below the light-transmitting hole in the shielding box. 14 N4H 22 The Pb2I8 sample was subjected to linear voltammetry tests under light and dark conditions.

[0088] Preferably, in step a, the diameter of the small holes on the shielding wire is 2 cm to 8 cm, which can provide sufficient light intensity to the sample without affecting the shielding effect of the shielding box against external interference, thereby achieving an optimal testing environment.

[0089] Preferably, in step b, the light source is a full-spectrum xenon lamp with a light density of 250 mW cm -2 , the distance between the light source and the sample is 10cm to 20cm to achieve the best light intensity effect.

[0090] We collected compound C 14 N4H 22 Linear voltammetric curves of Pb2I8 under light and dark conditions in the directions parallel to the a-axis (∥a) and parallel to the b-axis (∥b). Fig. 9 and Fig.10 C 14 N4H 22 The photoconductivity of Pb2I8 in the light and dark directions parallel to the a-axis (∥a) and the b-axis (∥b) was tested; under the light and dark conditions, the compound showed a good linear relationship in both directions, and it was an ohmic element. Under the light condition, the conductivity of the compound increased significantly compared with that in the dark, so that it showed different photoconductivity characteristics under light and dark, and showed good application value in the field of light-controlled switches. Fig. 9 and Fig.10 It can be seen that compound C 14 N4H 22 The conductivity of Pb2I8 is different in different directions, showing anisotropic photoconductivity.

[0091] The above-mentioned specific embodiments are only several preferred embodiments of the present invention. Based on the technical solutions of the present invention and the relevant inspirations of the above-mentioned embodiments, those skilled in the art can make various alternative improvements and combinations to the above-mentioned specific embodiments.

Claims

1. A novel viologen-based organic-inorganic hybrid photoconductive material, characterized in that: The novel viologen-based organic-inorganic hybrid photoconductive material is formed by using ethylamine viologen compound as a template to induce the construction of a one-dimensional iodine-lead chain to form an organic-inorganic hybrid photoconductive material; the molecular formula of the novel viologen-based organic-inorganic hybrid photoconductive material is: C 14 N4H 22 Pb2I8; crystallographic data are: The molecular structure of the ethylamine viologen compound is:

2. The method for preparing the novel viologen-based organic-inorganic hybrid photoconductive material as claimed in claim 1, characterized in that: The preparation method comprises the following steps: (1) Synthesis of ethylamine viologen compounds Mix 30 mmol of 4,4-bipyridine and 60-120 mmol of 2-iodoethylamine hydroiodide and dissolve them in 50 ml of acetonitrile, then heat and reflux at 50°C with stirring for 48 hours. After cooling, a yellowish brown powder is obtained. (2) Purification of ethylamine viologen compounds The khaki powder obtained in (1) is washed with cold methanol and dried; subsequently, the dried powder is dissolved in 10 ml of water, and the remaining small amount of undissolved powder can be heated to dissolve it to obtain an ethylamine viologen aqueous solution; then the ethylamine viologen aqueous solution is added dropwise to cold methanol until all the yellow powder is precipitated, filtered, and vacuum dried to obtain a pure ethylamine viologen compound, with a yield of 40%; (3) Viologen-based organic-inorganic hybrid material C 14 N4H 22 Preparation of Pb2I8 a. The lead iodide and the ethylamine viologen compound were sequentially added to 20 ml of a 55 wt% aqueous solution of hydroiodic acid, and 2 ml of a 50 wt% aqueous solution of hypophosphorous acid was added to inhibit the decomposition of hydroiodic acid during the reaction, and then the mixed solution was heated and stirred until the lead iodide and the ethylamine viologen compound were completely dissolved and the solution became a clear solution; b. The clear solution was heated and reacted for 2 h to complete the reaction, and then slowly cooled to gradually precipitate brown rectangular crystals, which were washed with a non-polar solvent, vacuum filtered, and dried at 40 ° C to obtain the novel viologen-based organic-inorganic hybrid photoconductive material C. 14 N4H 22 Pb2I8.

3. The method for preparing the novel viologen-based organic-inorganic hybrid photoconductive material as claimed in claim 2, characterized in that: The amount of lead iodide and ethylamine viologen compound used in step a is (0.5 mol to 1.5 mol): 0.5 mol; The heating temperature of the mixed solution in steps a and b is 120°C to 160°C; The cooling rate in step b is 5°C / h to 20°C / h.

4. The method for preparing the novel viologen-based organic-inorganic hybrid photoconductive material as claimed in claim 2, characterized in that: The non-polar solution in step b is any one of acetone, ether and ethylene dichloride, and the washing times are 3 to 5 times.

5. Use of the novel viologen-based organic-inorganic hybrid photoconductive material as claimed in claim 1 or the novel viologen-based organic-inorganic hybrid photoconductive material prepared according to any one of claims 2 to 4, characterized in that: The novel viologen-based organic-inorganic hybrid photoconductive material is applied in the fields of solar cells and light-controlled switches.

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