阅读说明：本技术 一种量子点薄膜及其制备方法 (Quantum dot film and preparation method thereof ) 是由 杨波波 梅时良 郭睿倩 张万路 解凤贤 叶怀宇 张国旗 于 2019-09-30 设计创作，主要内容包括：本发明公开一种量子点薄膜及其制备方法,薄膜包括多层荧光薄膜,其中,每层荧光薄膜包含钙钛矿量子点玻璃粉组分和粘合剂组分；所述钙钛矿量子点玻璃粉与粘合剂质量比为0.1～0.5:1。制备方法为：1.在玻璃基质中加入钙钛矿基质高温烧结并退火制备钙钛矿量子点玻璃粉；2.钙钛矿量子点玻璃粉与粘合剂混合,制备荧光胶混合物；3.荧光胶混合物经过两次加热固化形成量子点薄膜。本发明工艺简单,成本低,得到的量子点薄膜量子效率高、发射光谱窄、物理化学性质稳定,可应用于LED照明和显示技术,特别地可用于柔性发光器件。(The invention discloses a quantum dot film and a preparation method thereof, wherein the film comprises a plurality of layers of fluorescent films, wherein each layer of fluorescent film comprises a perovskite quantum dot glass powder component and an adhesive component; the mass ratio of the perovskite quantum dot glass powder to the adhesive is 0.1-0.5: 1. The preparation method comprises the following steps: 1. adding a perovskite substrate into the glass substrate, sintering at high temperature and annealing to prepare perovskite quantum dot glass powder; 2. mixing perovskite quantum dot glass powder with an adhesive to prepare a fluorescent glue mixture; 3. the fluorescent glue mixture is heated and cured twice to form the quantum dot film. The invention has simple process and low cost, and the obtained quantum dot film has high quantum efficiency, narrow emission spectrum and stable physical and chemical properties, can be applied to LED illumination and display technology, and particularly can be applied to flexible light-emitting devices.)

1. A quantum dot film, comprising: the material comprises a plurality of layers of fluorescent thin films, wherein each layer of fluorescent thin film comprises a perovskite quantum dot glass powder component and a binder component; the mass ratio of the perovskite quantum dot glass powder to the adhesive is 0.1-0.5: 1.

2. A quantum dot film according to claim 1, wherein: the perovskite quantum dot glass powder comprises a glass substrate and a perovskite substrate; the perovskite substrate accounts for 10 to 30 percent of the glass substrate in mole percentage; the glass matrix is Na₂O、ZnO、B₂O₃、SiO₂And a BaO mixture; the perovskite substrate is Cs₂CO₃，PbX₂And NaX mixture, or CsX and PbX₂Mixtures wherein X is Cl, Br or I.

3. A quantum dot film according to claim 2, wherein: perovskite matrix said mixture Cs₂CO₃：PbX₂: the NaX molar ratio is 1: 0.5-8: 1 or CsX: PbX₂Is 1: 0.5 to 4.

4. A quantum dot film according to claim 1, wherein: na in the glass powder₂O:10～20wt.％,ZnO:10～20wt.％,B₂O₃:30～50wt.％,SiO₂:20～30wt.％,BaO:5～15wt.％,Cs₂CO₃:1～10wt.％,PbX₂1-15 wt.%, NaX 1-10 wt.% or Na₂O:10～20wt.％,ZnO:10～20wt.％,B₂O₃:30～50wt.％,SiO₂:20～30wt.％,BaO:5～15wt.％,CsX：1～15wt.％，PbX₂: 1-15 wt.%, wherein X is Cl, Br or I.

5. A quantum dot film according to claim 1, wherein: the thickness of the quantum dot film is 0.05mm-2 mm.

6. A quantum dot film according to claim 5, wherein: the quantum dot film may be bent.

7. A preparation method of a quantum dot film is characterized by comprising the following steps: the method comprises the following steps:

s1: adding a perovskite substrate into a glass substrate to prepare perovskite quantum dot glass powder;

s2: mixing perovskite quantum dot glass powder with an adhesive to prepare a fluorescent glue mixture;

s3: the fluorescent glue mixture is heated and cured to form the quantum dot film comprising the multilayer fluorescent film.

8. A method for preparing a quantum dot film according to claim 7, wherein: the S1 includes:

s1.1, adding a perovskite substrate into a glass substrate;

s1.2, sintering at 950-1250 ℃ for 3-40 min to form a molten mass;

s1.3, casting the molten mass in a mold with the preheating temperature of 200-400 ℃ for molding, and preserving heat for 1-3 hours to obtain transparent glass;

s1.4 annealing the transparent glass at the temperature of 420-560 ℃ for 3-12 h and grinding into powder to prepare the perovskite quantum dot glass powder.

9. A method for preparing a quantum dot film according to claim 7, wherein: the S2 includes:

s2.1, mixing the perovskite quantum dot glass powder with an adhesive to prepare a fluorescent glue mixture;

s2.2, vacuumizing and defoaming the fluorescent glue mixture.

10. A method for preparing a quantum dot film according to claim 7, wherein: the S3 includes:

s3.1, adopting a spin coater to coat the fluorescent glue mixture on the substrate in a gradient manner from a fast speed to a slow speed in a spinning manner to form a single-layer fluorescent film;

s3.2, carrying out first heating curing on the single-layer fluorescent film;

s3.3, repeating the steps 3.1 and 3.2 to form a multilayer fluorescent film;

and S3.4, carrying out secondary heating solidification and cooling on the multilayer fluorescent film to obtain the quantum dot film.

11. A method for preparing a quantum dot film according to claim 10, wherein: the gradient spin coating comprises: the first stage spin coating speed is 200-; the second stage spin coating speed is 400-500rpm/s, and the spin coating time is 150-300 s.

12. A method of making a quantum dot film according to claim 7, wherein: the adhesive is any one or more of silicone material, epoxy resin, acrylic resin, polycarbonate or silica gel.

13. The method of any one of claims 7 or 12, wherein the binder comprises a group a binder and a group B binder; the mass ratio of the A-type adhesive to the B-type adhesive is 1: 1-4; the mass ratio of the perovskite quantum dot glass powder to the A-type adhesive is 0.1-0.5: 1.

14. A method for preparing a quantum dot thin film according to claim 10, wherein: the first heating curing conditions are as follows: the baking oven is baked for 8min to 40min at the temperature of 50 ℃ to 120 ℃.

15. A method for preparing a quantum dot thin film according to claim 10, wherein: the second heating curing condition is as follows: baking the mixture for 8-40 min at the temperature of 50-110 ℃, and then baking the mixture for 10-100 min at the temperature of 120-160 ℃ in an oven.

16. A method for preparing the quantum dot thin film according to any one of claims 1 to 6 or 7 to 15, wherein: the quantum dot film is applied to lighting, display or flexible light-emitting devices.

Technical Field

The invention relates to the technical field of semiconductor luminescent materials, in particular to a quantum dot film and a preparation method thereof.

Background

Recently, all-inorganic halides (CsPbX)₃) The perovskite quantum dot has great potential application value in the fields of light-emitting diodes, lasers, polaroids, solar cells, photodetectors and the like by virtue of adjustable light-emitting wavelength, high fluorescence quantum efficiency and narrow emission peak. CsPbX₃The quantum dots can be well dispersed in a plurality of non-polar solutions, and the oil phase perovskite quantum dots can be packaged into low-cost photoelectric devices. So far, the pure color CsPbX with the quantum size of 4-15nm, the luminous wavelength of which covers the whole visible spectrum (410 nm-700 nm), the luminous quantum efficiency of which reaches 90 percent₃Quantum dots have been reported. However, the perovskite quantum dots synthesized by the liquid phase have poor stability in air and poor water resistance, and the packaged devices have poor performances in the aspects of heat resistance, light aging resistance and the like, so that the further development of the perovskite quantum dots in the fields of photoelectric materials and devices is hindered.

In order to improve the stability of perovskite quantum dots, researchers have tried various methods including ligand exchange, high molecular materials or organosilicon coated quantum dots, and the like. The Zeng group in 2016 embeds quantum dots into a high molecular material PMMA, and protects the excellent optical performance of the quantum dots. Liu and collaborators thereof use mesoporous silica to coat CsPbBr3 perovskite quantum dots in a nonpolar solution, and Zhang and Rogach teams respectively use organosilicon (3-aminopropyl) triethoxysilane and polyhedral oligomeric silsesquioxane as end capping agents to generate a quantum dot/organosilicon composite material through hydrolysis. Further, Mn is concerned²⁺:CsPbCl₃/CsPbCl₃Quantum dots, CsPbX₃/ZnS heterostructure quantum dots, and phosphoric acid enhanced CsPbX₃The quantum dots can be reported to improve the stability of the quantum dots. However, because of the high oxygen dispersion coefficient in the organic matter, these methods cannot ensure that the quantum dots can effectively avoid photooxidation. Therefore, the improvement of the stability of the quantum dot organic composite material under extreme conditions needs to be further researched, especially the thermal stability of the quantum dot organic composite material. So far, no quantum dot can prepare a high-efficiency device which is stable for a long time. Therefore, there is an urgent need to develop a method that can not only enhance the stability of the quantum dots, but also ensure the excellent performance of the LED devices. Embedding quantum dots in a stable matrix, such as an inorganic glass matrix, with excellent mechanical, thermal and chemical stability, is undoubtedly an efficient method. At present, perovskite quantum dots prepared in glass are reported, and the fact that the glass matrix can effectively prevent the quantum dots from being attenuated and enhance the thermal stability of the quantum dots is proved.

The thin film of the luminescent material is an important premise for realizing the device formation, and the luminescent material and the high polymer material are combined to prepare the transparent thin film, so that the application of the transparent thin film in the aspects of flexibility, foldable luminescent devices and the like can be expanded. The traditional preparation process of the quantum dot film is directly prepared by coating a quantum dot solution or colloid on a substrate, the luminous stability of the traditional preparation process is limited by the stability of the quantum dot solution, the quantum efficiency of the traditional preparation process is greatly reduced, and the application of the traditional preparation process in a luminescent device is limited.

Disclosure of Invention

In order to solve the above problems, the present invention provides a quantum dot thin film comprising a plurality of layers of fluorescent thin films, wherein each layer of fluorescent thin film comprises a perovskite quantum dot glass frit component and a binder component; the mass ratio of the perovskite quantum dot glass powder to the adhesive is 0.1-0.5: 1.

Preferably, the perovskite quantum dot glass powder comprises a glass matrix and a perovskite matrix; the perovskite substrate accounts for 10 to 30 percent of the glass substrate in mole percentage; the glass matrix is Na₂O、ZnO、B₂O₃、SiO₂And a BaO mixture; the perovskite substrate is Cs₂CO₃，PbX₂And NaX mixture, or CsX and PbX₂Mixtures wherein X is Cl, Br or I.

Preferably, the perovskite substrate said mixture Cs₂CO₃：PbX₂: the NaX molar ratio is 1: 0.5-8: 1 or CsX: PbX₂Is 1: 0.5 to 4.

Preferably, Na in the glass powder₂O:10～20wt.％,ZnO:10～20wt.％,B₂O₃:30～50wt.％,SiO₂:20～30wt.％,BaO:5～15wt.％,Cs₂CO₃:1～10wt.％,PbX₂1-15 wt.%, NaX 1-10 wt.% or Na₂O:10～20wt.％,ZnO:10～20wt.％,B₂O₃:30～50wt.％,SiO₂:20～30wt.％,BaO:5～15wt.％,CsX：1～15wt.％，PbX₂: 1-15 wt.%, wherein X is Cl, Br or I.

Preferably, the thickness of the quantum dot film is 0.05mm-2 mm.

Preferably, the quantum dot film is flexible.

The invention also provides a preparation method of the quantum dot film, which comprises the following steps:

s1: adding a perovskite substrate into a glass substrate to prepare perovskite quantum dot glass powder; the precursor glass powder can be obtained by fully mixing the raw material of the matrix glass and the raw material of the perovskite quantum dot according to a certain proportion and sintering at one time.

S2: mixing perovskite quantum dot glass powder with an adhesive to prepare a fluorescent glue mixture;

s3: the fluorescent glue mixture is heated and cured to form the quantum dot film comprising the multilayer fluorescent film.

Preferably, the S1 includes:

s1.1, adding a perovskite substrate into a glass substrate;

s1.2, sintering at 950-1250 ℃ for 3-40 min to form a molten mass;

s1.3, casting the molten mass in a mold with the preheating temperature of 200-400 ℃ for molding, and preserving heat for 1-3 hours to eliminate internal stress to obtain transparent glass;

s1.4 annealing the transparent glass at the temperature of 420-560 ℃ for 3-12 h and grinding into powder to prepare the perovskite quantum dot glass powder.

Preferably, the S2 includes:

s2.1, mixing the perovskite quantum dot glass powder with an adhesive to prepare a fluorescent glue mixture;

s2.2, vacuumizing and defoaming the fluorescent glue mixture.

Preferably, the S3 includes:

s3.1, adopting a spin coater to coat the fluorescent glue mixture on the substrate in a gradient manner from a fast speed to a slow speed in a spinning manner to form a single-layer fluorescent film;

s3.2, carrying out first heating curing on the single-layer fluorescent film;

s3.3, repeating the steps 3.1 and 3.2 to form a multilayer fluorescent film;

and S3.4, carrying out secondary heating solidification and cooling on the multilayer fluorescent film to obtain the quantum dot film.

Preferably, the gradient spin coating comprises: the first stage spin coating speed is 200-: 400-500rpm/s, and the spin coating time is 150-300 s.

Preferably, the adhesive is any one or more of a silicone material, an epoxy resin, an acrylic resin, a polycarbonate, or a silicone gel.

Preferably, the binder comprises a class a binder and a class B binder; the mass ratio of the A-type adhesive to the B-type adhesive is 1: 1-4; the mass ratio of the perovskite quantum dot glass powder to the A-type adhesive is 0.1-0.5: 1.

Preferably, the first heat curing conditions are as follows: the baking oven is baked for 8min to 40min at the temperature of 50 ℃ to 120 ℃.

Preferably, the second heat curing conditions are: baking the mixture for 8-40 min at the temperature of 50-110 ℃, and then baking the mixture for 10-100 min at the temperature of 120-160 ℃ in an oven.

The quantum dot film prepared by the quantum dot film or the method can be applied to illumination, display or flexible light-emitting devices.

The invention has the beneficial effects that:

(1) the perovskite quantum dot glass is simple in preparation method and low in cost, the raw material of the matrix glass and the perovskite quantum dot raw material are fully mixed according to a certain proportion, precursor glass powder can be obtained through one-step sintering, then the quantum dot glass can be obtained through low-temperature heat treatment, the operation process is simple, and the quantum dot stability is good.

(2) In the preparation process of the perovskite quantum dot glass, borosilicate is selected as a glass raw material, the prepared glass has high transmittance, stable physical and chemical properties and good mechanical properties, and barium oxide, sodium oxide, zinc oxide and the like are added into the glass raw material, so that the strength of the glass can be enhanced, the melting temperature is reduced, and the energy-saving effect is achieved.

(3) The multilayer quantum dot film with uniform texture is prepared by gradient spin coating and twice curing, and the obtained quantum dot flexible luminescent film has high quantum efficiency, narrow emission spectrum and stable physical and chemical properties, can be applied to the technical field of LED illumination and display, and is particularly applied to flexible luminescent devices.

Drawings

Fig. 1 is a physical diagram of a flexible luminescent thin film based on perovskite quantum dot glass of example 1.

Fig. 2 is an emission spectrum of the flexible luminescent thin film based on perovskite quantum dot glass of example 1.

Fig. 3 is a pictorial view of an electroluminescent representation of an LED encapsulated with a flexible light-emitting film based on perovskite quantum dot glass as described in example 1.

Fig. 4 is a stability test chart of the flexible luminescent thin film based on perovskite quantum dot glass of example 1 under high temperature and high humidity conditions.

Fig. 5 is a stability test chart of the flexible luminescent thin film based on perovskite quantum dot glass of example 1 in a common air environment.

Fig. 6 is a stability test chart of the flexible luminescent thin film based on perovskite quantum dot glass of example 1 in deionized water.

Fig. 7 is a stability test chart of the flexible luminescent thin film based on perovskite quantum dot glass of example 1 under the condition of ultraviolet light irradiation.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to the accompanying drawings and examples. It should be understood, however, that the description herein of specific embodiments is only intended to illustrate the invention and not to limit the scope of the invention.