Spirocyclic ammonium salt, one-dimensional / two-dimensional perovskite crystal and preparation method and application of spiro ammonium salt and one-dimensional / two-dimensional perovskite crystal

Abstract

The invention relates to a spiro ammonium salt, a one-dimensional / two-dimensional perovskite crystal and a preparation method and application of the one-dimensional / two-dimensional perovskite crystal. Based on 3-mercaptopropylamine hydrochloride or 2-mercaptoethylamine hydrochloride, cyclohexanone or a derivative thereof is directionally converted into two spiro ammonium salts by adopting a thioketal reaction; then, based on the two spiro ammonium salts as ligand molecules, one-dimensional perovskite with a nanowire structure and a two-dimensional perovskite crystal material with a layered structure are directionally prepared, and the purpose of directionally regulating and controlling the dimension (one-dimensional or two-dimensional) of the perovskite through the ligand structure (the number of heterocycle atoms) is achieved; in addition, the one-dimensional / two-dimensional perovskite crystal material disclosed by the invention is excellent in crystal quality, obvious in characteristic absorption signal and high in PL emission intensity; the ligand molecule provided by the invention has strong qualitative expandability for one-dimensional and two-dimensional perovskite, and is beneficial to deep excavation of an influence mechanism of exciton emission in low-dimensional perovskite and design and preparation of more one-dimensional and two-dimensional perovskite with characteristic free exciton luminescence characteristics.

Description

Technical Field

[0001] This disclosure relates to the field of perovskite materials, specifically to a spirocyclic ammonium salt, a one-dimensional / two-dimensional perovskite crystal, its preparation method, and its application. Background Technology

[0002] Organic-inorganic hybrid perovskite materials have shown great application potential in optoelectronic devices such as solar cells, light-emitting diodes, lasers, and photodetectors due to their excellent optoelectronic properties, such as high quantum yield, tunable bandgap, and unique quantum well structure. The dimensionality (e.g., three-dimensional, two-dimensional, one-dimensional) of perovskite materials has a decisive influence on their optoelectronic properties and stability. Among them, low-dimensional (especially one-dimensional and two-dimensional) perovskites have attracted much attention due to their outstanding exciton binding energy, structural anisotropy, and tunable quantum confinement effect.

[0003] The dimensional control of perovskite materials primarily relies on the design and selection of organic amine ligands. Different ligands lead to significant differences in structure and properties between one-dimensional and two-dimensional perovskites. One-dimensional perovskites are composed of [BX6]. 4- (B: Metal cation Pb) 2+ Sn 2+ etc.; X: Halogen anion I - ,Br - Cl - The inorganic perovskite is a chain-like structure composed of octahedral coplanar (or edge-sharing) links, with organic ligands distributed around the inorganic chains; while two-dimensional perovskites are composed of [BX6]. 4- The perovskite is a layered structure with octahedral co-point connections, with organic ligands distributed as spacers between the inorganic layers. Generally, the organic amine ligands that can construct two-dimensional perovskites are mostly long-chain amines with simple structures (such as butylamine, 1,4-butanediamine, etc.) or aromatic amines (such as phenylethylamine, 1,4-phenylenediamine, etc.).

[0004] To further develop novel two-dimensional perovskite materials, various organic amines (O, S, N heterocyclic amines, etc.) have been developed as ligands for the preparation of two-dimensional perovskites. However, during the trial-and-error process, due to unsuitable structures or unclear properties of the designed or selected organic ligands, a class of one-dimensional perovskites has gradually emerged. These one-dimensional perovskites, as "byproducts" of two-dimensional perovskites, have been increasing in number in a short period of time. However, the current lack of clear ligand design schemes and directional guidance for the effective synthesis of one-dimensional perovskites severely restricts the directional design and controllable preparation of low-dimensional perovskite materials for specific optoelectronic applications, making it difficult to summarize universal synthesis rules and empirical systems.

[0005] Furthermore, due to the limited variety of organic amine ligands, extensive trial and error are still required to synthesize suitable novel low-dimensional perovskite organic amine ligands. Existing methods for synthesizing organic amines (halogenation, cyclization, etc.) not only suffer from limitations in reaction conditions (low temperature -10 °C, hydrogenation, oxidation prevention), long synthetic routes (>3 steps), and low overall yield (<60%), but also result in the randomness (one-dimensional or two-dimensional) of the low-dimensional perovskite structures constructed as ligands. Therefore, there is an urgent need to develop optimized ligand synthesis schemes to directionally realize one-dimensional and two-dimensional perovskite materials.

[0006] Spirocyclic ammonium salts, as ligands, play a crucial role in perovskites by providing defect passivation, structural stability, energy level matching, and ion migration suppression. They also possess the advantages of sulfur-based antioxidant properties and the steric hindrance of the spirocyclic framework, making them key functional materials for improving device efficiency and stability. However, there are no reports on their use for the directional control of perovskite dimensionality to achieve the directional preparation of one-dimensional and two-dimensional perovskite materials. Summary of the Invention

[0007] In view of this, this disclosure provides a spirocyclic ammonium salt, a one-dimensional / two-dimensional perovskite crystal, a preparation method thereof, and its application, solving the problem that the directional design and controllable preparation of one-dimensional / two-dimensional perovskite materials cannot be achieved at present.

[0008] To achieve the above-mentioned objectives, in a first aspect, the spirocyclic ammonium salts disclosed herein have the following general formula: (xn-TASp)·HX; Where x represents the para-position of H, CH3, or C2H5; n is 5 or 6, representing the number of atoms in the heterocyclic portion of the spiroring; xn-TASp + This indicates a spirocyclic ammonium cation formed by the cyclization reaction of cyclohexanone or its derivatives with 3-mercaptopropylamine or 2-mercaptoethylamine via a thioacetate cyclization reaction; X in HX - This indicates the anion that it pairs with.

[0009] Preferably, the cyclohexanone derivative is 4-methylcyclohexanone or 4-ethylcyclohexanone; and / or, The anion includes Cl. - ,Br - I - BF4 - PF6 - and TsO - .

[0010] Secondly, the method for preparing the spirocyclic ammonium salt described in the first aspect includes: 3-Mercaptopropylamine hydrochloride or 2-mercaptoethylamine hydrochloride is dissolved in a buffer solvent with cyclohexanone or its derivative to form a clear solution. The prepared solution is subjected to a thioketane cyclization reaction under sealed and heated conditions. The solution after the reaction is purified to obtain the spirocyclic ammonium salt.

[0011] Preferably, the molar ratio of the cyclohexanone or its derivative to 3-mercaptopropylamine hydrochloride or 2-mercaptoethylamine hydrochloride is 1:1; and / or, The buffer solvent is anhydrous methanol or anhydrous ethanol; and / or, The concentration of 3-mercaptopropylamine hydrochloride or 2-mercaptoethylamine hydrochloride in the clarified solution is 1–1.5 mol / L; and / or, The heating conditions are a temperature of 40–60 °C and a time of 12–48 h; and / or, The purification process includes vacuum rotary evaporation, filtration, washing, and recrystallization.

[0012] Preferably, the buffer solvent is anhydrous methanol; and / or, The concentration of the clarified solution is 1 mol / L; and / or, The heating conditions are a temperature of 50 °C and a time of 48 h; and / or, The cleaning agent used for cleaning is diethyl ether, and the solvent used for recrystallization is methanol or ethanol.

[0013] Thirdly, the one-dimensional / two-dimensional perovskite crystals described in this disclosure, wherein: The one-dimensional perovskite crystal has the general formula: (x-6-TASp)PbI3, where x-6-TASp represents a spirocyclic amine salt formed by the cyclization reaction of cyclohexanone or its derivatives with 3-mercaptopropylamine via a thioacetate cyclization reaction, and x represents H, CH3 or C2H5 at the para position. The two-dimensional perovskite crystal has the general formula: (x-5-TASp)2PbI4, where x-5-TASp represents a spirocyclic amine salt formed by the cyclization reaction of cyclohexanone or its derivatives with 2-mercaptoethylamine via a thioacetate cyclization reaction, and x represents H, CH3 or C2H5 at the para position.

[0014] Fourthly, the method for preparing the one-dimensional / two-dimensional perovskite crystals described in the third aspect includes: Spirocyclic ammonium salt and PbO were dissolved in HI aqueous solution. H3PO2 was added to the solution to obtain a crystal precursor solution. After heating and stirring the crystal precursor solution, the crystal was further subjected to programmed cooling crystallization, filtration, washing and vacuum drying to obtain one-dimensional / two-dimensional perovskite crystals.

[0015] Preferably, a 57 wt% HI aqueous solution is used to dissolve the spirocyclic ammonium salt and PbO, wherein the molar ratio of the spirocyclic ammonium salt to PbO is 2:1, and the concentration of the spirocyclic ammonium salt in the solution is 0.025–0.25 mol / L; and / or, By volume ratio, the H3PO2:HI = 1:10; and / or, The peak temperature of the programmed cooling crystallization is 125 °C, and the cooling rate is 3–5 °C / h; and / or, The vacuum drying temperature is 40–60 °C, and the drying time is 12–48 h.

[0016] Preferably, the concentration of the solution is 0.1 mol / L; and / or, The cooling rate for the programmed cooling crystallization is 5 °C / h; and / or, The vacuum drying temperature is 60 °C, and the drying time is 24 h.

[0017] Fifthly, the application of the one-dimensional / two-dimensional perovskite crystals described in the third aspect and the one-dimensional / two-dimensional perovskite crystals prepared by the method described in the fourth aspect in optoelectronic devices; The optoelectronic devices include LEDs, lasers, photodetectors, and solar cells.

[0018] The beneficial effects of this invention are: This disclosure uses 3-mercaptopropylamine hydrochloride or 2-mercaptoethylamine hydrochloride as cyclizing agents, employing a thioacetate reaction to directionally convert cyclohexanone or its derivatives into spirocyclic ammonium salts (x-6-TASp·HCl and x-5-TASp·HCl, where x represents the para-position H, CH3, or C2H5, and the numbers 6 and 5 represent the number of atoms on the heterocycle after cyclization). Then, using the spirocyclic ammonium salts obtained from these two cyclized molecules as ligand molecules, one-dimensional perovskite crystal materials with nanowire structures and two-dimensional perovskite crystal materials with layered structures are directionally prepared, achieving directional control of the perovskite dimension (one-dimensional or two-dimensional) through the ligand structure (number of heterocycle atoms). Furthermore, the one-dimensional / two-dimensional perovskite crystal materials prepared using the method of this disclosure exhibit excellent crystal quality, significant characteristic absorption signals, and high PL emission intensity. Moreover, the ligand molecules provided by this invention have strong qualitative scalability for one-dimensional and two-dimensional perovskites, which is beneficial for deeply exploring the influence mechanism of exciton emission in low-dimensional perovskites and designing and preparing more one-dimensional and two-dimensional perovskites with characteristic free exciton luminescence properties. Attached Figure Description

[0019] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this disclosure and, together with the specification, serve to illustrate the technical solutions of this disclosure.

[0020] Figure 1 This is a schematic diagram of a possible reaction mechanism for the formation of spirocyclic ammonium salts, using cyclohexanone as an example.

[0021] Figure 2This is a schematic diagram of the general reaction formula for the preparation of spirocyclic ammonium salts by the thioacetate reaction described in this invention.

[0022] Figure 3 These are optical images of the one-dimensional perovskite (Me-6-TASp)PbI3 crystal in Example 1 and the two-dimensional perovskite (Me-5-TASp)2PbI4 crystal in Example 2 of the present invention, used to characterize the color differences of the materials.

[0023] Figure 4 The images are SEM images of the one-dimensional perovskite (Me-6-TASp)PbI3 crystal in Example 1 and the two-dimensional perovskite (Me-5-TASp)2PbI4 crystal in Example 2 of this invention, used to characterize the morphological features of the materials.

[0024] Figure 5 The XRD patterns are those of the one-dimensional perovskite (Me-6-TASp)PbI3 crystal in Example 1 and the two-dimensional perovskite (Me-5-TASp)2PbI4 crystal in Example 2 of this invention, used to prove that the obtained crystals have a pure phase and good crystallinity.

[0025] Figure 6 The ultraviolet absorption spectra of the one-dimensional perovskite (Me-6-TASp)PbI3 crystal in Example 1 and the two-dimensional perovskite (Me-5-TASp)2PbI4 crystal in Example 2 are used to characterize the optical absorption of the materials.

[0026] Figure 7 The emission spectra of the one-dimensional perovskite (Me-6-TASp)PbI3 crystal in Example 1 and the two-dimensional perovskite (Me-5-TASp)2PbI4 crystal in Example 2 are used to characterize the emission properties of the materials.

[0027] Figure 8 This is a schematic diagram of the structure of a one-dimensional perovskite (Me-6-TASp)PbI3 crystal in Embodiment 1 of the present invention; in the figure, a, b, and c represent the stacking structure of the chiral perovskite observed along the a-axis, b-axis, and c-axis, respectively.

[0028] Figure 9 This is a schematic diagram of the structure of a two-dimensional perovskite (Me-5-TASp)2PbI4 crystal in Embodiment 2 of the present invention; in the figure, a, b, and c represent the stacking structure of the chiral perovskite observed along the a-axis, b-axis, and c-axis, respectively.

[0029] Figure 10 This is a schematic diagram of the structure of a one-dimensional perovskite (6-TASp)PbI3 crystal in Embodiment 3 of the present invention; in the figure, a, b, and c represent the stacking structure of the chiral perovskite observed along the a-axis, b-axis, and c-axis, respectively.

[0030] Figure 11This is a schematic diagram of the structure of a two-dimensional perovskite (5-TASp)2PbI4 crystal in Embodiment 4 of the present invention; in the figure, a, b, and c represent the stacking structure of the chiral perovskite observed along the a-axis, b-axis, and c-axis, respectively.

[0031] Figure 12 This is a schematic diagram of the structure of a one-dimensional perovskite (Et-6-TASp)PbI3 crystal in Embodiment 5 of the present invention; in the figure, a, b, and c represent the stacking structure of the chiral perovskite observed along the a-axis, b-axis, and c-axis, respectively.

[0032] Figure 13 This is a schematic diagram of the structure of a two-dimensional perovskite (Et-5-TASp)2PbI4 crystal in Embodiment 6 of the present invention; in the figure, a, b, and c represent the stacking structure of the chiral perovskite observed along the a-axis, b-axis, and c-axis, respectively.

[0033] Figure 14 This is the one-dimensional perovskite (Et-6-TASp)PbI3 crystal structure in Example 5 of the present invention; in the figure, a represents Et-6-TASp. + The distance between ligands; b in the figure represents Et-6-TASp + Hydrogen bonding interactions between ligands and inorganic chains; used to analyze the principles of directional synthesis of one-dimensional perovskites.

[0034] Figure 15 This is the two-dimensional perovskite (Et-5-TASp)2PbI4 crystal structure in Example 6 of the present invention; in the figure, a represents Et-5-TASp. + The distance between ligands; b in the figure represents Et-5-TASp + Hydrogen bonding interactions between ligands and inorganic layers; used to analyze the principles of directional synthesis of two-dimensional perovskites.

[0035] Figure 16 This is a summary diagram of the structural parameters of one-dimensional and two-dimensional perovskite crystals in Examples 1 to 6 of the present invention; in the figure, a represents the hydrogen bond interaction between organic ligands and inorganic layers in the one-dimensional and two-dimensional perovskite crystal structures in Examples 1 to 6; in the figure, b represents the distance between ligands in the one-dimensional and two-dimensional perovskite crystal structures in Examples 1 to 6; all are used to demonstrate the consistency of structural features. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of the embodiments of this invention will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0037] In view of the problems existing in the prior art, the present invention is the first to discover that by selecting whether the number of methylene groups connecting S and N in mercaptoamine hydrochloride is 2 or 3, the final dimension of the perovskite can be directly and directionally determined as two-dimensional or one-dimensional, thereby achieving precise control of the perovskite dimension.

[0038] Firstly, inspired by the aforementioned first discovery, this disclosure provides a spirocyclic ammonium salt based on mercaptoamine hydrochloride. By selecting whether the number of methylene groups connecting S and N in the mercaptoamine hydrochloride is 2 or 3, a spirocyclic ammonium salt with the general formula (xn-TASp)·HX is obtained, where x represents H, CH3, or C2H5 at the para position; n is an integer of 5 or 6, representing the number of atoms in the heterocyclic portion of the spirocycle; xn-TASp + This indicates a sulfur-containing spirocyclic ammonium cation formed by the cyclization reaction of the corresponding cyclohexanone or its derivative with 3-mercaptopropylamine or 2-mercaptoethylamine via a thioacetate cyclization reaction; X- in HX represents the paired anion, selected from chloride ions (Cl... - ), bromide ions (Br) - ), iodide ions (I - ), tetrafluoroborate (BF4) - ), hexafluorophosphate (PF6) - ) or p-toluenesulfonate (TsO - ).

[0039] The following uses cyclohexanone as an example, combined with Figure 1 The reaction mechanism of the spirocyclic ammonium salt described in this invention is illustrated below: 3-Mercaptopropylamine hydrochloride or 2-mercaptoethylamine hydrochloride provides a weakly acidic buffer environment, activating the carbonyl group of cyclohexanone. The thiol undergoes nucleophilic addition to the carbonyl group, forming a hemithiol. In the buffer solvent (such as methanol), the solvent molecules act as a proton transfer medium, assisting in the dehydration formation of the first CS bond in the thioacetate. Simultaneously, the amino group may participate in intramolecular nucleophilic attack or stabilize the intermediate, ultimately forming the final ammonium salt with a bicyclic spirocyclic structure through intramolecular cyclization and proton transfer.

[0040] Based on the above reaction mechanism, combined with Figure 2 As shown, the programmed reaction pathway for the spirocyclic ammonium salt provided by this invention is as follows: Cyclohexanone or its derivatives can be cyclized by reacting with 3-mercaptopropylamine hydrochloride or 2-mercaptoethylamine hydrochloride in a buffer solvent via a thioketene cyclization reaction; after the thioketene cyclization reaction is completed, the reaction product is purified to obtain the spirocyclic ammonium salt.

[0041] In specific embodiments, the buffer solvent is anhydrous methanol or anhydrous ethanol, preferably anhydrous methanol. Unlike traditional strong acid catalysis, the buffer solvent (such as methanol) used in this invention plays multiple crucial roles in this improved thioclase reaction, simultaneously acting as a reaction medium, buffer component, proton transfer promoter, and product stabilizer. This innovative buffer system control allows for the taming of reaction kinetics, effectively suppressing byproducts and laying a solid foundation for the synthesis of high-value functional spirocyclic ammonium salts and subsequent high-quality perovskite materials.

[0042] In a specific embodiment, the molar ratio of cyclohexanone or its derivative to 3-mercaptopropylamine hydrochloride or 2-mercaptoethylamine hydrochloride is 1:1; cyclohexanone or its derivative is dissolved and mixed with 3-mercaptopropylamine hydrochloride or 2-mercaptoethylamine hydrochloride in a buffer solvent to obtain a clear solution, wherein the concentration of 3-mercaptopropylamine hydrochloride or 2-mercaptoethylamine hydrochloride in the clear solution is 1 to 1.5 mol / L, preferably 1 mol / L.

[0043] In a specific embodiment, the temperature of the thioketone cyclization reaction is 40–60 °C, preferably 50 °C; the time of the thioketone cyclization reaction is 12–48 h, preferably 48 h.

[0044] In a specific embodiment, the purification process includes vacuum rotary evaporation, filtration, washing, and recrystallization; preferably, the cleaning agent used for washing is diethyl ether; and the solvent used for recrystallization is methanol or ethanol, preferably ethanol.

[0045] Secondly, because the sulfur-containing spirocyclic ammonium cation provided in this disclosure contains 3-mercaptopropylamine or 2-mercaptoethylamine groups, the sulfur-containing spirocyclic ammonium cation can be used as a perovskite ligand to achieve the directional preparation of one-dimensional / two-dimensional perovskite crystals.

[0046] Obviously, based on the spirocyclic ammonium salt of the first aspect, this disclosure can provide one-dimensional / two-dimensional perovskite crystals, wherein the one-dimensional perovskite crystal has the general formula: (x-6-TASp)PbI3, where x-6-TASp represents a spirocyclic amine salt formed by the thioacetal cyclization reaction of cyclohexanone or its derivatives with 3-mercaptopropylamine, and x represents H, CH3, or C2H5 at the para position. The internal structure of this one-dimensional perovskite crystal is [PbI6]. 4- Octahedrons are connected by coplanarity to form a one-dimensional chain structure. Spirocyclic molecules are distributed around the inorganic octahedral chains and are bonded to the inorganic octahedral chains by hydrogen bonds.

[0047] Similarly, a two-dimensional perovskite crystal has the general formula (x-5-TASp)₂PbI₄, where x-5-TASp represents a spirocyclic amine salt formed by the cyclization reaction of cyclohexanone or its derivatives with 2-mercaptoethylamine via a thioacetate cyclization reaction, and x represents H, CH₃, or C₂H₅ at the para position. The internal structure of this two-dimensional perovskite crystal is [PbI₆]. 4- Octahedrons are connected by common points to form a two-dimensional layered structure. Spirocyclic molecules have hydrogen bonding forces between the inorganic octahedral layers and the inorganic octahedral layers.

[0048] The following provides a method for preparing one-dimensional / two-dimensional perovskite crystals according to this disclosure, as detailed below: Spirocyclic ammonium salt and PbO were dissolved using a 57 wt% HI aqueous solution. H3PO2 reducing agent was added to the solution to obtain a crystal precursor solution. The crystal precursor solution was heated to a certain temperature and stirred at that temperature for a certain time. Then, one-dimensional / two-dimensional perovskite crystals were obtained by temperature-controlled crystallization, filtration, washing, and vacuum drying.

[0049] In a specific embodiment, the molar ratio of the spirocyclic ammonium salt to PbO is 2:1, and the concentration of the spirocyclic ammonium salt in the solution is 0.025–0.25 mol / L, with an optimal concentration of 0.1 mol / L.

[0050] In a specific embodiment, the volume ratio of the reducing agent added, V(H3PO2):V(HI), is 1:10. The peak temperature of the programmed cooling is 125 °C, and the cooling rate is 3–5 °C / h, preferably 5 °C / h. The vacuum drying temperature is 40–60 °C, and the drying time is 12–48 h. The preferred temperature is 60 °C, and the preferred drying time is 24 h.

[0051] The following are preferred embodiments provided in this disclosure.

[0052] The instruments and models involved in the test experiments in each embodiment are as follows: Scanning electron microscope (SEM) images were tested using a Regulus 8100 instrument.

[0053] X-ray diffraction (XRD) is performed using a Cu Kα ray source ( λ XRD analysis was performed on a Bruker D8 Advance diffractometer (λ = 1.54056 Å), and the data were obtained in 2... θ Collection range: 3–50 °, scan rate: 10 ° / min.

[0054] The ultraviolet-visible absorption (UV-Vis) spectrum was measured on an Agilent Cary 5000 spectrometer.

[0055] Photoluminescence (PL) spectra were measured on a HORIBA FluoroMax-4 spectrometer.

[0056] Crystallographic data were obtained by collecting single-crystal X-ray diffraction data using a Mo Kα X-ray source on an Apex Duo CCD diffractometer; the structure was resolved using a direct method with the SHELXL-2014 software package.

[0057] The 3-mercaptopropylamine hydrochloride or 2-mercaptoethylamine hydrochloride used in the examples all had a purity higher than 99%. Cyclohexanone, 4-methylcyclohexanone, and 4-ethylcyclohexanone all had a purity higher than 99%.

[0058] Example 1 Example 1 provides the preparation and characterization of one-dimensional perovskite (Me-6-TASp)PbI3 crystals with spirocyclic ligands, as detailed below: 1. Preparation of one-dimensional perovskite (Me-6-TASp)PbI3 crystals (1) Preparation of spirocyclic ammonium salt (Me-6-TASp·HCl) A mixture of 3-mercaptopropylamine hydrochloride (255.3 mg, 2.0 mmol) and 4-methylcyclohexanone (0.24 mL, 2.0 mmol) was dissolved in methanol (2.0 mL). The solution was stirred at a constant temperature of 50 °C for 48 h to form a yellowish-brown suspension. The solvent was then removed by vacuum rotary evaporation to obtain a light yellow powder product. As shown in Table 1, the yield of the spirocyclic ammonium salt Me-6-TASp·HCl reached 78.1%, indicating that the spirocyclic ammonium salt Me-6-TASp·HCl obtained in this invention has a high yield.

[0059] Table 1. Production data for the preparation of spirocyclic ammonium salts via spirocyclic reaction

[0060] (2) Synthesis of one-dimensional perovskite (Me-6-TASp)PbI3 crystals The reaction mixture was prepared in a 5 mL vial: Me-6-TASp·HCl (45.1 mg, 0.2 mmol) and PbO (46 mg, 0.1 mmol) were dissolved in 57 wt% HI (2 mL) and H3PO2 (0.2 mL). After the crystalline precursor solution was prepared, it was placed on a magnetically stirred heating plate and heated to 125 °C over 2 minutes. The mixture was heated (125 °C) with stirring for 1 h, and then slowly cooled to room temperature at a rate of 5 °C / h to obtain a yellow crystalline powder. After washing the crystals with diethyl ether, they were dried under vacuum at 60 °C for 24 h and stored in a glove box. The morphology of the obtained crystals is as follows. Figure 3 a and Figure 4 As shown in 'a', it exhibits a yellow one-dimensional rod-like structure. Unlike the needle-like morphology of the one-dimensional perovskite disclosed in patent CN120967513A, the one-dimensional perovskite prepared in this invention is more transparent and has larger crystals, indicating that the one-dimensional perovskite crystals prepared by the spirocyclic ammonium ligand in Example 1 are of higher quality.

[0061] 2. Quality testing of one-dimensional perovskite (Me-6-TASp)PbI3 crystals The XRD pattern of a one-dimensional perovskite (Me-6-TASp)PbI3 crystal is as follows: Figure 5 As shown in a, in 2 θ Obvious low-dimensional perovskite diffraction peaks appear in the range below 10°. Furthermore, the sharp diffraction peaks and narrow full width at half maximum (FWHM) (<0.1°) of the XRD indicate that the prepared one-dimensional perovskite (Me-6-TASp)PbI3 crystal has excellent crystal quality. Generally, one-dimensional perovskite crystals crystallize rapidly but have poor crystal quality (e.g., CN120967513A). Therefore, the high XRD diffraction intensity and narrow FWHM of the one-dimensional perovskite crystal prepared in Example 1 confirm the reliability of the method of this invention.

[0062] 3. UV-Vis spectroscopy of one-dimensional perovskite (Me-6-TASp)PbI3 crystals The UV-Vis spectrum of a one-dimensional perovskite (Me-6-TASp)PbI3 crystal is as follows: Figure 6 As shown in a, the crystal exhibits a distinct absorption signal in the 300-700 nm range. In particular, in the 350-450 nm range, the one-dimensional perovskite (Me-6-TASp)PbI3 crystal shows the characteristic high-energy absorption edge (375 nm) and self-trapped exciton absorption (405 nm) of low-dimensional perovskite crystals.

[0063] 4. PL spectroscopy of one-dimensional perovskite (Me-6-TASp)PbI3 crystals The PL spectrum of a one-dimensional perovskite (Me-6-TASp)PbI3 crystal is as follows: Figure 7 As shown in Figure a, the crystal exhibits a distinct PL emission peak at 410 nm. The high intensity of the emission peak further indicates high crystal quality and few defects within the crystal. The emission peak has a Stokes shift of approximately 5 nm, indicating a distortion deviation between the crystal structure and the ideal structure.

[0064] 5. Crystallographic data analysis of one-dimensional perovskite (Me-6-TASp)PbI3 crystals The crystallographic data of one-dimensional perovskite (Me-6-TASp)PbI3 crystals are shown in Table 2. The chemical formula of one-dimensional perovskite (Me-6-TASp)PbI3 is C3.10 H 20 NSPbI3, its crystallographic data includes: the crystal belongs to the orthorhombic crystal system. Pnma The space group exhibits mirror symmetry. The unit cell parameters are: a = 8.1316 Å, b = 8.7374 Å, c = 25.0707 Å. The c-axis is significantly longer than the a and b axes, directly supporting the extension of the inorganic chains along the c-axis, forming a one-dimensional structure. The a and b axes are similar but not equidistant, indicating a slight anisotropy in the inter-chain arrangement. The one-dimensional perovskite (Me-6-TASp)PbI3 crystal has three mutually perpendicular crystal axes (…). α =90°, β = 90°, γ = 90°), which indicates that the structure has high symmetry.

[0065] Table 2. Crystallographic data of one-dimensional (Me-6-TASp)PbI3 and two-dimensional (Me-5-TASp)2PbI4 perovskites

[0066] The single-crystal XRD structure of one-dimensional perovskite (Me-6-TASp)PbI3 crystal is as follows: Figure 8 As shown, the interior of the one-dimensional structure contains [PbI6]. 4- The octahedrons are connected by coplanar connections to form a one-dimensional chain structure, spirocyclic amine cation Me-6-TASp. + The molecules are distributed around the inorganic octahedral chains and are bonded to them by hydrogen bonds. Therefore, the prepared (Me-6-TASp)PbI3 crystal has a one-dimensional structure.

[0067] Example 2 Example 2 provides the preparation and characterization of two-dimensional perovskite (Me-5-TASp)2PbI4 crystals with spirocyclic ligands, as detailed below: 1. Preparation of two-dimensional perovskite (Me-5-TASp)2PbI4 crystals (1) Preparation of spirocyclic ammonium salt (Me-5-TASp·HCl) A mixture of 2-mercaptoethylamine hydrochloride (227.2 mg, 2.0 mmol) and 4-methylcyclohexanone (0.24 mL, 2.0 mmol) was dissolved in methanol (2.0 mL). The solution was stirred at a constant temperature of 50 °C for 48 h to form a yellowish-brown suspension. The solvent was then removed by vacuum rotary evaporation to obtain a light yellow powder product. As shown in Table 1, the yield of the spirocyclic ammonium salt Me-5-TASp·HCl reached 80.7%, indicating that the spirocyclic ammonium salt Me-5-TASp·HCl obtained in this invention has a high yield.

[0068] (2) Synthesis of two-dimensional perovskite (Me-5-TASp)2PbI4 crystals The reaction mixture was prepared in a 5 mL vial: Me-5-TASp·HCl (41.5 mg, 0.2 mmol) and PbO (46 mg, 0.1 mmol) were dissolved in 57 wt% HI (2 mL) and H3PO2 (0.2 mL). After the crystal precursor solution was prepared, it was placed on a magnetically stirred heating plate and heated to 125 °C over 2 minutes. The mixture was stirred at 125 °C for 1 h, and then slowly cooled to room temperature at a rate of 5 °C / h to obtain red crystals. The crystals were washed with diethyl ether, dried under vacuum at 60 °C for 24 h, and stored in a glove box. The morphology of the obtained crystals is as follows. Figure 3 b and Figure 4 As shown in b, it exhibits a red, layered structure.

[0069] 2. Quality testing of two-dimensional perovskite (Me-5-TASp)2PbI4 crystals The XRD pattern of a two-dimensional perovskite (Me-5-TASp)2PbI4 crystal is shown below. Figure 5 As shown in b in 2 θ Obvious low-dimensional perovskite diffraction peaks appear in the range below 10°. Furthermore, the sharp diffraction peaks and narrow half-maximum width (<0.1°) of the XRD indicate that the prepared two-dimensional perovskite has good crystallinity.

[0070] 3. UV-Vis spectroscopy of two-dimensional perovskite (Me-5-TASp)2PbI4 crystals The UV-Vis spectrum of a two-dimensional perovskite (Me-5-TASp)2PbI4 crystal is as follows: Figure 6 As shown in b, the crystal exhibits a distinct absorption edge at 550 nm. The two-dimensional perovskite (Me-5-TASp)2PbI4 crystal also shows the characteristic high-energy absorption edge (550 nm) and self-trapped exciton absorption (575 nm) of low-dimensional perovskite crystals.

[0071] 4. PL spectroscopy of two-dimensional perovskite (Me-5-TASp)2PbI4 crystals The PL spectrum of a two-dimensional perovskite (Me-5-TASp)2PbI4 crystal is as follows: Figure 7 As shown in b, the crystal exhibits a bimodal characteristic, with distinct PL double emission peaks at 550 nm and 580 nm. The high intensity of the emission peaks further indicates high crystal quality and few internal defects. The emission peaks show a Stokes shift of approximately 5 nm, suggesting that the organic ligands modulate the crystal structure through lattice distortion.

[0072] 5. Crystallographic data testing of two-dimensional perovskite (Me-5-TASp)2PbI4 crystals Crystallographic data for the two-dimensional perovskite (Me-5-TASp)₂PbI₄ crystal are shown in Table 2. The chemical formula of the two-dimensional perovskite (Me-5-TASp)₂PbI₄ is C₀. 18 H 36 N2S2PbI4, its crystallographic data includes: the crystal belongs to the orthorhombic crystal system. Pnma The space group has the following cell parameters: a = 9.5822 Å, b = 38.648 Å, c = 8.5929 Å. α = 90°, β = 90°, γ = 90°. The b-axis is significantly longer than the a and c-axis, a typical characteristic of two-dimensional perovskites. The direction of the longer b-axis corresponds to the alternating stacking direction of organic and inorganic layers (i.e., the interlayer spacing direction). The a and c-axis roughly correspond to [PbI6]. 4- The extended scale within the octahedral layer plane matches the size of the two-dimensional network formed by connecting octahedrons at common vertices.

[0073] 6. The single-crystal XRD structure of two-dimensional perovskite (Me-5-TASp)₂PbI₄ is shown in Figure 9. The internal structure contains [PbI₆]. 4- The octahedrons are connected at common points to form a two-dimensional layered structure, spirocyclic amine cation Me-5-TASp. + The molecules are distributed between the inorganic octahedral layers and are bonded to the inorganic octahedral chains. Therefore, the prepared (Me-5-TASp)2PbI4 crystal has a two-dimensional structure.

[0074] Example 3 This embodiment provides the preparation and characterization of one-dimensional perovskite (6-TASp)PbI3 crystals with spirocyclic ligands, as detailed below: The preparation method of the one-dimensional perovskite (Me-6-TASp)PbI3 in Example 1 is basically the same, except that 4-methylcyclohexanone in step (1) is replaced with cyclohexanone, and Me-6-TASp·HCl in step (2) is replaced with 6-TASp·HCl. The preparation steps, parameters, and characterization methods are the same as in Example 1, and will not be repeated here. As shown in Table 1, the yield of spirocyclic ammonium salt 6-TASp·HCl reached 82.2%, indicating that the spirocyclic ammonium salt 6-TASp·HCl obtained in this invention has a high yield.

[0075] The single-crystal XRD structure of one-dimensional perovskite (6-TASp)PbI3 crystal is as follows: Figure 10 As shown, the interior of the one-dimensional structure contains [PbI6]. 4-The octahedrons are connected by coplanar connections to form a one-dimensional chain structure, spirocyclic amine cation 6-TASp + The atoms are distributed around the inorganic octahedral chains and are bonded to them by hydrogen bonds. Therefore, the prepared (6-TASp)PbI3 crystal has a one-dimensional structure.

[0076] Example 4 Example 4 provides the preparation and characterization of two-dimensional perovskite (5-TASp)2PbI4 crystals with spirocyclic ligands, as detailed below: The preparation method of the two-dimensional perovskite (Me-5-TASp)2PbI4 in Example 2 is basically the same, except that 4-methylcyclohexanone in step (1) is replaced with cyclohexanone, and Me-5-TASp·HCl in step (2) is replaced with 5-TASp·HCl. The preparation steps, parameters, and characterization methods are the same as in Example 2, and will not be repeated here. As shown in Table 1, the yield of spirocyclic ammonium salt 5-TASp·HCl reached 85.4%, indicating that the spirocyclic ammonium salt 5-TASp·HCl obtained in this invention has a high yield.

[0077] The single-crystal XRD structure of two-dimensional perovskite (5-TASp)2PbI4 is shown below. Figure 11 As shown, the interior of the two-dimensional structure contains [PbI6]. 4- The octahedrons are connected at common points to form a two-dimensional layered structure, spirocyclic amine cation 5-TASp + The atoms are distributed between the inorganic octahedral layers and are bonded to the inorganic octahedral chains. Therefore, the prepared (5-TASp)₂PbI₄ crystal has a two-dimensional structure.

[0078] Example 5 Example 5 provides the preparation and characterization of one-dimensional perovskite (Et-6-TASp)PbI3 crystals with spirocyclic ligands, as detailed below: The preparation method of the one-dimensional perovskite (Me-6-TASp)PbI3 in Example 1 is basically the same, except that 4-methylcyclohexanone in step (1) is replaced with 4-ethylcyclohexanone, and Me-6-TASp·HCl in step (2) is replaced with Et-6-TASp·HCl. The preparation steps, parameters, and characterization methods are the same as in Example 1, and will not be repeated here. As shown in Table 1, the yield of spirocyclic ammonium salt Et-6-TASp·HCl reached 75.9%, indicating that the spirocyclic ammonium salt Et-6-TASp·HCl obtained in this invention has a high yield.

[0079] The single-crystal XRD structure of one-dimensional perovskite (Et-6-TASp)PbI3 crystal is as follows: Figure 12 As shown, the interior of the one-dimensional structure contains [PbI6]. 4-The octahedrons are connected by coplanar connections to form a one-dimensional chain structure, spirocyclic amine cation Et-6-TASp. + The molecules are distributed around the inorganic octahedral chains and are bonded to them by hydrogen bonds. Therefore, the prepared (Et-6-TASp)PbI3 crystal has a one-dimensional structure.

[0080] Example 6 Example 6 provides the preparation and characterization of two-dimensional perovskite (Et-5-TASp)2PbI4 crystals with spirocyclic ligands, as detailed below: The preparation method is basically the same as that of the two-dimensional perovskite (Me-5-TASp)2PbI4 in Example 2, except that 4-methylcyclohexanone in step (1) is replaced with 4-ethylcyclohexanone, and Me-5-TASp·HCl in step (2) is replaced with Et-5-TASp·HCl. The preparation steps, parameters, and characterization methods are the same as those in Example 1, and will not be repeated here. As shown in Table 1, the yield of spirocyclic ammonium salt Et-5-TASp·HCl reached 77.1%, indicating that the spirocyclic ammonium salt Et-5-TASp·HCl obtained in this invention has a high yield.

[0081] The single-crystal XRD structure of two-dimensional perovskite (Et-5-TASp)2PbI4 is as follows: Figure 13 As shown, the interior of the two-dimensional structure contains [PbI6]. 4- The octahedrons are connected at common points to form a two-dimensional layered structure, spirocyclic amine cation Et-5-TASp + The molecules are distributed between the inorganic octahedral layers and are bonded to the inorganic octahedral chains. Therefore, the prepared (Et-5-TASp)2PbI4 crystal has a two-dimensional structure.

[0082] The two types of spirocyclic amine ligands in the above embodiments achieve the directional construction of low-dimensional perovskites (one-dimensional or two-dimensional) by restricting steric hindrance. Here, we will specifically analyze the one-dimensional perovskite (Et-6-TASp)PbI3 and the two-dimensional perovskite (Et-5-TASp)2PbI4 structures of Examples 5 and 6.

[0083] First, the steric hindrance of spirocyclic amine ligands directly alters the linkage mechanism of the inorganic portion. For example... Figure 14 As shown in a, Et-6-TASp + The average spacing between ligands is 6.09 Å, indicating a dense arrangement of ligands within the perovskite lattice. Furthermore, Et-6-TASp... + The ligands exhibit a misaligned, alternating arrangement, significantly compressing the expansion space of the inorganic portion. In contrast, in the two-dimensional perovskite (Et-5-TASp)₂PbI₄ structure, Et-5-TASp… +The average spacing between ligands is 6.59 Å, and the ligands are arranged in an ordered parallel pattern within the lattice. Figure 15 (a) Therefore, Et-6-TASp with large space steric hindrance + The ligands confine the inorganic chains within ligand cages, dominating the formation of one-dimensional perovskites; the less sterically hindered Et-5-TASp + The ligands allow for extension in the planar dimension, which is beneficial for constructing two-dimensional perovskite structures.

[0084] Secondly, such as Figure 14 b and Figure 15 As shown in b, Et-6-TASp + Ligands and Et-5-TASp + The strength of hydrogen bonding interactions between the ligand and the inorganic portion of the structure varies. (Et-5-TASp) + Stronger hydrogen bonding between the ligands and the inorganic layer (2.60 Å) is more conducive to maintaining the two-dimensional layered network, ensuring the stability of the two-dimensional structure after crystallization. Conversely, the shortest hydrogen bond distance in one-dimensional perovskite (Et-6-TASp)PbI3 is 2.84 Å, indicating that Et-5-TASp... + The hydrogen bonding between the ligand and the inorganic chain is weak, and even the presence of a two-dimensional inorganic intermediate state in the synthesis reaction is insufficient to provide stable support. Therefore, it is difficult to form a two-dimensional perovskite, and it ultimately crystallizes stably as a more stable one-dimensional perovskite (Et-6-TASp)PbI3. Furthermore, Figure 16 The structural parameters of all the above embodiments were summarized, and the results are consistent with the one-dimensional and two-dimensional perovskite crystal structure information of Examples 5 and 6, further confirming that the present invention has directional and universal applicability to extended research.

[0085] In summary, this invention prepares one-dimensional perovskite crystals (6-TASp)PbI3, (Me-6-TASp)PbI3, and (Et-6-TASp)PbI3, and two-dimensional perovskite crystals (5-TASp)2PbI4, (Me-5-TASp)2PbI4, and (Et-5-TASp)2PbI4 using a cooling crystallization method. The crystals exhibit excellent quality, clear characteristic absorption signals, and high PL emission intensity. Furthermore, the ligand molecules demonstrate strong scalability for qualitative analysis of both one-dimensional and two-dimensional perovskites, which is beneficial for in-depth exploration of the influence mechanism of exciton emission within low-dimensional perovskites and for designing and preparing more one-dimensional and two-dimensional perovskites with characteristic free exciton luminescence properties.

[0086] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A spirocyclic ammonium salt, characterized in that, Its general formula is: (xn-TASp)·HX; Where x represents the para-position of H, CH3, or C2H5; n is 5 or 6, representing the number of atoms in the heterocyclic portion of the spiroring; xn-TASp + This indicates a spirocyclic ammonium cation formed by the cyclization reaction of cyclohexanone or its derivatives with 3-mercaptopropylamine or 2-mercaptoethylamine via a thioacetate cyclization reaction; X in HX - This indicates the anion that it pairs with.

2. The spirocyclic ammonium salt according to claim 1, characterized in that: The cyclohexanone derivative is 4-methylcyclohexanone or 4-ethylcyclohexanone; and / or... The anion includes Cl. - ,Br - I - BF4 - PF6 - and TsO - .

3. The method for preparing the spirocyclic ammonium salt according to claim 1 or 2, characterized in that, include: 3-Mercaptopropylamine hydrochloride or 2-mercaptoethylamine hydrochloride is dissolved in a buffer solvent with cyclohexanone or its derivative to form a clear solution. The prepared solution is subjected to a thioketane cyclization reaction under sealed and heated conditions. The solution after the reaction is purified to obtain the spirocyclic ammonium salt.

4. The method for preparing spirocyclic ammonium salt according to claim 3, characterized in that: The molar ratio of the cyclohexanone or its derivative to 3-mercaptopropylamine hydrochloride or 2-mercaptoethylamine hydrochloride is 1:1; and / or, The buffer solvent is anhydrous methanol or anhydrous ethanol; and / or, The concentration of 3-mercaptopropylamine hydrochloride or 2-mercaptoethylamine hydrochloride in the clarified solution is 1–1.5 mol / L; and / or, The heating conditions are a temperature of 40–60 °C and a time of 12–48 h; and / or, The purification process includes vacuum rotary evaporation, filtration, washing, and recrystallization.

5. The method for preparing spirocyclic ammonium salt according to claim 4, characterized in that: The buffer solvent is anhydrous methanol; and / or, The concentration of the clarified solution is 1 mol / L; and / or, The heating conditions are a temperature of 50 °C and a time of 48 h; and / or, The cleaning agent used for cleaning is diethyl ether, and the solvent used for recrystallization is methanol or ethanol.

6. A one-dimensional / two-dimensional perovskite crystal, characterized in that: The one-dimensional perovskite crystal has the general formula: (x-6-TASp)PbI3, where x-6-TASp represents a spirocyclic amine salt formed by the cyclization reaction of cyclohexanone or its derivatives with 3-mercaptopropylamine via a thioacetate cyclization reaction, and x represents H, CH3 or C2H5 at the para position. The two-dimensional perovskite crystal has the general formula: (x-5-TASp)2PbI4, where x-5-TASp represents a spirocyclic amine salt formed by the cyclization reaction of cyclohexanone or its derivatives with 2-mercaptoethylamine via a thioacetate cyclization reaction, and x represents H, CH3 or C2H5 at the para position.

7. The method for preparing one-dimensional / two-dimensional perovskite crystals according to claim 6, characterized in that, include: Spirocyclic ammonium salt and PbO were dissolved in HI aqueous solution. H3PO2 was added to the solution to obtain a crystal precursor solution. After heating and stirring the crystal precursor solution, the crystal was further subjected to programmed cooling crystallization, filtration, washing and vacuum drying to obtain one-dimensional / two-dimensional perovskite crystals.

8. The method for preparing one-dimensional / two-dimensional perovskite crystals according to claim 7, characterized in that: Spirocyclic ammonium salt and PbO were dissolved in a 57 wt% HI aqueous solution, wherein the molar ratio of spirocyclic ammonium salt to PbO was 2:1, and the concentration of spirocyclic ammonium salt in the solution was 0.025–0.25 mol / L; and / or, By volume ratio, the H3PO2:HI = 1:10; and / or, The peak temperature of the programmed cooling crystallization is 125 °C, and the cooling rate is 3–5 °C / h; and / or, The vacuum drying temperature is 40–60 °C, and the drying time is 12–48 h.

9. The method for preparing one-dimensional / two-dimensional perovskite crystals according to claim 8, characterized in that: The concentration of the spirocyclic ammonium salt in the solution is 0.1 mol / L; and / or, The cooling rate for the programmed cooling crystallization is 5 °C / h; and / or, The vacuum drying temperature is 60 °C, and the drying time is 24 h.

10. The application of the one-dimensional / two-dimensional perovskite crystal according to claim 6 and the one-dimensional / two-dimensional perovskite crystal prepared by the method according to any one of claims 7 to 9 in optoelectronic devices; The optoelectronic devices include LEDs, lasers, photodetectors, and solar cells.

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