Perovskite blue light quantum dot glass and preparation method and application thereof

Abstract

The invention discloses perovskite blue light quantum dot glass as well as a preparation method and application thereof, and relates to the technical field of inorganic photoelectric functional glass materials. The perovskite blue light quantum dot glass is composed of a component A and a component B, wherein the component A comprises the following components in percentage by mass based on the total mass of the component A: 9% of Na2CO3, 15-35% of SiO2, 45-65% of B2O3, 2-6% of ZnO, 1% of Cs2CO3, 2% of PbBr2 and 2% of NaBr; the component B is LaCl3 accounting for 0.1-4% of the total mass of the component A; the preparation method specifically comprises the following steps: weighing the raw materials, mixing, and grinding to obtain mixed powder; smelting the mixed powder to obtain a smelting solution; the smelting liquid is subjected to destressing, and a product subjected to destressing is obtained; and carrying out heat treatment on the product subjected to stress relief to obtain the perovskite blue light quantum dot glass. The prepared perovskite blue light quantum dot glass has excellent thermal stability, water stability and high light-emitting quantum efficiency, an LED device prepared from the quantum dot glass has stable blue light emission, and the preparation method is simple, low in cost and suitable for LED application.

Description

TECHNICAL FIELD

[0001] The application relates to a perovskite blue quantum dot glass and a preparation method and application thereof, and belongs to the technical field of inorganic photoelectric functional glass materials. BACKGROUND

[0002] All-inorganic perovskite quantum dots (CsPbX3, X=Cl, Br, I) are considered as an ideal candidate for the next generation of display, lighting and laser technology due to their narrow emission peak, high color purity, high luminescent efficiency and tunable emission wavelength. Among them, realizing high-efficiency and stable blue light emission (especially in the 470-480 nm wavelength range) is crucial for realizing full-color display and high-quality solid-state lighting. Meanwhile, blue light in this wavelength range can promote the secretion of melatonin in the human body, regulate the day-night sleep cycle, and reduce depression symptoms. In particular, 475 nm blue light has significant benefits for human health, providing potential possibilities for the development of various application scenarios. However, the development of blue perovskite quantum dots faces two major challenges. On the one hand, perovskite quantum dots (especially mixed chloride / bromide blue quantum dots) are extremely sensitive to water, oxygen and heat, and their crystal structure is prone to decomposition, leading to rapid decay of luminescent efficiency (PLQY) and spectral drift, which seriously restricts the performance of LED devices. On the other hand, compared with green and red perovskite quantum dots, the synthesis control of blue perovskite quantum dots is more difficult, and the defect density is higher, resulting in a large probability of non-radiative recombination. Therefore, the photoluminescence quantum yield is generally low. Researchers have used the strategy of adjusting the precursor concentration to control perovskite crystallization to improve the phase distribution and inhibit ion migration in mixed halide blue perovskite thin films. Although the EL spectrum of the high-efficiency sky blue perovskite light-emitting diode (PeLED) is stable at 482 nm, the external quantum efficiency is not high (EQE=8.5%). In addition, the PLQY of the solution-based perovskite blue quantum dots is between 30% and 70%, and such quantum dots are grown on a substrate. However, the high luminescent efficiency is derived from precise surface epitaxial growth and defect passivation, and the stability is poor. Therefore, it is necessary to develop a new type of perovskite blue quantum dot glass composite material, which has high stability and can effectively passivate quantum dot defects and improve the luminescent efficiency, thereby providing a broader application prospect for perovskite glasses. SUMMARY

[0003] In view of the deficiencies of the related art, the application provides a perovskite blue quantum dot glass and a preparation method and application thereof, which have excellent thermal stability, water stability and high quantum efficiency, and solve the problem of insufficient stability of quantum dot glasses.

[0004] One of the purposes of the present application is to provide a perovskite blue quantum dot glass, which is composed of component A and component B, wherein component A includes, in percentage of total mass of each raw material: 9% of Na2CO3, 15~35% of SiO2, 45~65% of B2O3, 2~6% of ZnO, 1% of Cs2CO3, 2% of PbBr2, 2% of NaBr, wherein the total mass of each raw material of component A is 100% in percentage; component B is 0.1~4% of LaCl3 of total mass of component A.

[0005] The second purpose of the present application is to provide a preparation method of perovskite blue quantum dot glass, which specifically includes the following steps: (1) The raw materials of each component are weighed according to the proportion, mixed and ground (preferably ground in an agate mortar for 30 min), to obtain a mixed powder.

[0006] (2) The mixed powder is subjected to high-temperature smelting (preferably high-temperature smelting in a box furnace), to obtain a smelting liquid.

[0007] (3) The smelting liquid is subjected to stress relief treatment, to obtain a post-stress relief product.

[0008] (4) The post-stress relief product is subjected to heat treatment (preferably heat treatment in a muffle furnace), to obtain a perovskite blue quantum dot glass.

[0009] Preferably, the high-temperature smelting in step (2) is performed at 1200~1300℃ for 15~20 min.

[0010] Preferably, the stress relief treatment in step (3) is performed at 350~370℃ for 2~2.5 h.

[0011] Preferably, the heat treatment in step (4) is performed at 450~500℃ for 10~12 h.

[0012] The third purpose of the present application is to provide an application of the perovskite blue quantum dot glass prepared by the present application in the preparation of optoelectronic devices (i.e. light-emitting diodes, LEDs) in display technology and lighting fields.

[0013] The mechanism of the present application: The application realizes accurate regulation of the glass network structure through the synergistic effect of LaCl3 doping and B2O3 / SiO2, ZnO, and then promotes the uniform nucleation, controllable growth and high-efficiency luminescence of quantum dots. The quantum dot glass prepared by the application does not produce competitive luminescence, and the blue light efficiency of the quantum dots is stable. In addition, the application realizes the evolution of the glass network from three-dimensional to two-dimensional layered structure, thereby reducing the energy barrier of ion migration, promoting the controllable crystallization and high-efficiency blue light emission of CsPbBrCl2 quantum dots, and the Cl - ion in LaCl3 has a strong affinity with Cs + and Pb 2+ large radius cations, which further catalyzes the nucleation of quantum dots. This mechanism not only solves the technical problems of non-uniform crystallization and poor stability of perovskite quantum dots in glass, but also provides a feasible technical path for developing high-performance and high-stability blue light emitting glass composite materials, which is suitable for LED, display, laser optoelectronic devices.

[0014] The beneficial effects of the application are as follows: (1) The perovskite blue quantum dot glass of the application has a luminescence wavelength of 475nm, and the luminescence quantum efficiency can reach 22.58% when heat treated at 450℃, which has high luminescence efficiency and good thermal stability and water stability.

[0015] (2) The LED device prepared from the glass powder of the application has excellent blue light emission characteristics.

[0016] (3) The preparation process of the perovskite quantum dot glass of the application is simple, cost-saving, and conducive to industrial production and application. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 The apparent morphology diagram of the glass samples prepared in the comparative examples 1~2 of the application.

[0018] Figure 2 The TEM diagram of the glass samples prepared in the comparative examples 1~2 of the application.

[0019] Figure 3 The luminescence diagram of the perovskite blue quantum dot glass prepared in the examples 1~5 of the application under the excitation of 365nm light source.

[0020] Figure 4 The XRD diagram of the perovskite blue quantum dot glass prepared in the examples 2~4 of the application.

[0021] Figure 5Figure 4 shows the emission spectra of the perovskite blue quantum dot glass prepared in Example 4 of this invention during single and multiple thermal cycles, as well as the emission spectra at different immersion times. Figure (a) shows the 477nm emission intensity of the CsPbBrCl2 quantum dot glass in the perovskite blue quantum dot glass prepared in Example 4 during a single thermal cycle; Figure (b) shows the 477nm emission intensity of the CsPbBrCl2 quantum dot glass in the perovskite blue quantum dot glass prepared in Example 4 during multiple thermal cycles; and Figure (c) shows the 477nm emission intensity of Example 4 at different immersion times.

[0022] Figure 6 Figure 4 shows the photoluminescence (PL) spectrum and chromatogram of the LED device prepared from perovskite blue quantum dot glass in Example 4 of this invention, as well as the PL spectrum change at 3.2V. Figure (a) shows the photoluminescence (PL) spectrum and chromatogram of CsPbBrCl2 quantum dot glass; Figure (b) shows the PL spectrum change after CsPbBrCl2 quantum dot glass is converted into a blue LED; and Figure (c) shows the PL spectrum change of CsPbBrCl2 quantum dot glass at 3.2V. Detailed Implementation

[0023] To better illustrate the purpose, technical solution, and advantages of this invention, the invention will be further described below with reference to specific embodiments. In the embodiments and comparative examples of this invention, unless otherwise specified, all chemical reagents used were commercially available analytical grade reagents.

[0024] Example 1 A method for preparing perovskite blue quantum dot glass specifically includes the following steps: (1) Weigh and mix component A and component B, grind them in an agate mortar for 30 minutes to obtain a mixed powder. Component A includes, by mass percentage of its total mass: 9% Na2CO3, 35% SiO2, 45% B2O3, 6% ZnO, 1% Cs2CO3, 2% PbBr2, and 2% NaBr; component B is 4% of the total mass of component A, which is LaCl3.

[0025] (2) Transfer the mixed powder to an alumina crucible, then cover it with an alumina lid, and melt it in a box furnace at 1200°C for 15 minutes to obtain a melt.

[0026] (3) Transfer the molten liquid to a brass mold preheated to 350°C and keep it at that temperature for 2 hours to achieve stress relief and obtain the precursor glass.

[0027] (4) The stress-relieved product was placed in a muffle furnace and annealed at 450°C for 10 hours to improve its structural stability and obtain perovskite blue quantum dot glass.

[0028] Example 2 A method for preparing perovskite blue quantum dot glass specifically includes the following steps: (1) Weigh and mix component A and component B, grind them in an agate mortar for 30 minutes to obtain a mixed powder. Component A includes, by mass percentage of its total mass: 9% Na2CO3, 34% SiO2, 50% B2O3, 2% ZnO, 1% Cs2CO3, 2% PbBr2, and 2% NaBr; component B is 0.1% LaCl3 of the total mass of component A.

[0029] (2) Transfer the mixed powder to an alumina crucible, then cover it with an alumina lid, and melt it in a box furnace at 1300°C for 16 minutes to obtain a melt.

[0030] (3) Transfer the molten liquid to a brass mold preheated to 370°C and keep it at that temperature for 2.25 hours to achieve stress relief and obtain the precursor glass.

[0031] (4) The stress-relief product was placed in a muffle furnace and annealed at 500°C for 11 hours to improve its structural stability and obtain perovskite blue quantum dot glass.

[0032] The XRD pattern of the perovskite blue quantum dot glass prepared in this embodiment is shown below. Figure 4 As shown.

[0033] Example 3 A method for preparing perovskite blue quantum dot glass specifically includes the following steps: (1) Weigh and mix component A and component B, grind them in an agate mortar for 30 minutes to obtain a mixed powder. Component A includes, by mass percentage of its total mass: 9% Na2CO3, 27% SiO2, 55% B2O3, 4% ZnO, 1% Cs2CO3, 2% PbBr2, and 2% NaBr; component B is 0.4% of the total mass of component A, which is LaCl3.

[0034] (2) Transfer the mixed powder to an alumina crucible, then cover it with an alumina lid, and melt it in a box furnace at 1250°C for 20 minutes to obtain a melt.

[0035] (3) Transfer the molten liquid to a brass mold preheated to 355°C and keep it at that temperature for 2.5 hours to achieve stress relief and obtain the precursor glass.

[0036] (4) The stress-relieved product was placed in a muffle furnace and annealed at 470°C for 12 hours to improve its structural stability and obtain perovskite blue quantum dot glass.

[0037] The XRD pattern of the perovskite blue quantum dot glass prepared in this embodiment is shown below. Figure 4 As shown.

[0038] Example 4 A method for preparing perovskite blue quantum dot glass specifically includes the following steps: (1) Weigh and mix component A and component B, grind them in an agate mortar for 30 minutes to obtain a mixed powder. Component A includes, by mass percentage of its total mass: 9% Na2CO3, 20% SiO2, 60% B2O3, 6% ZnO, 1% Cs2CO3, 2% PbBr2, and 2% NaBr; component B is 4% of the total mass of component A, which is LaCl3.

[0039] (2) Transfer the mixed powder to an alumina crucible, then cover it with an alumina lid, and melt it in a box furnace at 1200°C for 15 minutes to obtain a melt.

[0040] (3) Transfer the molten liquid to a brass mold preheated to 350°C and keep it at that temperature for 2 hours to achieve stress relief and obtain the precursor glass.

[0041] (4) The stress-relieved product was placed in a muffle furnace and annealed at 450°C for 10 hours to improve its structural stability and obtain perovskite blue quantum dot glass.

[0042] The XRD pattern of the perovskite blue quantum dot glass prepared in this embodiment is shown below. Figure 4 As shown; the emission spectra of the perovskite blue quantum dot glass prepared in this embodiment under single and multiple thermal cycles, and the emission spectra under different immersion times are shown in the figure. Figure 5 As shown, when the perovskite blue quantum dot glass is heated, the fluorescence weakens, causing a temporary decrease in PL intensity. When cooled, the PL intensity gradually recovers to its initial level (e.g., ...). Figure 5 (a) shows that the CsPbBrCl2 quantum dots are fully integrated within the glass matrix, avoiding crystal degradation and agglomeration. To test the thermal cycling stability of the CsPbBrCl2 quantum dot glass, the sample underwent 10 thermal cycles, heating and cooling from 30°C to 200°C, and the changes in luminescence intensity were observed (e.g., as shown in (a)). Figure 5 As shown in (b), although the luminescence intensity decreases slightly at approximately 477 nm, it remains at 92.9% of the initial intensity value throughout the experiment. This indicates that the prepared CsPbBrCl2 quantum dot glass exhibits excellent thermal cycling stability. Figure 5(c) The luminescence intensity of the sample with a borosilicate ratio of 3 was measured by time-release after continuous immersion for 30 days. The luminescence intensity of the CsPbBrCl2 quantum dots decreased slightly during water exposure, but remained at 92.29% of the initial intensity after 30 days; this confirms that the perovskite quantum dot glass has excellent water stability and performance suitable for practical applications; the luminescence quantum efficiency (PLQY value) of the perovskite blue quantum dot glass prepared in this embodiment can reach 22.58% after heat treatment at 450℃. The photoluminescence (PL) spectrum and chromatogram of the LED device prepared by the perovskite blue quantum dot glass in this embodiment, as well as the PL spectrum change at 3.2V, are shown in the figure. Figure 6 As shown in the figure, Figure (a) shows the photoluminescence (PL) spectrum and chromatogram of CsPbBrCl2 quantum dot glass. Figure (a) shows that the PL spectrum of CsPbBrCl2 quantum dot glass has a narrow peak shape, indicating that its emission has good monochromaticity and high color purity. At the same time, the blue-green light region corresponding to the spectral peak corresponds to the blue light spot in the upper right corner of the spectrum, confirming that its actual emission is blue-green. Figure (b) shows the PL spectrum change of CsPbBrCl2 quantum dot glass after being converted into a blue LED. This figure shows that the chromaticity coordinates of the blue LED made of quantum dot glass fall in the blue light region, which meets the color requirements of blue LED. The colored area in the figure is the variation range of the PL spectrum. The smaller the range, the less the color drift of the emitted light and the better the stability when the LED is working. Figure (c) shows the PL spectrum change of CsPbBrCl2 quantum dot glass at 3.2V. At 3.2V, the peak positions of the PL spectrum of quantum dot glass with different thicknesses are close, indicating that the thickness change does not significantly change the emission color, but the peak intensity is different, which shows that the thickness affects its luminous efficiency.

[0043] Example 5 A method for preparing perovskite blue quantum dot glass specifically includes the following steps: (1) Weigh and mix component A and component B, grind them in an agate mortar for 30 minutes to obtain a mixed powder. Component A includes, by mass percentage of its total mass: 9% Na2CO3, 15% SiO2, 65% B2O3, 6% ZnO, 1% Cs2CO3, 2% PbBr2, and 2% NaBr; component B is 4% of the total mass of component A, which is LaCl3.

[0044] (2) Transfer the mixed powder to an alumina crucible, then cover it with an alumina lid, and melt it in a box furnace at 1200°C for 15 minutes to obtain a melt.

[0045] (3) Transfer the molten liquid to a brass mold preheated to 350°C and keep it at that temperature for 2 hours to achieve stress relief and obtain the precursor glass.

[0046] (4) The stress-relieved product was placed in a muffle furnace and annealed at 450°C for 10 hours to improve its structural stability and obtain perovskite blue quantum dot glass.

[0047] like Figure 3 As shown in (ab), the perovskite blue quantum dot glass materials prepared in Examples 1-5 appear transparent yellow under sunlight and emit bright blue light under a 365nm excitation light source.

[0048] The XRD patterns of the perovskite blue quantum dot glasses prepared in Examples 1-5 show that the perovskite peaks are located within the standard diffraction peaks of CsPbBr3 and CsPbCl3. This indicates that some Cl atoms have been incorporated into the CsPbBr3 lattice, thereby partially replacing Br atoms; this demonstrates that CsPbBrCl2 perovskite quantum dots have been successfully synthesized.

[0049] The perovskite blue quantum dot glasses prepared in Examples 1-5 all exhibited significant emission intensity under 365nm ultraviolet light excitation, with an emission peak at 477nm and a narrow half-width at half-maximum. This narrow emission band is consistent with the emission peak and bandwidth of CsPbBrCl2 quantum dots, indicating high color purity.

[0050] In photoluminescence quantum yield (PLQY) testing, the perovskite blue quantum dot glass prepared using the method of this invention exhibited excellent luminescence efficiency. The perovskite blue quantum dot glasses prepared in Examples 1-5 achieved a luminescence quantum efficiency of 22.58% under 365nm ultraviolet light excitation, with high luminescence intensity. This demonstrates that high-performance blue light-emitting materials can be successfully obtained within the specified process parameters.

[0051] The emission spectra of the perovskite blue quantum dot glasses prepared in Examples 1-5 under single and multiple thermal cycles, as well as emission spectra at different immersion times, show that when the perovskite blue quantum dot glass is heated, fluorescence quenching leads to a temporary decrease in PL intensity. However, upon cooling, the PL intensity gradually recovers to its initial level, indicating that the CsPbBrCl2 quantum dots are fully integrated within the glass matrix, avoiding crystal deterioration and agglomeration. To test the thermal cycling stability of the CsPbBrCl2 quantum dot glass, the sample underwent 10 thermal cycles, heating and cooling from 30°C to 200°C, and the changes in emission intensity were observed. Although the emission intensity decreased slightly at 477 nm, the loss from the initial intensity was minimal throughout the experiment. This indicates that the prepared CsPbBrCl2 quantum dot glass possesses excellent thermal cycling stability.

[0052] Comparative Example 1 A method for preparing perovskite glass specifically includes the following steps: (1) Weigh the raw materials according to the following proportions based on the mass percentage of each component: 9% Na2CO3, 25% SiO2, 55% B2O3, 6% ZnO, 1% Cs2CO3, 2% PbBr2, and 2% NaBr. Mix them and grind them in an agate mortar for 30 minutes to obtain a mixed powder.

[0053] (2) Transfer the mixed powder to an alumina crucible, then cover it with an alumina lid, and melt it in a box furnace at 1200°C for 15 minutes to obtain a melt.

[0054] (3) Transfer the molten liquid to a brass mold preheated to 350°C and keep it at that temperature for 2 hours to achieve stress relief and obtain the precursor glass.

[0055] (4) The stress-relieved product was placed in a muffle furnace and annealed at 450°C for 10 hours to improve its structural stability and obtain perovskite glass.

[0056] Comparative Example 2 A method for preparing perovskite glass specifically includes the following steps: (1) Weigh the raw materials according to the following proportions based on the mass percentage of each component: 9% Na2CO3, 20% SiO2, 60% B2O3, 6% ZnO, 1% Cs2CO3, 2% PbBr2, and 2% NaBr. Mix them and grind them in an agate mortar for 30 minutes to obtain a mixed powder.

[0057] (2) Transfer the mixed powder to an alumina crucible, then cover it with an alumina lid, and melt it in a box furnace at 1200°C for 15 minutes to obtain a melt.

[0058] (3) Transfer the molten liquid to a brass mold preheated to 350°C and keep it at that temperature for 2 hours to achieve stress relief and obtain the precursor glass.

[0059] (4) The stress-relieved product was placed in a muffle furnace and annealed at 450°C for 10 hours to improve its structural stability and obtain perovskite glass.

[0060] The apparent morphology of the perovskite glasses prepared in Comparative Examples 1 and 2 is as follows: Figure 1 As shown, it exhibits a transparent glass-like appearance. TEM observations were performed on the perovskite glasses prepared in Comparative Examples 1 and 2 (e.g., Figure 2 As shown in the figure, no quantum dot precipitation was observed. This is because in Comparative Examples 1 and 2, which were undoped with LaCl3, the glass network could not effectively evolve from a three-dimensional structure to a two-dimensional layered structure that is more conducive to ion migration and quantum dot confinement growth. The ion diffusion barrier was too high, causing Cs to... + Pb 2+Precursor ions are difficult to migrate and aggregate to reach the critical nucleation concentration; the lack of Cl introduced by LaCl3 - Ion pairs Cs + Pb 2+ The strong affinity and coordination of large-radius cations cause the system to lose its active center for catalytic heterogeneous nucleation of quantum dots, resulting in the inability of quantum dots to be effectively initiated and grown. Therefore, the final product is only a uniform and transparent glass matrix with no quantum dots precipitated inside, and it has no luminescent properties at all.

[0061] The application of a perovskite blue quantum dot glass as an optoelectronic device (i.e., light-emitting diode (LED)) in display technology and lighting fields specifically includes the following steps: The blue luminescent CsPbBrCl2 quantum dot glass powder prepared according to this invention, epoxy resin A, and epoxy resin B are mixed in a mass ratio of 2:3:1 to obtain a mixture. After mixing, the mixture is dropped into the middle of a 365nm LED chip and left to stand for 12 hours to fully cure, thus obtaining a light-emitting diode (LED).

[0062] The fabricated LED emitted a bright blue light under a constant voltage of 3.2V. At this driving voltage, the device emitted light with a wavelength of 477nm and CIE color coordinates of 0.1362, 0.1612. Finally, to test color stability, the brightness intensity was measured using different driving currents. The results showed that as the current gain increased, the emission intensity increased, while the blue emission peak remained consistent, indicating stable blue light emission. Therefore, CsPbBrCl2 quantum dot glass is suitable for use in optical devices with good external effects and can be applied to practical LED production.

[0063] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or improvement of the technology in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A perovskite blue quantum dot glass, characterized in that, The perovskite blue quantum dot glass is composed of component A and component B. Component A comprises, by mass percentage of its total mass: 9% Na2CO3, 15-35% SiO2, 45-65% B2O3, 2-6% ZnO, 1% Cs2CO3, 2% PbBr2, and 2% NaBr, wherein the total mass of each raw material in component A is 100% by mass percentage. Component B is 0.1-4% LaCl3 by mass of component A.

2. The method for preparing the perovskite blue quantum dot glass according to claim 1, characterized in that, Specifically, the following steps are included: (1) Weigh each component raw material according to the proportion and mix and grind them to obtain a mixed powder; (2) The mixed powder is smelted at high temperature to obtain a molten liquid; (3) Stress relief treatment is performed on the molten liquid to obtain the stress-relieved product; (4) The stress-relief product is heat-treated to obtain perovskite blue quantum dot glass.

3. The method for preparing perovskite blue quantum dot glass according to claim 2, characterized in that, The conditions for high-temperature melting in step (2) are: melting at 1200~1300℃ for 15~20min.

4. The method for preparing perovskite blue quantum dot glass according to claim 2, characterized in that, The stress relief treatment in step (3) is performed at a temperature of 350~370℃ for 2~2.5h.

5. The method for preparing perovskite blue quantum dot glass according to claim 2, characterized in that, The heat treatment conditions in step (4) are: heat treatment at 450~500℃ for 10~12h.

6. The application of the perovskite blue quantum dot glass described in claim 1 in the fabrication of optoelectronic devices in the fields of display technology and lighting.

Images