A cerium ion-doped cesium borohydride halide anti-perovskite, a preparation method and application thereof

Abstract

The application belongs to the technical field of luminescent materials, and particularly relates to a cerium ion doped borohydride-based cesium halide anti-perovskite and a preparation method and application thereof. The cerium ion doped borohydride-based cesium halide anti-perovskite provided by the application has a structure of Cs3Cl[B 12 H 12 ]:Ce 3+ . The cerium ion doped borohydride-based cesium halide anti-perovskite is non-toxic, stable and has high luminous efficiency.

Description

Technical Field

[0001] This invention belongs to the field of luminescent materials technology, specifically relating to a cerium ion-doped boron-hydrogen-based cesium halide antiperovskite, its preparation method, and its application. Background Technology

[0002] Ce 3+ Ce is the most abundant and non-toxic rare earth element in the Earth's crust. Its spin- and parity-allowed 4f-5d transitions endow it with excellent luminescent properties, such as short luminescent lifetime and high luminescent efficiency, making it widely used in lighting technology, display devices, scintillation detectors, and medical imaging. 3+ Superior luminescent properties are often manifested as dopant. Common matrix materials such as lead-based cesium halide perovskites (chemical formula CsPbX3, X = Cl, Br, I) are widely favored general-purpose matrix materials due to their high luminescent efficiency, wide spectral tuning range, and other excellent optical properties. Importantly, Ce... 3+ The doping is mainly achieved through the hot injection method, by adjusting the ratio of halogens and Ce. 3+ High doping concentrations of Pb can achieve emission across the entire visible light spectrum, and light-emitting diodes (LEDs) fabricated based on doped materials exhibit excellent performance. However, the toxicity of Pb and the complex procedures involved in the thermal injection method hinder large-scale fabrication and application.

[0003] In recent years, an anion-cation inversion perovskite structure—anti-perovskite (general formula X3BA)—has attracted widespread attention. In anti-perovskite X3BA, the X site at the octahedral vertex is a cation, while the B and A sites are anions. Due to its structural similarity to perovskite, anti-perovskite serves as a Ce2-reactive perovskite. 3+ Potential photoluminescent matrix materials have also attracted much attention. However, related research reports are very few, and the only rare-earth-doped anti-perovskite matrix materials are Sr3(AlO4)F-based compounds. These matrix materials have a wide band gap (>4 eV), and rare-earth doping is achieved through high-temperature solid-state methods, resulting in good stability. However, their synthesis methods still suffer from high energy consumption and high cost. In addition, due to the inhomogeneity of the solid-state synthesis reaction, the photoluminescence quantum efficiency (PLQY) of the doped materials is generally low (<30%). Summary of the Invention

[0004] In view of this, the purpose of this invention is to provide a cerium ion-doped boron-hydrogen-based cesium halide antiperovskite, its preparation method and application. The cerium ion-doped boron-hydrogen-based cesium halide antiperovskite provided by this invention is non-toxic, has good stability and high luminous efficiency (up to 72%).

[0005] To achieve the above objectives, the present invention provides the following technical solution: This invention provides a cerium ion-doped boronhydride-based cesium halide antiperovskite with the structure: Cs3Cl[B 12 H 12 ]:Ce 3 + .

[0006] This invention also provides a method for preparing cerium ion-doped boron-hydrogen-based cesium halide antiperovskite as described in the above technical solution, comprising the following steps: Cs2[B 12 H 12 CsCl, cerium salt, and water are mixed, and the resulting mixed solution is successively frozen and freeze-dried to obtain the cerium ion-doped borohydride cesium halide antiperovskite.

[0007] Preferably, the cerium salt is CeCl3.

[0008] Preferably, the Cs2[B 12 H 12 The molar ratio of cerium salt to cerium salt is 0.3±0.01:0.01~0.05.

[0009] Preferably, the freezing is liquid nitrogen freezing; the freezing time is 8-10 minutes.

[0010] Preferably, the freeze-drying time is 48±2h, the vacuum degree is less than 20Pa, and the temperature is -53~-50℃.

[0011] Preferably, the mixing is carried out under heating and stirring conditions; the heating and stirring temperature is 60±2℃, the rate is 620±5r / min, and the time is 120±10min.

[0012] This invention also provides the application of the cerium ion-doped borohydride cesium halide antiperovskite described in the above technical solution or the cerium ion-doped borohydride cesium halide antiperovskite prepared by the preparation method described in the above technical solution in the preparation of down-conversion ultraviolet light-emitting diodes.

[0013] The present invention also provides a method for fabricating a down-conversion ultraviolet light-emitting diode, comprising the following steps: Cerium ion-doped cesium hydride antiperovskite and a sealant are mixed. After removing air bubbles from the mixture, it is dropped onto the window of a UV LED chip and cured to obtain a downconversion UV light-emitting diode. The cerium ion-doped cesium hydride halide antiperovskite is the cerium ion-doped cesium hydride halide antiperovskite described in the above technical solution or the cerium ion-doped cesium hydride halide antiperovskite prepared by the preparation method described in the above technical solution.

[0014] Preferably, the sealant is polydimethylsiloxane; the mass ratio of the cerium ion-doped boron-hydrogen-based cesium halide anti-perovskite to the sealant is 0.5~0.9:1.

[0015] This invention provides a cerium ion-doped boronhydride-based cesium halide antiperovskite with the structure: Cs3Cl[B 12 H 12 ]:Ce 3 + .

[0016] Beneficial effects: Compared to the traditional high-temperature solid-state synthesis method used for existing rare-earth-doped antiperovskites, the cerium ion-doped boron-hydrogen-based cesium halide antiperovskite provided by this invention is non-toxic, has good stability, and high luminous efficiency (up to 72%).

[0017] [B 12 H 12 ] 2- With I h Symmetry, electron density delocalization, and the distribution of double negative charges between the B and B bonds endow B with... 12 H 12 The base compound exhibits excellent thermal and chemical stability. Its high luminescence efficiency originates from the conversion of borohydride-based cesium halide antiperovskite to Ce. 3+ This provides a favorable matrix environment, and these matrix materials, as wide-bandgap (up to 5 eV) materials, effectively accommodate Ce. 3+ The presence of defect energy levels leads to favorable 5d→4f radiative transitions and high luminescence efficiency.

[0018] The preparation method provided by this invention produces cerium ion-doped borohydride cesium halide antiperovskite with high purity. This method is safe, simple, environmentally friendly, and low in cost.

[0019] This invention employs a freeze-drying method to directly sublimate ice into water vapor, effectively ensuring the integrity of the desired doped structure with almost no sample loss. Moreover, the entire process uses only water as a solvent, without using any organic or inorganic toxic solvents. The raw materials and solvents used are relatively economical, especially the cerium salt, which has extremely low cost. Attached Figure Description

[0020] Figure 1 For the undoped sample Cs3Cl[B 12 H 12 ] and Cs3Cl[B prepared in Example 1 12 H 12 Comparison of XRD results for 0.01Ce; Figure 2 Cs3Cl[B] provided in Example 1 12 H 12 ]:xCe3+ X-ray diffraction (XRD) pattern; Figure 3 Cs3Cl[B] provided in Example 1 12 H 12 Scanning electron microscopy-energy scattering spectroscopy (SEM-EDS) image (a) and major elemental diagram (b) of 0.04Ce; Figure 4 Cs3Cl[B] provided in Example 1 12 H 12 ] and Cs3Cl[B 12 H 12 X-ray photoelectron spectroscopy (XPS) of 0.04Ce (a) and Cs + High-resolution X-ray photoelectron spectrum (b); Figure 5 Cs3Cl[B] provided in Example 1 12 H 12 ] and Cs3Cl[B 12 H 12 ]:xCe 3+ Photoluminescence excitation (PLE) spectrum (a) and photoluminescence (PL) spectrum (b); Figure 6 Cs3Cl[B] provided in Example 1 12 H 12 ]:xCe 3+ Photoluminescent quantum yield (PLQY) plot; Figure 7 Cs3Cl[B] provided in Example 1 12 H 12 X-ray diffraction (XRD) patterns of a 0.04Ce sample before and after two months of storage in air. Figure 8 For example 1, Cs3Cl[B 12 H 12 ]:0.04Ce Photoluminescence (PL) spectrum of a light-emitting diode (LED) (inset is a photograph of an LED in operation). Detailed Implementation

[0021] This invention provides a cerium ion-doped boronhydride-based cesium halide antiperovskite with the structure: Cs3Cl[B 12 H 12 ]:Ce 3 + .

[0022] Unless otherwise specified, the present invention does not have special requirements on the source of raw materials used, and commercially available products well known to those skilled in the art can be used.

[0023] In one embodiment, the cerium ion-doped borohydride cesium halide antiperovskite has a spatial structure of space group R-3m (No. 166) in the trigonal crystal system.

[0024] This invention also provides a method for preparing cerium ion-doped boron-hydrogen-based cesium halide antiperovskite as described in the above technical solution, comprising the following steps: Cs2[B 12 H 12 CsCl, cerium salt, and water are mixed, and the resulting mixed solution is successively frozen and freeze-dried to obtain the cerium ion-doped borohydride cesium halide antiperovskite.

[0025] As one implementation method, the Cs2[B 12 H 12 The molar ratio of β-CsCl is 0.3±0.01:0.3±0.01, and in a specific embodiment it is 0.3:0.3; the cerium salt is CeCl3, and in a specific embodiment it is CeCl3·7H2O; the Cs2[B] 12 H 12 The molar ratio of cerium salt to cerium salt is 0.3±0.01:0.01~0.05, specifically 0.3:0.01, 0.3:0.02, 0.3:0.03, 0.3:0.04 or 0.3:0.05 in the embodiments; the water is deionized water; the Cs2[B 12 H 12 The ratio of the amount of substance to the volume of water is (0.3±0.01) mmol:(8±0.5) mL, and in the specific embodiment it is 0.3 mmol:8 mL.

[0026] In one embodiment, the mixing is carried out under heating and stirring conditions; the heating and stirring equipment is a magnetic heating stirrer; the heating and stirring temperature is 60±2℃, specifically 60℃ in this embodiment, the stirring speed is 620±5r / min, specifically 620r / min in this embodiment, and the time is 120±10min, specifically 120min in this embodiment; after mixing, the process further includes filtering the resulting mixed solution; the filtration is performed using filter paper with a pore size of 0.22±0.01μm, specifically 0.22μm filter paper in this embodiment.

[0027] As one implementation method, the specific filtration process is as follows: using a syringe with a hydrophilic polyvinylidene fluoride (PVDF) filter head containing filter paper to filter the mixed solution into a conical tube, and then capping the conical tube bottle.

[0028] In one embodiment, the freezing is liquid nitrogen freezing; the freezing time is 8-10 minutes, and in a specific embodiment it is 10 minutes; the specific freezing process is to place the conical flask containing the mixed solution into liquid nitrogen for freezing.

[0029] In one embodiment, the freeze-drying time is 48±2h, specifically 48h, the vacuum degree is less than 20Pa, and the temperature is -53~-50℃, specifically -53℃; the equipment used for freeze-drying is a freeze dryer; the specific process of freeze-drying is to take out the frozen conical tube, remove the bottle cap, seal it with plastic wrap with small holes, and then put it into the freeze dryer for freeze-drying.

[0030] In one embodiment, after freeze-drying, the process further includes: grinding the freeze-dried product; the grinding equipment is a mortar and pestle; the grinding time is 10-15 minutes, and in a specific embodiment it is 15 minutes.

[0031] This invention selects B 12 H 12 Cesium halide antiperovskite (chemical formula Cs3Cl[B]) 12 H 12 Ce, as a matrix material, possesses characteristics such as simple synthesis, wide bandgap, low toxicity, and excellent stability. Ce with excellent luminescent properties was successfully synthesized using a simple, environmentally friendly, and low-cost method (freeze-dried assisted recrystallization). 3+ Doped Cs3Cl[B 12 H 12 ](Cs3Cl[B 12 H 12 ]:Ce 3+ The key is that the entire process uses only deionized water (DIW) as a solvent, which effectively limits the use of other toxic organic solvents. In summary, this method provides an economical, simple and environmentally friendly technical solution for rare earth element doped anti-perovskite materials.

[0032] This invention also provides the application of the cerium ion-doped borohydride cesium halide antiperovskite described in the above technical solution or the cerium ion-doped borohydride cesium halide antiperovskite prepared by the preparation method described in the above technical solution in the preparation of down-conversion ultraviolet light-emitting diodes.

[0033] The present invention also provides a method for fabricating a down-conversion ultraviolet light-emitting diode, comprising the following steps: Cerium ion-doped cesium hydride antiperovskite and a sealant are mixed. After removing air bubbles from the mixture, it is dropped onto the window of a UV LED chip and cured to obtain a downconversion UV light-emitting diode. The cerium ion-doped cesium hydride halide antiperovskite is the cerium ion-doped cesium hydride halide antiperovskite described in the above technical solution or the cerium ion-doped cesium hydride halide antiperovskite prepared by the preparation method described in the above technical solution.

[0034] In one embodiment, the sealant is polydimethylsiloxane; the mass ratio of the cerium ion-doped borohydride cesium halide antiperovskite to the sealant is 0.5~0.9:1, and in a specific application example it is 0.8:1.

[0035] In one embodiment, the method for removing air bubbles involves placing the device in a vacuum drying oven at room temperature for 20-30 minutes, specifically 20-25 minutes in this application example; the wavelength of the ultraviolet LED chip is 300-310 nm, specifically 300-305 nm in this application example; the curing temperature is 65-70°C, specifically 65°C in this application example, and the time is 3.5-4 hours, specifically 4 hours in this application example; the curing is carried out in a vacuum drying oven.

[0036] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments thereof, but they should not be construed as limiting the scope of protection of the present invention.

[0037] Raw material types and sources: Cs2[B 12 H 12 CeCl3·7H2O (99.99%) and CsCl (99.99%) were purchased from Aladdin. CsCl (99.999%) was purchased from Adamas.

[0038] Example 1 S1, 125 mg (approximately 0.3 mmol) of Cs2[B 12 H 12 Samples with different doping amounts were prepared by adding 51.6 mg (approximately 0.3 mmol) of CsCl, 3.6, 7.2, 10.8, 14.4, and 18 mg (approximately 0.01, 0.02, 0.03, 0.04, and 0.05 mmol) of CeCl3·7H2O and 8 mL of deionized water into 10 mL glass vials. The vials were then heated and stirred for 120 min at 60 °C and 620 r / min using a magnetic stirrer until the solution became clear and transparent. S2. Use a syringe with a 10mL hydrophilic polyvinylidene fluoride (PVDF) filter head containing 0.22μm pore size filter paper to filter the solution into a 30mL conical tube, and then cap the conical tube. S3. Place the conical tube in liquid nitrogen and freeze for 10 minutes; S4. Remove the conical tube, remove the bottle cap, seal it with plastic wrap with small holes, and then put it in a freeze dryer for 48 hours. The vacuum degree of the freeze dryer is less than 20 Pa and the temperature is -53℃. S5. Grind the obtained powder sample using a small mortar for 15 minutes to obtain a fine powder, yielding cerium ion-doped boron-hydrogen-based cesium halide antiperovskite (denoted as Cs3Cl[B 12 H 12 ]:xCe 3+ ).

[0039] The products obtained when the feed amounts of CeCl3·7H2O were 0.01, 0.02, 0.03, 0.04, and 0.05 mmol were respectively denoted as Cs3Cl[B 12 H 12 ]:0.01Ce、Cs3Cl[B 12 H 12 ]:0.02Ce, Cs3Cl[B 12 H 12 ]:0.03Ce, Cs3Cl[B 12 H 12 ]:0.04Ce, Cs3Cl[B 12 H 12 ]:0.05Ce.

[0040] Application Example 1 Cs3Cl[B] prepared in Example 1 12 H 12 The following are the specific steps for preparing down-conversion ultraviolet light-emitting diodes using 0.04Ce powder: S1, Cs3Cl[B 12 H 12 ]: 0.04Ce powder is mixed into polydimethylsiloxane (PDMS) sealant, Cs3Cl[B 12 H 12 The mass ratio of 0.04Ce powder to polydimethylsiloxane is 0.8:1 to obtain a homogeneous mixture; S2. Place the mixture in a vacuum drying oven at room temperature for 20 minutes to remove air bubbles. S3. Drop the mixture onto the window of a 300nm ultraviolet LED chip and cure it in a vacuum oven (cured in a vacuum drying oven at 65℃ for 4 hours) to obtain a photoexcited ultraviolet light diode.

[0041] Performance testing Figure 1 For the undoped sample Cs3Cl[B 12 H 12 ] and Cs3Cl[B prepared in Example 1 12H 12 Comparison of XRD results for 0.01Ce.

[0042] from Figure 1 It can be seen that the doped sample Cs3Cl[B 12 H 12 The main diffraction peak of 0.01Ce is significantly higher than that of the undoped sample Cs3Cl[B]. 12 H 12 The main diffraction peak shifts to a larger angle, indicating lattice shrinkage.

[0043] Figure 2 Cs3Cl[B] provided in Example 1 12 H 12 ]:xCe 3+ X-ray diffraction (XRD) pattern.

[0044] like Figure 2 As shown, undoped Cs3Cl[B 12 H 12 Powder and different Ce 3+ The diffraction peaks of the doped powder sample corresponded well to the standard card, with almost no other impurity diffraction peaks, proving that the sample prepared in this invention has high phase purity; further analysis of the main diffraction peaks revealed that due to Ce... 3+ With a smaller ionic radius (approximately 10² pm), it replaced the larger Cs. + The presence of ions (with an ionic radius of approximately 167 pm) causes lattice contraction, resulting in a large-angle shift of the (021) crystal plane diffraction peak.

[0045] Figure 3 Cs3Cl[B] provided in Example 1 12 H 12 Scanning electron microscopy-energy scattering spectroscopy (SEM-EDS) plot (a) and major elemental plot (b) of 0.04Ce.

[0046] from Figure 3 As can be seen from image a, the elemental distribution of Cs, Cl, B, and Ce in the doped sample is uniform, proving that Ce... 3+ Successful doping. Figure 3 The b in the diagram shows that the main elements are Cs, Cl, B, and Ce.

[0047] Figure 4 Cs3Cl[B] provided in Example 1 12 H 12 ] and Cs3Cl[B 12 H 12 X-ray photoelectron spectroscopy (XPS) of 0.04Ce (a) and Cs + High-resolution X-ray photoelectron spectrum (b).

[0048] like Figure 4 As shown in Figure a, Ce 3+ The appearance of XPS characteristic peaks in Ce ions proves that Ce 3+ Cs3Cl[B] ions were incorporated into it. 12 H 12 In the crystal lattice of ], Figure 4 b is Cs + The high-resolution X-ray photoelectron spectroscopy, with its shifted peak position, indicates that Ce... 3+ Doping and substituting Cs + The lattice position causes changes in the crystal field, leading to Cs + The XPS peak position shifted.

[0049] Figure 5 Cs3Cl[B] provided in Example 1 12 H 12 ] and Cs3Cl[B 12 H 12 ]:xCe 3+ Photoluminescence excitation (PLE) spectrum (a) and photoluminescence (PL) spectrum (b).

[0050] pass Figure 5 The excitation spectrum (a) and emission spectrum (b) show different amounts of Ce. 3+ The regulation of luminescence properties by ion doping, and the intrinsic material Cs3Cl[B 12 H 12 The sample does not emit light; the doped sample has two emission peaks at 346 nm and 371 nm. 3 + The luminescence was strongest when the ion doping concentration was 0.04 mmol.

[0051] Figure 6 Cs3Cl[B] provided in Example 1 12 H 12 ]:xCe 3+ Photoluminescent quantum yield (PLQY) plot.

[0052] pass Figure 6 It can be seen that different amounts of Ce 3+ The change in luminescence efficiency of samples under ion doping, when Ce 3+ When the ion doping amount is 0.04 mmol, the maximum luminescence quantum efficiency is 72%, and the variation law of luminescence efficiency is consistent with the variation law of PL intensity.

[0053] Figure 7 Cs3Cl[B] provided in Example 1 12 H 12X-ray diffraction (XRD) patterns of a 0.04Ce sample before and after two months of storage in air.

[0054] pass Figure 7 It can be seen that after being stored in air for 2 months, no impurity peaks were observed in the doped sample, and the diffraction peaks matched well with those of the fresh sample, proving that Cs3Cl[B 12 H 12 The 0.04Ce powder sample exhibits good stability.

[0055] Figure 8 For example 1, Cs3Cl[B 12 H 12 ]:0.04Ce Photoluminescence (PL) spectrum of a light-emitting diode (LED) (inset is a photograph of an LED in operation).

[0056] pass Figure 8 It can be seen that coating Cs3Cl[B] onto a 300~305nm ultraviolet light-emitting diode... 12 H 12 A mixture of 0.04Ce powder and PDMS can produce a downconversion ultraviolet-emitting LED operating at 6.5V and 350mA. The illustration shows that the device has bright ultraviolet light emission.

[0057] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention and not all embodiments. People can obtain other embodiments based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A cerium ion-doped cesium borohydrido halide anti-perovskite, characterized in that, Structure: Cs3Cl[B 12 H 12 ]:Ce 3+ .

2. The method for preparing cerium ion-doped boron-hydrogen-based cesium halide antiperovskite according to claim 1, characterized in that, Includes the following steps: Cs2[B 12 H 12 ]、CsCl、cerium salt and water are mixed, and the resulting mixed solution is sequentially subjected to freezing and freeze-drying to obtain the cerium ion-doped cesium borohydride halide anti-perovskite.

3. The production method according to claim 2, characterized by, The cerium salt is CeCl3.

4. The production method according to claim 2 or 3, characterized by, The Cs2[B 12 H 12 The molar ratio of the Ce salt to the Cs2[B 5. The production method according to claim 2, characterized by, The freezing is performed using liquid nitrogen; the freezing time is 8-10 minutes.

6. The production method according to claim 2, characterized by, The freeze-drying time is 48±2h, the vacuum degree is less than 20Pa, and the temperature is -53~-50℃.

7. The production method according to claim 2, characterized by, The mixing is carried out under heating and stirring conditions; the heating and stirring temperature is 60±2℃, the rate is 620±5r / min, and the time is 120±10min.

8. The application of the cerium ion-doped borohydride cesium halide antiperovskite according to claim 1 or the cerium ion-doped borohydride cesium halide antiperovskite prepared by any one of claims 2 to 7 in the preparation of down-conversion ultraviolet light-emitting diodes.

9. A method of fabricating a down-conversion ultraviolet light emitting diode, comprising: Includes the following steps: Cerium ion-doped cesium hydride antiperovskite and a sealant are mixed. After removing air bubbles from the mixture, it is dropped onto the window of a UV LED chip and cured to obtain a downconversion UV light-emitting diode. The cerium ion-doped cesium hydride halide antiperovskite is the cerium ion-doped cesium hydride halide antiperovskite according to claim 1 or the cerium ion-doped cesium hydride halide antiperovskite prepared by the preparation method according to any one of claims 2 to 7.

10. The method of claim 9, wherein, The sealant is polydimethylsiloxane; the mass ratio of the cerium ion-doped boron-hydrogen-based cesium halide anti-perovskite to the sealant is 0.5~0.9:1.

Images