Double-coordination passivated red-light perovskite quantum dot and preparation method and application thereof

Abstract

The invention relates to a double-coordination passivated red-light perovskite quantum dot and a preparation method and application thereof. The preparation method comprises the following steps: preparing a monovalent cation precursor from cesium carbonate, 1-octadecene and oleic acid; preparing a lead source precursor from lead halide, zinc halide, 1-octadecene, diisooctyl hypophosphorous acid and oleylamine; thermally injecting the monovalent cation precursor into the lead source precursor, and cooling to prepare a perovskite quantum dot solution; performing anti-solvent purification on the perovskite quantum dot solution to obtain red light perovskite quantum dots; a process of preparing a double-coordination passivated red light perovskite quantum dot from the red light perovskite quantum dot and taurosulfonamide hydrochloride; the invention also discloses an application of the double-coordination passivated red light perovskite quantum dot prepared by the preparation method in preparation of an electroluminescent diode. The post-treatment passivation operation method is simple and convenient, and the quantum dot treated by the double-coordination ligand achieves the purpose of preparing the halide perovskite quantum dot with excellent optical performance and excellent performance of the prepared electroluminescent diode.

Description

Technical Field

[0001] This invention relates to the technical field of perovskite quantum dots, and in particular to a dual-coordinate passivated red perovskite quantum dot, its preparation method, and its application. Background Technology

[0002] Halide perovskite quantum dots possess a series of exceptional properties, the most notable being their extremely high fluorescence quantum yield, indicating their ability to efficiently convert absorbed energy into light energy and release it. Simultaneously, their extremely narrow full width at half maximum (FWHM) results in highly pure and precise emission spectra. Furthermore, halide perovskite quantum dots exhibit a wide color gamut, displaying rich and vibrant colors, and possess solution-processability, a characteristic that greatly facilitates their large-scale production and application. Due to these superior properties, halide perovskite quantum dots show immense promise for applications in optoelectronic devices. For example, in high-efficiency pure red quantum dot light-emitting diodes (LEDs), they can achieve high-brightness, high-purity red light emission, which is crucial for improving the color performance of display devices; in large-size television displays, they are expected to deliver more immersive visual effects; in flexible medical lighting, their unique optical properties can meet the special light quality requirements of medical environments; and in ultra-high resolution Micro-LED technology, halide perovskite quantum dots contribute to achieving finer and clearer display effects.

[0003] The synthesis of halide perovskite quantum dots (HQDs) is a diverse process, each with its unique characteristics and applicable scope. Common methods include hot-injection, ligand-assisted co-precipitation, and ball milling. During HQD synthesis, organic ligands, such as oleic acid and oleylamine, are typically added. These organic ligands play crucial roles in the synthesis process. Firstly, they effectively passivate defects on the quantum dot surface, thereby improving the optical properties of the quantum dots. Secondly, they prevent quantum dot aggregation, ensuring the stable monodisperse state of the quantum dots. However, the binding force between these organic ligands and the perovskite quantum dot surface is relatively weak, leading to ligand detachment during subsequent separation and purification. Ligand detachment results in insufficient coordination on the quantum dot surface, severely impacting the luminescence performance and stability of the quantum dots, which is extremely detrimental to the fabrication of efficient and stable optoelectronic devices. Furthermore, these long-chain ligands themselves possess electrical insulation properties, hindering the application of perovskite quantum dots in high-performance light-emitting diode (LED) devices, as electrical insulation affects the charge transport efficiency within the device. Therefore, in the synthesis of halide perovskite quantum dots, subsequent surface modification treatments, such as dual-coordination passivation and ligand exchange, are usually required to obtain halide perovskite quantum dots with high fluorescence quantum yield, good conductivity and stability.

[0004] To further improve key performance indicators such as fluorescence quantum yield, conductivity, and stability of halide perovskite quantum dots, researchers typically employ a series of measures after quantum dot nucleation, such as ligand exchange and double-coordinate passivation. For example, related research reports show that after successfully synthesizing halide perovskite quantum dots, ligand exchange treatment can indeed yield quantum dot samples with improved fluorescence quantum yield. However, in-depth research and analysis reveal that the passivation effect of quantum dots prepared using this method is not ideal and still has room for improvement. Therefore, achieving efficient double-coordinate passivation and thus preparing halide perovskite quantum dots with excellent optical properties suitable for high-efficiency light-emitting diodes remains a major challenge for researchers. Achieving this goal requires researchers to invest more effort in further exploration and in-depth research, continuously optimizing and improving multiple aspects such as material synthesis processes and surface treatment technologies to overcome existing technological bottlenecks. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the first objective of this invention is to provide a method for preparing dual-coordinated passivated red perovskite quantum dots, which achieves the goal of preparing halide perovskite quantum dots with excellent optical properties, good passivation effect, and excellent electroluminescent diode performance.

[0006] The second objective of this invention is to provide a dual-coordinated passivated red perovskite quantum dot, which has the advantages of surface defect passivation and improved conductivity.

[0007] The third objective of this invention is to provide an application of dual-coordination passivated red perovskite quantum dots, which has the advantages of improving the luminescence performance and stability of electroluminescent diodes. Compared with the prior art, this invention is the first to adopt a dual-coordination post-treatment strategy using taurine hydrochloride, simultaneously achieving surface defect passivation and conductivity improvement, thus solving the problem that traditional long-chain ligands have strong insulation but weak passivation effect.

[0008] To achieve the first objective mentioned above, the present invention provides the following technical solution: A method for preparing dual-coordinate passivated red perovskite quantum dots, comprising, The process for preparing a monovalent cationic precursor from cesium carbonate, 1-octadecene and oleic acid; The process for preparing lead source precursors from lead halides, zinc halides, 1-octadecene, diisooctylphosphite and oleylamine; The process of thermally injecting the monovalent cation precursor into the lead source precursor and then cooling it to prepare a perovskite quantum dot solution; The process of purifying the perovskite quantum dot solution by antisolvent to obtain red light perovskite quantum dots; The process of preparing dual-coordinate passivated red perovskite quantum dots from the aforementioned red perovskite quantum dots and taurine hydrochloride.

[0009] Furthermore, in the process of preparing the monovalent cation precursor, the ratio of cesium carbonate, 1-octadecene and oleic acid is controlled to be 100 mg: (3.4~3.6) mL: (0.3~0.5) mL.

[0010] Furthermore, in the process of preparing the monovalent cation precursor, cesium carbonate, 1-octadecene, and oleic acid are continuously stirred at a speed of 600 r / min or higher, heated to 60-80°C, and vacuum dried for 30-60 min. Then, nitrogen gas is maintained and the temperature is raised to 100-120°C and held for more than 20 min to obtain the monovalent cation precursor.

[0011] Furthermore, in the preparation of the lead source precursor, the ratio of lead halide, zinc halide, 1-octadecene, diisooctylphosphite and oleylamine is controlled to be (0.2~5.0) mmol: (0.5~15.0) mmol: (5~30) mL: (2~12) mL: (2~12) mL.

[0012] Furthermore, in the preparation of the lead source precursor, lead halide, zinc halide, 1-octadecene, diisooctylphosphite and oleylamine are continuously stirred at a speed of 600 r / min or higher, and nitrogen is purged and circulated multiple times at room temperature. Then, the nitrogen is maintained and the temperature is raised to 150~170°C and held for more than 10 min to obtain the lead source precursor.

[0013] Furthermore, in the preparation of perovskite quantum dots, the ratio of monovalent cation precursor to lead source precursor is controlled to be 0.4 mL: (5~15) mL.

[0014] Furthermore, in the preparation of perovskite quantum dots, a monovalent cation precursor is thermally injected into the lead source precursor under stirring at 150~170℃, and then cooled in an ice-water bath after 5s to below 40℃ to obtain a perovskite quantum dot solution with an emission wavelength of 620~650nm.

[0015] Furthermore, in obtaining the red-light perovskite quantum dots, the perovskite quantum dot solution is purified by xylene / methyl acetate and methyl acetate antisolvent. The purified precipitate is dissolved in one or more of the following mixed solvents: hexane, octane, and xylene, to obtain the red-light perovskite quantum dots.

[0016] Furthermore, in the preparation of the dual-coordinated passivated red perovskite quantum dots, the ratio of red perovskite quantum dots to taurine hydrochloride is controlled to be (0.5~1.0) mL: 2 mg.

[0017] Furthermore, in the preparation of dual-coordinate passivated red perovskite quantum dots, the red perovskite quantum dots are post-treated with taurine hydrochloride and stirred for 30 min, and the post-treated pure red quantum dot solution is centrifuged at 3000 r / min or higher for 3-5 min to obtain dual-coordinate passivated red perovskite quantum dots.

[0018] To achieve the second objective mentioned above, the present invention provides the following technical solution: A dual-coordinated passivated red perovskite quantum dot was prepared by the above-described method.

[0019] To achieve the third objective mentioned above, the present invention provides the following technical solution: An application of a dual-coordinated passivated red perovskite quantum dot: the application of the dual-coordinated passivated red perovskite quantum dot prepared by the above method in the preparation of electroluminescent diodes.

[0020] Furthermore, the application of the double-coordinated passivated red perovskite quantum dots prepared by the above method in the preparation of quantum dot light-emitting layers for electroluminescent diodes.

[0021] Furthermore, the specific implementation method in the fabrication of the electroluminescent diode is as follows: S1 First, the ITO conductive glass is ultrasonically treated with acetone, deionized water and alcohol in sequence, and then treated with ultraviolet ozone to obtain the bottom electrode. S2 spin-coated a PEDOT / PSS solution on the bottom electrode surface at a speed of 4000 rpm for 45 s, and then annealed it at 160 °C for 15 min in an atmospheric atmosphere to obtain the first hole transport layer. S3 spin-coated a 5 mg / mL PTAA chlorobenzene solution onto the surface of the first hole transport layer at 2000 rpm in a glove box for 45 s, and then annealed at 170 °C for 20 min under a nitrogen atmosphere to obtain the second hole transport layer. S4 spin-coated 10 mg / mL dual-coordination passivated red perovskite quantum dots on the surface of the second hole transport layer at a speed of 4000 rpm for 45 s to obtain a quantum dot luminescent layer. S5 operates at a vacuum level of 1×10⁻⁶. -7 Inside the vacuum chamber of the torr, TPBi thin films, CNT2T thin films, LiF thin films and Al thin films are sequentially evaporated and deposited on the surface of the quantum dot light-emitting layer. The thicknesses of the thin films are 5 nm, 60 nm, 1.5 nm and 50 nm, respectively. Among them, TPBi and CNT2T are electron transport layers, and LiF / Al is used as the top electrode to obtain an electroluminescent diode.

[0022] In summary, the beneficial technical effects of the present invention are as follows: 1. The preparation method of the present invention provides a dual-coordination passivation effect through taurine hydrochloride, providing a stronger binding ability compared to the original ligand. At the same time, its short side chain structure optimizes the conductivity of perovskite quantum dots, resulting in red perovskite quantum dots with fewer surface defects, good stability, good luminescence performance, and suitable for electroluminescent diodes. 2. The double-coordinated passivated red perovskite quantum dots prepared by this invention can be used as quantum dot emitting layers in the fabrication of electroluminescent diodes, effectively improving carrier injection capability and having advantages such as improving the luminous performance (e.g., maximum brightness, external quantum efficiency, etc.) and spectral stability of electroluminescent diodes. Attached Figure Description

[0023] Figure 1 This is the photoluminescence spectrum of the double-coordinated passivated red perovskite quantum dots prepared in Example 2 of the present invention.

[0024] Figure 2 This is a PLQY test image of the double-coordinated passivated red perovskite quantum dots prepared in Example 2 of the present invention.

[0025] Figure 3 This is a performance diagram of the LED device of the electroluminescent diode obtained in Embodiment 3 of the present invention.

[0026] Figure 4 This is a TEM image of the double-coordinated passivated red perovskite quantum dots prepared in Example 4 of this invention.

[0027] Figure 5 This is the XRD pattern of the double-coordinated passivated red perovskite quantum dots prepared in Example 4 of this invention.

[0028] Figure 6 This is the Fourier transform infrared (FTIR) image of the double-coordinated passivated red perovskite quantum dots prepared in Example 4 of this invention.

[0029] Figure 7 This is the XPS test image of the double-coordinated passivated red perovskite quantum dots prepared in Example 4 of this invention.

[0030] Figure 8 This is a TRPL test image of the double-coordinated passivated red perovskite quantum dots prepared in Example 4 of the present invention.

[0031] Figure 9 This is a conductivity test diagram of the double-coordinated passivated red perovskite quantum dots prepared in Example 4 of the present invention.

[0032] Figure 10 This is a performance diagram of the LED device of the electroluminescent diode obtained in Embodiment 5 of the present invention. Detailed Implementation

[0033] To make the technical means, creative features, objectives and effects of this invention clearer and easier to understand, the invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0034] Example 1: A method for preparing dual-coordinated passivated red perovskite quantum dots disclosed in this invention, comprising, The process for preparing a monovalent cationic precursor from cesium carbonate, 1-octadecene and oleic acid; The process for preparing lead source precursors from lead halides, zinc halides, 1-octadecene, diisooctylphosphite and oleylamine; The process of thermally injecting a monovalent cation precursor into a lead source precursor and then cooling it to prepare a perovskite quantum dot solution. The process of purifying perovskite quantum dot solution by antisolvent to obtain red light perovskite quantum dots; The process of preparing dual-coordinate passivated red perovskite quantum dots from red perovskite quantum dots and taurine hydrochloride.

[0035] The present invention also discloses a dual-coordinated passivated red perovskite quantum dot, which is prepared by the above-described method.

[0036] This invention also discloses an application of dual-coordinated passivated red perovskite quantum dots, specifically the application of dual-coordinated passivated red perovskite quantum dots prepared by the above method in the fabrication of electroluminescent diodes.

[0037] Example 2: This is a method for preparing dual-coordinate passivated red perovskite quantum dots disclosed in this invention. The difference from Example 1 is that it includes the following steps: S1. 100 mg of cesium carbonate was added to a 25 mL three-necked flask, followed by 3.5 mL of 1-octadecene and 0.4 mL of oleic acid. The mixture was stirred continuously at 850 r / min, heated to 80 °C and dried under vacuum for 30 min. Then, nitrogen gas was purged and the temperature was raised to 120 °C and held for at least 10 min. The mixture was then placed in a 25 mL three-necked flask and stored for later use to obtain a monovalent cation precursor. S2: 88 mg lead iodide, 244 mg zinc iodide, 86 mg zinc bromide, 5.0 mL 1-octadecene, 1.8 mL diisooctyl hypophosphite, and 1.8 mL oleylamine were added to a 25 mL three-necked flask and stirred continuously at 850 r / min. Nitrogen gas was purged at room temperature for 1-5 cycles, and then the temperature was raised to 170 °C while maintaining nitrogen purging for more than 10 min to obtain the lead source precursor. S3 was heated by injecting 0.4 mL of monovalent cation precursor into lead source precursor under stirring at 170 °C. After 5 s, it was cooled in an ice-water bath to 40 °C to obtain perovskite quantum dot solution. S4. Add 5 mL of a 1:1 xylene / methyl acetate mixture to the perovskite quantum dot solution, centrifuge at 3000 r / min for 3 min, then take the supernatant and add 20 mL of methyl acetate, centrifuge at 9000 r / min for 3 min, dissolve the precipitate in 1 mL of xylene to obtain a first-purified perovskite quantum dot solution. S5. Add 10 mL of methyl acetate to the first-purified perovskite quantum dot solution, centrifuge at 9000 r / min for 3 min, dissolve the precipitate in 0.6 mL of n-octane to obtain the second-purified perovskite quantum dot solution, which is the red light perovskite quantum dot without double coordination passivation. S6. 2 mg of taurine hydrochloride was added to the red light perovskite quantum dots prepared above, and the mixture was stirred with a magnetic stirrer for 30 min. Then, it was centrifuged at 3000 r / min for 3 min. The supernatant was the prepared double-coordinated passivated red light perovskite quantum dots.

[0038] Example 3: This example illustrates an application of a dual-coordinated passivated red perovskite quantum dot disclosed in this invention. The difference from Example 2 lies in the specific implementation method used in fabricating the electroluminescent diode. S1 First, the ITO conductive glass is ultrasonically treated with acetone, deionized water and alcohol in sequence, and then treated with ultraviolet ozone to obtain the bottom electrode. S2 spin-coated a PEDOT / PSS solution on the bottom electrode surface at a speed of 4000 rpm for 45 s, and then annealed it at 160 °C for 15 min in an atmospheric atmosphere to obtain the first hole transport layer. S3 spin-coated a PTAA solution with a concentration of 5 mg / mL chlorobenzene onto the first hole transport layer at a speed of 2000 rpm in a glove box for 45 s, and then annealed it at 170 °C for 20 min under a nitrogen atmosphere to obtain the second hole transport layer. S4 spin-coated a 10 mg / mL concentration of dual-coordinated passivated red perovskite quantum dots on the second hole transport layer at a rotation speed of 4000 rpm for 45 s to obtain a quantum dot luminescent layer. S5 operates at a vacuum level of 1×10⁻⁶. -7 Inside the vacuum chamber of the torr, TPBi thin films, CNT2T thin films, LiF thin films and Al thin films are sequentially evaporated and deposited on the quantum dot light-emitting layer. The thicknesses of the thin films are 5 nm, 60 nm, 1.5 nm and 50 nm, respectively. Among them, TPBi and CNT2T are electron transport layers, and LiF / Al is used as the top electrode to obtain an electroluminescent diode.

[0039] Example 4: This is a method for preparing dual-coordinate passivated red perovskite quantum dots disclosed in this invention. The difference from Example 1 is that it includes the following steps: S1. 100 mg of cesium carbonate was added to a 25 mL three-necked flask, followed by 3.5 mL of 1-octadecene and 0.4 mL of oleic acid. The mixture was stirred continuously at 850 r / min, heated to 80 °C and dried under vacuum for 30 min. Then, nitrogen gas was purged and the temperature was raised to 120 °C and maintained for more than 10 min. The mixture was then placed in a 25 mL three-necked flask and kept warm for later use to obtain a monovalent cation precursor. S2: 88 mg lead iodide, 244 mg zinc iodide, 72 mg zinc bromide, 5.0 mL 1-octadecene, 1.8 mL diisooctyl hypophosphite and 1.8 mL oleylamine were added to a 25 mL three-necked flask and stirred continuously at 850 r / min. Nitrogen gas was purged at room temperature and circulated multiple times. Then, the temperature was raised to 170 °C while maintaining nitrogen purging and held for more than 10 min to obtain the lead source precursor. S3 was heated by injecting 0.4 mL of monovalent cation precursor into lead source precursor under stirring at 170 °C. After 5 s, it was cooled in an ice-water bath to 40 °C to obtain perovskite quantum dot solution. S4. Add 5 mL of a 1:1 xylene / methyl acetate mixture to the perovskite quantum dot solution, centrifuge at 3000 r / min for 3 min, then take the supernatant and add 10 mL of methyl acetate, centrifuge at 9000 r / min for 3 min, dissolve the precipitate in 1 mL of xylene to obtain a first-purified perovskite quantum dot solution. S5. Add 10 mL of methyl acetate solution to the first-purified perovskite quantum dot solution, centrifuge at 9000 r / min for 3 min, dissolve the precipitate in 0.6 mL of n-octane to obtain the second-purified perovskite quantum dot solution, which is the red light perovskite quantum dot without double coordination passivation. S6 added 4 mg of taurine hydrochloride to the red light perovskite quantum dots prepared above, added a magnetic stirrer and stirred for 30 min, then centrifuged at 3000 r / min for 3 min, and the supernatant was the prepared double-coordinated passivated red light perovskite quantum dots.

[0040] Example 5: This example illustrates an application of a dual-coordinated passivated red perovskite quantum dot disclosed in this invention. The difference from Example 4 lies in the specific implementation method used in fabricating the electroluminescent diode. In a glove box, a chlorobenzene solution with PTAA and TAPC both at a concentration of 5 mg / mL was spin-coated onto the first hole transport layer at a speed of 2000 rpm for 45 s. The layer was then annealed at 170 °C for 20 min under a nitrogen atmosphere to obtain the second hole transport layer. Separately, TMPI (10 mg / mL) was added to a perovskite quantum dot solution with post-dual coordination treatment at a volume ratio of 10:1, and passivated red perovskite quantum dots were spin-coated at a speed of 4000 rpm for 45 s to obtain the quantum dot luminescent layer.

[0041] Experimental Example 1: The double-coordinated passivated red perovskite quantum dots prepared in Example 2 were irradiated with a 450 nm excitation light source. The resulting spectrum was collected, and the results were obtained. Figure 1 The photoluminescence spectrum shown has an emission peak at 637 nm and a half-width at half-maximum of 43 nm.

[0042] Experimental Example 2: A blank solvent cuvette and the double-coordinated passivated red perovskite quantum dots prepared in Example 2 were irradiated with a 450 nm excitation light source. The spectra of both were collected, and the following results were obtained: Figure 2 The photoluminescence spectra shown are obtained by converting the light intensity of the blank and the sample from Example 2 into photon counts, and then dividing the number of photon counts after photoluminescence of the double-coordinate passivated red perovskite quantum dots by the number of photoluminescence photon counts when irradiating the blank solvent, finally yielding the corresponding photoluminescence quantum yield (PLQY). Compared to the perovskite quantum dots without double-coordinate passivation, the PLQY of the double-coordinate passivated red perovskite quantum dots prepared in Example 2 increased from 68.4% to 87.5%, indicating that this post-treatment double-coordinate passivation can effectively improve the PLQY of perovskite quantum dots and reduce the defects inherent in the perovskite quantum dots themselves.

[0043] Experimental Example 3: Further testing was conducted on the light-emitting performance of the LED obtained in Example 3. Figure 3 The JLV and EQE-L curves for the PeLEDs device are shown. Compared to PeLEDs without taurine hydrochloride post-treatment, the maximum luminance of the device is 3574 cd / m². 2 It is far lower than the 6840 cd / m³ after passivation with taurine hydrochloride post-treatment. 2 In addition, PeLEDs based on taurine hydrochloride passivation exhibited a higher device efficiency of 18.4%, significantly higher than the 8.9% of untreated devices. These experiments demonstrate that taurine hydrochloride passivation effectively reduces surface defects in quantum dots, and that the short side-chain structure of the ligand effectively increases the conductivity of the light-emitting layer compared to the original oleic acid-oleylamine ligand.

[0044] Experimental Example 4: The perovskite quantum dot solution prepared in Example 4 was dropped onto an ultrathin carbon film and allowed to air dry. The morphology of the perovskite quantum dots was characterized by TEM, and the results were as follows. Figure 4 The TEM image shown shows that the interplanar spacing of the quantum dots is 0.63 nm before and after taurine hydrochloride treatment, and the quantum dots exhibit a regular cubic phase.

[0045] Experimental Example 5: The red perovskite quantum dot solutions prepared in Example 4 before and after treatment were dropped into an XRD tank and air-dried. The double-coordinated passivated red perovskite quantum dots were characterized by XRD to obtain the following results. Figure 5 The XRD patterns shown indicate that the XRD diffraction peaks of the perovskite quantum dots before and after taurine hydrochloride treatment correspond to the α-phase CsPbI3, and the lattice did not change after treatment.

[0046] Experimental Example 6: Fourier transform infrared spectroscopy was performed by dropping uncoordinated passivated red perovskite quantum dots prepared in Example 4 and a solution of coordinated passivated red perovskite quantum dots onto a KBr pellet. The results were as follows: Figure 6 The infrared spectrum shown indicates that the perovskite quantum dots treated with taurine hydrochloride exhibit characteristic functional groups of ligands, suggesting that taurine hydrochloride was successfully bound to the surface of the quantum dots through dual coordination post-treatment.

[0047] Experimental Example 7: The dual-coordinated passivated red perovskite quantum dots prepared in Example 4 were spin-coated onto quartz glass at a speed of 2500 rpm, and XPS tests were performed to obtain the following results. Figure 7 The XPS spectra of S, Pb, and I elements are shown. It can be seen that the perovskite quantum dots treated with taurine hydrochloride exhibit an S spectrum, indicating that taurine hydrochloride was successfully introduced into the perovskite quantum dots. The Pb and I elements shift to lower binding energies after the introduction of taurine hydrochloride, indicating that there is an interaction between taurine hydrochloride and Pb and I.

[0048] Experimental Example 8: Fluorescence lifetime tests were performed on the perovskite quantum dot solution prepared in Example 4, and the following results were obtained: Figure 9 The PL decay plot shown indicates that the decay of perovskite quantum dots slows down after the introduction of taurine hydrochloride, and the fluorescence lifetime increases from 25.7 ns to 28.8 ns. This suggests that the introduction of taurine hydrochloride reduces the number of non-radiative decay channels in the perovskite quantum dots, leading to an increase in fluorescence lifetime.

[0049] Experimental Example 9: ITO / quantum dot / Ag electroluminescent diode device structures were fabricated using the red-light perovskite quantum dots obtained in Example 4 before and after treatment, for conductivity testing. A steeper slope in the curve indicates better conductivity of the quantum dot film. Figure 9 As shown, the quantum dots passivated with taurine hydrochloride have a larger slope, indicating that the passivation by dual coordination of taurine hydrochloride can improve the conductivity of quantum dots.

[0050] Experimental Example 10: The photoelectric performance of the electroluminescent diode prepared in Example 5 was characterized, and the following results were obtained: Figure 10 The EL curve shown is also included. Figure 10 This demonstrates that the treated electroluminescent diode exhibits excellent spectral stability, maintaining spectral stability throughout the voltage range from 3-7V. The LED device performance curve is shown in the figure. Figure 10As shown, devices fabricated from passivated perovskite quantum dots exhibit higher brightness and efficiency. The maximum brightness increases from 3783 cd / m². 2 Increased to 7142 cd / m 2 The device efficiency increased from 10.1% to 19.42%.

[0051] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for preparing dual-coordinate passivated red perovskite quantum dots, characterized in that: include, The process for preparing a monovalent cationic precursor from cesium carbonate, 1-octadecene and oleic acid; The process for preparing lead source precursors from lead halides, zinc halides, 1-octadecene, diisooctylphosphite and oleylamine; The process of thermally injecting the monovalent cation precursor into the lead source precursor and then cooling it to prepare a perovskite quantum dot solution; The process of purifying the perovskite quantum dot solution by antisolvent to obtain red light perovskite quantum dots; The process of preparing dual-coordinate passivated red perovskite quantum dots from the aforementioned red perovskite quantum dots and taurine hydrochloride.

2. The method for preparing dual-coordinate passivated red perovskite quantum dots according to claim 1, characterized in that: In the process of preparing the monovalent cation precursor, the ratio of cesium carbonate, 1-octadecene and oleic acid is controlled to be 100 mg: (3.4~3.6) mL: (0.3~0.5) mL.

3. The method for preparing dual-coordinated passivated red perovskite quantum dots according to claim 2, characterized in that: In the process of preparing the monovalent cation precursor, cesium carbonate, 1-octadecene and oleic acid are continuously stirred at a speed of more than 600 r / min, heated to 60~80℃ and dried under vacuum for 30~60 min, and then heated to 100~120℃ while maintaining nitrogen gas and holding for more than 20 min to obtain the monovalent cation precursor.

4. The method for preparing dual-coordinate passivated red perovskite quantum dots according to claim 1, characterized in that: In the preparation of the lead source precursor, the ratio of lead halide, zinc halide, 1-octadecene, diisooctylphosphite and oleylamine is controlled as (0.2~5.0) mmol: (0.5~15.0) mmol: (5~30) mL: (2~12) mL: (2~12) mL.

5. The method for preparing dual-coordinate passivated red perovskite quantum dots according to claim 4, characterized in that: In the preparation of the lead source precursor, lead halide, zinc halide, 1-octadecene, diisooctyl hypophosphite and oleylamine are continuously stirred at a speed of 600 r / min or higher, and nitrogen is purged and circulated multiple times at room temperature. Then, nitrogen is maintained and the temperature is raised to 150~170℃ and held for more than 10 min to obtain the lead source precursor.

6. The method for preparing dual-coordinate passivated red perovskite quantum dots according to claim 1, characterized in that: In the preparation of perovskite quantum dots, the ratio of monovalent cation precursor to lead source precursor is controlled to be 0.4 mL: (5~15) mL.

7. The method for preparing dual-coordinate passivated red perovskite quantum dots according to claim 1, characterized in that: In the preparation of dual-coordinated passivated red perovskite quantum dots, the ratio of red perovskite quantum dots to taurine hydrochloride is controlled to be (0.5~1.0) mL: 2 mg. Under stirring at 150~170℃, a monovalent cation precursor is thermally injected into the lead source precursor, and after 5 s, it is cooled in an ice-water bath to below 40℃ to obtain a perovskite quantum dot solution with an emission wavelength of 620~650 nm.

8. The method for preparing dual-coordinate passivated red perovskite quantum dots according to claim 1, characterized in that: In the preparation of dual-coordinate passivated red perovskite quantum dots, the red perovskite quantum dots were post-treated with taurine hydrochloride and stirred for 30 min. The post-treated pure red quantum dot solution was then centrifuged at a speed of 3000 r / min or higher for 3-5 min to obtain dual-coordinate passivated red perovskite quantum dots.

9. A dual-coordinate passivated red perovskite quantum dot, characterized in that: Prepared by the preparation method according to any one of claims 1 to 8.

10. An application of a dual-coordinate passivated red perovskite quantum dot, characterized in that: Application of the double-coordinated passivated red perovskite quantum dots prepared by any one of the preparation methods according to claims 1 to 8 in the preparation of electroluminescent diodes.

Images