Functionalized modified quantum dot and preparation method and application thereof

Abstract

The invention discloses a functional modified quantum dot as well as a preparation method and application thereof. The functional modified quantum dot comprises a quantum dot core and a barrier protective layer, the barrier protection layer is at least formed by organic aluminum silicate, in the barrier protection layer, the Si element tends to be distributed close to the core of the quantum dot, and the Al element tends to be distributed away from the core of the quantum dot. The organic aluminum silicate salt is utilized to perform surface functional modification treatment on the quantum dots, surface passivation modification of the quantum dots is completed without a catalyst, the surfaces of the quantum dots are coated with a barrier protective layer, water and oxygen erosion is effectively blocked through passivation modification, the carrier non-radiative recombination process is inhibited, the quantum dots are protected, and the quantum dots are further protected. The fluorescence efficiency and the photo-thermal stability of the quantum dots are improved, and the problem that the luminous efficiency of the quantum dots is greatly reduced in the quantum dot ligand exchange and glue light curing processes is solved; meanwhile, organic groups in the organic aluminum silicate are well compatible with glue resin components, so that the dispersity of the quantum dots and a glue system is improved.

Description

Technical Field

[0001] The present invention relates to the field of quantum dot display technology, and in particular to a functionalized modified quantum dot, a preparation method and application thereof. Background Art

[0002] Quantum dots (QDs) are a new generation of luminescent materials with outstanding features such as narrow emission spectrum, adjustable emission wavelength, and high quantum yield. Their novel optoelectronic properties make them of great application value in the electronics, optoelectronics, photovoltaics, biomedicine and other industries. In the display field, quantum dots have attracted extensive attention from researchers due to their unique color expression. For example, in VR / AR display, Micro-LED technology is used in combination with the color conversion characteristics of quantum dots to achieve full-color display: placing red and green quantum dot color conversion film layers on blue light Micro-LED units to replace red and green LED units is considered to be one of the important technical routes to solve the problems faced by Micro LED display, such as the lack of red light LED units and mass transfer.

[0003] In the application of quantum dots, the quantum dots can usually be protected and given excellent luminescence properties in a preset glue environment through quantum dot surface functionalization modification technology, thereby preparing functional quantum dot glue. Combined with spin coating, inkjet printing, photolithography, etching and other processing methods, the patterning technology continues to develop, which together provides more possibilities for the application of quantum dot color conversion technology in the field of optoelectronic device display.

[0004] However, the preparation of traditional quantum dot glue is mostly through the ligand exchange method. The oil-soluble quantum dots are first dispersed into the organic solvent corresponding to the glue system (such as propylene glycol methyl ether acetate, PGMEA), and then the resulting solution is mixed with functional components such as photocuring glue and light diffuser to obtain quantum dot glue. This kind of traditional ligand exchange process will basically replace the original ligand. The exchange process will damage the quantum dots, bring more surface defects and even cause structural damage, and damage the material performance. In addition, due to the lack of protection for the quantum dots, the quantum dots will also be damaged during the curing process of the glue, affecting the performance of the quantum dots. Summary of the invention

[0005] In view of the deficiencies in the prior art, the object of the present invention is to provide a functionalized modified quantum dot, a preparation method and application thereof.

[0006] In order to achieve the above-mentioned invention object, the technical solution adopted by the present invention includes:

[0007] In a first aspect, the present invention provides a functionalized modified quantum dot, which comprises a quantum dot core and a barrier protection layer covering the quantum dot core;

[0008] The material of the quantum dot core includes any one or a combination of two or more of transition metal sulfides, transition metal phosphides, transition metal selenides, and perovskite compounds;

[0009] The barrier protective layer is at least formed of an organic aluminum silicate, and the general formula of the organic aluminum silicate is:

[0010] (R1-O)3-Si-O-Al-O-R2

[0011] Among them, the R2 group and the three R1 groups are independently selected from alkyl groups; in the barrier protection layer, the Si element tends to be distributed relatively close to the core of the quantum dots, and the Al element tends to be distributed relatively far away from the core of the quantum dots.

[0012] Furthermore, at least part of the organic aluminum silicate is combined with oxygen to form silicon aluminum oxide, and the barrier protective layer comprises the silicon aluminum oxide. In an embodiment of the present invention, when the combination of the organic aluminum silicate is initially completed, the surface of the barrier protective layer is mainly composed of the organic aluminum silicate, and in the subsequent preparation or application of the glue, it will contact with oxygen to form silicon aluminum oxide, further enhancing the protectiveness.

[0013] In a second aspect, the present invention further provides a method for preparing the above-mentioned functionalized modified quantum dots, which comprises:

[0014] The quantum dot core and the organic aluminum silicate are dissolved in a solvent to form a functionalized reaction system;

[0015] The functionalized reaction system is stirred until the surface of the quantum dot core is covered with a barrier protection layer.

[0016] In a third aspect, the present invention further provides a photocurable quantum dot glue, which comprises a resin, a photocuring agent, a solvent and the above-mentioned functionalized modified quantum dots.

[0017] In a fourth aspect, the present invention further provides a quantum dot functional layer, wherein the quantum dot functional layer is formed by curing the above-mentioned photocurable quantum dot glue.

[0018] Based on the above technical solution, compared with the prior art, the beneficial effects of the present invention at least include:

[0019] The present invention utilizes organic aluminum silicate to perform surface functional modification on quantum dots, completes the surface passivation modification of quantum dots without the need for a catalyst, and coats the surface of the quantum dots with a barrier protection layer. The passivation modification effectively blocks water and oxygen erosion and inhibits the non-radiative recombination process of carriers, thereby protecting the quantum dots, improving the fluorescence efficiency and photothermal stability of the quantum dots, and improving the problem of a significant decrease in the luminous efficiency of the quantum dots during the quantum dot ligand exchange and glue photocuring process. At the same time, the good compatibility of the organic groups in the organic aluminum silicate with the glue resin components improves the dispersibility of the quantum dots and the glue system, and can successfully obtain a clear, transparent, and uniformly dispersed photocurable quantum dot glue, effectively solving the problem of uniform dispersion of the quantum dots in the photocurable glue system.

[0020] The functionalized modified light-cured quantum dot glue obtained by the present invention is clear and bright, has a uniform texture, a flat film surface after curing, and has a uniform film thickness, and can well achieve a light color conversion patterning process effect.

[0021] The above description is only an overview of the technical solution of the present invention. In order to enable those skilled in the art to more clearly understand the technical means of the present application and implement them according to the contents of the specification, the following is a description of the preferred embodiments of the present invention in conjunction with detailed drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a process flow diagram of a method for preparing functionalized modified quantum dots provided by a typical implementation case of the present invention;

[0023] Figure 2 This is a macroscopic photograph of green light quantum dot glue provided by a typical implementation case of the present invention;

[0024] Figure 3 This is a macroscopic photograph of the green light quantum dot glue curing into a film provided by a typical implementation case of the present invention;

[0025] Figure 4 This is a macroscopic photograph of green light quantum dot glue provided by another typical implementation case of the present invention;

[0026] Figure 5 This is a macroscopic photograph of the green light quantum dot glue curing into a film provided in another typical implementation case of the present invention. DETAILED DESCRIPTION

[0027] In view of the deficiencies in the prior art, the inventor of this case has proposed the technical solution of the present invention after long-term research and extensive practice. The technical solution, its implementation process and principle will be further explained as follows.

[0028] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the protection scope of the present invention is not limited to the specific embodiments disclosed below.

[0029] Moreover, relational terms such as “first” and “second” are merely used to distinguish one component or method step from another with the same name, but do not necessarily require or imply any such actual relationship or order between these components or method steps.

[0030] The embodiment of the present invention provides a functional modified quantum dot, which includes a quantum dot core and a barrier protection layer covering the quantum dot core; the material of the quantum dot core includes any one or a combination of two or more of transition metal sulfides, transition metal phosphides, transition metal selenides, and perovskite compounds; the barrier protection layer is at least formed by an organic aluminum silicate, and the general formula of the organic aluminum silicate is:

[0031] (R1-O)3-Si-O-Al-O-R2

[0032] Among them, the R2 group and the three R1 groups are independently selected from alkyl groups; in the barrier protective layer, the Si element tends to be relatively close to (closer than the Al element) the quantum dot core distribution, and the Al element tends to be relatively far away (farther than the Si element) the quantum dot core distribution.

[0033] In the application field of quantum dots, many existing technologies have actually taken into account the barrier protection of quantum dots, and many technical solutions also involve the technical solutions of modification and protection using silane coupling agents, such as using reagents such as trialkoxyvinyl (or amide) silane as silane coupling agents.

[0034] The principle of silane coupling agent modification is: silane alkoxy is compatible with the inorganic phase, the organic functional group is reactive and compatible with the organic phase, and the silane coupling agent forms a -Si-O- protective layer at the organic-inorganic interface and promotes interface fusion.

[0035] Although in terms of overall principle, the modification of the organosilicate aluminum salt system is similar and is also divided into inorganic phase surface action and organic phase fusion action, the modification subject of the traditional silane coupling agent modification is still the single protection effect of the -Si-O- unit, which cannot exert the best protection and compatibility; the modification of the organosilicate aluminum salt adopted in the present invention is mainly the -Si-O-Al-O- binary protection. The protection layer formed by the binary combination can reduce the formation of vacancy defects in the film layer at the microscopic level compared with the single -Si-O- protection layer, thereby reducing the formation of pinhole defects in the film layer. In terms of modification effect, the modification advantage of the organosilicate aluminum salt compared with the silane coupling agent is mainly reflected in the avoidance of damage to the quantum dots brought about by the silicon-aluminum binary modification formed simultaneously on the surface of the quantum dots and the higher compatibility of the quantum dots with the resin.

[0036] In addition, in some embodiments, especially after the organic aluminum silicate is combined with the surface of the quantum dot core, at least part of the organic aluminum silicate will also combine with oxygen to form silicon aluminum oxide, and the barrier protection layer includes the silicon aluminum oxide. Specifically, silicon aluminum combines with oxygen elements in the component atmosphere or the ambient atmosphere to form silicon aluminum oxide to participate in the formation of the barrier protection layer, thereby achieving a better coating protection effect on the quantum dot core.

[0037] Regarding the specific selection of the organosilicate aluminum salt, in some embodiments, the R1 group and the R2 group are independently selected from any one of the linear alkyl groups having 1 to 4 carbon atoms, specifically, organic groups such as methyl / ethyl / propyl.

[0038] In some more specific embodiments, the organosilicate aluminum salt may include any one or a combination of two or more of dibutoxyaluminum trimethyl silicate, dibutoxyaluminum triethyl silicate {also known as bis(sec-butyl)orthosilicate triethyl aluminum orthosilicate}, and dibutoxyaluminum tripropyl silicate. However, it is not limited thereto. The above-mentioned organosilicate aluminum salt is a typical reagent commercially available during the research and development of the present invention. Based on the same principle, when the organic group, especially the R2 group, selects other alkyl groups with different carbon atoms, similar technical effects can still be achieved.

[0039] In addition, regarding the quantum dot core itself, in some embodiments, the quantum dot core includes any one or a combination of two or more of CdSe, CdS, CdZnSe, CdZnS, CdZnSeS, ZnSeS, ZnSe, CuInS, CuInSe, InP, InZnP, PbS and perovskite quantum dots.

[0040] In some embodiments, the functionalized modified quantum dots may also include original ligands, which are attached to the surface of the quantum dot core together with the organosilicate aluminum salt (and / or the silicon aluminum oxide formed by the conversion of the organosilicate aluminum salt). The original ligands of the quantum dots play a role of dispersion and preliminary protection, mainly outside the shell of the quantum dots and in contact with the shell, and in the binding reaction process of the organosilicate aluminum salt, part of the original ligands will be replaced, and a certain equilibrium value will be reached outside the shell, forming a state where the original ligands and the organosilicate aluminum salt coexist.

[0041] In some specific embodiments, the ligand may include any one or a combination of two or more of tetradecanoic acid, pentadecanoic acid, hexadecanoic acid, heptadecanoic acid, octadecanoic acid, tetradecenoic acid, pentadecenoic acid, hexadecenoic acid, heptadecanoic acid, octadecenoic acid, tributylamine, tri-n-octylamine and oleylamine, but is not limited thereto.

[0042] Correspondingly, the second aspect of the embodiment of the present invention further provides a method for preparing the functionalized modified quantum dots provided in any of the above embodiments, which comprises the following steps:

[0043] The quantum dot core and the organic aluminum silicate are dissolved in a solvent to form a functionalized reaction system;

[0044] The functionalized reaction system is stirred until the surface of the quantum dot core is covered with a barrier protection layer.

[0045] Regarding specific reaction conditions, in some embodiments, the reaction temperature of the functionalized reaction system is generally room temperature, for example, it can be around 25°C, with a rough range of 15-35°C, and the reaction time can be 8-96h, but is not limited to this. The specific temperature and time conditions may need to be appropriately adjusted based on the reaction activity between different quantum dots, original ligands and organosilicate aluminum salts.

[0046] In addition, regarding the ratio of reactants, in some embodiments, the concentration of the quantum dot core in the functionalized reaction system is generally about 50 mg / ml, and the specific range is, for example, 10-100 mg / ml.

[0047] In some embodiments, the mass ratio of the organosilicate aluminum salt to the quantum dot core in the functionalized reaction system is generally 0.1-0.3:1.

[0048] However, it should be pointed out that the above-mentioned ratio range is the upper and lower limits involved in the experimental process, but it does not mean that the corresponding functionalized modified quantum dots cannot be obtained beyond this range. The feasible implementation scope of the present invention should also be based on obtaining specific microstructures and realizing corresponding functions.

[0049] As a specific example, the above-mentioned quantum dot surface functionalization modification treatment method includes: mixing the quantum dot core with an organic aluminum silicate in a solvent according to a preset ratio, stirring for 8 to 96 hours, and synthesizing a passivation barrier on the quantum dot surface through a mild sol-gel reaction process. The organic aluminum silicate contains a RO-Si-O-Al-OR bond, and the structural formulas of several organic aluminum silicates used in the example are as follows:

[0050]

[0051]

[0052] Although the R2 groups in the above three organosilicate aluminum salts are all n-butyl, other organosilicate aluminum salts with similar structures can also obtain similar protective effects. Combined with the above content, it can be seen that the (O-Si-O-Al-O) structure in the modifier organosilicate aluminum salt is the key to realizing the silicon-aluminum protective layer at the same time, that is, it is believed that the alkyl group on the oxyaluminate is universal; the main reason why the specific experimental case in the present invention uses dibutoxyaluminate as a typical example is to consider the convenience of the source of the reagent.

[0053] Furthermore, an embodiment of the present invention also provides an application method of the above-mentioned functionalized modified quantum dots, namely, a photocurable quantum dot glue, which includes a resin, a photocuring agent, a solvent and the functionalized modified quantum dots provided by any of the above-mentioned embodiments.

[0054] Regarding the specific ratio of the photocurable quantum dot glue, the mass fraction of the resin in the photocurable quantum dot glue is 20-45%, the mass fraction of the photocuring agent is 1-5%, the mass fraction of the solvent is 30-70%, the mass fraction of the functionalized modified quantum dots is 5-40%, and the mass fraction of the selected auxiliary agent is 0.1-5%. Of course, it is not limited to this. The above-mentioned ratio range is the commonly used ratio range for preparing photocurable glue, and it does not mean that the photocurable quantum dot glue that can be used cannot be obtained after exceeding this ratio range.

[0055] As a typical example of the above-mentioned photocurable quantum dot glue, its main components include polymer resin, photocuring agent, organic solvent and functional additives. Functionalized modified quantum dots participate in the glue system as a kind of functional additive. The mass proportions of the main components are as follows:

[0056] The mass percentage of polymer resin is about 20wt% to 45wt%; the mass percentage of photoinitiator is about 1wt% to 5wt%; the mass percentage of organic solvent is about 30wt% to 70wt%; the mass percentage of functionalized modified quantum dots is about 5wt% to 40wt%; the mass percentage of other additives (i.e. selected additives, such as functional additives such as dispersants) is about 0.1wt% to 5wt%.

[0057] In some embodiments, in the above-mentioned light-curable quantum dot glue, the polymer resin is soluble in propylene glycol methyl ether acetate solvent, including one or a mixture of polymethyl methacrylate (also known as acrylic resin), polyethyl methacrylate, polyester acrylate, epoxy acrylate, and polyurethane acrylate. Various resins all show good compatibility with the functionalized modified quantum dots provided in the embodiments of the present invention, but in the propylene glycol methyl ether acetate solvent system, the compatibility of polyethyl methacrylate (MMA) with the above-mentioned functionalized modified quantum dots is more prominent.

[0058] In some embodiments, the photocuring agent includes a mixture of one or more of a cleavage-type free radical photoinitiator, a hydrogen abstraction-type free radical photoinitiator, a cationic photoinitiator, a macromolecular photoinitiator, a polymerizable photoinitiator, a UV-LED photoinitiator, and a visible light initiator. Among them, the polymerizable photoinitiator may include di-tert-butyl peroxide; the cationic photoinitiator may include one or two of aryl ferrocenium salt and aryl diazonium salt; the macromolecular photoinitiator may include macromolecular benzophenone; and the cleavage-type free radical photoinitiator may include a mixture of one or more of azobisisobutyronitrile, diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide, and trimethylbenzoyl-diphenylphosphine oxide.

[0059] In some embodiments, the organic solvent includes a mixture of one or more of a monofunctional reactive diluent, a bifunctional reactive diluent, a multifunctional reactive diluent, a vinyl ether reactive diluent, and a methacrylate reactive diluent. The monofunctional reactive diluent includes a mixture of one or more of propyl methacrylate, isobornyl acrylate, and octadecyl acrylate; the bifunctional reactive diluent includes a mixture of one or more of dipropylene glycol diacrylate, propoxylated glycerol triacrylate, tripropylene glycol diacrylate, ethylene glycol diacrylate, and propylene glycol diacrylate; the multifunctional reactive diluent includes a mixture of one or more of trimethylolpropane triacrylate, pentaerythritol triacrylate, dipentaerythritol pentaacrylate, and propylene glycol methyl ether acetate.

[0060] In some embodiments, the functional additives include various components for adjusting the properties of the glue, and the functionalized modified quantum dots can be used as a functional additive in the glue system; the quantum dots are uniformly mixed, gradient mixed or core-shell types, and the quantum dots contain ligands, and the ligands include one or more of a mixture of C6-C18 saturated amines, unsaturated amines, saturated acids and unsaturated acids. The ligands contained in the quantum dots are a mixture of one or more of tetradecanoic acid, pentadecanoic acid, hexadecanoic acid, heptadecanoic acid, octadecanoic acid, tetradecenoic acid, pentadecenoic acid, hexadecenoic acid, heptadecanoic acid, octadecenoic acid, tributylamine, tri-n-octylamine and oleylamine.

[0061] The method for preparing the photocurable quantum dot glue may include: stirring a mixture of resin, photocuring agent, organic solvent and functional additive for 1 to 20 hours to obtain the photocurable quantum dot glue, wherein the stirring temperature is generally 25 to 50°C.

[0062] Finally, an embodiment of the present invention further provides a quantum dot functional layer, wherein the quantum dot functional layer is formed by curing the photocurable quantum dot glue provided by any of the above embodiments.

[0063] The quantum dot functional layer provided by the present invention has the characteristics of high light conversion efficiency and excellent uniformity, and can be applied to a display device, which includes a display substrate and a quantum dot functional layer arranged on the display substrate, wherein the quantum dot functional layer can be formed by spin coating the photocurable quantum dot glue as described above.

[0064] The technical solution of the present invention is further described in detail below through several embodiments and in conjunction with the accompanying drawings. However, the selected embodiments are only used to illustrate the present invention, and do not limit the scope of the present invention.

[0065] Example 1

[0066] 0.5g of CdSe series red light quantum dots are dissolved in 2ml of propylene glycol methyl ether acetate solvent, and di(sec-butyl)orthosilicate triethyl aluminum orthosilicate is added to the mixed solution according to the mass percentage of quantum dots of 15wt%, and the functionalized quantum dot solution is obtained after gentle stirring at 25°C for 48h; the functionalized quantum dot solution is mixed with blank photocurable glue in a volume ratio of 1:2 to obtain functionalized quantum dot photocurable glue (wherein the proportion of each component of the blank photocurable glue is: polyester acrylate 22wt%, acrylic resin 16wt%, propylene glycol methyl ether acetate 50wt%, acrylate isobornyl ester 10wt%, and azobisisobutyronitrile 2wt%); the photocurable quantum dot glue is obtained after gentle stirring at 25°C for 10h. The obtained photocurable quantum dot glue is spin-coated into a film, UV irradiated and cured for 5 minutes, and heated at 80°C for 5 minutes to obtain a quantum dot functional layer, which can be used for the preparation of display devices.

[0067] Example 2

[0068] 0.5g of CdSe series green light quantum dots are dissolved in 2ml of propylene glycol methyl ether acetate solvent, and di(sec-butyl)orthosilicate triethyl aluminum orthosilicate is added to the mixed solution according to the mass percentage of quantum dots of 10wt%, and the functionalized quantum dot solution is obtained after gentle stirring at 25°C for 40h; the functionalized quantum dot solution is mixed with blank photocurable glue in a volume ratio of 1:2 to obtain functionalized quantum dot photocurable glue (wherein the proportion of each component of the blank photocurable glue is: polyester acrylate 22wt%, acrylic resin 16wt%, propylene glycol methyl ether acetate 50wt%, acrylate isobornyl ester 10wt%, and azobisisobutyronitrile 2wt%); the photocurable quantum dot glue is obtained after gentle stirring at 25°C for 10h. The obtained photocurable quantum dot glue is spin-coated into a film, UV irradiated and cured for 5 minutes, and heated at 80°C for 5 minutes to obtain a quantum dot functional layer, which can be used for the preparation of display devices.

[0069] The state of the glue prepared by the above process is as follows Figure 2 As shown, the quantum dot functional layer formed by curing is as follows Figure 3 shown.

[0070] Example 3

[0071] 1.5g of CdSe series red light quantum dots are dissolved in 3ml of propylene glycol methyl ether acetate solvent, and di(sec-butyl)orthosilicate triethyl aluminum orthosilicate is added to the mixed solution according to the mass percentage of quantum dots of 15wt%, and the functionalized quantum dot solution is obtained after gentle stirring at 25°C for 72h; the functionalized quantum dot solution is mixed with blank photocurable glue in a volume ratio of 1:1 to obtain functionalized quantum dot photocurable glue (wherein the proportion of each component of the blank photocurable glue is: polyester acrylate 20wt%, acrylic resin 12wt%, propylene glycol methyl ether acetate 56wt%, acrylate isobornyl ester 10wt%, and azobisisobutyronitrile 2wt%); and the photocurable quantum dot glue is mixed after gentle stirring at 25°C for 15h to obtain the photocurable quantum dot glue. The obtained photocurable quantum dot glue is spin-coated into a film, UV irradiated and cured for 5 minutes, and heated at 80°C for 5 minutes to obtain a quantum dot functional layer, which can be used for the preparation of display devices.

[0072] Example 4

[0073] 1.5g of CdSe series green light quantum dots are dissolved in 3ml of propylene glycol methyl ether acetate solvent, and di(sec-butyl)orthosilicate triethyl aluminum orthosilicate is added to the mixed solution according to the mass percentage of quantum dots of 20wt%, and the functionalized quantum dot solution is obtained after gentle stirring at 25°C for 60h; the functionalized quantum dot solution is mixed with blank photocurable glue in a volume ratio of 1:1 to obtain functionalized quantum dot photocurable glue (wherein the proportion of each component of the blank photocurable glue is: polyester acrylate 20wt%, acrylic resin 12wt%, propylene glycol methyl ether acetate 56wt%, acrylate isobornyl ester 10wt%, and azobisisobutyronitrile 2wt%); the photocurable quantum dot glue is obtained after gentle stirring at 25°C for 15h. The obtained photocurable quantum dot glue is spin-coated into a film, UV irradiated and cured for 5 minutes, and heated at 80°C for 5 minutes to obtain a quantum dot functional layer, which can be used for the preparation of display devices.

[0074] The state of the glue prepared by the above process is as follows Figure 4 As shown, the quantum dot functional layer formed by curing is as follows Figure 5 shown.

[0075] Comparative Example 1

[0076] This comparative example is substantially the same as Example 1, except that the organosilicate aluminum salt is not used for quantum dot functionalization, and the selected CdSe series red light quantum dots are directly mixed into the blank light-curing glue, and the amount and basic ratio of the glue remain unchanged;

[0077] 0.5g of CdSe series red light quantum dots are dissolved in 2ml of propylene glycol methyl ether acetate solvent, and the quantum dot solution and blank photocurable glue are mixed in a volume ratio of 1:2 to obtain functional quantum dot photocurable glue (wherein the proportions of the components of the blank photocurable glue are: polyester acrylate 22wt%, acrylic resin 16wt%, propylene glycol methyl ether acetate 50wt%, acrylate isobornyl ester 10wt%, and azobisisobutyronitrile 2wt%); after gentle stirring at 25°C for 10h, the photocurable quantum dot glue is obtained. The obtained photocurable quantum dot glue is spin-coated into a film, UV irradiated and cured for 5 minutes, and heated at 80°C for 5 minutes to obtain a quantum dot functional layer, which can be used for the preparation of display devices.

[0078] Comparative Example 2

[0079] This comparative example is substantially the same as Example 2, except that the organosilicate aluminum salt is not used for quantum dot functionalization, and the selected CdSe series green light quantum dots are directly mixed into the blank light-curing glue, and the amount and basic ratio of the glue remain unchanged;

[0080] 0.5g of CdSe series green light quantum dots are dissolved in 2ml of propylene glycol methyl ether acetate solvent, and the quantum dot solution and blank photocurable glue are mixed in a volume ratio of 1:2 to obtain functional quantum dot photocurable glue (wherein the proportions of the components of the blank photocurable glue are: polyester acrylate 22wt%, acrylic resin 16wt%, propylene glycol methyl ether acetate 50wt%, acrylate isobornyl ester 10wt%, and azobisisobutyronitrile 2wt%); after gentle stirring at 25°C for 10h, the photocurable quantum dot glue is obtained. The obtained photocurable quantum dot glue is spin-coated into a film, UV irradiated and cured for 5 minutes, and heated at 80°C for 5 minutes to obtain a quantum dot functional layer, which can be used for the preparation of display devices.

[0081] Comparative Example 3

[0082] This comparative example is substantially the same as Example 2, except that the organic aluminum silicate used is replaced by a silane coupling agent, specifically KH570, and the dosage and modification process conditions remain unchanged;

[0083] 0.5g of CdSe series green light quantum dots are dissolved in 2ml of propylene glycol methyl ether acetate solvent, silane coupling agent KH570 is added to the mixed solution according to the mass percentage of quantum dots of 10wt%, and the functionalized quantum dot solution is obtained after gentle stirring at 25°C for 40h; the functionalized quantum dot solution is mixed with blank photocurable glue in a volume ratio of 1:2 to obtain functionalized quantum dot photocurable glue (wherein the proportion of each component of the blank photocurable glue is: polyester acrylate 22wt%, acrylic resin 16wt%, propylene glycol methyl ether acetate 50wt%, acrylate isobornyl ester 10wt%, and azobisisobutyronitrile 2wt%); the photocurable quantum dot glue is obtained after gentle stirring at 25°C for 10h. The obtained photocurable quantum dot glue is spin-coated into a film, UV irradiated and cured for 5 minutes, and heated at 80°C for 5 minutes to obtain a quantum dot functional layer, which can be used for the preparation of display devices.

[0084] The absorption performance and aging resistance of the quantum dot functional layer prepared in the above embodiment were tested, and the specific results are shown in the following table:

[0085] Table 1 Performance test results of quantum dot functional layer

[0086]

[0087] It can be seen from the aging test that the functionalized quantum dots obtained by surface modification using the preferred organosilicate aluminum salt of the present invention have excellent aging resistance. In the early stage of aging (i.e., before 25 hours), the fluorescence quantum yield (PLQY) of both the embodiment and the comparative example showed an upward trend, but the difference was that in the middle and late stages of aging, the comparative example showed obvious attenuation, while in the multiple embodiments provided by the present invention, due to the excellent protective properties of the organosilicate aluminum salt and the generated oxide, the PLQY showed almost no obvious attenuation.

[0088] Based on the above embodiments and control examples, it can be clearly seen that the embodiments of the present invention utilize organic aluminum silicate to perform surface functional modification treatment on quantum dots, complete the surface passivation modification of quantum dots without the need for a catalyst, and coat the surface of the quantum dots with a barrier protective layer. The passivation modification effectively blocks water and oxygen erosion and inhibits the non-radiative recombination process of carriers, thereby protecting the quantum dots, improving the fluorescence efficiency and photothermal stability of the quantum dots, and improving the problem of a significant decrease in the luminescence efficiency of the quantum dots during the quantum dot ligand exchange and glue photocuring process. At the same time, the good compatibility of the organic groups in the organic aluminum silicate with the glue resin components improves the dispersibility of the quantum dots and the glue system, and can successfully obtain a clear, transparent, and uniformly dispersed photocurable quantum dot glue, effectively solving the problem of uniform dispersion of quantum dots in the photocurable glue system.

[0089] It should be understood that the above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A functionalized modified quantum dot, characterized in that: It includes a quantum dot core and a barrier protection layer covering the quantum dot core; The material of the quantum dot core includes any one or a combination of two or more of transition metal sulfides, transition metal phosphides, transition metal selenides, and perovskite compounds; The barrier protective layer is at least formed of an organic aluminum silicate, and the general formula of the organic aluminum silicate is: (R1-O)3-Si-O-Al-O-R2 Among them, the R2 group and the three R1 groups are independently selected from alkyl groups; in the barrier protection layer, the Si element has a first centralization trend, and the Al element has a second centralization trend, and the first centralization trend is closer to the quantum dot core than the second centralization trend.

2. The functionalized modified quantum dots according to claim 1, characterized in that: At least a portion of the organic aluminum silicate combines with oxygen to form silicon aluminum oxide, and the barrier protection layer includes the silicon aluminum oxide.

3. The functionalized modified quantum dots according to claim 1, characterized in that: The R1 group and the R2 group are independently selected from any one of straight-chain alkyl groups having 1 to 4 carbon atoms.

4. The functionalized modified quantum dots according to claim 1, characterized in that: The organic aluminum silicate includes any one of dibutoxyaluminum trimethyl silicate, dibutoxyaluminum triethyl silicate and dibutoxyaluminum tripropyl silicate or a combination of two or more thereof.

5. The functionalized modified quantum dots according to claim 1, characterized in that: The quantum dot core includes any one or a combination of two or more of CdSe, CdS, CdZnSe, CdZnS, CdZnSeS, ZnSeS, ZnSe, CuInS, CuInSe, InP, InZnP, PbS and perovskite quantum dots. And / or, the functionalized modified quantum dots also include original ligands, and the original ligands and the organic aluminum silicate are attached to the surface of the quantum dot core together; the original ligands include any one of tetradecanoic acid, pentadecanoic acid, hexadecanoic acid, heptadecanoic acid, octadecanoic acid, tetradecenoic acid, pentadecenoic acid, hexadecenoic acid, heptadecanoic acid, octadecenoic acid, tributylamine, tri-n-octylamine and oleylamine, or a combination of two or more thereof.

6. The method for preparing functionalized modified quantum dots according to any one of claims 1 to 5, characterized in that: include: The quantum dot core and the organic aluminum silicate are dissolved in a solvent to form a functionalized reaction system; The functionalized reaction system is stirred until the surface of the quantum dot core is covered with a barrier protection layer.

7. The preparation method according to claim 6, characterized in that: The reaction temperature of the functionalization reaction system is 15-35°C, and the reaction time is 8-96h; and / or, the concentration of the quantum dot core in the functionalized reaction system is 10-100 mg / ml; And / or, the mass ratio of the organic aluminum silicate to the quantum dot core in the functionalized reaction system is (0.1-0.3):

1.

8. A photocurable quantum dot glue, characterized in that: The invention comprises a resin, a photocuring agent, a solvent and the functionalized modified quantum dots described in any one of claims 1 to 5.

9. The light-curable quantum dot glue according to claim 8, characterized in that: The mass fraction of the resin in the photocurable quantum dot glue is 20-45%, the mass fraction of the photocuring agent is 1-5%, the mass fraction of the solvent is 30-70%, the mass fraction of the functionalized modified quantum dots is 5-40%, and the mass fraction of the selected auxiliary agent is 0.1-5%.

10. The light-curable quantum dot glue according to claim 8, characterized in that: The resin includes any one or a combination of two or more of polymethyl methacrylate, polyethyl methacrylate, polyester acrylate, epoxy acrylate, and polyurethane acrylate; And / or, the photocuring agent includes any one or a combination of two or more of di-tert-butyl peroxide, aryl ferrocenium salt, aryl diazonium salt, macromolecular benzophenone, azobisisobutyronitrile, diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide, and trimethylbenzoyl-diphenyl phosphine oxide; And / or, the solvent includes any one or a combination of two or more of propyl methacrylate, isobornyl acrylate, octadecyl acrylate, dipropylene glycol diacrylate, propoxylated glycerol triacrylate, tripropylene glycol diacrylate, ethylene glycol diacrylate, propylene glycol diacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, dipentaerythritol pentaacrylate, and propylene glycol methyl ether acetate.

11. A quantum dot functional layer, characterized in that: The quantum dot functional layer is formed by curing the photocurable quantum dot glue described in any one of claims 8 to 10.

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