A perovskite quantum dot glass with enhanced luminescence ability and its preparation method and application

Abstract

The present invention discloses a perovskite quantum dot glass with enhanced luminescence capability, a preparation method thereof, and an application thereof, and belongs to the field of perovskite quantum dot glass display technology. The present invention regulates the network structure of borosilicate glass by adding ZrO2, so that the perovskite quantum precursor glass gradually changes from self-crystallization to transparency and finally to devitrification, the network structure of the glass matrix is ​​ordered, the surface defects at the interface between the perovskite quantum dots and the glass matrix are passivated, and the radiation recombination probability is increased, thereby obtaining a perovskite quantum dot glass with significantly improved photoluminescence performance. The perovskite quantum dot glass has a green light emission wavelength of 527nm, a full width at half maximum (FWHM) of 25.8nm, an internal quantum dot efficiency of 93.1%, and a brightness of 375cd / m ‑2 The maximum green light brightness under the excitation of the blue light (450nm) plate can reach 2647cd / m ‑2 When this perovskite quantum dot glass is used as an LED backlight module in LCD display, it can achieve a color gamut area of ​​118% of the NTSC standard, which is 1.73 times the color gamut of commercial displays, achieving a wide color gamut display effect.

Description

Technical Field

[0001] The present invention belongs to the field of perovskite quantum dot glass display technology, and specifically relates to a perovskite quantum dot glass with enhanced luminescence capability, and a preparation method and application thereof. Background Art

[0002] All-inorganic CsPbX3 (X = Cl, Br, I) perovskite quantum dot materials have become a research hotspot due to their excellent optical properties, including high photoluminescence quantum yield, narrow-band emission, and wide color gamut. In recent years, researchers have optimized quantum dot materials through various methods, including synthesis methods and structural / performance optimization, achieving unprecedented progress in the practical applications of quantum dot LEDs, LCDs, lasers, photodetectors, and scintillators. However, colloidal CsPbX3 quantum dots prepared by methods such as cation / anion exchange, solvothermal reaction, and hot injection generally exhibit poor long-term stability in the presence of water, heat, and light due to the large surface energy of the quantum dots and the influence of their inherent ionic structure. The non-dense structures obtained by these methods are insufficient to protect the quantum dots from external environmental influences. Therefore, attempts were made to embed CsPbX3 quantum dots into glass to prepare CsPbX3 quantum dot glass. By utilizing the dense structure and excellent physical / chemical stability of glass, the perovskite quantum dots were controlled to precipitate in situ in the glass matrix, so that the perovskite quantum dot glass was completely encapsulated, isolating it from the external environment and effectively improving its stability.

[0003] At the same time, as an emerging luminescent and optoelectronic material, perovskite quantum dot glass is being studied for its luminescence and photoelectric conversion properties. It is being used in applications such as LED backlighting and display materials, LED active layer luminescent materials, laser gain medium materials, detector materials, and solar cell photoconversion materials. Among them, green-emitting perovskite (CsPbBr3, CsPb2Br5, and Cs4PbBr6) quantum dots exhibit strong exciton absorption and steep short-wavelength cutoff characteristics. When coupled with commercially available blue InGaN chips, they can form white LEDs that meet the requirements of wide color gamut displays, and are therefore attracting increasing attention in the backlight display industry.

[0004] However, in the process of preparing precursor glass by melting and rapid cooling, and then inducing crystal precipitation and growth by subsequent heat treatment, the rigidity of the glass network structure or the growth of perovskite crystals in the network gap are restricted, resulting in many surface defects in the interface contact between it and the glass matrix, resulting in a generally lower luminescence ability than colloidal quantum dots. Therefore, the development of a perovskite quantum dot glass with improved luminescence ability and the ability to meet the requirements of wide color gamut display is of great significance and application value.

[0005] The invention with publication number CN110534631A discloses a wide color gamut backlight source for display combining LED with perovskite quantum dot microcrystalline glass. The backlight source includes LED and perovskite quantum dot microcrystalline glass. By utilizing perovskite quantum dot microcrystalline glass in combination with LED as a backlight source for display, the luminous quantum efficiency, environmental stability and mechanical stability are improved. However, this invention does not provide a relevant solution to the problem of low luminescence ability caused by surface defects between perovskite crystals and glass matrix; the invention with publication number CN115806385A provides a CsPbBr3 perovskite quantum dot glass with high light stability and high thermal stability, and its preparation method and application. The prepared CsPbBr3 perovskite quantum dot glass can still maintain a high luminescence intensity at high temperature. This invention focuses on improving the thermal stability of perovskite quantum dot glass. How to improve its photoluminescence performance, improve the crystallization environment of perovskite quantum dots in the glass matrix and the probability of radiation recombination has not yet been mentioned. Summary of the Invention

[0006] The present invention discloses a perovskite quantum dot glass with enhanced luminescence ability, a preparation method and an application thereof. By adding ZrO2 to regulate the network structure of borosilicate glass, the network structure of the glass matrix is ​​ordered, thereby significantly improving the photoluminescence performance of the perovskite quantum dot glass.

[0007] The technical solutions of the present invention are as follows:

[0008] One of the objectives of the present invention is to provide a perovskite quantum dot glass with enhanced luminescence ability. The perovskite quantum dot glass is made from glass matrix raw material powder and quantum dot raw material powder as raw materials, and is marked as CsPbBr3@glass, wherein the glass matrix raw material powder is composed of SiO2, B2O3, ZnO, SrCO3, K2CO3, Ba2CO3, Sb2O3, and ZrO2, and the quantum dot raw material powder is composed of Cs2CO3, PbBr2, and NaBr.

[0009] Furthermore, the glass matrix raw material powder is weighed and proportioned according to the respective molar percentages of 30~50 SiO2-75~90 B2O3-25~35 ZnO-4~10 SrO-4~10 K2CO3-1~5 BaO-1~3 Sb2O3-X ZrO2.

[0010] Furthermore, the quantum dot raw material powders are weighed and mixed according to the respective molar percentages of 10-20 Cs2CO3, 25-40 PbBr2, and 25-40 NaBr.

[0011] Furthermore, the ZrO2 addition amount X is 0-8 mol%.

[0012] A second object of the present invention is to provide a method for preparing perovskite quantum dot glass with enhanced luminescence capability, comprising the following steps:

[0013] S1. Grind the glass matrix raw material powder and quantum dot raw material powder evenly in an agate mortar, transfer the ground materials to an alumina crucible, and place them in a high-temperature muffle furnace for calcination;

[0014] S2, pouring the molten glass calcined in step S1 into a brass mold and rapidly cooling it to obtain precursor glass;

[0015] S3. The precursor glass is subjected to heat treatment and crystallization at 500-530°C to induce the in-situ growth of CsPbBr3 nanocrystals in the glass matrix to obtain perovskite quantum dot glass CsPbBr3@glass.

[0016] Furthermore, the calcination temperature in S1 is 1100-1300° C., and the calcination time is 10-45 minutes.

[0017] Furthermore, the crystallization time of the precursor glass in S3 is 2-12 hours.

[0018] The third object of the present invention is to provide a perovskite quantum dot glass with improved luminescence ability for use in an LED backlight module. When the perovskite quantum dot glass diffuser is used to make an LED backlight module for LCD display, a wide color gamut display effect can be achieved.

[0019] Furthermore, the LED backlight module preparation method is as follows:

[0020] (1) ball milling the perovskite quantum dot glass into powder, mixing it with red perovskite quantum dot glass powder CsPb(Br / I)3PeQDs at a mass ratio of 2:1 to obtain a composite powder, and then mixing the composite powder with LED high refractive index organic silica gel at a mass ratio of 1:6 and stirring evenly;

[0021] (2) Evenly apply composite powder-organic silica gel on the surface of 450nm InGaN blue LED strip, and place the LED strip in a drying oven for curing;

[0022] (3) Fix the LED light strips obtained in step (2) on the reflective film plastic plate at equal intervals, then stack the light guide plate, diffusion film, light enhancement film, and reflective polarized light enhancement film in sequence below, and finally package them into a module through connecting wires.

[0023] Furthermore, in step (1), the average particle size of the perovskite quantum dot glass powder is less than 10 μm; and in step (2), the curing process is an initial bake at 100° C. for 1 hour and a long bake at 150° C. for 3 hours.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] 1. The present invention proposes for the first time to add ZrO2 to the glass matrix raw material powder to regulate the network structure of borosilicate glass, so that the network structure of the glass matrix is ​​ordered, effectively reducing the surface defects at the interface between the perovskite quantum dots and the glass matrix, and increasing the probability of radiative recombination of the perovskite quantum dot glass. Thanks to the ordered network structure of the borosilicate glass, the crystallization environment of the perovskite quantum dots in the glass matrix is ​​improved, promoting a significant improvement in the photoluminescence performance of the prepared perovskite quantum dot glass.

[0026] 2. The present invention provides a perovskite quantum dot glass with enhanced luminescence capability. The perovskite quantum dot glass has an emission wavelength of 527 nm, a full width at half maximum (FWHM) of 25.8 nm, an internal quantum dot efficiency of 93.1%, and a green light emission capacity of 375 cd / m -2 Under the excitation of the blue light (450 nm) plate, the maximum green light brightness can reach 2647 cd / m -2 .

[0027] 3. When the perovskite quantum dot glass prepared by the present invention is used as an LED backlight module for LCD display, the produced LED backlight module can meet the wide color gamut display effect. Its color gamut area can reach 1.73 times the color gamut of commercial displays and reach 118% of the color gamut area of ​​NTSC (through a color filter). In addition, the preparation method provided by the present invention has readily available raw materials, a simple preparation process, conforms to the concept of green chemistry, has strong repeatability, and is suitable for large-scale preparation. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 a is an X-ray diffraction pattern of the perovskite quantum dot glass precursor glass with different ZrO2 contents prepared in Example 1 of the present invention; Figure 1 b is the X-ray diffraction pattern of the precursor glass after heat treatment;

[0029] Figure 2 The Raman spectra of the perovskite quantum dot glass with different ZrO2 contents prepared in Example 1 of the present invention are shown in FIG.

[0030] Figure 3 This is a probability diagram of radiative recombination and non-radiative recombination of perovskite quantum dot glass with different ZrO2 contents prepared in Example 1 of the present invention;

[0031] Figure 4CIE chromaticity diagram of the commercial liquid crystal display color gamut (red dotted line), the NSTC 1953 standard color gamut (blue dotted line), the Rec. 2020 standard color gamut (gray dotted line), and the color gamut of the white light obtained by the perovskite quantum dot glass LED backlight module prepared in Example 2 of the present invention after being filtered through a commercial color filter (black solid line);

[0032] Figure 5 This is a spectrum diagram of the blue light excitation plate used in the performance test of the perovskite quantum dot glass for luminous brightness testing;

[0033] Figure 6 This is a statistical chart of the luminous brightness test of perovskite quantum dot glass in the performance test of the present invention. DETAILED DESCRIPTION

[0034] The present invention will be further described below in conjunction with the accompanying drawings and preferred embodiments. The given embodiments are only for illustrating the present invention, rather than for limiting the scope of the present invention.

[0035] Unless otherwise specified, the materials and reagents used in the following examples can be obtained from commercial sources.

[0036] The quantitative tests in the following examples were repeated three times, and the results were averaged.

[0037] The experimental methods in the following examples are conventional methods unless otherwise specified.

[0038] Example 1

[0039] This embodiment provides a perovskite quantum dot glass with enhanced luminescence capability, and the preparation method thereof is as follows:

[0040] S1. Weigh and proportion the raw materials according to the following molar percentages: 42SiO2-80B2O3-30ZnO-7SrO-7K2CO3-3BaO-2Sb2O3-16Cs2CO3-35PbBr2-35NaBr-x ZrO2 (x=0, 2, 4, 6, 8) (in mol%);

[0041] S2. Grind the raw materials in an agate mortar for 5 minutes until uniform, then transfer them to an alumina crucible, and place them in a high-temperature muffle furnace and calcine them at 1200° C. for 10 minutes to obtain molten glass;

[0042] S3. Pour the molten glass calcined in step S2 into a brass mold and quench it to obtain a precursor glass. The precursor glass is heat-treated and crystallized at 530°C for 10 h to induce the in-situ growth of CsPbBr3 nanocrystals in the glass matrix to obtain perovskite quantum dot glass CsPbBr3@glass.

[0043] The preparation method of the perovskite quantum dot glass can adjust the calcination conditions to 500° C. / 45 min or 515° C. / 30 min, and the crystallization time to 12 h or 2 h according to the actual preparation process.

[0044] Example 2

[0045] This embodiment provides a perovskite quantum dot glass with enhanced luminescence capability for use in an LED backlight module. When the perovskite quantum dot glass diffuser is used to manufacture an LED backlight module for LCD display, a wide color gamut display effect can be achieved. The LED backlight module is manufactured as follows:

[0046] S1. Ball mill the perovskite quantum dot glass 6ZrO2CsPbBr3@glass described in Example 1 to a powder with an average particle size of 8 μm, mix the perovskite quantum dot glass powder in a mass ratio of 2:1 to obtain a composite powder, wherein the composite powder comprises 5 g of green 6ZrO2CsPbBr3@glass and 2.5 g of red perovskite quantum dot glass powder, and then mix the composite powder with LED high-refractive index organic silica gel in a mass ratio of 1:6 and stir evenly;

[0047] S2. Use an LED dispensing machine to evenly apply composite powder-silicone to the surface of four (96 in total) 450nm InGaN blue LED strips. Then place the LED strips in a drying oven and bake them at 100°C for 1 hour and then at 150°C for 3 hours to cure.

[0048] S3, fix the LED light strips obtained in step (2) on the reflective film plastic plate at equal intervals, then stack the light guide plate, diffusion film, light enhancement film, reflective polarized light enhancement film in sequence, and finally package them into a module through connecting wires.

[0049] Performance Testing

[0050] First, the perovskite quantum dot glass after heat treatment and crystallization in Example 1 was ball milled to an average particle size of 9 μm;

[0051] Secondly, 3g of perovskite quantum dot glass powder and 7g of ultraviolet curing adhesive (UV adhesive) were placed in a beaker and stirred evenly for 1h;

[0052] Finally, cut the diffuser into equal pieces of 2x2 cm 2 Square, use a doctor blade to evenly apply perovskite quantum dot glass-UV glue on the top of the diffusion film to form a three-layer structure of diffusion film-perovskite quantum dot powder-diffusion film, and use a 365nm ultraviolet curing lamp to irradiate for 10s for curing.

[0053] Performance Characterization

[0054] 1. Figure 1a is an X-ray diffraction pattern of the perovskite quantum dot glass precursor glass prepared by adding different amounts of ZrO2 in Example 1 of the present invention, indicating that the ZrO2 diffraction peak appears on the amorphous structure of the precursor glass doped with excessive ZrO2 (x=8); Figure 1 b is the X-ray diffraction pattern of the precursor glass after heat treatment, which proves that cubic CsPbBr3 quantum dots appear in the matrix of borosilicate glass after heat treatment;

[0055] 2. Figure 2 The Raman spectra of the perovskite quantum dot glass with different ZrO2 contents prepared in Example 1 of the present invention are shown in Figure 1. The characteristic peak of CsPbBr3 is between 20 and 80 cm -1 At 1200-1400 cm -1 The vibration peak intensity shows a trend of first increasing and then decreasing with the increase of ZrO2 content; in addition, the ZrO2 signal is detected in the 8mol% ZrO2 sample, indicating that the glass network structure shows changes.

[0056] 3. Figure 3 This is a probability diagram of radiative recombination and non-radiative recombination of the perovskite quantum dot glass with different ZrO2 contents prepared in Example 1 of the present invention. It can be seen that the doping of ZrO2 increases the radiative recombination probability of the perovskite quantum dot glass, thereby increasing the luminous brightness of the perovskite quantum dot glass.

[0057] 4. Figure 4 The CIE chromaticity diagram shows the color gamut of commercial liquid crystal displays (red dotted line), the NSTC 1953 standard color gamut (blue dotted line), the Rec. 2020 standard color gamut (gray dotted line), and the color gamut of white light obtained by the perovskite quantum dot glass LED backlight module prepared in Example 2 after filtering through a commercial color filter (black solid line). By comparing the color gamuts, the perovskite quantum dot glass diffuser plate prepared in Example 2 can achieve a color gamut area that is 1.73 times that of a commercial display when used as a backlight source in a liquid crystal display, and also reaches a color gamut area of ​​118% of NTSC (after the action of the color filter), which is sufficient to meet most of the demands for wide color gamut display.

[0058] 5. Figure 5 This is a spectrum of the blue light excitation plate used to test the luminous brightness of the perovskite quantum dot glass in the performance test of the present invention. The spectrum shows that the luminance of the perovskite quantum dot glass described in Example 1 is 375 cd / m under the excitation of the 450 nm blue light excitation plate. -2 .

[0059] 6. Figure 6This is a statistical graph of the luminous brightness test of the perovskite quantum dot glass in the performance test of the present invention. It can be seen from the figure that with the addition of ZrO2, the brightness of the perovskite quantum dot glass described in Example 1 is improved, and the maximum green light brightness is 2647cdm -2 .

[0060] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A perovskite quantum dot glass with enhanced luminescence capability, characterized in that: The perovskite quantum dot glass is made from glass matrix raw material powder and quantum dot raw material powder as raw materials, and is labeled as CsPbBr3@glass, wherein the glass matrix raw material powder is composed of SiO2, B2O3, ZnO, SrCO3, K2CO3, Ba2CO3, Sb2O3, and ZrO2, and the quantum dot raw material powder is composed of Cs2CO3, PbBr2, and NaBr; The glass matrix raw material powder is weighed and proportioned according to the respective molar percentages of 30-50 SiO2-75-90 B2O3-25-35 ZnO-4-10SrO-4-10 K2CO3-1-5 BaO-1-3 Sb2O3- X ZrO2, where X = 2, 4, 6, or 8; The quantum dot raw material powders are weighed and mixed according to the molar percentage of 10-20 Cs2CO3, 25-40 PbBr2, and 25-40 NaBr.

2. A method for preparing perovskite quantum dot glass with enhanced luminescence capability as claimed in claim 1, characterized in that: The following steps are involved: S1. Grind the glass matrix raw material powder and quantum dot raw material powder evenly in an agate mortar, transfer the ground materials to an alumina crucible, and place them in a high-temperature muffle furnace for calcination; S2, pouring the molten glass calcined in step S1 into a brass mold and rapidly cooling it to obtain precursor glass; S3. The precursor glass is subjected to heat treatment and crystallization at 500-530°C to induce the in-situ growth of CsPbBr3 nanocrystals in the glass matrix to obtain perovskite quantum dot glass CsPbBr3@glass.

3. The method for preparing perovskite quantum dot glass with enhanced luminescence capability according to claim 2, wherein: In the S1, the calcination temperature is 1100-1300° C., and the calcination time is 10-45 minutes.

4. The method for preparing perovskite quantum dot glass with enhanced luminescence capability according to claim 2, wherein: The crystallization time of the precursor glass in S3 is 2-12 hours.

5. The perovskite quantum dot glass with enhanced luminescence capability as claimed in claim 1 is used in an LED backlight module, wherein: When the perovskite quantum dot glass diffusion plate is used to make an LED backlight module for LCD display, a wide color gamut display effect can be achieved.

6. The use of the perovskite quantum dot glass with enhanced luminescence capability as claimed in claim 5, characterized in that: The LED backlight module preparation method is as follows: (1) ball milling the perovskite quantum dot glass according to claim 1 into powder, mixing it with red perovskite quantum dot glass powder CsPb(Br / I)3PeQDs at a mass ratio of 2:1 to obtain a composite powder, and then mixing the composite powder with LED high refractive index organic silica gel at a mass ratio of 1:6 and stirring evenly; (2) Evenly apply composite powder-organic silica gel on the surface of 450nm InGaN blue LED strip, and place the LED strip in a drying oven for curing; (3) Fix the LED light strips obtained in step (2) on the reflective film plastic plate at equal intervals, then stack the light guide plate, diffusion film, light enhancement film, and reflective polarized light enhancement film in sequence below, and finally package them into a module through connecting wires.

7. The use of the perovskite quantum dot glass with enhanced luminescence capability as claimed in claim 6, characterized in that: The average particle size of the perovskite quantum dot glass powder in step (1) is less than 10 μm; and the curing process in step (2) is an initial bake at 100° C. for 1 hour and a long bake at 150° C. for 3 hours.

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