A Sb 3+ Activated tellurium-based metal chloride red light crystals and methods of preparation

Abstract

This application belongs to the field of luminescent material synthesis technology, specifically relating to an Sb 3+ Activated tellurium-based metal chloride red light crystal and its preparation method. The chemical composition of the tellurium-based metal chloride red light crystal is expressed as: (C 25 H 21 ClP)2TeCl6:xSb 3+ Where x represents Sb 3+ With Te 4+ The molar ratio of Sb is such that 0.05 ≤ x ≤ 0.3. The crystal of this invention produces broadband emission dominated by red light under ultraviolet or blue light excitation, with a wide excitation range and high luminous efficiency; wherein 0.3 Sb 3+ The fluorescence quantum efficiency of the doped crystal can reach 59.9%. This invention employs a method combining room-temperature solution reaction and anti-solvent diffusion crystallization, eliminating the need for high-temperature calcination and complex equipment. The reaction conditions are mild, the operation is simple, the crystallization process is easy to control, and it exhibits good reproducibility. The red light crystal of this invention can be matched with near-ultraviolet or blue LED chips and can be composited with blue and green light-emitting materials to prepare high color rendering warm white LEDs. It can also be applied to displays, fluorescent anti-counterfeiting devices, and optoelectronic devices.

Description

Technical Field

[0001] This application belongs to the field of luminescent material synthesis technology, specifically relating to an Sb 3+ Activated tellurium-based metal chloride red light crystals and their preparation method. Background Technology

[0002] Organic-inorganic hybrid metal halides combine the diverse and easily tunable structures of their organic components with the excellent photoelectric properties of their inorganic components. By altering the metal center, halogen type, and organic cation structure, the crystal structure, band state, and luminescence properties of these materials can be regulated, leading to widespread interest in solid-state lighting, novel displays, photoelectric detection, and fluorescent anti-counterfeiting. Low-dimensional organic-inorganic hybrid metal halides, in particular, often have inorganic luminescent units separated by organic cations, forming relatively independent localized structures with strong quantum confinement effects and exciton-phonon coupling. When photoexcited, the excited-state lattice readily undergoes local distortion and forms self-trapped excitons, resulting in broadband emission, large Stokes shift, and low self-absorption.

[0003] Tellurium-based organic-inorganic hybrid chlorides are an important type of luminescent material among low-dimensional metal halides. 4+ With 5s 2 Lone pair electron configuration, which is similar to Cl - [TeCl6] formed through coordination 2- Octahedral structures exhibit strong structural deformability and readily undergo lattice distortion in the excited state, which is conducive to the formation of self-trapped excitons and radiative recombination. Furthermore, by introducing larger organic cations, adjacent [TeCl6] atoms can be... 2- The octahedral structure spatially separates the inorganic light-emitting units, weakens the interaction between them, enhances the localization of excitons, and can improve the stability of the crystal structure to some extent. Compared with traditional lead-based halides, tellurium chlorides do not contain lead, which gives them an advantage in terms of environmental friendliness, and therefore they are worth further development.

[0004] However, the intrinsic luminescence of existing undoped tellurium chlorides is mainly affected by the matrix band structure and local lattice environment. Excited state energy may be lost through defect trapping, lattice vibration and other nonradiative processes, resulting in low room temperature luminescence efficiency (Reference: Breaking the Zero Dimensional Illusion in Te (IV) Metal HalideHybrids via Electronic Dimensionality Control. The Journal of Physical Chemistry Letters. 2026, 17(3): 761-71.). In addition, the absorption and excitation spectral ranges of some tellurium chlorides are narrow, and the spectral matching degree between them and commonly used near-ultraviolet or blue LED chips is limited, making it difficult to fully utilize the excitation light energy (Reference: Structure and luminescent properties of complex compounds oftellurium (IV) with ammonium bases. Optics and Spectroscopy. 2015, 119(1):54-8.). Furthermore, the emission wavelength, emission bandwidth, and thermal stability of the material are also affected by factors such as crystal structure, local coordination environment, and preparation conditions (Reference: Application of voronoi polyhedra for analysis of electronic dimensionality in emissive halide materials. Journal of the American Chemical Society. 2024, 146(51): 35449.), which limits its practical application in high color rendering lighting and display devices. Summary of the Invention

[0005] To address the above problems, the present invention provides an Sb 3+ Activated tellurium-based metal chloride red light crystal, wherein the chemical composition of the tellurium-based metal chloride red light crystal is expressed as: (C 25 H 21 ClP)2TeCl6:xSb 3+ Where x represents Sb 3 + With Te 4+ The molar ratio is such that 0.05 ≤ x ≤ 0.3.

[0006] Furthermore, tellurium-based metal chloride red light crystals are monoclinic with space group C2 / c.

[0007] Furthermore, tellurium-based metal chloride red light crystals possess a zero-dimensional crystal structure, Sb 3+ and Te 4+ respectively with Cl - Coordination forms isolated [TeCl6] ions. 2- Octahedron and [SbCl6] 3- Octahedral, the [TeCl6] 2- Octahedron and [SbCl6] 3- Octahedrons do not form connections with each other by sharing vertices, edges, or faces, and are composed of organic cations [C 25 H 21 ClP] + Separation.

[0008] This invention constructs Sb 3+ The activated zero-dimensional telluride chloride crystal structure enables synergistic regulation of excitation energy absorption, local and radiative recombination processes: [TeCl6] is isolated from each other. 2- Octahedron and [SbCl6] 3- Octahedral bodies are surrounded by large organic cations [C 25 H 21 ClP] + Sufficient separation confines electrons and holes within independent inorganic octahedrons, reducing the migration of excitation energy within the lattice and its probability of being trapped by defects, which is beneficial for the formation of stable self-trapped excitons; Te 4+ and Sb 3+ All have 5s 2 The lone pair electron configuration can induce strong local lattice relaxation in the excited state, resulting in broadband red light emission. Sb 3+ The introduction of [SbCl6] also creates new localized luminescent centers and excitation levels in the tellurium lattice, enhancing the material's absorption of near-ultraviolet light and allowing some of the excitation energy to pass through the [SbCl6] lattice. 3- The self-trapped excitons in the octahedron undergo efficient radiative recombination, thereby broadening the excitation spectrum, increasing the number of effective luminescent centers, and suppressing non-radiative energy loss. Simultaneously, the zero-dimensional ordered structure and the spatial isolation effect of the organic cations reduce the interaction between luminescent centers and concentration quenching. Therefore, this crystal can achieve high luminescence efficiency, a wide emission range, and good stability of red light emission under ultraviolet or blue light excitation, thus solving the problems of narrow excitation range, insufficient luminescence efficiency, and poor matching with practical light sources found in existing tellurium chlorides.

[0009] Furthermore, tellurium-based metal chloride red light crystals exhibit broadband emission, primarily red light emission, under ultraviolet or blue light excitation, with the main emission peak located at 626-636 nm.

[0010] On the other hand, the present invention provides an Sb 3+ The preparation method of activated tellurium-based metal chloride red light crystals includes the following steps: Step 1: Weigh tellurium dioxide and antimony trichloride according to the target doping ratio, add tellurium dioxide and antimony trichloride to hydrochloric acid to react, and obtain a yellow clear mixed hydrochloric acid solution; Step 2: Add (2-chlorobenzyl)triphenylphosphonium chloride to the mixed hydrochloric acid solution and react at room temperature. After the reaction is complete, centrifuge to obtain a yellow powder. Step 3: Vacuum dry the yellow powder, then dissolve the dried yellow powder in acetonitrile, and filter the resulting solution to obtain a clear yellow precursor solution. Step 4: Place the yellow precursor solution in the first container, and then place the first container in the second container containing the antisolvent. The liquid level of the antisolvent should be lower than the opening of the first container. Seal the second container and let it stand to allow the antisolvent vapor to diffuse into the yellow precursor solution until crystals precipitate. Step 5: Collect the precipitated crystals and wash them to obtain the Sb. 3+ Activated tellurium-based metal chloride red light crystal.

[0011] The preparation method of this invention achieves Sb through a process of chlorine coordination reaction, organic cation assembly, precursor purification, and slow diffusion crystallization in an antisolvent. 3+ Controllable preparation of uniform doping and zero-dimensional crystal structures: First, tellurium dioxide and antimony trichloride are converted into Te-containing crystals in a strongly acidic, high-chloride-ion environment provided by hydrochloric acid. 4+ and Sb 3+ The addition of chlorine coordination units allows for uniform mixing of the two at the molecular scale according to a target ratio. Upon addition of (2-chlorobenzyl)triphenylphosphonium chloride, the organic phosphonium cation and the inorganic chlorine coordination anion undergo electrostatic bonding and structural assembly, forming a solid precursor containing Te, Sb, and organic cations. Centrifugation and vacuum drying reduce the interference of residual hydrochloric acid, moisture, and soluble impurities on subsequent crystallization. The precursor is then dissolved in acetonitrile and filtered to obtain a clear precursor solution with homogeneous composition and few impurities and suspended particles. During sealed standing, the antisolvent vapor slowly diffuses into the acetonitrile solution, gradually reducing the solubility of the precursor and allowing the solution to reach supersaturation at a more gradual rate. This reduces instantaneous nucleation and amorphous precipitation, promoting the orderly arrangement of ions according to the crystal lattice structure and allowing Sb to... 3+ It enters the tellurium chloride lattice in a dispersed state, forming isolated [TeCl6] crystals. 2- and [SbCl6] 3- Octahedral; finally, by washing, residual reactants and impurities on the crystal surface are removed, thereby obtaining Sb with complete crystal structure, uniform composition, few defects, and stable luminescence properties.3+ Activate tellurium-based metal chloride red light crystals.

[0012] Furthermore, in step 1, the molar ratio of antimony trichloride to tellurium dioxide is x:1; in step 2, the ratio of the total molar amount of tellurium dioxide and antimony trichloride to the molar amount of (2-chlorobenzyl)triphenylphosphonium chloride is 1:2.

[0013] Furthermore, in step 1, the reaction time of tellurium dioxide and antimony trichloride in hydrochloric acid is 0.5-1 h; in step 2, the reaction time after adding the (2-chlorobenzyl)triphenylphosphonium chloride is 3-5 h.

[0014] Furthermore, in step 3, the vacuum drying temperature of the yellow powder is 50°C, and the filtration is performed using a needle filter with a pore size of 0.45 μm.

[0015] Furthermore, in step 4, the second container is left to stand in a light-protected environment at 15-30°C for more than 3 days.

[0016] Furthermore, the antisolvent in step 4 is selected from one or more of diethyl ether, acetone, dichloromethane, acetic acid, and ethyl acetate; the solvent used to wash the crystals in step 5 is selected from one or more of diethyl ether, acetone, dichloromethane, acetic acid, and ethyl acetate.

[0017] The beneficial effects of this invention are: (1) The crystal of the present invention produces broadband emission dominated by red light under ultraviolet or blue light excitation, with a wide excitation range and high luminous efficiency; wherein 0.3 Sb 3+ The fluorescence quantum efficiency of the doped crystal can reach 59.9%.

[0018] (2) The zero-dimensional crystal structure and the spatial isolation effect of organic cations in this invention are conducive to maintaining the structural stability of inorganic light-emitting units. The resulting crystals are not prone to moisture absorption, and the luminescence intensity and spectrum do not change significantly after being placed in the air for a week.

[0019] (3) The present invention adopts a method combining room temperature solution reaction and antisolvent diffusion crystallization, which does not require high temperature calcination and complex equipment. The reaction conditions are mild, the operation is simple, the crystallization process is easy to control, and it has good repeatability.

[0020] (4) The red light crystal of the present invention can be matched with near-ultraviolet or blue light LED chips, and can be combined with blue and green light-emitting materials to prepare high color rendering warm white light LEDs. It can also be applied to displays, fluorescent anti-counterfeiting and optoelectronic devices.

[0021] In summary, the present invention has good application prospects in the field of luminescent material synthesis and application technology. Attached Figure Description

[0022] Figure 1 For (C) 25 H 21 PCl)2TeCl6: 0.3 Sb 3+ Single crystal structure diagram; Figure 2 For (C) 25 H 21 PCl)2TeCl6: x Sb 3+ X-ray diffraction pattern of (x = 0, 0.05, 0.1, 0.15, 0.2, 0.25, 0.3); Figure 3 For (C) 25 H 21 PCl)2TeCl6: 0.3 Sb 3+ Scanning electron microscope image of a single crystal; Figure 4 For (C) 25 H 21 PCl)2TeCl6: 0.3 Sb 3+ Mapping diagram of a single crystal; Figure 5 For (C) 25 H 21 PCl)2TeCl6: x Sb 3+ (x = 0, 0.05, 0.1, 0.15, 0.2, 0.25, 0.3) Excitation spectrum at room temperature (monitoring wavelength 626 nm); Figure 6 For (C) 25 H 21 PCl)2TeCl6: x Sb 3+ (x = 0, 0.05, 0.1, 0.15, 0.2, 0.25, 0.3) Emission spectrum at room temperature (excitation wavelength 363 nm); Figure 7 For (C) 25 H 21 PCl)2TeCl6: x Sb 3+ (x = 0, 0.05, 0.1, 0.15, 0.2, 0.25, 0.3) Emission spectrum at room temperature (excitation wavelength 421 nm); Figure 8 For the middle (C) 25 H 21 PCl)2TeCl6: 0.3 Sb 3+ The emission spectrum of a single crystal at room temperature depends on the excitation wavelength; Figure 9 For (C)25 H 21 PCl)2TeCl6: 0.3 Sb 3+ Single-crystal PLQY (excitation wavelength 363 nm, monitoring wavelength 626 nm); inset is a magnified view of wavelengths from 500 nm to 800 nm; Figure 10 For (C) 25 H 21 PCl)2TeCl6: 0.3 Sb 3+ FWHM 2 Fitting curve with 2kT; Figure 11 To be excited by a current of 40 mA (C 25 H 21 PCl)2TeCl6: 0.3 Sb 3+ Electroluminescence spectrum of a single crystal. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided with reference to the accompanying drawings and embodiments.

[0024] Example 1

[0025] At room temperature, 0.0798 g of tellurium dioxide and 0.0342 g of antimony trichloride were weighed and mixed with 5 mL of hydrochloric acid, and reacted at room temperature for 0.5 h to obtain a clear yellow mixed hydrochloric acid solution. 0.4233 g of (2-chlorobenzyl)triphenylphosphonium chloride was added to the above mixed solution, followed by 10 mL of hydrochloric acid, and the reaction was carried out at room temperature for 4 h. After the reaction was complete, centrifugation was performed to obtain a yellow powder.

[0026] The powder was dried in a vacuum drying oven at 50°C. 0.0348 g of the dried yellow powder was weighed and acetonitrile was added dropwise until the yellow powder was completely dissolved. The resulting solution was then filtered through a 0.45 µm syringe filter to obtain a clear yellow precursor solution.

[0027] Under air conditions, the yellow precursor solution was added to a small glass bottle until it was 1 / 3 full. The small glass bottle was sealed with plastic wrap, and three vent holes were punched in the plastic wrap. The small glass bottle containing the precursor solution was placed in a large beaker containing ether, with the ether level below the mouth of the small glass bottle. The large beaker was sealed and placed in a dark room at room temperature, allowing the ether vapor to slowly diffuse into the yellow precursor solution. After 4 days, the yellow color of the solution faded, and crystals precipitated. The precipitated crystals were collected, and the resulting crystals were washed with ether to obtain (C). 25 H 21 PCl)2TeCl6: 0.3Sb 3+Tellurium-based metal chloride luminescent crystal.

[0028] Following the above method, by changing the feed ratio of tellurium trichloride to tellurium dioxide, (C) were prepared respectively. 25 H 21 PCl)2TeCl6: xSb 3+ Crystals, where x are 0, 0.05, 0.10, 0.15, 0.20, 0.25 and 0.30 respectively.

[0029] like Figure 1 As shown, (C) 25 H 21 PCl)2TeCl6: 0.3Sb 3+ The crystal has a zero-dimensional crystal structure, belonging to the monoclinic crystal system with space group C2 / c. In this crystal structure, Te... 4+ and Sb 3+ The coordination numbers of all three are 6, respectively with Cl - [TeCl6] is formed. 2- Octahedron and [SbCl6] 3- Octahedron. [TeCl6] 2- Octahedron and [SbCl6] 3- The octahedrons do not form connections with each other by sharing vertices, edges, or faces; instead, they are distributed as isolated "islands," separated by (2-chlorobenzyl)triphenylphosphonium cations. Organic cations [C 25 H 21 ClP] + It not only plays a role in charge balance, but also firmly confines excitons (electron-hole pairs) inside a single octahedron, forming a self-trapped exciton (STE).

[0030] (C 25 H 21 The cell parameters of PCl)2TeCl6 single crystals are shown in the table below.

[0031]

[0032] Figure 2 For (C) 25 H 21 PCl)2TeCl6: x Sb 3+ The XRD diffraction pattern of the single crystal (x = 0-0.3) is consistent with the results of the single crystal test. This indicates that Sb 3+ The introduction of [the substance] did not disrupt or alter the original crystal structure of the matrix. The crystal maintained its original crystal system, space group, and atomic arrangement, without undergoing a phase transition. No impurities were generated in the system, maintaining a high phase purity. "Simulated" refers to the single-crystal test results of the sample.

[0033] Figure 3 For (C) 25 H 21 PCl)2TeCl6: 0.3 Sb 3+ Electron micrograph of the crystal. The crystal appears as a blocky structure with smooth crystal faces and sharp edges, indicating excellent crystallinity. This further demonstrates that Sb... 3+ The introduction of [the substance] did not damage or change the original crystal structure of the matrix.

[0034] Figure 4 For (C) 25 H 21 PCl)2TeCl6: 0.3 Sb 3+ Elemental plane scan of a crystal. (From...) Figure 4 It was found that Te, P, Cl, C, and Sb elements were detected in the crystal, while no other impurity elements were observed. Furthermore, the elements exhibited a highly uniform microscopic distribution, without obvious aggregation points (bright spots) or grain boundary enrichment. This indicates that Sb... 3+ It has successfully entered the main lattice. This highly uniform composition distribution helps to suppress local stress concentration and performance quenching, laying the foundation for the stable optical properties of the crystal through its microstructure.

[0035] Figure 5 , Figure 6 and Figure 7 The images show the excitation spectra (monitoring wavelength 626 nm) and emission spectra (excitation wavelengths 363 nm and 421 nm) of the sample at different gradients at room temperature. The excitation spectrum of the doped sample is significantly broadened, and new excitation peaks appear at 285 nm and 363 nm, corresponding to Sb, respectively. 3+ Ionic 1 S0→ 1 P1 and 1 S0→ 3 P1 level transition. Correspondingly, under 363 nm light excitation, with Sb... 3+ With increasing concentration, the number of luminescent centers increases, and the emission intensity increases linearly. Under 421 nm light excitation, an emission peak with an unchanged position appears. The emission spectrum at this point is mainly composed of Te... 4+ Broadband emission of trapped excitons dominates. With Sb 3+ The emission peak showed little change with increasing concentration, indicating that Sb 3+ It merely physically replaced part of the position; it did not annihilate Te by stealing energy. 4+ .

[0036] Figure 8 For (C) 25 H 21 PCl)2TeCl6: 0.3Sb 3+The emission spectrum at room temperature is excitation-dependent. The position of the emission spectrum changes under different excitation wavelengths; the emission peak monitored in the 380 nm-440 nm range is located at 636 nm, which is consistent with (C 25 H 21 The intrinsic emission of PCl)2TeCl6 is consistent with that of Te, and the emission spectrum at this time is mainly composed of Te 4+ Broadband emission from self-trapped excitons (STEs) dominates. The emission peak monitored in the 300 nm-360 nm range is located at 626 nm, where the emission spectrum is mainly composed of Sb. 3+ The self-trapped exciton broadband emission is dominant. Therefore, it can be concluded that this crystal can form broadband emission dominated by red light under different excitation wavelengths.

[0037] Figure 9 For (C) 25 H 21 PCl)2TeCl6: 0.3 Sb 3+ PLQY measured in a single crystal at an excitation wavelength of 363 nm and a monitoring wavelength of 626 nm. (C) 25 H 21 PCl)2TeCl6: 0.3 Sb 3+ The PLQY (59.9%) of Sb was significantly higher than that of other previously reported tellurium chlorides (Biswas, A.; Bakthavatsalam, R.; Bahadur, V.; Biswas, C.; Mali, BP; Raavi, SSK; Gonnade, RG; Kundu, J. Lead-free zero dimensionaltellurium(iv) chloride-organic hybrid with strong room temperature emission as a luminescent material. J. Mater. Chem. C 2021, 9 (12), 4351-4358.). This is a very ideal and typical "activator-enhanced luminescence" phenomenon. The self-trapped excitons (STEs) of tellurium chlorides may encounter strong thermal quenching or defect trapping in the excited state, or their radiation rate may be slow due to parity forbidden conditions, resulting in a large number of excitons annihilating through non-radiative pathways. Therefore, the PLQY of pure tellurium chlorides is low. 3+ Occupied local sites ([SbCl6)) 3- The polyhedron forms a very deep self-trapped state, with a high intersection point between its excited potential energy surface and the ground potential energy surface. This means that Sb 3+The probability of a self-trapped exciton overcoming the thermal activation energy and undergoing nonradiative relaxation is extremely low. Once it is directly excited, almost all excitons will release photons through radiative recombination, exhibiting extremely high radiative efficiency, thereby increasing the overall PLQY.

[0038] Figure 10 For (C) 25 H 21 PCl)2TeCl6: 0.3 Sb 3+ FWHM 2 The curve fitted to 2kT. (C) 25 H 21 PCl)2TeCl6:0.3 Sb 3+ The fitted Huang Kun factor S was 11.76, which is smaller than other previously reported tellurium chlorides (Yun, X.; Nie, J.; Hu, H.; Zhong, H.; Xu, D.; Shi, Y.; Li, H. Zero-Dimensional Tellurium-Based Organic-Inorganic Hybrid Halide Single Crystal with Yellow-Orange Emission from Self-Trapped Excitons. Nanomaterials 2023, 14 (1), 46.). At room temperature (300 K) or even higher, the thermal energy provided by lattice phonons is far from sufficient for excitons to overcome this high energy barrier. Excitons cannot undergo nonradiative relaxation at the crossover point and can only emit photons in the form of radiative recombination. Therefore, the (C) with a smaller Huang Kun factor... 25 H 21 PCl)2TeCl6: 0.3 Sb 3+ It is generally less prone to severe thermal quenching and has superior luminescent thermal stability.

[0039] Figure 11 The figure shows the excitation current of 40 mA, (C) 25 H 21 PCl)2TeCl6: 0.3 Sb 3+ , Commercial β-SiAlON: Eu 2+ Green phosphors and commercial BAM: Eu 2+The electroluminescence spectrum of a warm white LED device made with blue phosphor and an ultraviolet LED chip (λ= 365 nm). This white LED device has excellent photoelectric parameters, including a color temperature of 3832 K and a color rendering index (CRI) of 90.1. A color temperature of around 3800 K falls within the transition region from warm white to natural white. This color temperature is close to natural sunlight one hour after dawn or dusk, avoiding the glaring coldness and high blue light hazards of cool white light (>5000 K) and the excessive drowsiness caused by extremely warm light (<2700 K). It is ideal for long-term indoor work and living lighting. A CRI greater than 90 is defined by the International Commission on Illumination (CIE) as "the highest color rendering level." This means that objects illuminated by this LED light will display colors almost identically to those seen under natural sunlight.

[0040] The samples prepared by this invention, when placed in air for one week, showed no significant changes in luminescence intensity and spectrum, demonstrating the high chemical stability of the samples prepared by this invention. The high chemical stability of the samples prepared by this invention is due to their stable chemical properties and low hygroscopicity.

[0041] Example 2

[0042] This embodiment is basically the same as Example 1, except that acetonitrile in Example 1 is replaced with acetone in the preparation of the yellow precursor solution, while the amounts of other raw materials, reaction conditions, and crystallization conditions remain unchanged. Experimental results show that using acetone as a solvent can also obtain (C 25 H 21 PCl)2TeCl6: 0.3 Sb 3+ The resulting crystals are luminescent, but the crystals are smaller in size and their morphology is not as regular as when acetonitrile is used as a solvent.

[0043] Example 3

[0044] This embodiment is basically the same as Example 1, except that in preparing the yellow precursor solution, acetonitrile in Example 1 is replaced with N,N-dimethylformamide, while the amounts of other raw materials, reaction conditions, and crystallization conditions remain unchanged. Experimental results show that using N,N-dimethylformamide as a solvent can obtain (C 25 H 21 PCl)2TeCl6: 30% Sb 3+ It produces luminescent crystals, but the crystal growth rate is slow, requiring nearly half a month of rest to obtain the crystals.

[0045] Example 4

[0046] This embodiment is basically the same as Example 1, except that acetonitrile in Example 1 was replaced with dichloromethane in the preparation of the yellow precursor solution, while the amounts of other raw materials, reaction conditions, and crystallization conditions remained unchanged. Experimental results show that using dichloromethane as a solvent failed to obtain a completely morphologically intact (C... 25 H 21 PCl)2TeCl6: 30% Sb 3+ The crystals are obtained, and the resulting products are mainly in powder form.

[0047] As can be seen from Examples 1-4, acetonitrile, acetone, and N,N-dimethylformamide can all be used to dissolve precursors and grow crystals under certain conditions. Among them, acetonitrile, when used as a solvent, results in faster crystal growth, larger crystal size, and more regular morphology, making it the preferred solvent. Dichloromethane is not conducive to the formation of crystals with complete morphology.

[0048] In summary, this invention introduces Sb into zero-dimensional tellurium-based metal chloride crystals. 3+ A luminescent crystal exhibiting broadband red light emission under ultraviolet or blue light excitation was obtained, effectively broadening the excitation range and improving luminous efficiency. The preferred crystal achieved a fluorescence quantum efficiency of 59.9%. The obtained crystal exhibited good crystallinity and uniform component distribution, and its luminescent performance remained essentially stable after being placed in air for one week. Furthermore, this invention employs a preparation method combining room-temperature solution reaction and anti-solvent diffusion crystallization, which is mild, simple to operate, and requires no high-temperature calcination or complex equipment, demonstrating good repeatability and ease of implementation. This red light crystal can be composited with near-ultraviolet LED chips and blue and green luminescent materials to prepare high color rendering warm white LED devices, showing good practical value and application prospects in fields such as solid-state lighting, novel displays, and fluorescent anti-counterfeiting.

[0049] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A type of Sb 3+ The activated tellurium-based metal chloride red light crystal is characterized by: The chemical composition of the tellurium-based metal chloride red light crystal is expressed as: (C 25 H 21 ClP)2TeCl6:xSb 3+ Where x represents Sb 3+ With Te 4+ The molar ratio is such that 0.05 ≤ x ≤ 0.

3.

2. The Sb as described in claim 1 3+ The activated tellurium-based metal chloride red light crystal is characterized by: The tellurium-based metal chloride red light crystal is a monoclinic crystal with space group C2 / c.

3. The Sb as described in claim 2 3+ The activated tellurium-based metal chloride red light crystal is characterized by: The tellurium-based metal chloride red light crystal has a zero-dimensional crystal structure, Sb 3+ and Te 4+ respectively with Cl - Coordination forms isolated [TeCl6] ions. 2- Octahedron and [SbCl6] 3- Octahedral, the [TeCl6] 2- Octahedron and [SbCl6] 3- Octahedrons do not form connections with each other by sharing vertices, edges, or faces, and are composed of organic cations [C 25 H 21 ClP] + Separation.

4. The Sb as described in claim 3 3+ The activated tellurium-based metal chloride red light crystal is characterized by: The tellurium-based metal chloride red light crystal produces broadband emission, mainly red light emission, under ultraviolet or blue light excitation, with its main emission peak located at 626-636 nm.

5. The Sb as described in claim 1 3+ A method for preparing activated tellurium-based metal chloride red light crystals, characterized in that, Includes the following steps: Step 1: Weigh tellurium dioxide and antimony trichloride according to the target doping ratio, add the tellurium dioxide and antimony trichloride to hydrochloric acid to react, and obtain a yellow and clear mixed hydrochloric acid solution; Step 2: Add (2-chlorobenzyl)triphenylphosphonium chloride to the mixed hydrochloric acid solution and react at room temperature. After the reaction is complete, centrifuge to obtain a yellow powder. Step 3: Vacuum dry the yellow powder, then dissolve the dried yellow powder in acetonitrile, and filter the resulting solution to obtain a clear yellow precursor solution; Step 4: Place the yellow precursor solution in a first container, then place the first container in a second container containing an antisolvent, with the antisolvent level below the opening of the first container. Seal the second container and let it stand, allowing the antisolvent vapor to diffuse into the yellow precursor solution until crystals precipitate. Step 5: Collect the precipitated crystals and wash them to obtain the Sb3+ activated tellurium-based metal chloride red light crystals.

6. The Sb as described in claim 5 3+ A method for preparing activated tellurium-based metal chloride red light crystals, characterized in that: In step 1, the molar ratio of antimony trichloride to tellurium dioxide is x:1; in step 2, the ratio of the total molar amount of tellurium dioxide and antimony trichloride to the molar amount of (2-chlorobenzyl)triphenylphosphonium chloride is 1:

2.

7. The Sb as described in claim 6 3+ A method for preparing activated tellurium-based metal chloride red light crystals, characterized in that: In step 1, the reaction time of tellurium dioxide and antimony trichloride in hydrochloric acid is 0.5-1 h; in step 2, the reaction time after adding (2-chlorobenzyl)triphenylphosphonium chloride is 3-5 h.

8. The Sb as described in claim 7 3+ A method for preparing activated tellurium-based metal chloride red light crystals, characterized in that: In step 3, the vacuum drying temperature of the yellow powder is 50°C, and the filtration is performed using a needle filter with a pore size of 0.45 μm.

9. The Sb as described in claim 8 3+ A method for preparing activated tellurium-based metal chloride red light crystals, characterized in that: In step 4, the second container is left to stand in a light-protected environment at 15-30°C for more than 3 days.

10. The Sb as described in claim 9 3+ A method for preparing activated tellurium-based metal chloride red light crystals, characterized in that: The antisolvent in step 4 is selected from one or more of diethyl ether, acetone, dichloromethane, acetic acid, and ethyl acetate; the solvent used to wash the crystals in step 5 is selected from one or more of diethyl ether, acetone, dichloromethane, acetic acid, and ethyl acetate.

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