Wave type one-dimensional lead bromide perovskite crystal and preparation method and application thereof

Abstract

The invention discloses a wavy one-dimensional lead bromide perovskite crystal and a preparation method and application thereof. The molecular general formula of the perovskite crystal is (PEA) 2Pb2Br10. H2O (PEA is N-aminoethyl piperazine trivalent cation), in the crystal structure, [PbBr6] octahedrons form wavy inorganic chains, water molecules are limited in wavy pockets of the inorganic chains through hydrogen bond interaction with bromide ions and cation PEA to form a unique hydrogen bond network, the inorganic chains are alternately and vertically stacked, and the molecular weight of the perovskite crystal is increased. The compound has high stability below 387K, shows broadband emission, high quantum yield and excellent photoluminescence performance, and has application prospects in the aspects of solid-state illumination, liquid crystal display and the like. The preparation method is simple, can easily obtain high-quality crystals and films, and is suitable for large-scale preparation.

Description

Technical Field

[0001] The present invention relates to a wavy one-dimensional lead-bromine perovskite crystal and a preparation method and application thereof, and in particular to a wavy one-dimensional lead-bromine perovskite crystal with excellent broadband emission performance and a preparation method and application thereof. Background Art

[0002] In the field of solid-state luminescence, hybrid metal halides can achieve single-component broadband emission through a self-trapped exciton mechanism, making them strong candidates for rare-earth-free solid-state luminescent materials and phosphor mixtures. At the same time, the organic composition, halide and structural size of hybrid metal halides provide additional tunability, which can precisely control the emission color and polarization state, which further enhances their potential in various optoelectronic applications. Studies have shown that compared with classical three-dimensional hybrid metal halides (such as CsPbBr3, CH3NH3PbBr3 and CH3NH3PbCl3), the highly localized charges generated by strong quantum and dielectric confinement effects in low-dimensional hybrid metal halides have higher exciton binding energy and photoluminescence quantum yield (PLQY), making them the preferred structure for developing efficient broadband luminescent materials. However, in the synthesis of one-dimensional materials, large-sized or sterically hindered organic cations are usually selected, and there is a lack of effective synthetic strategies to guide the synthesis of metal halides with one-dimensional structures. Therefore, it is urgent to develop single-component broadband solid-state fluorescent materials with low cost and superior performance and to form effective design strategies.

[0003] US20210071075 discloses a novel low-dimensional hybrid perovskite crystal for efficient white light emission, the molecular formula of which is A a M m X x yH2O, where A is an alkyl-substituted piperazine, M is a metal atom, and X is a halogen. Through research, it was found that the crystal has a ladder-type one-dimensional chain structure composed of corner-sharing and edge-sharing [PbBr6] octahedra, and emits cold white light with a color temperature of 7458K, so its use in warm white toning scenes is limited. Summary of the invention

[0004] Purpose of the invention: The first purpose of the present invention is to provide a wavy one-dimensional lead-bromine perovskite crystal with broadband emission performance, the second purpose is to provide a method for preparing the perovskite crystal, and the third purpose is to provide an application of the perovskite crystal in the field of solid-state display.

[0005] Technical solution: The molecular formula of the wavy one-dimensional lead-bromine perovskite crystal described in the present invention is (PEA)4AgBiBr8·H2O, wherein PEA is an N-aminoethylpiperazine cation; the space group of the crystal is P21 / c, and the PEA cations are arranged alternately upward and downward between adjacent inorganic chains through NH···Br hydrogen bonds formed with the wavy one-dimensional inorganic chains, and the PEA cations and water molecules jointly support the stability of the wavy one-dimensional inorganic chains through hydrogen bond interactions with [PbBr6].

[0006] Preferably, the wavy one-dimensional inorganic chain is formed by [PbBr6] octahedra that share angles, and adjacent inorganic chains in the crystallographic b direction are alternately stacked vertically.

[0007] In the wavy one-dimensional lead bromine perovskite crystal structure described in the present invention, under the synergistic effect of water molecules, PEA cations and water molecules induce the wavy arrangement of [PbBr6] octahedrons in the inorganic chain through strong NH···Br hydrogen bonding interactions, and water molecules are confined in the pockets of the wavy inorganic chain through hydrogen bonds with bromide ions, forming a unique NH···Br and OH···Br hydrogen bonding network, so that the formed wavy one-dimensional lead bromide inorganic chain is alternately stacked vertically in the b direction, promoting the generation of localized polarons in the structure and the enhancement of the photoluminescence effect.

[0008] Preferably, the unit cell parameters of the wavy one-dimensional lead-bromine perovskite crystal are α=103.726(2)°, γ=90.085(2)°, β=103.280(2)°, Z=11,

[0009] Preferably, based on 2θ±0.02°, the wavy one-dimensional lead-bromine perovskite crystal has characteristic diffraction peaks at 10.17°, 12.77°, 13.82°, 16.36°, 20.34°, 27.87°, 30.15°, 32.88°, 37.81°, 42.26° and 45.63°.

[0010] Preferably, the weight loss of the wavy one-dimensional lead-bromine perovskite crystal in the range of 387-410K is 1.2%.

[0011] Preferably, the optical band gap value of the wavy one-dimensional lead bromine perovskite crystal is 3.22 eV.

[0012] Preferably, the wavy one-dimensional lead-bromine perovskite crystal has broadband yellow-white light emission in the spectral range of 400 to 800 nm.

[0013] Further preferably, the optimal half-peak width of the wavy one-dimensional lead-bromine perovskite crystal is 182 nm.

[0014] Preferably, the International Optical Commission chromaticity coordinates of the wavy one-dimensional lead-bromine perovskite crystal are (0.42, 0.47), and the correlated color temperature is 3550K.

[0015] Preferably, the quantum yield of the wavy one-dimensional lead-bromine perovskite crystal is 10.9%.

[0016] Preferably, the fluorescence lifetime of the wavy one-dimensional lead-bromine perovskite crystal is 23.8 ns.

[0017] The method for preparing the wavy one-dimensional lead-bromine perovskite crystal of the present invention comprises the following steps:

[0018] (1) Preparing a precursor solution: dissolving lead acetate trihydrate in hydrobromic acid to obtain a hydrobromic acid solution containing divalent lead ions; dissolving N-aminoethylpiperazine in hydrobromic acid to obtain a hydrobromide solution containing N-aminoethylpiperazine; mixing the two solutions, and then stirring and heating until the solution becomes clear, thereby obtaining a precursor solution;

[0019] (2) Preparing wavy one-dimensional lead-bromine perovskite crystals: cooling the precursor solution obtained in step (1) to crystallize, thereby obtaining the wavy one-dimensional lead-bromine perovskite crystals.

[0020] Wherein, in step (1), the chemical molar ratio of N-aminoethylpiperazine to hydrobromic acid is 1:5, and the heating temperature is 80±2°C; and in step (2), the specific method of cooling and crystallizing is to cool the precursor solution from 353K to 298K at a cooling rate of 2K / day, thereby obtaining the wavy one-dimensional lead-bromine perovskite crystal.

[0021] The wavy one-dimensional lead-bromine perovskite crystal of the present invention is used in the preparation of solid-state fluorescent materials.

[0022] Preferably, the solid-state fluorescent material is obtained by directly grinding the wavy one-dimensional lead-bromine perovskite crystals described in the present invention.

[0023] Preferably, the wavy one-dimensional lead-bromine perovskite crystals described in the present invention are used in the preparation of high-performance solid-state display devices, and are specifically used in advanced optical and optoelectronic technology fields such as laser manufacturing, multiphoton microscopy, communications, terahertz detection, and medical treatment.

[0024] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages:

[0025] The wavy one-dimensional lead-bromine perovskite single crystal designed by the present invention has excellent photoluminescence performance, broadband yellow-white light emission, International Commission on Optics (CIE) chromaticity coordinates of (0.42, 0.47), correlated color temperature (CCT) of 300K, quantum yield (PLQY) of 10.9%, and has good application prospects in the fields of optoelectronic devices such as LEDs and liquid crystal displays. The preparation method is simple, high-quality crystals and films are easily obtained, and the perovskite is suitable for large-scale preparation. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a wavy one-dimensional lead bromine perovskite crystal (PEA) 2Pb2Br 10 ·The asymmetric unit structure of H2O;

[0027] Figure 2 It is a wavy one-dimensional lead bromine perovskite crystal (PEA) 2Pb2Br 10 ·H2O structural stacking diagram;

[0028] Figure 3 It is a wavy one-dimensional lead bromine perovskite crystal (PEA) 2Pb2Br 10 ·X-ray diffraction pattern of H2O;

[0029] Figure 4 It is a wavy one-dimensional lead bromine perovskite crystal (PEA) 2Pb2Br 10 Thermogravimetric analysis of H2O;

[0030] Figure 5 It is a wavy one-dimensional lead bromine perovskite crystal (PEA) 2Pb2Br 10 ·Spectral absorption and optical band gap diagram of H2O;

[0031] Figure 6 It is a wavy one-dimensional lead bromine perovskite crystal (PEA) 2Pb2Br 10 Photoluminescence performance diagram of H2O. DETAILED DESCRIPTION

[0032] The technical solution of the present invention is further described below in conjunction with embodiments.

[0033] The X-ray single crystal diffractometer was a Mini single crystal diffractometer from Rigaku, Japan; the X-ray diffractometer (PXRD) was a Rigaku SmartLab X-ray diffractometer; the thermogravimetric analyzer was an HTG-1 thermogravimetric analyzer from Beijing Hengjiu Experimental Equipment Co., Ltd.; the photoluminescence was measured on an FLS1000 spectrometer; and the emission spectrum of the sample was measured using an nF920 nanosecond flash lamp. The reagents PEA, lead acetate trihydrate, and hydrobromic acid (47%) used in the laboratory were all analytically pure reagents.

[0034] Example 1: Wave-shaped one-dimensional lead-bromine perovskite optical crystal (PEA) 2Pb2Br 10 Preparation and structural characterization of H2O

[0035] 1. Crystal preparation

[0036] First, 10mmol of lead acetate trihydrate was dissolved in 80mL of HBr solution to obtain an HBr aqueous solution containing PbBr2, and then 10mmol of N-aminoethylpiperazine was dissolved in 50mL of HBr solution to obtain an HBr solution containing N-aminoethylpiperazine; wherein the mass concentration of the HBr solution was 47%. The HBr solution containing PbBr2 was mixed with the HBr solution containing N-aminoethylpiperazine, and a clear solution was obtained by continuous stirring at 353K. Crystals were obtained by a solution cooling method, with a cooling rate of 2K / day to 298K, to obtain light yellow-green transparent block crystals with a yield of about 60%.

[0037] 2. Crystal structure characterization

[0038] Select (PEA)2Pb2Br with the size of 0.2×0.2×0.2mm 10 Bulk single crystals of H2O were analyzed on an X-ray single crystal diffractometer using a Rigaku (Mo) X-ray source. The crystal data was collected at 298K. The structure was solved directly using SHELXL-2018 software. All non-hydrogen atoms were anisotropically refined and all hydrogen atoms were added by theoretical hydrogenation. 10 The crystallographic structure characterization data of H2O are shown in Table 1.

[0039] Table 1 Crystal structure characterization data

[0040]

[0041] a R1=Σ||F o |-|F c || / |F o |;

[0042] b wR2=[Σw(F o 2 -F c 2 ) 2 ] / Σw(F o 2 ) 2 ] 1 / 2 ;

[0043] cMaximumandminimumresidualelectrondensity.

[0044] Figure 1 (PEA)2Pb2Br 10 The smallest asymmetric unit of the H2O crystal structure, Figure 2 (PEA)2Pb2Br 10 ·Structure diagram of H2O crystal. Figure 2 In (a), the corner-sharing [PbBr6] octahedra form an inorganic layer, and PEA as a spacer cation is oriented and arranged between the inorganic chains in an alternating upward and downward manner. The octahedra in the inorganic chain are stacked in a wavy manner, and three octahedra form a pocket. The pocket is fixed by water molecules and organic cations PEA through hydrogen bonds with the octahedra to maintain the overall stability of the structure ( Figure 2 (b)). The b-axis of the wavy inorganic chain is stacked alternately and vertically ( Figure 2 (c)).

[0045] 3. Evaluation of crystal phase purity

[0046] Crystal (PEA)2Pb2Br 10 The H2O sample was subjected to X-ray diffractometer (PXRD) to collect diffraction data. The test angle range was 0° to 50°, and the test rate was 20° / min. The XRD spectra of the data obtained by X-ray diffraction were compared with those obtained by room temperature single crystal structure simulation. The obtained crystals were pure phase ( Figure 3 , black is measured data, red is simulated data).

[0047] 4. Evaluation of thermal stability of crystals

[0048] Thermogravimetric analysis of (PEA)2Pb2Br 10 The H2O crystal sample was subjected to temperature stability analysis. It began to lose the crystal water in the unit cell at 387K, and the structure changed ( Figure 4 ).

[0049] Example 2: Wave-shaped one-dimensional lead bromine perovskite crystal (PEA) 2Pb2Br 10 Evaluation of the optical band gap and photoluminescence properties of H2O crystals

[0050] 1. Evaluation of the optical bandgap performance of crystals

[0051] The light absorption performance was tested using UV-visible reflectance spectroscopy and first-principles calculations (DFT). The results are as follows: Figure 5 (a) shown. Figure 5 (b) is (PEA)2Pb2Br 10The semiconductor band gap of the H2O sample calculated from the UV-visible reflectance spectrum and the Kubelka-Munk equation shows an optical band gap of 3.22 eV.

[0052] 2. Evaluation of the photoluminescence performance of crystals

[0053] Using FLS1000 spectrometer to analyze the crystal (PEA)2Pb2Br 10 The H2O sample was tested for photoluminescence, and the results were as follows: Figure 6 shown. Figure 6 The wavy one-dimensional lead bromine perovskite crystal (PEA) prepared in Example 1 is 2Pb2Br 10 Photoluminescence test chart of H2O, where Figure 6 (a) Wave-shaped one-dimensional lead-bromine perovskite crystal (PEA) 2Pb2Br 10 Photoluminescence spectrum of H2O, Figure 6 (b) is the chromaticity coordinate of the International Commission on Optics (CIE), Figure 6 (c) The wave-shaped one-dimensional lead-bromine perovskite crystal (PEA) 2Pb2Br was measured using a standard integrating sphere. 10 Quantum yield graph of H2O samples, Figure 6 (d) Wave-shaped one-dimensional lead-bromine perovskite crystal (PEA) 2Pb2Br 10 ·The lifetime decay curve of H2O photoluminescence. Figure 6 It can be seen that the two-dimensional hybrid perovskite crystal (PEA) 2Pb2Br 10 H2O has broadband emission characteristics, with an emission spectrum ranging from 400 to 800nm ​​and an optimal half-peak width of 182nm. The International Commission on Optics (CIE) chromaticity coordinates are (0.42, 0.47), the correlated color temperature (CCT) is 3550K, the quantum yield (PLQY) is 10.9%, and the fluorescence lifetime is 23.8ns. It has great application prospects in the application fields of optoelectronic devices such as LEDs and liquid crystal displays.

Claims

1. A wavy one-dimensional lead-bromine perovskite crystal, characterized in that: Its molecular formula is (PEA)2Pb2Br 10 ·H2O, wherein PEA is a trivalent N-aminoethylpiperazine cation; the space group of the crystal is P21 / c, and the PEA cations are arranged alternately upward and downward between adjacent inorganic chains through NH···Br hydrogen bonds formed with the wavy one-dimensional inorganic chains, and the PEA cations and water molecules jointly support the stability of the wavy one-dimensional inorganic chains through hydrogen bond interactions with [PbBr6].

2. The wavy one-dimensional lead-bromine perovskite crystal according to claim 1, characterized in that: The wavy one-dimensional inorganic chain is composed of [PbBr6] that share an angle, and adjacent inorganic chains in the crystallographic b direction are alternately stacked vertically.

3. The wavy one-dimensional lead-bromine perovskite crystal according to claim 1, characterized in that: Its unit cell parameters are α=γ=90°, β=96.191(2)°, Z=4, 4. The wavy one-dimensional lead-bromine perovskite crystal according to claim 1, characterized in that: In terms of 2θ±0.02°, it has characteristic diffraction peaks at 10.17°, 12.77°, 13.82°, 16.36°, 20.34°, 27.87°, 30.15°, 32.88°, 37.81°, 42.26° and 45.63°.

5. The wavy one-dimensional lead-bromine perovskite crystal according to claim 1, characterized in that: Its optical band gap value is 3.22 eV.

6. The wavy one-dimensional lead-bromine perovskite crystal according to claim 1, characterized in that: It has broadband yellow-white light emission in the 400-800nm ​​spectral range.

7. The wavy one-dimensional lead-bromine perovskite crystal according to claim 1, characterized in that: It has an International Commission on Optics chromaticity coordinate of (0.42, 0.47) and a correlated color temperature of 3550K.

8. The wavy one-dimensional lead-bromine perovskite crystal according to claim 1, characterized in that: It has a quantum yield of 10.9%.

9. A method for preparing the wavy one-dimensional lead-bromine perovskite crystal according to claim 1, characterized in that: The following steps are involved: (1) Preparing a precursor solution: dissolving lead acetate trihydrate in hydrobromic acid to obtain a hydrobromic acid solution containing divalent lead ions; dissolving N-aminoethylpiperazine in hydrobromic acid to obtain a hydrobromide solution containing N-aminoethylpiperazine; mixing the two solutions, and then stirring and heating until the solution becomes clear, thereby obtaining a precursor solution; (2) Preparing wavy one-dimensional lead-bromine perovskite crystals: cooling the precursor solution obtained in step (1) to crystallize, thereby obtaining the wavy one-dimensional lead-bromine perovskite crystals.

10. Use of the wavy one-dimensional lead-bromine perovskite crystal according to claim 1 in preparing solid-state fluorescent materials.

Images