Lanthanide ion co-doped double perovskite nanocrystal and preparation method and application thereof

Abstract

The invention is applicable to the technical field of near-infrared luminescent materials, and provides lanthanide ion co-doped double perovskite nanocrystals and a preparation method and application thereof, and the preparation method comprises the following steps: taking cesium acetate, sodium acetate, terbium acetate, antimony acetate and lanthanide ion acetate containing Sm < 3 + >, Nd < 3 + > and Er < 3 + > according to a specific raw material ratio, additionally taking oleic acid and oleylamine, and adding the taken materials and octadecene into a reaction container; vacuumizing the container, filling nitrogen for gas washing, heating to a preset temperature, continuously vacuumizing, and stirring until the solution is clear; and heating the solution to 180 DEG C in an inert atmosphere, injecting trimethylchlorosilane, reacting for a preset time, rapidly cooling, centrifuging, dispersing the solvent, and drying to obtain the lanthanide ion co-doped double perovskite nanocrystal. The lead-free halogen double perovskite matrix has the advantages of low phonon energy, high stability and no toxicity, and can provide an ideal coordination field; after the three lanthanide ions are co-doped, the infrared emission spectrum of the nanocrystalline covers 850-1650nm, and the luminous efficiency is up to 70%.

Description

Technical Field

[0001] This application belongs to the field of near-infrared luminescent materials technology, and particularly relates to a Cs2NaTbCl6:xSb 3+ Colloidal nanocrystals, lanthanide ion co-doped double perovskite nanocrystals, their preparation methods and applications. Background Technology

[0002] Wide-band NIR light sources have shown great application potential in fields such as optical communication, night vision, food analysis, health monitoring, bioimaging, and biosensing. Compared with traditional narrow-band emission, broadband emission can provide richer spectral information, thereby achieving higher recognition accuracy and signal-to-noise ratio. However, traditional near-infrared light sources, such as halogen tungsten filament lamps, suffer from drawbacks such as large size, low luminous efficiency, short lifespan, and significant thermal effects. Therefore, the preparation of efficient and stable broadband near-infrared luminescent materials remains a challenge in the current research field.

[0003] Currently, in the research of broadband near-infrared luminescent materials, traditional near-infrared materials such as iron- and chromium-doped oxides or fluorides typically suffer from drawbacks such as high preparation temperatures, difficulty in solution processing, and often low luminescence efficiency. While lead-based perovskites possess excellent luminescence properties and tunability, the toxicity of lead limits their application in biomedicine and other fields, posing serious environmental and safety concerns. Among reported near-infrared luminescent materials, trivalent lanthanide ion-doped perovskites have attracted particular attention due to their stability, non-toxicity, and rich infrared energy levels. Despite these advantages, rare-earth ion-doped perovskites are mostly limited to narrowband infrared emission. Furthermore, the inherent parity-forbidden ff transitions of lanthanides and the easy coupling between lattice vibrations and NIR transitions leading to luminescence quenching result in generally low quantum efficiencies in near-infrared emission. Traditional single lanthanide ion doping typically only produces narrowband, specific wavelength near-infrared light. This narrowband luminescence is useful in certain specific applications (such as lasers), but it cannot meet the needs of applications requiring broadband light sources, such as night vision illumination and biological tissue imaging. Therefore, the preparation of highly efficient lanthanide rare earth ion-doped broadband near-infrared luminescent materials remains a bottleneck that urgently needs to be overcome. Summary of the Invention

[0004] The purpose of this application is to provide a method for preparing double perovskite nanocrystals co-doped with multiple lanthanide ions, aiming to solve the problems of low luminescence efficiency, narrow spectrum, high toxicity, and high preparation difficulty in existing near-infrared luminescent materials, so as to achieve efficient, stable, and non-toxic broadband near-infrared luminescence and promote the practical application of lead-free perovskite materials in the field of near-infrared optoelectronics.

[0005] This application provides a Cs2NaTbCl6:xSb 3+ Methods for preparing colloidal nanocrystals include: Weigh out acetate raw materials containing cesium acetate, sodium acetate, terbium acetate and antimony acetate according to the molar ratio of cesium acetate: sodium acetate: (terbium acetate + antimony acetate) = 13:9:9, wherein the doping ratio of antimony acetate is 2%~8%; and prepare oleic acid and oleylamine according to the volume ratio of oleic acid: oleylamine = 4:1, mix them with octadecene and add them to the reaction vessel. The reaction vessel containing the raw materials is evacuated and purged with nitrogen. Then the temperature is raised and maintained at the preset temperature while the vacuum is continuously evacuated, and the solution is stirred until it is clear and transparent. Under an inert atmosphere, the solution was heated to 160-200°C, trimethylchlorosilane was injected, and after a preset reaction time, it was rapidly cooled. Following centrifugation, solvent dispersion, and drying, Cs₂NaTbCl₆:xSb was obtained. 3+ Colloidal nanocrystals.

[0006] This application also provides a Cs2NaTbCl6:xSb embodiment. 3+ Colloidal nanocrystals, namely Cs2NaTbCl6:xSb 3+ Colloidal nanocrystals are composed of the above Cs2NaTbCl6:xSb 3+ The colloidal nanocrystals were prepared using a specific method.

[0007] This application also provides a lanthanide ion co-doped double perovskite nanocrystal, wherein the lanthanide ion co-doped double perovskite nanocrystal is prepared using the above-mentioned Cs2NaTbCl6: 4%Sb 3+ As the matrix, co-doped with Sm 3+ 、Nd 3+ Er 3+ The Sm 3+ 、Nd 3+ Er 3+ The total molar amount is 0.018 mmol, and the molar ratio of the three is 1:2:1, 1:1:2, or 2:1:1.

[0008] This application also provides a method for preparing the above-mentioned lanthanide ion co-doped double perovskite nanocrystals, including: Take cesium acetate, sodium acetate, terbium acetate, antimony acetate, and Sm-containing compounds. 3+ 、Nd 3+ Er 3+ Lanthanide ion acetates, wherein the antimony acetate doping ratio x is 4%, and Sm in the lanthanide ion acetates 3+ 、Nd 3+ Er 3+ The molar ratio is 1:2:1, 1:1:2 or 2:1:1; oleic acid and oleylamine are taken and placed together with octadecene in a reaction vessel; The reaction vessel containing the raw materials is evacuated and purged with nitrogen. Then the temperature is raised and maintained at the preset temperature while the vacuum is continuously evacuated, and the solution is stirred until it is clear and transparent. Under an inert atmosphere, the solution was heated to 180°C, trimethylchlorosilane was injected, and after a preset reaction time, it was rapidly cooled. After centrifugation, solvent dispersion, and drying, various lanthanide ion co-doped double perovskite nanocrystals were obtained.

[0009] This application also provides an application of the above-mentioned lanthanide ion co-doped double perovskite nanocrystals in the near-infrared optoelectronic field, which includes optical communication, night vision, food analysis, health monitoring, bioimaging or biosensing.

[0010] Compared with the prior art, the embodiments of this application have the following beneficial effects: Non-toxic and environmentally friendly: Utilizes lead-free halogen double perovskite Cs2NaTbCl6:xSb 3+ Using colloidal nanocrystals as a matrix avoids the toxicity issues of lead-based materials and can be safely applied in toxicity-sensitive fields such as biomedicine (e.g., bioimaging, health monitoring), meeting environmental and safety requirements. High-efficiency broadband light emission: via Sm 3+ 、Nd 3+ Er 3+ Three lanthanide ions are co-doped, combined with Sb 3+ Optimization of matrix luminescence performance has enabled a wide-spectrum near-infrared emission range of 850nm to 1650nm with a luminescence efficiency of up to 70%. This solves the core problems of narrow band and low efficiency of traditional materials, and can provide richer spectral information, thereby improving recognition accuracy and signal-to-noise ratio. The preparation process is user-friendly: it adopts an improved hot injection method, the reaction temperature is lower than the preparation temperature of traditional oxide / fluoride materials, and it can be achieved through solution processing. The operation is simple, highly reproducible, and easy to scale up. Performance is controllable: by adjusting Sb 3+ The doping ratio can optimize the matrix luminescence intensity by adjusting the Sm 3+ 、Nd 3+ Er 3 The molar ratio allows for adjustable peak shape over a wide spectral range, adapting to the needs of different near-infrared optoelectronic scenarios and demonstrating strong practicality. Attached Figure Description

[0011] Figure 1 The Cs2NaTbCl6 nanocrystals and Cs2NaTbCl6: 4%Sb provided in the embodiments of this application 3+ Absorption spectrum of nanocrystals; Figure 2 shows the Cs2NaTbCl6 nanocrystals and Cs2NaTbCl6: 4%Sb provided in the embodiments of this application. 3+ Excitation spectrum of nanocrystals; Figure 3 shows the different Sb provided in the embodiments of this application. 3+ Emission spectra of Cs₂NaTbCl₆ nanocrystals doped with concentrations (0%, 2%, 4%, 6%, 8%); Figure 4 shows the Cs2NaTbCl6: 4%Sb at different heat injection temperatures provided in the embodiments of this application. 3+ Emission spectrum of nanocrystals; Figure 5 shows the Sm provided in the embodiment of this application. 3+ 、Nd 3+ Er 3+ Emission spectra of lanthanide ion co-doped double perovskite nanocrystals at a molar ratio of 1:2:1; Figure 6 shows the Sm provided in the embodiment of this application. 3+ 、Nd 3+ Er 3+ Emission spectra of lanthanide ion co-doped double perovskite nanocrystals with a molar ratio of 1:1:2; Figure 7 shows the Sm provided in the embodiment of this application. 3+ 、Nd 3+ Er 3+ Emission spectra of lanthanide ion co-doped double perovskite nanocrystals at a molar ratio of 2:1:1; Figure 8 shows the various lanthanide ions (Sm) provided in the embodiments of this application. 3+ 、Nd 3+ Er 3+ Excitation spectrum of infrared emission. Detailed Implementation

[0012] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0013] This application provides a Cs2NaTbCl6:xSb 3+ Methods for preparing colloidal nanocrystals include: Weigh out acetate raw materials containing cesium acetate, sodium acetate, terbium acetate and antimony acetate according to the molar ratio of cesium acetate: sodium acetate: (terbium acetate + antimony acetate) = 13:9:9, wherein the doping ratio of antimony acetate is 2%~8%; and prepare oleic acid and oleylamine according to the volume ratio of oleic acid: oleylamine = 4:1, mix them with octadecene and add them to the reaction vessel. The reaction vessel containing the raw materials is evacuated and purged with nitrogen. Then the temperature is raised and maintained at the preset temperature while the vacuum is continuously evacuated, and the solution is stirred until it is clear and transparent. Under an inert atmosphere, the solution was heated to 160-200°C, trimethylchlorosilane was injected, and after a preset reaction time, it was rapidly cooled. Following centrifugation, solvent dispersion, and drying, Cs₂NaTbCl₆:xSb was obtained. 3+ Colloidal nanocrystals.

[0014] Preferably, the doping ratio x of antimony acetate is 4%.

[0015] Preferably, under an inert atmosphere, the solution is heated to 180°C, trimethylchlorosilane is injected, the reaction is carried out for a preset time, then rapidly cooled, and after centrifugation, solvent dispersion, and drying, Cs₂NaTbCl₆:xSb is obtained. 3+ Colloidal nanocrystals.

[0016] In one embodiment of this application, the Cs2NaTbCl6:xSb 3+ Methods for preparing colloidal nanocrystals include: Weigh out 0.65 mmol of cesium acetate (CsOAc), 0.45 mmol of sodium acetate (NaOAc), 0.45 (1-x) mmol of terbium acetate (Tb(OAc)3), 0.45x mmol of antimony acetate (Sb(OAc)3), 2.8 mL of oleic acid, 0.7 mL of oleylamine, and 10 mL of octadecene (ODE), where x is the doping ratio of antimony acetate, which can be 2%, 4%, 6%, or 8%. Place the above acetate raw materials, oleic acid, oleylamine, and octadecene together in a reaction vessel. The reaction vessel containing the raw materials was evacuated and purged with nitrogen to remove air from the vessel. The temperature was raised to 120°C and evacuated for 1 hour. The mixture was stirred until the solution was clear and transparent. Under a nitrogen atmosphere, the solution was heated to 160-200°C, and 0.5 mL of trimethylchlorosilane (TMS-Cl) was injected. After reacting for 20 seconds, the solution was cooled to room temperature in an ice-water bath to obtain the reaction solution. The reaction solution was centrifuged at 9000 rpm for 10 min, dispersed in toluene, centrifuged at 10000 rpm for 10 min, lyophilized, dispersed in n-hexane, and centrifuged at 5000 rpm for 5 min. The supernatant was collected to obtain Cs2NaTbCl6:xSb. 3+ Colloidal nanocrystals.

[0017] This application also provides a Cs2NaTbCl6:xSb embodiment. 3+ Colloidal nanocrystals, namely Cs2NaTbCl6:xSb 3+Colloidal nanocrystals are composed of the above Cs2NaTbCl6:xSb 3+ The colloidal nanocrystals were prepared using a specific method.

[0018] This application also provides a lanthanide ion co-doped double perovskite nanocrystal, wherein the lanthanide ion co-doped double perovskite nanocrystal is prepared using the above-mentioned Cs2NaTbCl6: 4%Sb 3+ As the matrix, co-doped with Sm 3+ 、Nd 3+ Er 3+ The Sm 3 + 、Nd 3+ Er 3+ The total molar amount is 0.018 mmol, and the molar ratio of the three is 1:2:1, 1:1:2, or 2:1:1.

[0019] Preferably, the Sm 3+ 、Nd 3+ Er 3+ The molar ratio is 1:1:2.

[0020] This application also provides a method for preparing lanthanide ion co-doped double perovskite nanocrystals, including: Take cesium acetate, sodium acetate, terbium acetate, antimony acetate, and Sm-containing compounds. 3+ 、Nd 3+ Er 3+ Lanthanide acetate ions, wherein the antimony acetate doping ratio x is 4%, and the antimony acetate doping ratio x in lanthanide acetate ion (Ln(OAc)3) is Sm 3+ 、Nd 3+ Er 3+ The molar ratio is 1:2:1, 1:1:2 or 2:1:1; oleic acid and oleylamine are taken and placed together with octadecene in a reaction vessel; The reaction vessel containing the raw materials is evacuated and purged with nitrogen. Then the temperature is raised and maintained at the preset temperature while the vacuum is continuously evacuated, and the solution is stirred until it is clear and transparent. Under an inert atmosphere, the solution was heated to 180°C, trimethylchlorosilane was injected, and after a preset reaction time, it was rapidly cooled. After centrifugation, solvent dispersion, and drying, various lanthanide ion co-doped double perovskite nanocrystals were obtained.

[0021] In one embodiment of this application, the method for preparing the lanthanide ion co-doped double perovskite nanocrystals includes: Weigh out 0.65 mmol of cesium acetate, 0.45 mmol of sodium acetate, 0.414 mmol of terbium acetate, 0.018 mmol of antimony acetate, 0.018 mmol of lanthanide acetate, 2.8 mL of oleic acid, 0.7 mL of oleylamine, and 10 mL of octadecene; the lanthanide acetate is a mixture of samarium acetate, neodymium acetate, and erbium acetate, and the molar ratio of samarium acetate:neodymium acetate:erbium acetate is 1:2:1, 1:1:2, or 2:1:1; place the above acetate raw materials, oleic acid, oleylamine, and octadecene together in a reaction vessel; The reaction vessel containing the raw materials was evacuated and purged with nitrogen to remove air from the vessel. The temperature was raised to 120°C and evacuated for 1 hour. The mixture was stirred until the solution was clear and transparent. Under a nitrogen atmosphere, the solution was heated to 160-200°C, 0.5 mL of trimethylchlorosilane was injected, and after reacting for 20 seconds, it was cooled to room temperature in an ice-water bath to obtain the reaction solution. The reaction solution was centrifuged at 9000 rpm for 10 min, dispersed in toluene, centrifuged at 10000 rpm for 10 min, lyophilized, dispersed in n-hexane, and centrifuged at 5000 rpm for 5 min. The supernatant was collected to obtain double perovskite nanocrystals co-doped with various lanthanide ions.

[0022] This application also provides an application of the above-mentioned lanthanide ion co-doped double perovskite nanocrystals in the near-infrared optoelectronic field, which includes optical communication, night vision, food analysis, health monitoring, bioimaging or biosensing.

[0023] The following specific embodiments illustrate the Cs2NaTbCl6:xSb provided in this application. 3+ Colloidal nanocrystals, lanthanide ion co-doped double perovskite nanocrystals, and their preparation methods are described in detail, but the scope of protection of this application is not limited to the following embodiments. Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods; the materials and reagents used are commercially available unless otherwise specified.

[0024] Example 1: Cs2NaTbCl6:xSb 3+ Synthesis method of colloidal nanocrystals (x = 0, 0.02, 0.04, 0.06, 0.08 respectively) First, 0.65 mmol of CsOAc, 0.45 mmol of NaOAc, 0.45 (1-x) mmol of Tb(OAc)3, 0.45x mmol of Sb(OAc)3 (x = 0, 0.02, 0.04, 0.06, 0.08), 2.8 mL of oleic acid, 0.7 mL of oleylamine, and 10 mL of ODE were transferred into a 50 mL three-necked flask. The solution was then evacuated, purged with nitrogen three times, and heated to 120 °C. The solution was then evacuated for 1 h with continuous stirring until it became clear and transparent. Subsequently, under a nitrogen atmosphere, the solution temperature was raised to 180 °C, and 0.5 mL of TMS-Cl was injected. After reacting for 20 s, the solution was rapidly cooled to room temperature in an ice-water bath. Finally, centrifugation was used to purify the solution and obtain Cs2NaTbCl6:xSb. 3+ Nanocrystals. The reacted solution was aliquoted into two 10 mL centrifuge tubes and centrifuged at 9000 rpm for 10 min. The supernatant was then removed, and the precipitate was dispersed in 5 mL of toluene solvent. After homogenization using a shaker, the precipitate was centrifuged at 10000 rpm for 10 min. The supernatant was then discarded, and the precipitate was lyophilized. The powder was then dispersed in 3 mL of n-hexane solution, homogenized, and centrifuged at 5000 rpm for 5 min. At this point, Cs₂NaTbCl₆:xSb could be obtained from the supernatant. 3+ Nanocrystals.

[0025] Figure 1 Cs2NaTbCl6 nanocrystals and Cs2NaTbCl6:Sb 3+ Absorption spectrum of nanocrystals, doped with Sb 3+ The nanocrystals introduced new absorption channels at 280 nm and 320 nm, with the absorptions at 280 nm and 320 nm originating from Sb, respectively. 3+ of 1 S0- 3 P2 and 1 S0- 3 The transition of P1; Figure 2 Cs2NaTbCl6 nanocrystals and Cs2NaTbCl6:Sb were demonstrated. 3+ Excitation spectrum of nanocrystals; Figure 3 For different Sb 3+ Emission spectra of Cs₂NaTbCl₆ nanocrystals with high concentration doping. Under 320 nm excitation, these samples exhibit strong Tb-derived emission near 550 nm. 3+ The green light emission can be seen in Sb 3+ The nanocrystals exhibit the highest luminescence intensity when the doping concentration is 4%, and the intensity increases with more Sb. 3+When introduced into Cs2NaTbCl6, PLQY decreases, which is due to the concentration quenching of the dopant ions.

[0026] Example 2: Cs2NaTbCl6: 4%Sb at different heat injection temperatures (160 ℃, 170 ℃, 180 ℃, 190 ℃, 200 ℃) 3+ Synthesis methods of colloidal nanocrystals First, 0.65 mmol of CsOAc, 0.45 mmol of NaOAc, 0.45 (1-x) mmol of Tb(OAc)3, 0.45x mmol of Sb(OAc)3 (x = 0.04), 2.8 mL of oleic acid, 0.7 mL of oleylamine, and 10 mL of ODE were transferred into a 50 mL three-necked flask. The solution was then evacuated, purged with nitrogen three times, and heated to 120 °C. The flask was then evacuated for 1 h with continuous stirring until it became clear and transparent. Subsequently, under a nitrogen atmosphere, the solution temperature was raised to 160 °C, 170 °C, 180 °C, 190 °C, and 200 °C, respectively. 0.5 mL of TMS-Cl was injected, and after reacting for 20 s, the solution was rapidly cooled to room temperature in an ice-water bath. Finally, centrifugation was used to purify the solution, yielding Cs2NaTbCl6:xSb. 3+ Nanocrystals. The reacted solution was aliquoted into two 10 mL centrifuge tubes and centrifuged at 9000 rpm for 10 min. The supernatant was then removed, and the precipitate was dispersed in 5 mL of toluene solvent. After homogenization using a shaker, the precipitate was centrifuged at 10000 rpm for 10 min. The supernatant was then discarded, and the precipitate was lyophilized. The powder was then dispersed in 3 mL of n-hexane solution, homogenized, and centrifuged at 5000 rpm for 5 min. At this point, Cs₂NaTbCl₆:xSb could be obtained from the supernatant. 3+ Nanocrystals.

[0027] Figure 4 Cs2NaTbCl6:Sb at different heat injection temperatures 3+ The emission spectrum of nanocrystals shows that the luminescence intensity of nanocrystals is highest at a reaction temperature of 180℃.

[0028] Example 3: Different Sm 3+ :Nd 3+ Er 3+ Synthesis method of lanthanide ion co-doped double perovskite nanocrystals with different doping ratios First, 0.65 mmol of CsOAc, 0.45 mmol of NaOAc, 0.414 mmol of Tb(OAc)3, 0.018 mmol of Sb(OAc)3, and 0.018 mmol of Ln(OAc)3 (Sm3+ :Nd 3+ Er 3+ The proportions were 1:2:1, 1:1:2, and 2:1:1, respectively. 2.8 mL of oleic acid, 0.7 mL of oleylamine, and 10 mL of ODE were transferred into a 50 mL three-necked flask. The solution was then evacuated, purged with nitrogen three times, and heated to 120°C. Vacuum was maintained for 1 h with continuous stirring until the solution became clear and transparent. Subsequently, under a nitrogen atmosphere, the solution temperature was raised to 180°C, and 0.5 mL of TMS-Cl was injected. The reaction was allowed to proceed for 20 s, followed by rapid cooling to room temperature in an ice-water bath. Finally, centrifugation was used to purify the solution and obtain Cs₂NaTbCl₆:Sb 3+ Nanocrystals. The reacted solution was aliquoted into two 10 mL centrifuge tubes and centrifuged at 9000 rpm for 10 min. The supernatant was then removed, and the precipitate was dispersed in 5 mL of toluene solvent. After homogenization using a shaker, the mixture was centrifuged at 10000 rpm for 10 min. The supernatant was then discarded, and the mixture was lyophilized. The powder was dispersed in 3 mL of n-hexane solution, homogenized, and then centrifuged at 5000 rpm for 5 min. At this point, rare earth ions (Sm) could be obtained from the supernatant. 3+ 、Nd 3+ Er 3+ Doped Cs₂NaTbCl₆: 4% Sb 3+ Nanocrystals.

[0029] Figure 5 , Figure 6 , Figure 7 It shows rare earth ions (Sm 3+ 、Nd 3+ Er 3+ Doped Cs₂NaTbCl₆: 4% Sb 3+ The emission spectrum of the nanocrystals shows that the infrared spectrum covers the range of 850 nm to 1650 nm. This was achieved through analysis of the Cs₂NaTbCl₆:Sb₂ 3+ Sm regulation in nanocrystals 3+ 、Nd 3+ Er 3+ By adjusting the doping ratio, tunable wide-coverage NIR luminescence with different peak shapes can be obtained. Sm 3+ 、Nd 3+ Er 3+ When the doping ratio is 1:1:2, the infrared luminescence efficiency is the highest, at 70%. Figure 8 The excitation spectra of infrared emission of each lanthanide ion were monitored, indicating that the emission of each lanthanide ion originates from the energy transfer from the matrix to the lanthanide ion.

[0030] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

[0031] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A Cs2NaTbCl6:xSb 3+ A method for preparing colloidal nanocrystals, characterized in that, include: Weigh out acetate raw materials containing cesium acetate, sodium acetate, terbium acetate and antimony acetate according to the molar ratio of cesium acetate: sodium acetate: (terbium acetate + antimony acetate) = 13:9:9, wherein the doping ratio of antimony acetate is 2%~8%; and prepare oleic acid and oleylamine according to the volume ratio of oleic acid: oleylamine = 4:1, mix them with octadecene and add them to the reaction vessel. The reaction vessel containing the raw materials is evacuated and purged with nitrogen. Then the temperature is raised and maintained at the preset temperature while the vacuum is continuously evacuated, and the solution is stirred until it is clear and transparent. Under an inert atmosphere, the solution was heated to 160-200°C, trimethylchlorosilane was injected, and after a preset reaction time, it was rapidly cooled. Following centrifugation, solvent dispersion, and drying, Cs₂NaTbCl₆:xSb was obtained. 3+ Colloidal nanocrystals.

2. The Cs₂NaTbCl₆:xSb according to claim 1 3+ A method for preparing colloidal nanocrystals, characterized in that, The doping ratio of antimony acetate, x, is 4%.

3. The Cs₂NaTbCl₆:xSb according to claim 1 3+ A method for preparing colloidal nanocrystals, characterized in that, Under an inert atmosphere, the solution was heated to 180°C, trimethylchlorosilane was injected, and after a preset reaction time, it was rapidly cooled. Following centrifugation, solvent dispersion, and drying, Cs₂NaTbCl₆:xSb was obtained. 3+ Colloidal nanocrystals.

4. The Cs₂NaTbCl₆:xSb according to claim 1 3+ A method for preparing colloidal nanocrystals, characterized in that, include: Weigh out 0.65 mmol of cesium acetate, 0.45 mmol of sodium acetate, 0.45 (1-x) mmol of terbium acetate, 0.45x mmol of antimony acetate, 2.8 mL of oleic acid, 0.7 mL of oleylamine, and 10 mL of octadecene, where x is the doping ratio of antimony acetate, which can be 2%, 4%, 6%, or 8%. Place the above acetate raw materials, oleic acid, oleylamine, and octadecene together in a reaction vessel. The reaction vessel containing the raw materials was evacuated and purged with nitrogen to remove air from the vessel. The temperature was raised to 120°C and evacuated for 1 hour. The mixture was stirred until the solution was clear and transparent. Under a nitrogen atmosphere, the solution was heated to 160-200°C, 0.5 mL of trimethylchlorosilane was injected, and after reacting for 20 seconds, it was cooled to room temperature in an ice-water bath to obtain the reaction solution. The reaction solution was centrifuged at 9000 rpm for 10 min, dispersed in toluene, centrifuged at 10000 rpm for 10 min, lyophilized, dispersed in n-hexane, and centrifuged at 5000 rpm for 5 min. The supernatant was collected to obtain Cs2NaTbCl6:xSb. 3+ Colloidal nanocrystals.

5. A Cs2NaTbCl6:xSb 3+ Colloidal nanocrystals, characterized in that, The Cs2NaTbCl6:xSb 3+ Colloidal nanocrystals are derived from any of the Cs₂NaTbCl₆:xSb compounds according to claims 1-4. 3+ The colloidal nanocrystals were prepared using a specific method.

6. A lanthanide ion co-doped double perovskite nanocrystal, characterized in that, The lanthanide ion co-doped double perovskite nanocrystals are based on the Cs₂NaTbCl₆: 4%Sb₂ as described in claim 5. 3+ As the matrix, co-doped with Sm 3+ 、Nd 3+ Er 3+ The Sm 3 + 、Nd 3+ Er 3+ The total molar amount is 0.018 mmol, and the molar ratio of the three is 1:2:1, 1:1:2, or 2:1:

1.

7. The lanthanide ion co-doped double perovskite nanocrystals according to claim 6, characterized in that, The Sm 3+ 、Nd 3 + Er 3+ The molar ratio is 1:1:

2.

8. A method for preparing lanthanide ion co-doped double perovskite nanocrystals as described in claim 6, characterized in that, include: Take cesium acetate, sodium acetate, terbium acetate, antimony acetate, and Sm-containing compounds. 3+ 、Nd 3+ Er 3+ Lanthanide ion acetates, wherein the antimony acetate doping ratio x is 4%, and Sm in the lanthanide ion acetates 3+ 、Nd 3+ Er 3+ The molar ratio is 1:2:1, 1:1:2 or 2:1:1; oleic acid and oleylamine are taken and placed together with octadecene in a reaction vessel; The reaction vessel containing the raw materials is evacuated and purged with nitrogen. Then the temperature is raised and maintained at the preset temperature while the vacuum is continuously evacuated, and the solution is stirred until it is clear and transparent. Under an inert atmosphere, the solution was heated to 180°C, trimethylchlorosilane was injected, and after a preset reaction time, it was rapidly cooled. After centrifugation, solvent dispersion, and drying, lanthanide ion co-doped double perovskite nanocrystals were obtained.

9. The method for preparing lanthanide ion co-doped double perovskite nanocrystals according to claim 8, characterized in that, include: Weigh out 0.65 mmol of cesium acetate, 0.45 mmol of sodium acetate, 0.414 mmol of terbium acetate, 0.018 mmol of antimony acetate, 0.018 mmol of lanthanide acetate, 2.8 mL of oleic acid, 0.7 mL of oleylamine, and 10 mL of octadecene; the lanthanide acetate is a mixture of samarium acetate, neodymium acetate, and erbium acetate, and the molar ratio of samarium acetate:neodymium acetate:erbium acetate is 1:2:1, 1:1:2, or 2:1:1; place the above acetate raw materials, oleic acid, oleylamine, and octadecene together in a reaction vessel; The reaction vessel containing the raw materials was evacuated and purged with nitrogen to remove air from the vessel. The temperature was raised to 120°C and evacuated for 1 hour. The mixture was stirred until the solution was clear and transparent. Under a nitrogen atmosphere, the solution was heated to 160-200°C, 0.5 mL of trimethylchlorosilane was injected, and after reacting for 20 seconds, it was cooled to room temperature in an ice-water bath to obtain the reaction solution. The reaction solution was centrifuged at 9000 rpm for 10 min, dispersed in toluene, centrifuged at 10000 rpm for 10 min, lyophilized, dispersed in n-hexane, and centrifuged at 5000 rpm for 5 min. The supernatant was collected to obtain lanthanide ion co-doped double perovskite nanocrystals.

10. An application of the lanthanide ion co-doped double perovskite nanocrystals as described in claim 6 in the near-infrared optoelectronic field, characterized in that, The near-infrared optoelectronic field includes optical communication, night vision, food analysis, health monitoring, bioimaging, or biosensing.

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