Preparation method and application of nonlinear frequency multiplication device and chiral perovskite material

Abstract

Nonlinear frequency multiplication device, chiral perovskite material and preparation method and application thereof. The present application relates to a kind of chiral perovskite material and preparation method and application thereof.The present application selects R / S-2-methylpiperidine as chiral organic amine, first obtains one-dimensional chiral perovskite material with new structure, provides lead-based perovskite with R / S-2-methylpiperidine as chiral organic amine, solves the application limitation caused by inherent defect of perovskite material itself, with the following characteristics: huge second harmonic generation signal and second-order nonlinear property, can realize phase matching, high polarization ratio, wide transparent window in ultraviolet, visible light region and infrared region;Good laser damage threshold, excellent air stability and good thermal stability, and high-quality large crystal can be prepared by simple volatilization method;Meet all the properties that a high-quality nonlinear crystal should have, which is a great progress for perovskite in the field of nonlinear optics.

Description

Technical Field

[0001] The present invention belongs to the field of perovskite materials, and in particular relates to a preparation method and application of a chiral perovskite material and a nonlinear frequency doubling device. Background Art

[0002] Chirality underlies fundamental phenomena and laws of life in nature and is closely intertwined with the entire universe. An object exhibits chirality when its rotation or movement prevents it from aligning with its mirror image. The design and preparation of functional materials with chiral optical activity has become a key development direction in chemistry, life sciences, materials science, and physics. Chiral materials have crucial applications in biomedicine, such as pharmaceuticals, diagnostic analysis, and bioengineering. Some drugs have both left-handed and right-handed forms, with identical chemical properties, but their microscopic mechanisms of action, potency, and toxicity can be completely different. For some drugs, only one of their molecular structures is effective against a disease, while the enantiomer has little or no effect or can even be highly toxic. By measuring the chiral optical behavior of molecules, the concentration of the enantiomer can be determined. Chiral materials also show promising application prospects in optoelectronics. The most notable feature of chiral materials is their ability to generate circular dichroism and circularly polarized luminescence. For example, chiral europium complexes can be used to generate electroinduced circularly polarized luminescence. Circularly polarized light is central to many photonic technologies. Optically or electrically excited circularly polarized light is very important for the development of 3D displays, optical information storage, spintronics devices, solar cells, quantum cryptography light sources and low-threshold circularly polarized lasers.

[0003] Perovskite is a semiconductor material with excellent performance and is widely used in optoelectronics, photovoltaics, luminescence and other fields. The common composition of perovskite is ABX3 (three-dimensional) and A2BX4 (two-dimensional), where the A position is a monovalent organic cation (such as MA + , FA + etc.), the B position is a divalent inorganic cation (such as Pb 2+ 、Sn 2+ 、Cu 2+ etc.), X is a negative monovalent halogen ion (such as I - Br - 、Cl - Perovskite materials can achieve continuous adjustment of their structure and band gap by regulating their organic and inorganic components. With the addition of chiral cations at the A site, the central inversion symmetry of the perovskite is broken, and chirality is transferred from the A site ions to the perovskite crystal structure. Chiral perovskites possess unique physical properties such as chiral optical activity, nonlinear optical response, and ferroelectricity. The introduction of these new physical properties, combined with the excellent optoelectronic properties of perovskite materials, gives chiral perovskites potential for broad application in circularly polarized light detection, nonlinear optics, ferroelectrics, spintronics, and other fields.

[0004] Perovskite nanocrystals have attracted increasing attention due to their advantages such as tunable band gap, high fluorescence quantum yield, narrow spectral half-maximum width, and simple preparation methods. Introducing chirality into chiral perovskite nanocrystals combines the excellent optoelectronic properties of perovskite nanocrystals with the chiral optical activity of chiral materials. Chiral perovskite nanocrystals have potential applications in circularly polarized luminescence, nonlinear optics, spintronics, and other fields. Traditional chiral perovskite materials include:

[0005] Chinese invention patent application 201711391308.3 discloses a chiral perovskite nanocrystal, which is a chiral compound formed by covalently linking a chiral ligand to the surface of the perovskite nanocrystal. Further: the perovskite nanocrystal is a CsPbX3 nanocrystal, wherein X is any one or a combination of at least two of Cl, Br or I, and the chiral ligand is (1S,

[0006] 2S)-1,2-cyclohexanediamine, (1R,2R)-1,2-cyclohexanediamine or Any one of, wherein R is any one of hydrogen, methyl, ethyl, fluorine, chlorine, bromine or iodine or a combination of at least two, the chiral perovskite nanocrystal has

[0007] The following structure: in Perovskite nanocrystals.

[0008] Chinese invention patent application 201810690799.X discloses a method for preparing chiral perovskite nanowire crystals, comprising providing a chiral organic amine and a hydrohalic acid, so that the chiral organic amine and the hydrohalic acid form a chiral ammonium salt; dissolving the chiral ammonium salt and lead halide in a first solvent and using an anti-solvent vapor-assisted crystallization method to prepare the chiral perovskite nanowire crystals. Furthermore: the chiral organic amine includes one or more of chiral alicyclic amines, chiral aromatic amines, and chiral naphthylamines; the chiral alicyclic amines include one or more of chiral aromatic amines, and chiral naphthylamines; the chiral aromatic amines include one or more of chiral aromatic amines, and chiral naphthylamines; the chiral aromatic amines include one or more of chiral aromatic amines, and chiral naphthylamines.

[0009] The cyclic amines include compounds of the following formulas IA1-IA6, the chiral aromatic amines include compounds of the following formulas IB1 and IB2, the chiral naphthylamines include compounds of the following formulas IC1-IC2, and the hydrohalic acid includes one or more of hydroiodic acid, hydrobromic acid and hydrochloric acid.

[0010] As exemplified above, the traditional chiral perovskite has the defect of poor deliquescence resistance. Summary of the Invention

[0011] In view of the above background technology, the main purpose of the present invention is to provide a preparation method and application of a chiral perovskite material.

[0012] The object of the present application can be achieved by the following technical solutions.

[0013] In a first aspect, the present application provides a nonlinear frequency multiplication device, which comprises a frequency multiplication device and a filter device in sequence along a light transmission direction; the material of the frequency multiplication device comprises the chiral perovskite material, and the chiral perovskite material is a lead-based perovskite with R / S-2-methylpiperidine as a chiral organic amine.

[0014] In one of the embodiments, the filter device is selected from colored glass filter, interference band-pass filter, neutral density absorption filter, neutral density reflection filter, circularly variable neutral density filter, birefringent filter, magneto-optical modulator or electro-optical modulator; or the filter device is a light adjusting ring, a slit or a circular hole.

[0015] In one of the embodiments, the molecular formula of the chiral perovskite is C6H 14 NPbX3; wherein X is Cl, Br or I.

[0016] In a second aspect, the present application provides a chiral perovskite material, which is a lead-based perovskite with R / S-2-methylpiperidine as a chiral organic amine.

[0017] In one of the embodiments, the molecular formula of the chiral perovskite is C6H 14 NPbX3; wherein X is Cl, Br or I.

[0018] In a third aspect, the present application provides a preparation method of the chiral perovskite material as described above, which comprises the following steps:

[0019] Under the condition of a hydrogen halide acid, R / S-2-methylpiperidine is heated to react with lead halide, impurities in the obtained reaction solution are removed, and the reaction solution is evaporated.

[0020] In one of the embodiments, the heating temperature is 60-70°C.

[0021] In one of the embodiments, the ratio of the amount of R / S-2-methylpiperidine, lead halide and hydrogen halide acid is (8-8.5 mmol):(8-8.5 mmol):(45-55 mL).

[0022] In one of the embodiments, the impurities in the reaction solution are removed by filtration.

[0023] In one of the embodiments, the filtration is performed by using a filter membrane with a pore size of 0.15-0.25 µm.

[0024] In one of the embodiments, the evaporation is performed in a constant temperature manner.

[0025] In one embodiment, the constant temperature condition is 20°C-30°C.

[0026] In one embodiment, the drying is performed by varying the temperature.

[0027] In one embodiment, the temperature changing conditions include: first at 45°C-55°C for 10h-14h and then decreasing to 20°C-30°C at a rate of 0.45°C-0.55°C / d.

[0028] In a fourth aspect, the present invention provides the use of the chiral perovskite material as described above in the preparation of electronic materials, display materials or semiconductor materials.

[0029] In a fifth aspect, the present invention provides a nonlinear crystal frequency doubling device, wherein the nonlinear frequency doubling device is installed inside or outside the resonant cavity of the nonlinear crystal frequency doubling device.

[0030] The present invention has the following technical advantages and positive effects:

[0031] The present invention selects R / S-2-methylpiperidine as a chiral organic amine and prepares a one-dimensional chiral perovskite material with a new structure for the first time. The lead-based perovskite with R / S-2-methylpiperidine as the chiral organic amine solves the application limitations (including nonlinear and other fields) caused by the inherent defects of the perovskite material itself. The perovskite has the following characteristics: a huge second harmonic generation signal and second-order nonlinear properties, the ability to achieve phase matching, a high polarization ratio, and a wide transparency window in the ultraviolet, visible light and infrared regions; a good laser damage threshold, excellent air stability and good thermal stability, and high-quality large crystals can be prepared by a simple volatilization method. It meets all the properties that a high-quality nonlinear crystal should have, which is a great progress for the use of perovskites in the field of nonlinear optics.

[0032] In particular, the nonlinear frequency doubling device using lead-based perovskite material with R / S-2-methylpiperidine as the chiral organic amine as the frequency doubling device showed that its XRD characterization spectrum remained basically unchanged after being placed in a natural environment for two years, indicating that it has good resistance to deliquesce. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0034] Figure 1This is a photo of large-grained bulk crystals of chiral perovskite, a nonlinear optical material, obtained in one embodiment of the present invention;

[0035] Figure 2 This is a schematic structural diagram of a single crystal of a nonlinear optical material, chiral perovskite, according to an embodiment of the present invention;

[0036] Figure 3 The XRD pattern of a single crystal of a chiral perovskite, a nonlinear optical material, according to an embodiment of the present invention;

[0037] Figure 4 This is an ultraviolet absorption spectrum of a polycrystalline thin film of a chiral perovskite, a nonlinear optical material, according to an embodiment of the present invention;

[0038] Figure 5 This is a circular dichroism spectrum of a polycrystalline thin film of chiral perovskite, a nonlinear optical material according to an embodiment of the present invention;

[0039] Figure 6 This is a graph showing the UV-visible-near-infrared transmission spectrum of a polycrystalline thin film of a chiral perovskite, a nonlinear optical material, according to an embodiment of the present invention;

[0040] Figure 7 This is a scanning electron microscope image of a single crystal of a chiral perovskite, a nonlinear optical material according to an embodiment of the present invention;

[0041] Figure 8 This is a transmission electron microscope image of a single crystal of a chiral perovskite, a nonlinear optical material according to an embodiment of the present invention;

[0042] Figure 9 This is a graph showing the stability test results of a chiral perovskite crystal, a nonlinear optical material, according to an embodiment of the present invention;

[0043] Figure 10 This is a graph showing the test results of the frequency-doubled-frequency signal of a chiral perovskite sample powder, a nonlinear optical material, according to an embodiment of the present invention;

[0044] Figure 11 This is a phase matching diagram of the frequency doubling effect of a chiral perovskite sample powder, a nonlinear optical material, according to an embodiment of the present invention;

[0045] Figure 12 This is a diagram of the laser damage threshold of a chiral perovskite single crystal sample, a nonlinear optical material, according to an embodiment of the present invention;

[0046] Figure 13 This is a comparison chart of the signal intensity of a chiral perovskite single crystal sample, a nonlinear optical material according to an embodiment of the present invention, at 980nm, compared with urea and quartz;

[0047] Figure 14 This is a graph showing the polarization ratio test results of a single crystal sample of a nonlinear optical material chiral perovskite at 800 nm according to an embodiment of the present invention;

[0048] Figure 15 Schematic diagram of the structure within the resonant cavity of a nonlinear frequency doubling device for a lead-based perovskite material with R / S-2-methylpiperidine as a chiral organic amine, provided in one embodiment of the present invention; 1 is a frequency doubling device made of a lead-based perovskite crystal with R / S-2-methylpiperidine as a chiral organic amine, 2 is a filtering device, arrows indicate light transmission directions, A is fundamental frequency light, and B is frequency doubling light;

[0049] Figure 16 This is a schematic diagram of the structure outside the resonant cavity of a nonlinear frequency doubling device based on a lead-based perovskite material with R / S-2-methylpiperidine as a chiral organic amine according to an embodiment of the present invention; 1 is a frequency doubling device made of a lead-based perovskite crystal with R / S-2-methylpiperidine as a chiral organic amine, 2 is a filtering device, 3 is a light transmission direction, A is fundamental frequency light, and B is frequency doubling light. DETAILED DESCRIPTION

[0050] To facilitate understanding of the present invention, the present invention will be described in more detail below. However, it should be understood that the present invention can be implemented in many different forms and is not limited to the embodiments or examples described herein. On the contrary, the purpose of providing these embodiments or examples is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0051] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which the present invention pertains. The terms used herein in the specification of the present invention are intended only to describe specific embodiments or examples and are not intended to limit the present invention. The optional scope of the term "and / or" as used herein includes any one of two or more related listed items, and also includes any and all combinations of the related listed items, including any combination of any two related listed items, any more related listed items, or all related listed items.

[0052] Unless otherwise specified or incompatible herewith, the terms and phrases used herein shall have the following meanings:

[0053] The optional scope of the terms "and / or", "or / and", and "and / or" used in this document includes any one of two or more related listed items, and also includes any and all combinations of the related listed items, and the said any and all combinations include any two related listed items, any more related listed items, or a combination of all related listed items.

[0054] Herein, “preferred” is only used to describe an implementation method or example with better effects, and it should be understood that it does not constitute a limitation on the scope of protection of the present invention.

[0055] In the present invention, “first aspect”, “second aspect”, “third aspect”, etc. are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or quantity, nor can they be understood as implicitly indicating the importance or quantity of the indicated technical features.

[0056] In the present invention, the technical features described in an open manner include closed technical solutions composed of the listed features, and also include open technical solutions containing the listed features.

[0057] In the present invention, when a numerical range is involved, unless otherwise specified, both endpoints of the numerical range are included.

[0058] Unless otherwise specified, the percentage contents mentioned in the present invention refer to mass percentage for solid-liquid phase mixing and solid-solid phase mixing, and refer to volume percentage for liquid-liquid phase mixing.

[0059] The percentage concentrations mentioned in the present invention, unless otherwise specified, refer to the final concentration, which refers to the percentage of the added component in the system after the addition of the component.

[0060] The temperature parameters in the present invention, unless otherwise specified, allow for either constant temperature treatment or treatment within a certain temperature range. The constant temperature treatment allows for temperature fluctuations within the precision range controlled by the instrument.

[0061] Unless otherwise specified, the experimental methods described in the following examples are all conventional methods; the reagents and biological materials described are all commercially available unless otherwise specified.

[0062] In the following examples, the percentages are by mass unless otherwise specified.

[0063] In a first aspect, the present invention provides a chiral perovskite material, wherein the chiral perovskite material is a lead-based perovskite with R / S-2-methylpiperidine as a chiral organic amine.

[0064] In one example, the chiral perovskite has a molecular formula of C6H 14 NPbX3; wherein X is Cl, Br or I. Preferably, the chiral perovskite has the structural formula:

[0065]

[0066] In a second aspect, the present invention provides a method for preparing the chiral perovskite material as described above, the preparation method comprising the following steps:

[0067] Under hydrohalic acid conditions, R / S-2-methylpiperidine and lead halide are heated to react, and impurities in the resulting reaction solution are removed and evaporated to dryness.

[0068] The main synthetic route of the present invention is as follows:

[0069]

[0070] In one example, the heating temperature is 60° C.-70° C., such as 60° C., 65° C., 70° C., etc.

[0071] In one embodiment, the ratio of the R / S-2-methylpiperidine, the lead halide, and the hydrohalic acid is (8 mmol-8.5 mmol): (8 mmol-8.5 mmol): (45 mL-55 mL), for example, 8.3 mmol: 8.3 mmol: 50 mL, 8.5 mmol: 8.5 mmol: 45 mL, 8 mmol: 8 mmol: 55 mL, etc.

[0072] In one example, filtration is used to remove impurities from the reaction solution.

[0073] In one example, a filter membrane with a pore size of 0.15µm-0.25µm is used for filtration. It is understood that the present invention does not specifically limit the material of the filter membrane, including but not limited to using a polytetrafluoroethylene filter membrane to filter.

[0074] In one example, the drying is performed at a constant temperature.

[0075] In one example, the constant temperature condition is 20°C-30°C, such as 20°C, 25°C, 30°C, etc.

[0076] In one example, the drying is performed using a variable temperature method.

[0077] In one example, the temperature ramp conditions include: first maintaining the temperature at 45°C-55°C for 10-14 hours and then decreasing the temperature to 20°C-30°C at a rate of 0.45°C-0.55°C / day. For example: first maintaining the temperature at 50°C for 12 hours and then decreasing the temperature to 25°C at a rate of 0.5°C / day; first maintaining the temperature at 45°C for 14 hours and then decreasing the temperature to 20°C at a rate of 0.45°C / day; first maintaining the temperature at 55°C for 10 hours and then decreasing the temperature to 30°C at a rate of 0.55°C / day.

[0078] In a third aspect, the present invention provides the use of the chiral perovskite material as described above in the preparation of electronic materials, display materials or semiconductor materials.

[0079] Laser frequency doubling (FHD) technology is the most important and widely used technique in nonlinear optics. It enables the continuous expansion of laser wavelengths into the ultraviolet and even deep ultraviolet spectral regions, broadening the application of lasers. Developing new FHD materials with high FHD conversion efficiency, high deliquescence resistance, and a high damage threshold is a hot topic of research both domestically and internationally.

[0080] Continuously tunable lasers are lasers that can continuously change their wavelength within a certain range. They are widely used in optical communications, optical sensing, spectroscopy, photochemistry, integrated optics, medicine, biology, pollution detection, and semiconductor processing. In medicine, 532nm lasers are the optimal wavelength for red and brown pigments. The biological effect of lasers on pigments is thermal, which can cause tissue coagulation, necrosis, and inflammation, thereby destroying pigment cells. 532nm lasers can destroy red and brown pigments and are used to remove red lips and brown eyebrow tattoos, remove red blood streaks, port-wine stains (purple birthmarks), malformed naevi, and permanently remove freckles and spider veins. Multi-point laser therapy with a 532nm wavelength is a safe, effective, and economical treatment for pigmentary disorders.

[0081] To use BBO crystals, which are prone to deliquesce, for extended periods, it is necessary to control the operating environment of the BBO crystals and polish and coat their surfaces. This significantly increases the cost of generating the laser frequency-doubled signal. Improving the deliquesce resistance of the frequency-doubled crystals has become a way to reduce the cost of crystal use.

[0082] In a fourth aspect, the present invention provides a nonlinear frequency doubling device, which includes a frequency doubling device and a filtering device in sequence along the light transmission direction; the material of the frequency doubling device includes the chiral perovskite material.

[0083] In one example, the filtering device is a colored glass filter, an interference bandpass filter, a neutral density absorption filter, a neutral density reflection filter, a circular gradient neutral density filter, a birefringent filter, a magneto-optical modulator or an electro-optical modulator; or the filtering device is an aperture, a slit, or a circular hole.

[0084] In a fifth aspect, the present invention provides a nonlinear crystal frequency doubling device, wherein the nonlinear frequency doubling device is installed inside or outside the resonant cavity of the nonlinear crystal frequency doubling device.

[0085] In one example, the laser emitting device of the nonlinear crystal frequency doubling device is selected from Nd:YAG laser, Nd:YLF laser, Ti:Sappire laser, Alexandrite laser, dye laser, argon ion laser, ruby ​​laser, Cu-vapor laser, optical parametric amplifier or optical parametric oscillator.

[0086] The nonlinear frequency multiplication device provided by the present invention and its working method include the following steps:

[0087] The laser emitting device generates laser light;

[0088] The laser generates frequency-doubled light through the frequency-doubling device;

[0089] The frequency-doubled light is filtered and purified by a filter device.

[0090] When the nonlinear frequency doubling device of the present invention is used to generate frequency-doubled light, laser light in the wavelength range of 800nm ​​to 1064nm passes through a frequency doubling crystal and generates laser light in the wavelength range of 400nm to 532nm through nonlinear conversion.

[0091] The present invention provides a nonlinear frequency doubling device based on a lead-based perovskite material with R / S-2-methylpiperidine as a chiral organic amine. The XRD characterization pattern of the lead-based perovskite material with R / S-2-methylpiperidine as a chiral organic amine remains essentially unchanged after being placed in a natural environment for two years, indicating that it has good deliquescence resistance. The device 2 inside and outside the resonant cavity can both effectively filter out unwanted fundamental frequency light.

[0092] Example 1

[0093] The synthesis route of the chiral perovskite nonlinear optical material involved in this embodiment is as follows:

[0094]

[0095] (1) Dissolve S-2-methylpiperidine (1 mL, 8.3 mmol) and lead bromide (3.05 g, 8.3 mmol) in 50 mL of hydrobromic acid and heat at 65°C with continuous stirring until a colorless, transparent solution is formed.

[0096] (2) After cooling, filter the solution through a 0.2 µm polytetrafluoroethylene filter into a beaker and place it in an undisturbed room to evaporate naturally.

[0097] The nonlinear optical material provided in this embodiment is a lead-based perovskite with S-2-methylpiperidine as a chiral organic amine, and its molecular formula is C6H 14 NPbBr3, the crystal is orthorhombic system, and the space group is P212121.

[0098] The synthetic route provided in this example is as described above. After one step of dissolution and evaporation at room temperature, colorless large block crystals with a size of 6 mm × 6 mm × 2 mm are obtained after a few weeks. Figure 1 . Figure 1 This is a photo of the bulk crystal of the obtained nonlinear optical material chiral perovskite.

[0099] A single crystal diffractometer (Rigaku XtalAB PRO MM007 DW, Japan) was used to determine the single crystal structure of chiral perovskite (Cu target, λ = 1.5418 Å). The test selected a high-quality nonlinear optical material chiral perovskite transparent crystal with a size of approximately 0.5mm × 0.2mm × 0.1mm, which was wrapped with silicone oil and glued to the LOOP ring for testing. The collection parameters were adjusted using the test software CryAlispro to obtain ideal single crystal data. The data was analyzed and refined using Olex2. The results are shown in Figure 2. Figure 2 shown.

[0100] The structure of the prepared nonlinear optical material chiral perovskite single crystal was characterized by powder XRD diffractometer. The silicon wafer was selected as the substrate and the single crystal sample was evenly spread in the sample tank. The test conditions were selected as 5 degrees Celsius / minute and the test range was 3 degrees Celsius-50 degrees Celsius. The results are as follows: Figure 3 As shown. Figure 3 As shown, the XRD pattern of the chiral perovskite single crystal sample is consistent with the data simulated based on the single crystal X-ray diffraction results, indicating that the prepared chiral perovskite single crystal has high phase purity. After two years of storage in air, the XRD pattern of the sample crystal still matches the simulated data well, indicating that the crystal has excellent air stability, especially good deliquescence resistance.

[0101] The absorption spectrum of the crystal film grown on the quartz substrate was tested using a UV-visible spectrometer. The absorption spectrum of the film sample measured in standard mode is as follows: Figure 4 As shown. Figure 4 , the crystal thin film sample has an absorption peak at 309nm, and the absorption extends to about 350nm.

[0102] The crystal film grown on the quartz substrate was tested using a circular dichroism spectrometer. The results are as follows: Figure 5 As shown. Figure 5 , the crystal thin film sample has obvious circular dichroism behavior between 250nm-350nm.

[0103] The crystal film grown on the quartz substrate was tested using a UV-Vis-NIR spectrometer. The transmission spectrum of the film sample is shown in the figure below. Figure 6 As shown. Figure 6 The crystal thin film samples have ultra-high transmittance (>80%) between 300nm and 2500nm.

[0104] The morphology and structure of the prepared single crystal were characterized by scanning electron microscopy and transmission electron microscopy. Figure 7 shown. Figure 7 The results show that the crystals are regular rod-shaped structures and are flat and smooth. Figure 8The results shown in Figure 2 show that the single crystal transmission data analysis results of the chiral perovskite are consistent with the single crystal structure. This test requires good crystal stability, which is rare in perovskite materials. This indirectly confirms that the nonlinear optical material chiral perovskite provided by the present invention has excellent stability.

[0105] The stability test of the crystal of the chiral perovskite sample was conducted using a thermogravimetric analyzer: 8 mg of chiral perovskite sample was weighed, the temperature range was 25°C-800°C in air atmosphere, and the heating rate was 10°C per minute. The results are as follows: Figure 9 As shown. Figure 9 , chiral perovskite crystals have good thermal stability and a decomposition temperature of 317 °C.

[0106] The frequency-doubling performance of the chiral perovskite sample synthesized in this example was obtained using the Kurtz-Perry single crystal powder test method. The obtained bulk crystal material was ground into powders of different particle size ranges, placed in a sample cell and placed in the laser light path. A Nd:YAG pulsed laser was used as the light source to generate 1064 nm fundamental frequency light that was injected into the sample cell. KDP single crystal powder of the same particle size was used as a reference, and the signal was displayed on an oscilloscope through a photomultiplier tube. Samples with a particle size of 300 μm to 350 μm were selected for comparison with the reference signal intensity, as shown in Figure 2. Figure 10 Therefore, the signal of the sample at 1064nm is about 1.5 times that of KDP, which is higher than all the chiral perovskite materials currently available. Powders between 50 microns and 350 microns were screened and the intensity of the SHG signals of different particle sizes was tested, such as Figure 11 As shown, this indicates that the compound is capable of phase matching.

[0107] The present invention also utilized a self-built confocal microscopy system to further characterize the SHG performance of a single sample crystal. A chiral perovskite single crystal of appropriate size was placed on a quartz substrate on the sample stage. A femtosecond pulsed laser (Maitai HP, 690-1040 nm, <100 fs, 80 MHz) was used as the light source. The fundamental frequency light passed through a polarizer and incident on the sample. The reflected SHG signal was collected by an objective lens, passed through a filter, and imaged on a CCD. The spectral signal was then coupled to a spectrometer via optical fiber for measurement. Figure 12 The intensity of the second harmonic generation (SHG) signal generated by the chiral perovskite sample at different incident powers varies. The results show that the chiral perovskite crystal can withstand a power greater than 700mW. Figure 13 This is a comparison of the signal loudness of the sample crystal and commonly used commercial nonlinear crystals (urea and quartz) at 980nm under the same test conditions. The signal intensity of the sample at 980nm is 5.1 times that of urea. Figure 14 This is the dependence of the SHG signal intensity of the sample at 800nm ​​on the polarization angle. The calculated polarization ratio is as high as 96%.

[0108] Overall, the chiral perovskite nonlinear optical material prepared in this example exhibits outstanding second-order nonlinear properties (the SHG signal of its powder is the strongest among all currently available chiral perovskites, and the SHG signal of a single crystal is comparable to that of urea, the earliest applied organic nonlinear crystal, and even surpasses urea at high wavelengths). It is also easy to prepare large crystals and exhibits excellent stability. It exhibits a wider transmission band, a larger nonlinear optical coefficient, a higher laser damage threshold, and is easier to grow large, high-quality crystals.

[0109] Example 2

[0110] As shown in FIG15 , this embodiment provides a nonlinear crystal doubling device for generating frequency doubling in a resonant cavity, which includes a frequency doubling device 1 made of a lead-based perovskite crystal with R / S-2-methylpiperidine as a chiral organic amine and a filter device 2 .

[0111] The filtering device 2 can filter the fundamental frequency laser to obtain pure frequency-doubled light. This device can be a colored glass filter, an interference bandpass filter, a neutral density absorption filter, a neutral density reflection filter, a circular gradient neutral density filter, a birefringent filter, a magneto-optical modulator or an electro-optical modulator.

[0112] In this way, the nonlinear crystal frequency-doubling device is placed inside a resonant cavity. When polarized fundamental frequency light that meets the phase-matching condition passes through a lead-based perovskite crystal containing R / S-2-methylpiperidine as a chiral organic amine, nonlinear frequency-doubled light (B) and fundamental frequency light (A) are transmitted from the back of the crystal.

[0113] Subsequently, the fundamental frequency light (A) is reflected or absorbed by the optical filter 2, and the pure doubled frequency light (B) is obtained after filtering by the optical filter 2. That is, this doubled frequency device uses a highly deliquescent material to obtain a high doubled frequency conversion efficiency and good doubled frequency light beam quality.

[0114] Please refer to Figure 15 again: A nonlinear frequency doubling device based on a lead-based perovskite crystal with R / S-2-methylpiperidine as a chiral organic amine was fabricated to double 980nm infrared light to produce a 480nm laser. The fundamental frequency source was a Ti:Sappire laser, using a Type I phase matching scheme. The parameters used for frequency doubling device 1 and filter device 2, made of lead-based perovskite crystals with R / S-2-methylpiperidine as a chiral organic amine, were: dimensions 5×5×1mm. 3 , vertical incidence (meeting the phase matching condition).

[0115] like Figure 16As shown, this embodiment provides a nonlinear crystal frequency doubling device for generating frequency doubling in an optical path outside a resonant cavity, comprising a frequency doubling device 1 made of a lead-based perovskite crystal with R / S-2-methylpiperidine as a chiral organic amine, and a filter device 2; the filter device 2 can block the fundamental frequency laser to obtain pure frequency doubling light, and the device can be an adjustable aperture, a slit, or a circular hole.

[0116] In this way, the nonlinear crystal frequency-doubling device is placed in the optical path outside the resonant cavity. When two beams of polarized fundamental frequency light (A) that meet phase-matching conditions overlap at a certain angle on a lead-based perovskite crystal containing R / S-2-methylpiperidine as a chiral organic amine, nonlinear frequency-doubled light (B) and two beams of fundamental frequency light (A) are transmitted from the back of the crystal. Subsequently, the fundamental frequency light (A) is blocked by the filter 2, while the frequency-doubled light (B) is emitted from the gap in the filter 2. After being blocked by the filter 2, the pure frequency-doubled light is obtained. This frequency-doubling device uses highly deliquescent materials, resulting in high frequency-doubled conversion efficiency and good frequency-doubled light beam quality.

[0117] Please refer to Figure 16 again: A nonlinear frequency doubling device based on a lead-based perovskite crystal with R / S-2-methylpiperidine as a chiral organic amine was fabricated to frequency-double 980nm infrared light to generate a 480nm laser. The fundamental frequency light source was derived from a Ti:Sappire laser, using a type I phase matching scheme. The parameters used for frequency doubling device 1 and filter device 2, made of lead-based perovskite crystals with R / S-2-methylpiperidine as a chiral organic amine, were: dimensions 5×5×1mm. 3 , the incident angle θ is 0° to 4° (meeting the phase matching condition).

[0118] The embodiments described above only express several implementation methods of the present invention, which are convenient for understanding the technical solutions of the present invention in a specific and detailed manner, but they cannot be understood as limiting the scope of protection of the invention patent. It should be pointed out that for ordinary technicians in this field, without departing from the concept of the present invention, several variations and improvements can be made, which all fall within the scope of protection of the present invention. It should be understood that the technical solutions obtained by those skilled in the art through logical analysis, reasoning or limited experiments on the basis of the technical solutions provided by the present invention are all within the scope of protection of the attached claims described in the present invention. Therefore, the scope of protection of the patent of the present invention shall be based on the content of the attached claims, and the description and drawings can be used to interpret the content of the claims.

Claims

1. A nonlinear frequency multiplication device, characterized in that: The nonlinear frequency doubling device includes a frequency doubling device and a filtering device in sequence along the light transmission direction; the material of the frequency doubling device includes a chiral perovskite material, and the chiral perovskite material is a lead-based perovskite with R / S-2-methylpiperidine as the chiral organic amine.

2. The nonlinear frequency multiplication device according to claim 1, characterized in that: The filtering device is selected from a colored glass filter, an interference bandpass filter, a neutral density absorption filter, a neutral density reflection filter, a circular gradient neutral density filter, a birefringent filter, a magneto-optical modulator or an electro-optical modulator; or the filtering device is an aperture, a slit or a circular hole.

3. The nonlinear frequency multiplication device according to claim 1, characterized in that: The molecular formula of the chiral perovskite is C6H 14 NPbX3; wherein X is Cl, Br or I, orthorhombic crystal system, space group is P212121.

4. A method for preparing a chiral perovskite material, characterized in that: The preparation method comprises the following steps: Under the condition of hydrohalic acid, R / S-2-methylpiperidine and lead halide are heated to react, and impurities in the resulting reaction solution are removed and evaporated; The chiral perovskite material obtained by the preparation method is a lead-based perovskite with R / S-2-methylpiperidine as the chiral organic amine.

5. The method for preparing a chiral perovskite material according to claim 4, wherein: The molecular formula of the chiral perovskite obtained by the preparation method is C6H 14 NPbX3; wherein X is Cl, Br or I, orthorhombic crystal system, space group is P212121.

6. The method for preparing a chiral perovskite material according to claim 4, wherein: The heating temperature is 60° C.-70° C.; or / and, the usage ratio of the R / S-2-methylpiperidine, the lead halide, and the hydrohalic acid is (8 mmol-8.5 mmol): (8 mmol-8.5 mmol): (45 mL-55 mL); or / and, impurities in the reaction solution are removed by filtration; or / and, evaporation is performed by a constant temperature method or a variable temperature method.

7. The method for preparing a chiral perovskite material according to claim 6, wherein: The filtration adopts a filter membrane with a pore size of 0.15µm-0.25µm; or / and, the constant temperature condition is 20℃-30℃; or / and, the variable temperature conditions include: first at 45℃-55℃ for 10h-14h and then decreasing to 20℃-30℃ at 0.45℃-0.55℃ / d.

8. Use of the chiral perovskite material according to claim 4 or 5 in the preparation of electronic materials, display materials or semiconductor materials.

9. A nonlinear crystal frequency multiplier, characterized in that: The nonlinear frequency doubling device according to claim 1 or 2 is installed inside or outside the resonant cavity of the nonlinear crystal frequency multiplier.

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