Ferroelectric photovoltaic semiconductor material Hg 0.75 Pb 0.25 MnO3 and methods of making and using the same

Abstract

The application provides a ferroelectric photovoltaic semiconductor material Hg 0.75 Pb 0.25 MnO3. The application also provides a method for preparing the ferroelectric photovoltaic semiconductor material Hg 0.75 Pb 0.25 MnO3, which comprises the following steps: (1) mixing PbO, HgO and MnO2 in a molar ratio of 1:3:4 to obtain a mixture; then grinding the mixture to obtain a powder; (2) sealing the powder obtained in step (1) and then performing a heating and pressurizing treatment, quenching and pressure releasing to a room temperature environment to obtain the ferroelectric photovoltaic semiconductor material Hg 0.75 Pb 0.25 MnO3. The application also provides the ferroelectric photovoltaic semiconductor material Hg 0.75 Pb 0.25 MnO3 according to the application or the ferroelectric photovoltaic semiconductor material Hg 0.75 Pb 0.25 MnO3 prepared by the method according to the application. The ferroelectric photovoltaic semiconductor material Hg 0.75 Pb 0.25 MnO3 has ferroelectricity at room temperature and good environmental stability, can reverse the photoelectric current direction with the direction of an external field, and has the characteristics of absorbing visible light.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of materials. Specifically, the present application relates to a ferroelectric photovoltaic semiconductor material Hg 0.75 Pb 0.25 MnO3, a preparation method and application thereof. BACKGROUND

[0002] The conventional photovoltaic effect generally refers to the conversion of light energy into carriers by capturing solar energy. In order to reduce the energy capture loss, the second generation solar cell (quantum dot solar cell) and the third generation solar cell (organic solar cell) have been widely studied due to their low loss characteristics. The ferroelectric photovoltaic effect originates from the spontaneous polarization in the ferroelectric, which is completely different from the conventional photovoltaic effect of the p-n junction, and the direction of the photocurrent can be switched with the flipping of the direction of the external electric field.

[0003] On the one hand, the ferroelectric is usually highly insulating, and the band gap energy between the valence band and the conduction band is all above 3eV (for example, the band gap energy of BaTiO3 is 3.2eV, and the band gap energy of PbTiO3 is 3.88eV), which is not suitable for carrier transport and light absorption. On the other hand, some organic / inorganic hybrid ferroelectrics with excellent photoelectric performance are prone to environmental degradation.

[0004] Inorganic oxides can provide better structural and environmental stability. Therefore, it is an urgent problem to find inorganic ferroelectric semiconductors with appropriate band gaps for visible light absorption. Such semiconductors can provide potential application value for the development of the next generation of self-powered optoelectronic devices. SUMMARY

[0005] The present application aims to provide a ferroelectric photovoltaic semiconductor material Hg 0.75 Pb 0.25 MnO3, which has ferroelectricity and good environmental stability, can flip the direction of the photocurrent with the direction of the external field, and has the characteristics of absorbing visible light. Another object of the present application is to provide a method for preparing the ferroelectric photovoltaic semiconductor material Hg 0.75 Pb 0.25 MnO3 of the present application.

[0006] The above object of the present application is achieved by the following technical solutions.

[0007] On the one hand, the present application provides a ferroelectric photovoltaic semiconductor material Hg 0.75 Pb 0.25MnO3, wherein the X-ray powder diffraction pattern expressed in terms of 2θ angle using Cu target Kα1 has diffraction peaks at 22.78°, 23.74°, 26.38°, 33.14°, 33.62°, 34.02°, 35.59°, 41.00°, 41.34°, 42.28°, 46.54°, 48.58°, 48.92°, 50.05° with an error of ±0.005°

[0008] Preferably, the ferroelectric photovoltaic semiconductor material Hg 0.75 Pb 0.25 MnO3 according to the present application has a perovskite structure, wherein the ferroelectric photovoltaic semiconductor material Hg 0.75 Pb 0.25 MnO3 is of an orthorhombic system, space group Ama2, and has a lattice constant of a=5.45A, b=5.62A, c=3.89A.

[0009] Preferably, the ferroelectric photovoltaic semiconductor material Hg 0.75 Pb 0.25 MnO3 according to the present application has a perovskite structure, wherein the ferroelectric photovoltaic semiconductor material Hg 0.75 Pb 0.25 MnO3 has ferroelectricity at room temperature, and a coercive field of 0.5eV.

[0010] Preferably, the ferroelectric photovoltaic semiconductor material Hg 0.75 Pb 0.25 MnO3 according to the present application has a perovskite structure, wherein the ferroelectric photovoltaic semiconductor material Hg 0.75 Pb 0.25 MnO3 has an optical direct band gap of 2.25eV at room temperature, and has light absorption in the visible light band.

[0011] In another aspect, the present application provides a method for preparing the ferroelectric photovoltaic semiconductor material Hg 0.75 Pb 0.25 MnO3 according to the present application, comprising the following steps:

[0012] (1) mixing PbO, HgO and MnO2 in a molar ratio of 1:3:4 to obtain a mixture; and then grinding the mixture thoroughly to obtain a powder;

[0013] (2) sealing the powder obtained in step (1) and then performing a heating and pressurizing treatment, and quenching and depressurizing to room temperature environment to obtain the ferroelectric photovoltaic semiconductor material Hg 0.75 Pb 0.25 MnO3.

[0014] Preferably, in the method according to the present application, the grinding in step (1) is performed for 30-90min.

[0015] Preferably, in the method of the present application, the treatment in step (2) is carried out under the conditions of a treatment temperature of 1000-1200℃, a treatment pressure of 15-20 GPa, and a treatment time of 20-30 min.

[0016] Preferably, in the method of the present application, the sealing in step (2) is carried out by using a gold capsule or a platinum capsule.

[0017] Preferably, in the method of the present application, the gold capsule or the platinum capsule is in a cylindrical shape.

[0018] Preferably, in the method of the present application, the cylindrical capsule has an outer diameter of 2-3 mm, a length of 2-4 mm, and a wall thickness of 0.01-0.05 mm.

[0019] Preferably, in the method of the present application, the treatment in step (2) is carried out in a two-stage pushing Walker-type large press.

[0020] In a third aspect, the present application provides a ferroelectric photovoltaic semiconductor material Hg 0.75 Pb 0.25 MnO3 or a ferroelectric photovoltaic semiconductor material Hg 0.75 Pb 0.25 MnO3 prepared by the method of the present application for use in a photovoltaic device.

[0021] In the use of the present application, the photovoltaic device can be composed of ITO / Ag / Hg 0.75 Pb 0.25 MnO3 / Au layers.

[0022] Preferably, in the use of the present application, the Hg 0.75 Pb 0.25 MnO3 layer has a thickness of 0.1-0.2 mm.

[0023] In the present application, the switchable photovoltaic effect can be realized under a polarization voltage of ±15 V and under the switching condition of a controlled light source; preferably, the switching light source is 1 sun (100 mW·cm -2 ).

[0024] The present application has the following effects:

[0025] The ferroelectric photovoltaic semiconductor material Hg 0.75 Pb 0.25 MnO3 of the present application has ferroelectricity at room temperature and good environmental stability, can reverse the direction of photocurrent with the direction of external field, and has the characteristic of absorbing visible light. In addition, the ferroelectric photovoltaic semiconductor material Hg 0.75 Pb 0.25The ferroelectricity operating temperature range of MnO3 is wide. The ferroelectric photovoltaic semiconductor material Hg 0.75 Pb 0.25 MnO3 can be used in the field of photoelectric devices, such as solar cells. BRIEF DESCRIPTION OF DRAWINGS

[0026] Hereinafter, the embodiments of the present application will be described in detail with reference to the accompanying drawings, in which:

[0027] Figure 1 The X-ray diffraction pattern of the ferroelectric photovoltaic semiconductor material Hg 0.75 Pb 0.25 MnO3 of Example 1 of the present application;

[0028] Figure 2 The crystal structure diagram of the ferroelectric photovoltaic semiconductor material Hg 0.75 Pb 0.25 MnO3 of Example 1 of the present application;

[0029] Figure 3 The piezoelectric force microscope (PFM) room temperature electric hysteresis loop of the ferroelectric photovoltaic semiconductor material Hg 0.75 Pb 0.25 MnO3 of Example 1 of the present application;

[0030] Figure 4 The two-step electrode polarization domain pattern of the ferroelectric photovoltaic semiconductor material Hg 0.75 Pb 0.25 MnO3 of Example 1 of the present application;

[0031] Figure 5 The optical absorption coefficient versus wavelength diagram of the ferroelectric photovoltaic semiconductor material Hg 0.75 Pb 0.25 MnO3 of Example 1 of the present application, the inset shows the fitting result of the optical direct band gap;

[0032] Figure 6 The schematic diagram of the photoelectric device using the ferroelectric photovoltaic semiconductor material Hg 0.75 Pb 0.25 MnO3 of Example 1 of the present application;

[0033] Figure 7 The repeatable time-dependent switching photovoltaic effect diagram of the ferroelectric photovoltaic semiconductor material Hg 0.75 Pb 0.25 MnO3 of Example 1 of the present application;

[0034] Figure 8 The flow chart of the preparation of the ferroelectric photovoltaic semiconductor material Hg 0.75 Pb 0.25 MnO3 of the present application. Detailed Implementation

[0035] The present invention will be further described in detail below with reference to specific embodiments. The embodiments given are only for illustrating the present invention and are not intended to limit the scope of the present invention.

[0036] Example 1

[0037] (1) Mix 1 gram of PbO (purity > 99.9%), HgO (purity > 99.9%), and MnO2 (purity > 99.9%) in a stoichiometric ratio of 1:3:4. Then, grind the mixture in a mortar for 1 hour to ensure thorough mixing and obtain a powder.

[0038] (2) The powder obtained in step (1) is sealed in a cylindrical gold capsule, wherein the gold capsule has a diameter of 2 mm, a height of 2 mm, and a wall thickness of 0.02 mm. Then, it is subjected to high temperature and high pressure treatment for 30 min in a two-stage pusher Walker-type large press, wherein the treatment pressure is 15 GPa and the treatment temperature is 1100℃. Then, it is quenched and depressurized to room temperature to obtain the ferroelectric photovoltaic semiconductor material Hg. 0.75 Pb 0.25 MnO3.

[0039] Figure 1 Hg, the ferroelectric photovoltaic semiconductor material of Embodiment 1 of the present invention 0.75 Pb 0.25 X-ray diffraction pattern of MnO3. X-ray diffraction of ferroelectric photovoltaic semiconductor material Hg using Cu target Kα1. 0.75 Pb 0.25 The X-ray powder diffraction pattern of MnO3, expressed in 2θ angles, shows diffraction peaks at 22.78°, 23.74°, 26.38°, 33.14°, 33.62°, 34.02°, 35.59°, 41.00°, 41.34°, 42.28°, 46.54°, 48.58°, 48.92°, and 50.05°, with an error of ±0.005°.

[0040] Figure 2 Hg, the ferroelectric photovoltaic semiconductor material of Embodiment 1 of the present invention 0.75 Pb 0.25 A schematic diagram of the crystal structure of MnO3. The crystal structure parameters are as follows: The space group is polarized Ama2 (no. 40), the atomic positions of Hg / Pb are 4b (0.25, y, z), Mn occupies 4a (0, 0, 0), O1 occupies 8c (x, y, z), and O2 occupies 4b (0.25, y, z).

[0041] Figure 3Hg 0.75 Pb 0.25 MnO3. Figure 3 The phase of PFM shows clear hysteresis behavior from -3.2V to +3.2V, and the amplitude shows typical butterfly behavior, which means that the ferroelectric photovoltaic semiconductor material Hg 0.75 Pb 0.25 MnO3 has ferroelectricity at room temperature.

[0042] Figure 4 Hg 0.75 Pb 0.25 MnO3. 0.75 Pb 0.25 MnO3 has ferroelectricity at room temperature.

[0043] Figure 5 Hg 0.75 Pb 0.25 MnO3. 2 -hν curve, that is, the optical band gap value E g =2.25eV, α is the absorption coefficient, hν is the photon energy, and it is consistent with the direct allowed transition band gap.

[0044] Example 2

[0045] (1) 0.5 grams of PbO (purity > 99.9%), HgO (purity > 99.9%), and MnO2 (purity > 99.9%) were mixed in a stoichiometric ratio of 1:3:4. Then, the mixture was ground in a mortar for 30 minutes to ensure thorough mixing, resulting in a powder;

[0046] (2) The powder obtained in step (1) was sealed and wrapped with a cylindrical gold capsule, with a diameter of 3 mm, a height of 3 mm, and a wall thickness of 0.05 mm. Then, high-temperature and high-pressure treatment was performed in a two-stage Walker-type large press for 20 minutes, with a treatment pressure of 18 GPa and a treatment temperature of 1200°C. Then, quenching and pressure release were performed to room temperature environment, resulting in the ferroelectric photovoltaic semiconductor material Hg 0.75 Pb 0.25 MnO3.

[0047] The ferroelectric photovoltaic semiconductor material Hg 0.75 Pb 0.25 MnO3 of the embodiment 1.

[0048] Embodiment 3

[0049] The ferroelectric photovoltaic semiconductor material Hg 0.75 Pb 0.25 MnO3 of the embodiment 1 is used for a photoelectric device. Specifically, the structure of the photoelectric device obtained is: ITO / Ag / Hg 0.75 Pb 0.25 MnO3 / Au, wherein the thickness of the Hg 0.75 Pb 0.25 MnO3 layer is 0.15 mm. Then the function of the switchable photovoltaic effect of the photoelectric device obtained is tested.

[0050] Figure 6 The ferroelectric photovoltaic semiconductor material Hg 0.75 Pb 0.25 MnO3 of the embodiment 1 is used for a photoelectric device. Specifically, the structure of the photoelectric device obtained is: ITO / Ag / Hg 0.75 Pb 0.25 MnO3 of the embodiment 1. The switchable time-dependent photovoltaic effect diagram of the ferroelectric photovoltaic semiconductor material Hg

[0051] Figure 7 The ferroelectric photovoltaic semiconductor material Hg 0.75 Pb 0.25 MnO3 of the embodiment 1. The switchable time-dependent photovoltaic effect diagram of the ferroelectric photovoltaic semiconductor material Hg

[0051] Figure 7 The ferroelectric photovoltaic semiconductor material Hg 0.75 Pb 0.25 MnO3 of the embodiment 1. The switchable time-dependent photovoltaic effect diagram of the ferroelectric photovoltaic semiconductor material Hg

[0051] Figure 7 The ferroelectric photovoltaic semiconductor material Hg 0.75 Pb 0.25 MnO3 of the embodiment 1. The switchable time-dependent photovoltaic effect diagram of the ferroelectric photovoltaic semiconductor material Hg

[0051] Figure 7 The ferroelectric photovoltaic semiconductor material Hg 0.75 Pb 0.25 MnO3 of the embodiment 1. The switchable time-dependent photovoltaic effect diagram of the ferroelectric photovoltaic semiconductor material Hg

[0051] Figure 7 The ferroelectric photovoltaic semiconductor material Hg 0.75 Pb 0.25 MnO3 of the embodiment 1. The switchable time-dependent photovoltaic effect diagram of the ferroelectric photovoltaic semiconductor material Hg

[0051] Figure 7 The ferroelectric photovoltaic semiconductor material Hg 0.75 Pb 0.25 MnO3 of the embodiment 1. The switchable time-dependent photovoltaic effect diagram of the ferroelectric photovoltaic semiconductor material Hg

[0051] Figure 7 The ferroelectric photovoltaic semiconductor material Hg 0.75 Pb 0.25

Claims

1. A ferroelectric photovoltaic semiconductor material Hg 0.75 Pb 0.25 MnO3, of which X-ray diffraction using a Cu target Kα1 yielded X-ray powder diffraction patterns expressed in 2θ angles at 22.78°, 23.74°, 26.38°, 33.14°, 33.62°, 34.02°, 35.59°, 41.00°, 41.34°, 42.28°, 46.54°, 48.58°, 48.92°, and 50.05°, with an error of ±0.005°. The ferroelectric photovoltaic semiconductor material Hg 0.75 Pb 0.25 MnO3 has an orthorhombic crystal system, space group Ama2, and lattice constants a = 7.7996 Å, b = 5.3266 Å, c = 5.2670 Å. The ferroelectric photovoltaic semiconductor material Hg 0.75 Pb 0.25 MnO3 exhibits ferroelectricity at room temperature and has a coercive field of 0.5 eV; The ferroelectric photovoltaic semiconductor material Hg 0.75 Pb 0.25 The direct optical bandgap of MnO3 at room temperature is 2.25 eV.

2. A method for preparing the ferroelectric photovoltaic semiconductor material Hg as described in claim 1 0.75 Pb 0.25 The method for using MnO3 includes the following steps: (1) PbO, HgO and MnO2 are mixed in a molar ratio of 1:3:4 to obtain a mixture; then the mixture is thoroughly ground to obtain a powder; (2) After sealing and packaging the powder obtained in step (1), heat and pressurize it, then quench and depressurize it to room temperature to obtain the ferroelectric photovoltaic semiconductor material Hg. 0.75 Pb 0.25 MnO3.

3. The method according to claim 2, wherein, The grinding in step (1) shall be carried out for 30 to 90 minutes.

4. The method according to claim 2, wherein, The treatment in step (2) is carried out under the following conditions: the treatment temperature is 1000℃~1200℃, the treatment pressure is 15 GPa~20 GPa, and the treatment time is 20~30 min.

5. The method according to claim 2, wherein, The sealing and wrapping in step (2) is done by using gold capsules or platinum capsules.

6. The method according to claim 5, wherein, The gold or platinum capsules are cylindrical.

7. The method according to claim 6, wherein, The cylindrical shape has an outer diameter of 2-3 mm, a length of 2-4 mm, and a wall thickness of 0.01-0.05 mm.

8. The method according to claim 2, wherein, The processing in step (2) is carried out in a two-stage push Walker type large press.

9. The ferroelectric photovoltaic semiconductor material Hg according to claim 1 0.75 Pb 0.25 MnO3 or the ferroelectric photovoltaic semiconductor material Hg prepared according to any one of claims 2-8 0.75 Pb 0.25 Applications of MnO3 in optoelectronic devices.

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