Perovskite quantum dot glass film composite material and preparation method and application thereof

Abstract

The invention discloses a perovskite quantum dot glass film composite material and a preparation method and application thereof. The preparation method comprises the following steps: blending glass powder containing CsPb (BrxI1-x) 3 quantum dots with an organic carrier to obtain heat conduction slurry; spin-coating the sapphire substrate with the heat-conducting slurry; the sapphire substrate coated with the heat conduction slurry is subjected to stepped heat treatment, and the heat treatment comprises a glue discharging step at the temperature of 150-250 DEG C and a high-temperature dense bonding step at the temperature of 500-600 DEG C, so that interface bonding between the glass film and the sapphire substrate is achieved. According to the invention, the interface-bonded perovskite quantum dot glass film is constructed on the sapphire substrate, so that the problem of hot stacking is effectively solved. The prepared composite material has a heat conductivity coefficient as high as 34.81 W / m.k, and a fluorescent color wheel device assembled based on the composite material shows a wide color gamut (the heat conductivity coefficient reaches 93.7% under the Rec.2020 standard) and high working stability under excitation of blue laser, and has a wide application prospect in the field of laser display.

Description

Technical Field

[0001] This invention relates to the field of fluorescent glass films, and more particularly to a perovskite quantum dot glass film composite material, its preparation method, and its application. Background Technology

[0002] In the traditional display field, fluorescent glass films are the core color conversion material for high-luminous-flux display systems such as laser projection and Mini / Micro-LED. Current technologies generally use YAG:Ce. 3+ or β-SiAlON:Eu 2+ A single-phase structure consisting of phosphor and low-melting-point glass powder co-fired (see patent CN112645592A). In this type of system, the temperature rise on the glass side surface often exceeds 120°C when the power density of blue laser is high, leading to thermal quenching of the phosphor, light decay >20%, and color coordinate drift Δx >0.02, making it difficult to meet the long-term stability requirements of the Rec.2020 color gamut.

[0003] Perovskite quantum dot (CsPbX3) glasses, due to their narrow full width at half maximum (FWHM) (<25nm) and high PLQY, can achieve more saturated luminescence in the red region and are considered a promising replacement for traditional phosphors. However, perovskite quantum dots are temperature-sensitive; their luminescence intensity decreases rapidly with increasing temperature. Current published literature mainly focuses on improving the stability of the quantum dots themselves, while a systematic solution is still lacking to address the heat source bottleneck of the low thermal conductivity of the glass matrix.

[0004] On the other hand, to improve heat dissipation, Chinese patent application CN115893858A proposes a method of adding traditional phosphors (such as YAG:Ce) and thermally conductive fillers (such as Al2O3) to glass powder followed by low-temperature sintering. While this method can improve the thermal conductivity of the material to some extent, it has two inherent drawbacks: First, the thermally conductive filler particles are randomly and isolatedly distributed in the glass matrix, failing to form continuous and efficient thermal conduction pathways, thus limiting the improvement in thermal conductivity (e.g., the disclosed improvement from 1.7 W / m·K to 2.3 W / m·K). Second, the introduction of a large amount of filler increases light scattering, affecting light extraction efficiency and uniformity. More importantly, this method uses high-temperature resistant traditional phosphors and a low-temperature sintering process, failing to address and solve the problem of efficient heat dissipation for perovskite quantum dot materials, which are more sensitive to temperature. Therefore, how to construct continuous thermal conduction channels with low addition amounts (≤20 wt%) while balancing the luminescent performance and surface smoothness of perovskite quantum dots remains a key unsolved problem in existing technologies.

[0005] In summary, existing technologies, whether using bulk glass or filler-mixed sintering, have failed to provide an effective solution to the thermal deposition problem of perovskite quantum dots at high power densities. Summary of the Invention

[0006] In view of the shortcomings of the prior art, the purpose of this invention is to provide a high-efficiency heat dissipation perovskite quantum dot glass thin film composite material and its preparation method, aiming to solve the problems of heat accumulation and performance degradation caused by the poor thermal conductivity of the glass matrix in the prior art. A mixed thermally conductive slurry containing perovskite quantum dot glass powder is coated onto a sapphire substrate with high thermal conductivity, baked to remove the adhesive, and then interfacial bonding is performed at high temperature to obtain a high-efficiency heat dissipation perovskite quantum dot glass thin film composite material, improving the problem of internal heat accumulation caused by directly using perovskite quantum dot glass. Another object of this invention is to provide applications of the perovskite quantum dot glass thin film composite material described above.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] S1: Containing CsPb(Br) x I 1-x )3 Quantum dot glass powder is blended with an organic carrier to obtain a thermally conductive slurry, where x ranges from 0 to 1;

[0009] S2: Spin-coat the thermally conductive paste onto a highly thermally conductive sapphire substrate to form a wet film;

[0010] S3: Perform a stepped heat treatment on the sapphire substrate with wet film. Specifically, first, perform a desizing process at a temperature of 150-250℃ to remove the organic carrier; then, perform a high-temperature heat treatment at a temperature of 500-600℃ to melt the glass powder and form a dense interfacial bond with the surface of the sapphire substrate, thus forming a strong interfacial bond.

[0011] Preferably, x = 0.2, 0.4, 0.6, 0.8.

[0012] Furthermore, in step S1, the organic carrier is obtained by mixing terpineol and ethyl cellulose at a mass ratio of 8-10:1 and heating at 70-90°C for 25-30 minutes.

[0013] Furthermore, in step S1, the thermally conductive slurry is obtained by mixing glass powder and organic carrier at a mass ratio of 1:10-11, and then centrifuging in a centrifuge for 1-2 minutes.

[0014] Furthermore, in step S2, the spin coating is performed in a spin coater with a machine speed of 100-200 rpm and a spin coating time of 1-2 minutes.

[0015] Furthermore, in step S3, the drying temperature is 150–250°C, the duration is 1–2 hours, and then it is allowed to cool naturally.

[0016] Furthermore, in step S3, the heat treatment temperature is 500–600°C, and the heat treatment time is 1 hour.

[0017] The preparation mechanism of the thin film composite material is as follows: a slurry of ethyl cellulose and terpineol serves as an organic carrier, which is then mixed with glass powder to obtain a thermally conductive slurry. Due to its volatile nature when heated, a layer of quantum dot glass powder film remains on the sapphire substrate after heating. Finally, when heated to 500–600°C, the quantum dot glass powder material can fuse with the sapphire substrate to form a unified whole, thus forming a thin film composite material with a substrate.

[0018] One or more technical solutions provided in the embodiments of this application have at least the following technical effects or advantages:

[0019] 1. The CsPb(Br) used in this invention x I 1-x 3. Quantum dot perovskite quantum dot glass powder, as a fluorescence conversion material, can increase the number of color conversion modules in laser displays and achieve adjustable emission wavelength by adjusting different Br:I ratios.

[0020] 2. This invention utilizes sapphire, which has a high intrinsic thermal conductivity, as the substrate and innovatively employs a high-temperature interface bonding process of 500-600℃. This results in a strong chemical bond between the glass powder and the sapphire substrate with no significant interfacial thermal resistance, constructing an efficient and continuous heat conduction channel from the heat source to the heat dissipation substrate. This is completely different from the bulk glass structure of existing technologies (such as CN114394753A) and also differs from the scheme of existing technologies (such as CN115893858A) which adds dispersed thermally conductive fillers inside the glass, fundamentally changing the heat dissipation path.

[0021] Therefore, compared with using a whole piece of perovskite quantum dot glass directly, the thermal conductivity of the composite material prepared by this invention is improved by an order of magnitude (thermal conductivity as high as 34.81 W / m·k), which can quickly dissipate the heat generated by laser excitation, effectively solve the problem of heat accumulation, and significantly improve the working stability of the material at high power density.

[0022] 3. The fluorescent color wheel device made from perovskite quantum dot glass thin film composite material of the present invention exhibits a wide color gamut under blue laser excitation. Attached Figure Description

[0023] Figure 1 The normalized photoluminescence (PL) spectra of the perovskite quantum dot glass film composites prepared in Examples 1-5 at different Br / I ratios are shown.

[0024] Figure 2The graph shows a comparison of the fluorescence quantum yield (PLQY) of the perovskite quantum dot glass film composites prepared in Examples 1-5.

[0025] Figure 3 This is a scanning electron microscope (SEM) cross-sectional morphology image of the perovskite quantum dot glass film composite material prepared in Example 2.

[0026] Figure 4 This is a temperature change diagram of the surface of the perovskite quantum dot glass in Example 2 under blue laser excitation.

[0027] Figure 5 The graph shows the temperature change of the surface of the perovskite quantum dot glass film composite material prepared in Example 2 under blue laser excitation.

[0028] Figure 6 (i) a physical image under sunlight, (ii) a light emission image under ultraviolet light, and (iii) a dynamic operation diagram of a fluorescent color wheel device fabricated using the composite material prepared in Example 2 of the present invention.

[0029] Figure 7 for Figure 6 The graph shows a comparison of the color gamut calculated from the emission spectrum of the fluorescent color wheel device with the NTSC and Rec.2020 standards. Detailed Implementation

[0030] This invention provides a highly efficient heat dissipation perovskite quantum dot glass thin film composite material and its preparation method. To make the objectives, technical solutions, and effects of this invention clearer and more explicit, the invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only for explaining the invention and are not intended to limit the scope of protection of the invention.

[0031] Pre-preparation example: CsPb(Br) x I 1-x 3. Preparation of perovskite quantum dot glass powder

[0032] According to a predetermined molar percentage, the matrix glass raw material (e.g., oxides or carbonates of SiO2, B2O3, ZnO, etc.) and the perovskite precursor raw material (e.g., Cs2CO3, PbO, NaBr, PbI2, etc.) are mixed evenly in an agate mortar. The mixed raw material is placed in a corundum crucible and melted in a muffle furnace at 1100-1200℃ for about 30 minutes to form a clear glass melt. The melt is quickly poured onto a preheated copper plate and quenched to form a glass block containing perovskite quantum dots. Subsequently, the glass block is thoroughly ground in a planetary ball mill and sieved through a 200-mesh sieve to obtain the CsPb(Br)2O3 / PbO2 / PbI ... x I 1-x3. Perovskite quantum dot glass powder. By adjusting the ratio of bromide to iodide in the perovskite precursor raw material, glass powders with different x values ​​can be prepared to achieve different emission wavelengths. Those skilled in the art will understand that the above glass formulations and process parameters are merely examples, and any method capable of preparing glass containing the target perovskite quantum dots and grinding it into powder is applicable.

[0033] Example 1:

[0034] (1) Preparation of organic carrier: Terpineol and ethyl cellulose were mixed at a mass ratio of 8:1 and heated at 90°C for 30 minutes to obtain organic carrier.

[0035] (2) Preparation of thermally conductive paste: Obtaining CsPb(Br) with x = 0 x I 1-x )3 Perovskite quantum dot glass powder was mixed with the organic carrier obtained in step (1) at a mass ratio of 1:10 and processed in a centrifuge for 2 minutes to obtain a uniform thermally conductive slurry.

[0036] (3) Coating and heat treatment: The thermally conductive slurry was spin-coated onto a sapphire substrate in a spin coater at 200 rpm for 2 minutes. After removal, it was first dried at 200°C for 2 hours to remove the organic carrier, and then heat-treated in a muffle furnace at 500°C for 1 hour to ensure a dense bond between the glass powder and the substrate at the interface. After natural cooling, a perovskite quantum dot glass film composite material was obtained.

[0037] Example 2:

[0038] (1) Preparation of organic carrier: Terpineol and ethyl cellulose were mixed at a mass ratio of 8:1 and heated at 90°C for 30 minutes to obtain organic carrier.

[0039] (2) Preparation of thermally conductive paste: Obtain CsPb(Br) with x = 0.2 x I 1-x )3 Perovskite quantum dot glass powder was mixed with the organic carrier obtained in step (1) at a mass ratio of 1:10 and processed in a centrifuge for 2 minutes to obtain a uniform thermally conductive slurry.

[0040] (3) Coating and heat treatment: The thermally conductive slurry was spin-coated onto a sapphire substrate in a spin coater at 200 rpm for 2 minutes. After removal, it was first dried at 200°C for 2 hours to remove the organic carrier, and then heat-treated in a muffle furnace at 500°C for 1 hour to ensure a dense bond between the glass powder and the substrate. After natural cooling, a perovskite quantum dot glass film composite material was obtained.

[0041] (4) A fluorescent color wheel device is fabricated by inserting a perovskite quantum dot glass film and a CsPbBr3 perovskite quantum dot glass film into a rotating wheel.

[0042] Example 3:

[0043] This embodiment provides a highly efficient heat-dissipating perovskite quantum dot glass thin film composite material and its preparation method. The preparation method of this embodiment is basically the same as that of Embodiment 2, the main difference being that the CsPb(Br) used is different. x I 1-x The x-value of the perovskite quantum dot glass powder is 0.4.

[0044] Example 4:

[0045] This embodiment provides a method for preparing perovskite quantum dot glass thin film composite materials and their applications. The preparation method in this embodiment is basically the same as that in Example 2, the main difference being that the CsPb(Br) used is different. x I 1-x The x-value of the perovskite quantum dot glass powder is 0.6.

[0046] Example 5:

[0047] This embodiment provides a method for preparing perovskite quantum dot glass thin film composite materials and their applications. The preparation method in this embodiment is basically the same as that in Example 2, the main difference being that the CsPb(Br) used is different. x I 1-x The x-value of the perovskite quantum dot glass powder is 0.8.

[0048] Example 6:

[0049] The preparation method in this embodiment is basically the same as that in Example 2, with the main difference being:

[0050] (1) The organic carrier was prepared by terpineol and ethyl cellulose in a mass ratio of 9:1.

[0051] (2) The thermally conductive paste is prepared by glass powder and organic carrier at a mass ratio of 1:10.5.

[0052] (3) In the coating and heat treatment steps, the drying temperature is 220℃ and the high temperature heat treatment temperature is 550℃.

[0053] The resulting composite material also exhibits excellent thermal conductivity and luminescence stability.

[0054] The above embodiments are described in detail based on the test results and the accompanying drawings, as follows:

[0055] Figure 1The normalized photoluminescence (PL) spectra of the perovskite quantum dot glass thin film composites prepared in Examples 1-5 are shown in the figure. As can be seen from the figure, the emission wavelength of the thin film prepared in Example 1 is 699 nm, the thin film in Example 2 is 657 nm, the thin film in Example 3 is 616 nm, the thin film in Example 4 is 563 nm, and the thin film in Example 5 is 537 nm. Meanwhile, from Example 5 to Example 1, it can be seen that with the increase of CsPb(Br)... x I 1-x As the molar fraction of Br in 3 decreases, the PL spectrum gradually redshifts.

[0056] Figure 2 The figures show the PLQY of the perovskite quantum dot glass film composites prepared in Examples 1-5. It can be seen from the figures that the film prepared in Example 2 has the best light emission effect, with PLQY = 38.3%. Therefore, subsequent tests were all conducted on the film prepared in Example 2.

[0057] Figure 3 The image shows a cross-sectional morphology of the perovskite quantum dot glass thin film composite material prepared in Example 2. As can be seen from the image, the upper thin film layer is tightly bonded to the sapphire substrate layer without cracking, verifying the excellent film-forming properties of the film layer. Simultaneously, the upper thin film layer exhibits pores, which provide more opportunities for light to enter the film and refract and diffuse within the gaps. The sapphire contact surface at the bottom can also act as a reflective surface, reflecting light and causing the thin film layer to emit more converted red light, thereby reducing light energy loss.

[0058] Table 1 compares the thermal conductivity of perovskite quantum dot glass and perovskite quantum dot glass film in Example 2 (test error ±5%). The table shows that the thermal conductivity of the perovskite quantum dot glass film composite material is 34.81 W / m·K, and the thermal diffusivity is 11.97 mm². 2 / s, compared to the perovskite quantum dot glass morphology, the thin film has a significant improvement in thermal conductivity.

[0059] Table 1

[0060]

[0061]

[0062] Figures 4-5The figures show the surface temperature variations of the perovskite quantum dot glass and the perovskite quantum dot glass film composite material under blue laser excitation, as well as the changes in laser power and laser spot radius (in this test, a laser beam with a beam expander was used, and the spot size was adjusted by changing the distance between the sample and the laser source). As the distance increases, the sample surface temperature decreases with increasing spot radius and increases with increasing laser power, with the rate of temperature increase slowing down when the laser power is greater than 4W. Conversely, even under 5.29W irradiation, the surface temperature of the perovskite quantum dot glass film composite material remains below 120℃, while the surface temperature of the perovskite quantum dot glass exhibits a high temperature of around 300℃, reaching 185.4℃ even at the maximum spot radius of 6mm, which is 2-3 times higher than that of the perovskite quantum dot glass film composite material. Compared to the perovskite quantum dot glass, consistent with the previously measured thermal conductivity, the perovskite quantum dot glass film composite material still primarily relies on the sapphire substrate for heat dissipation, indicating that this perovskite quantum dot glass film composite material possesses highly efficient heat dissipation characteristics.

[0063] Figure 6 This is a fluorescent color wheel device fabricated based on the perovskite quantum dot glass thin film composite material and CsPbBr3 perovskite quantum dot glass spacer inserted into the rotating wheel in Example 2. Figure 6 (i) is a sample image of the device under sunlight; Figure 6 (ii) is a sample image of the device under ultraviolet light. In the image, the thin film emits red light and the CsPbBr3 perovskite quantum dot glass emits green light. Figure 6 (iii) is a dynamic operation diagram of the device under blue laser irradiation at a rotation speed of 1000 rpm. In the diagram, the rotating fluorescent color wheel device can be seen emitting red, green and blue primary color light.

[0064] Figure 7 This is a comparison chart of the color gamut area of ​​the described phosphor color wheel device with NTSC and Rec.2020 standards. As can be seen from the chart, the color gamut area of ​​this device is 127.5% of the National Television Standards Committee (NTSC) standard and 93.7% of the Rec.2020 color standard (color coding standard), and it also shows an improvement over the color gamut area in patent CN118495817A. Therefore, based on the wide color gamut characteristics of this model, it is expected to have significant advantages in the field of laser displays.

[0065] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the invention by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the invention should be included within the scope of protection of the invention.

Claims

1. A method for preparing a perovskite quantum dot glass thin film composite material, characterized in that, Includes the following steps: S1: Containing CsPb(Br) x I 1-x )3 Quantum dot glass powder is blended with an organic carrier to obtain a thermally conductive slurry, where x ranges from 0 to 1; S2: Spin-coat the thermally conductive paste onto a highly thermally conductive sapphire substrate to form a wet film; S3: Perform a stepped heat treatment on the sapphire substrate with wet film. Specifically, first, perform a desizing process at a temperature of 150-250℃ to remove the organic carrier; then, perform a high-temperature heat treatment at a temperature of 500-600℃ to melt the glass powder and form a dense interfacial bond with the surface of the sapphire substrate, thus forming a strong interfacial bond.

2. A perovskite quantum dot glass thin film composite material, characterized in that, include: A sapphire substrate; And a layer of perovskite quantum dot glass film, which is bonded to the surface of the sapphire substrate by high-temperature dense bonding.

3. The method for preparing a perovskite quantum dot glass thin film composite material according to claim 1, characterized in that, In step S1, the organic carrier is obtained by mixing terpineol and ethyl cellulose at a mass ratio of 8-10:1 and heating at 70-90°C for 25-30 minutes.

4. The method for preparing a perovskite quantum dot glass thin film composite material according to claim 1, characterized in that, In step S1, the thermally conductive slurry is obtained by mixing glass powder and organic carrier at a mass ratio of 1:10-11, and then centrifuging in a centrifuge for 1-2 minutes.

5. The method for preparing a perovskite quantum dot glass thin film composite material according to claim 1, characterized in that, In step S2, the spin coating process is carried out in a spin coater with a machine speed of 100-200 rpm and a spin coating time of 1-2 minutes.

6. The method for preparing a perovskite quantum dot glass thin film composite material according to claim 1, characterized in that, In step S3, when the drying temperature is 150-250℃, the baking time is 1-2 hours.

7. The method for preparing a perovskite quantum dot glass thin film composite material according to claim 1, characterized in that, In step S3, the heat treatment time at 500-600℃ is 1 hour.

8. The application of the perovskite quantum dot glass film composite material according to claim 2 in laser display.

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