CN110713754A

CN110713754A - Block copolymer, composite particle, printing ink and preparation method and application thereof

Info

Publication number: CN110713754A
Application number: CN201810755748.0A
Authority: CN
Inventors: 李雪; 张滔; 向超宇
Original assignee: TCL Corp
Current assignee: TCL Corp
Priority date: 2018-07-11
Filing date: 2018-07-11
Publication date: 2020-01-21
Anticipated expiration: 2038-07-11
Also published as: CN110713754B

Abstract

The invention provides a composite particle, which comprises an inorganic nanoparticle and a block copolymer combined on the surface of the inorganic nanoparticle, wherein the block copolymer comprises a block chain A and a block chain B, the block chain A is a block chain with hole transmission property, the block chain B is polystyrene, the block copolymer at least contains one terminal mercapto group, and the block copolymer is combined with the inorganic nanoparticle through the terminal mercapto group,wherein, the structural unit in the block chain A is selected from at least one of structures shown in formula I and formula II.

Description

Block copolymer, composite particle, printing ink and preparation method and application thereof

Technical Field

The invention belongs to the technical field of electroluminescent diode display, and particularly relates to a block copolymer, a composite particle, ink, and a preparation method and application thereof.

Background

Quantum Dots (QDs), also known as nanocrystals, are nanoparticles composed of elements of groups II-VI or III-V. Quantum dots are zero-dimensional (zero-dimensional) nano-semiconductor materials, the dimensions of each of the three dimensions are no more than twice the exciton bohr radius of the corresponding semiconductor material, and the performance of the quantum dots is generally affected by quantum confinement effect (quantum confinement effect), surface effect and doping. The quantum dot luminescent material has the characteristics of changing emission frequency along with size change, narrow emission line width, relatively high luminescent quantum efficiency, and ultrahigh light stability and solution processing. In recent years, quantum dot luminescent materials play a great role in the fields of LED illumination, liquid crystal display and the like, and quantum dots replace traditional fluorescent powder, so that the color gamut of LED and liquid crystal display is effectively improved. Recently, quantum dot light emitting diodes (QLEDs) using a light emitting material as a light emitting layer have a wide application prospect in the fields of solid state lighting, flat panel display, and the like, and have received wide attention from the academic and industrial fields.

The solution processing property of the quantum dots enables the quantum dot light-emitting layer to be prepared in various ways such as spin coating, blade coating, spraying, ink-jet printing and the like. In contrast to the previous methods, the ink-jet printing technique can deposit the quantum dot luminescent material in the proper position according to the required amount accurately, so that the semiconductor material is uniformly deposited to form the thin film layer. The quantum dot light-emitting layer is prepared by ink-jet printing, the utilization rate of the material is very high, a manufacturer can reduce the production cost, simplify the manufacturing process, and easily popularize mass production and reduce the cost. The ink jet printing technology is an effective method which is recognized at present and can solve the manufacturing problem of the large-size QLED screen.

However, quantum dots are basically directly dispersed in a solvent in the current quantum dot ink, and the obtained quantum dot ink has very low viscosity, so that the prepared quantum dot film is inconsistent in thickness and poor in film forming uniformity, and leakage current is easily caused; meanwhile, the electron hole injection of the quantum dot light emitting layer is unbalanced, and the energy transfer among quantum dots is caused due to the reduction of the quantum dot spacing, so that the light efficiency is reduced.

Disclosure of Invention

The invention aims to provide composite particles, aiming at solving the problems that the prepared inorganic nano material film such as a quantum dot film has poor uniformity and generates leakage current due to low viscosity of the existing inorganic nano material printing ink; and the problem of reduced light efficiency caused by influencing the electron hole injection balance of inorganic nano material films such as quantum dot light-emitting layers.

It is another object of the present invention to provide a block polymer.

It is a further object of the present invention to provide an ink containing the composite particles of the present invention, and a method for preparing the same and use thereof.

In order to achieve the purpose, the invention adopts the following technical scheme:

the invention provides a composite particle, which comprises an inorganic nanoparticle and a block copolymer bonded on the surface of the inorganic nanoparticle, wherein the block copolymer comprises a block chain A and a block chain B, the block chain A is a block chain with hole transport property, the block chain B is polystyrene, the block copolymer at least contains one terminal mercapto group, and the block copolymer is bonded with the inorganic nanoparticle through the terminal mercapto group, wherein the structural unit in the block chain A is selected from at least one of structures shown in formula I and formula II,

in another aspect of the present invention, there is provided a block copolymer comprising a middle block chain, wherein the middle block chain is composed of a block chain a and a block chain B, one end of the middle block chain is connected with a terminal thiol group, the block chain a contains a carbazolyl structure, the block chain B is polystyrene, and the structural unit in the block chain a is selected from at least one of the structures represented by formula i and formula ii,

the invention further provides ink, which comprises composite particles and a solvent, wherein the composite particles comprise inorganic nanoparticles and a block copolymer bonded on the surfaces of the inorganic nanoparticles, the block copolymer comprises a block chain A and a block chain B, the block chain A is a block chain with hole transport property, the block chain B is polystyrene, a modifier of the block copolymer at least contains one terminal mercapto group, and the block copolymer is bonded with the inorganic nanoparticles through the terminal mercapto group, wherein structural unit structural units in the block chain A are selected from at least one of structures shown in formula I and formula II,

in another aspect, the present invention provides a method for preparing an ink, comprising the steps of:

providing inorganic nanoparticles, a block copolymer, and a solvent;

and dispersing the block copolymer and the inorganic nano particles in a solvent to form the ink.

And, a method for preparing a thin film, comprising the steps of:

providing the ink of the invention;

and depositing the printing ink on a carrier, and drying to obtain the film.

The composite particle provided by the invention comprises an inorganic nanoparticle and a block copolymer bonded on the surface of the inorganic nanoparticle. And the block copolymer at least contains one terminal sulfydryl, so that the block copolymer can be effectively combined with metal ions on inorganic nanoparticles of the inorganic nanoparticles to form a stable ligand system. On the basis, the block copolymer comprises a block chain A and a block chain B, and A, B two block chains, wherein one block chain has a hole transport property, and the other block chain is polystyrene. The obtained material can effectively adjust the distance between inorganic nano-particle particles of the inorganic nano-particles, avoid energy transfer caused by too close distance between inorganic nano-particle particles of the inorganic nano-particles, reduce energy loss and improve quantum efficiency; moreover, the block chain A with the hole transmission characteristic and polystyrene without the charge transmission characteristic coexist to form a block copolymer, the block chain A can improve the hole transmission performance, the polystyrene has certain insulation performance, meanwhile, the polystyrene chain segment has certain flexibility relatively, and can form better micro-area uniform arrangement in the film together with the block chain A, the charge transmission performance is cooperatively adjusted by the block chain A and the polystyrene chain segment, the hole injection balance of inorganic nanoparticles such as quantum dots is improved, and the light emitting performance of the inorganic nanoparticles is further improved. Furthermore, the structural unit in the block A is selected from at least one of structures shown in a formula I and a formula II, the carbazolyl band gap energy in the block chain A is relatively large, and the highest occupied orbital (HOMO) energy is about-5.81 eV, so that the HOMO energy level of the quantum dot light emitting layer is increased, the energy barrier with the hole transport layer is reduced, and the HOMO energy level can be further regulated and controlled by regulating and controlling the introduced group on the N atom. Specifically, the butyl group has an electron donating ability, so that the HOMO energy level of the butyl group is further improved relative to carbazole, and the butyl group is matched with the charge transport layer, so that the butyl group has stronger hole transport ability, is convenient for hole transport, and enables the hole and electron transport of the device to be balanced and improved.

The block copolymer provided by the invention comprises a middle block chain, and one end of the middle block chain is connected with a terminal sulfydryl, so that the block copolymer can be effectively combined with metal ions on inorganic nano-particles to form a stable ligand system when being used for inorganic nano-ink. On the basis, the block copolymer comprises a block chain A and a block chain B, wherein the block chain A contains a carbazolyl structure, and the block chain B is polystyrene. When the block copolymer is used for an inorganic nano film, the carbazolyl band gap energy in the block chain A is relatively large, and the highest occupied orbital (HOMO) energy is about-5.81 eV, so that the HOMO energy level of a quantum dot light-emitting layer is increased to a certain extent, the energy barrier with a hole transport layer is reduced, and the HOMO energy level can be further regulated and controlled by regulating and controlling an introduction group on an N atom. Specifically, the butyl group has an electron donating ability, so that the HOMO energy level of the butyl group is further improved relative to carbazole, and the butyl group is matched with the charge transport layer, so that the butyl group has stronger hole transport ability, is convenient for hole transport, and enables the hole and electron transport of the device to be balanced and improved. The polystyrene has a certain insulating property, the block chain A and the block chain B coordinate to adjust the charge transmission property, the hole injection balance of inorganic nanoparticles such as quantum dots is improved, and the luminescent property of the inorganic nanoparticles is further improved.

The ink provided by the invention contains inorganic nanoparticles and a block copolymer, and the block copolymer at least contains one terminal sulfydryl, so that the block copolymer modifier can be effectively combined with metal ions on the inorganic nanoparticles to form a stable ligand system. On the basis, the block copolymer modifier comprises a block chain A and a block chain B, wherein one block chain A has a hole transport characteristic, and the other block chain B is polystyrene and has a certain insulating property. The obtained inorganic nano-particles can effectively adjust the distance between the particles of the inorganic nano-particles, avoid energy transfer caused by too close distance between the particles of the inorganic nano-particles, reduce energy loss and improve quantum efficiency. And the structural unit in the block chain A is selected from at least one of structures shown in formula I and formula II, the carbazolyl band gap energy in the block chain A is relatively large, and the highest occupied orbital (HOMO) energy is about-5.81 eV, so that the HOMO energy level of the quantum dot light emitting layer is increased, the energy barrier with the hole transport layer is reduced, and the HOMO energy level can be further regulated and controlled by regulating and controlling the introduced group on the N atom. Specifically, the butyl group has an electron donating ability, so that the HOMO energy level of the butyl group is further improved relative to carbazole, and the butyl group is matched with the charge transport layer, so that the butyl group has stronger hole transport ability, is convenient for hole transport, and enables the hole and electron transport of the device to be balanced and improved. Therefore, the block chain A with the hole transport property and the polystyrene without the charge transport property coexist to form the block copolymer modifier, the polystyrene chain segment has better solubility in the ink, the solubility and the film forming property of the ink can be enhanced, the block chain A and the polystyrene cooperate to adjust the charge transport property, the hole injection balance of inorganic nano particles such as quantum dots is improved, and the luminescent property of the inorganic nano particles is further improved. In addition, the inorganic nanoparticles are modified by the block copolymer modifier, so that the viscosity of the ink can be adjusted, the printing manufacturability and the film forming property are improved, the inorganic nanoparticle printing ink can meet the requirements of ink-jet printing, the ink is stably discharged, the ink is stably spread, the drying is uniform, and the film forming is uniform.

The preparation method of the ink provided by the invention only needs to disperse the inorganic nano particles in the organic solvent, is simple and easy to control in operation, does not need harsh conditions, and can realize mass production.

The preparation method of the film provided by the invention can be obtained by only carrying out ink-jet printing and drying on the ink on the carrier, and the method is simple and is easy to realize standardized control.

Detailed Description

In order to make the technical problems, technical solutions and advantageous effects to be solved by the present invention more clearly apparent, the present invention is further described in detail below with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

In the description of the present invention, it is to be understood that the terms "first", "second" and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implying any number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise.

Composite particles

The composite particle comprises an inorganic nanoparticle and a block copolymer bonded on the surface of the inorganic nanoparticle, wherein the block copolymer comprises a block chain A and a block chain B, the block chain A is a block chain with hole transport property, the block chain B is polystyrene, the block copolymer at least contains one terminal mercapto group, and the block copolymer is bonded with the inorganic nanoparticle through the terminal mercapto group, wherein the structural unit in the block chain A is selected from at least one of structures shown in formula I and formula II,

the composite particle provided by the embodiment of the invention comprises an inorganic nanoparticle and a block copolymer bonded on the surface of the inorganic nanoparticle. And the block copolymer at least contains one terminal sulfydryl, so that the block copolymer can be effectively combined with metal ions on the inorganic nanoparticles to form a stable ligand system. On the basis, the block copolymer comprises a block chain A and a block chain B, and A, B two block chains, wherein one block chain has a hole transport property, and the other block chain is polystyrene. The obtained material can effectively adjust the distance between the particles of the inorganic nano particles, avoid energy transfer caused by too close distance between the particles of the inorganic nano particles, reduce energy loss and improve quantum efficiency; moreover, the block chain A with the hole transmission characteristic and polystyrene without the charge transmission characteristic coexist to form a block copolymer, the block chain A can improve the hole transmission performance, the polystyrene has certain insulation performance, meanwhile, the polystyrene chain segment has certain flexibility relatively, and can form better micro-area uniform arrangement in the film together with the block chain A, the charge transmission performance is cooperatively adjusted by the block chain A and the polystyrene chain segment, the hole injection balance of inorganic nanoparticles such as quantum dots is improved, and the light emitting performance of the inorganic nanoparticles is further improved. Furthermore, the structural unit in the block A is selected from at least one of structures shown in a formula I and a formula II, the carbazolyl band gap energy in the block chain A is relatively large, and the highest occupied orbital (HOMO) energy is about-5.81 eV, so that the HOMO energy level of the quantum dot light emitting layer is increased, the energy barrier between the quantum dot light emitting layer and the hole transport layer is reduced, and the HOMO energy level can be further regulated and controlled by regulating and controlling an introduced group on an N atom. Specifically, the butyl group has an electron donating ability, so that the HOMO energy level of the butyl group is further improved relative to carbazole, and the butyl group is matched with the charge transport layer, so that the butyl group has stronger hole transport ability, is convenient for hole transport, and enables the hole and electron transport of the device to be balanced and improved.

In the embodiment of the present invention, the block chain a used for forming the block copolymer has not only an appropriate volume to adjust the distance between particles of the inorganic nanoparticles, thereby improving quantum efficiency; more importantly, the block chain A also has hole transmission characteristics, so that the hole injection balance of inorganic nanoparticles such as quantum dots is improved, and the light-emitting performance is improved. In addition, the block copolymer formed by the block chain A and the block chain B has better solubility in an organic solvent so as to be uniformly dissolved and dispersed in the inorganic nanoparticle printing ink.

The block chain B used to form the block copolymer, i.e., polystyrene, has certain insulating properties; meanwhile, the polystyrene chain segment has good solubility in ink, can enhance the solubility and film-forming property of the ink, has certain flexibility, can enhance the uniform distribution of micro-areas of the block chain A, and effectively adjusts hole transmission.

Specifically, in the embodiment of the present invention, the block chain a and the block chain B constitute a block copolymer, and the block copolymer obtained thereby contains at least one terminal thiol group, so that the block copolymer is bonded to the inorganic nanoparticle such as a quantum dot. That is, it can be understood that the terminal mercapto group exists in three forms in the block copolymer. A, B represents a block chain A and a block chain B, respectively, and as one embodiment, the terminal mercapto group in the block copolymer is located at one end of the block chain A, and the block copolymer is abbreviated as SH-A-B; as a second implementation case, the terminal thiol group in the block copolymer is located at one end of the block chain B, the block copolymer being abbreviated SH-B-a; as a third embodiment, the block chain B and the block chain A in the block copolymer both have a terminal mercapto group, and the block copolymer is abbreviated as SH-B-A-SH.

As a preferred embodiment, the block copolymer comprises a mid-block chain consisting of a block chain a and a block chain B, one end of the mid-block chain being linked to one of the terminal thiol groups. Further preferably, in the block copolymer, the other end to which the intermediate block chain is connected is an aliphatic group having 3 to 10 carbon atoms or an aromatic group having 3 to 10 carbon atoms.

In the embodiment of the present invention, preferably, the weight average molecular weight of the block copolymer is 1000-50000, and the weight average molecular weight of the block copolymer is controlled within the above range, so that the block chain A and the polystyrene segment have better combinability; on the other hand, the surface of the quantum dot ligand can chelate enough block copolymer ligand, so that the stability of the quantum dot is ensured, and meanwhile, the charge transmission property, the ink solubility and the film forming distribution of the quantum dot ink are adjusted. If the weight average molecular weight of the block copolymer is too small, the proportion of the block chain A or polystyrene is improperly adjusted, resulting in a decrease in charge transport properties or a decrease in ink solubility. Further preferably, the block copolymer has a weight average molecular weight of 5000-10000.

Further preferably, the weight percentage of the block chain A is 10-90% based on the total weight of the block copolymer as 100%. The appropriate content of the block chain A can ensure that the modified inorganic nanoparticles have higher charge transfer performance, and meanwhile, the appropriate addition of polystyrene can avoid the situation that the charge transfer performance is too high to inhibit the generation of excitons, thereby ensuring better luminescence performance. In order to obtain better luminescence properties while ensuring suitable ink jet printing properties, the weight percentage of the block chain a is further preferably from 40% to 60%, based on 100% by weight of the total weight of the block copolymer.

Preferably, the weight percentage of the block copolymer is 10% to 80% based on 100% of the total weight of the composite particle. Further preferably, the weight percentage of the block copolymer is 20 to 50% based on 100% of the total weight of the composite particle.

Block copolymer

The embodiment of the invention provides a block copolymer, which comprises an intermediate block chain, wherein the intermediate block chain consists of a block chain A and a block chain B, one end of the intermediate block chain is connected with a terminal sulfydryl, the block chain A contains a carbazolyl structure, the block chain B is polystyrene, and a structural unit in the block chain A is selected from at least one of structures shown in a formula I and a formula II,

the block copolymer provided by the embodiment of the invention comprises a middle block chain, and one end of the middle block chain is connected with a terminal sulfydryl, so that the block copolymer can be effectively combined with metal ions on inorganic nano-particles to form a stable ligand system when being used for inorganic nano-ink. On the basis, the block copolymer comprises a block chain A and a block chain B, wherein the block chain A contains a carbazolyl structure, and the block chain B is polystyrene. When the block copolymer is used for an inorganic nano film, the carbazolyl band gap energy in the block chain A is relatively large, and the highest occupied orbital (HOMO) energy is about-5.81 eV, so that the HOMO energy level of a quantum dot light-emitting layer is increased to a certain extent, the energy barrier with a hole transport layer is reduced, and the HOMO energy level can be further regulated and controlled by regulating and controlling an introduction group on an N atom. Specifically, the butyl group has an electron donating ability, so that the HOMO energy level of the butyl group is further improved relative to carbazole, and the butyl group is matched with the charge transport layer, so that the butyl group has stronger hole transport ability, is convenient for hole transport, and enables the hole and electron transport of the device to be balanced and improved. The polystyrene has a certain insulating property, the block chain A and the block chain B coordinate to adjust the charge transmission property, the hole injection balance of inorganic nanoparticles such as quantum dots is improved, and the luminescent property of the inorganic nanoparticles is further improved.

Specifically, in the present embodiment, the terminal mercapto group exists in three forms in the block copolymer. A, B represents a block chain A and a block chain B, respectively, and as one embodiment, the terminal mercapto group in the block copolymer is located at one end of the block chain A, and the block copolymer is abbreviated as SH-A-B; as a second implementation case, the terminal thiol group in the block copolymer is located at one end of the block chain B, the block copolymer being abbreviated SH-B-a; as a third embodiment, the block chain B and the block chain A in the block copolymer both have a terminal mercapto group, and the block copolymer is abbreviated as SH-B-A-SH. The other end of the block copolymer is an aliphatic group of 3 to 10 carbon atoms or an aromatic group of 3 to 10 carbon atoms.

In the embodiment of the present invention, preferably, the weight average molecular weight of the block copolymer is 1000-50000, and the weight average molecular weight of the block copolymer is controlled within the above range, so that the block chain A and the polystyrene segment have better combinability; on the other hand, when the block copolymer is used for manufacturing inorganic nano films such as quantum dot films, the surface of a quantum dot ligand can be chelated with a sufficient amount of block copolymer ligand, so that the stability of quantum dots is ensured, and meanwhile, the charge transport property, the ink solubility and the film forming distribution of the quantum dot ink are adjusted. Further preferably, the block copolymer has a weight average molecular weight of 5000-10000.

Printing ink

The embodiment of the invention provides an ink, which comprises composite particles and a solvent, wherein the composite particles comprise inorganic nanoparticles and a block copolymer bonded on the surfaces of the inorganic nanoparticles, the block copolymer comprises a block chain A and a block chain B, the block chain A is a block chain with hole transport property, the block chain B is polystyrene, a block copolymer modifier at least contains one terminal mercapto group, and the block copolymer is bonded with the inorganic nanoparticles through the terminal mercapto group, wherein the structural unit in the block chain A is selected from at least one of structures shown in formula I and formula II,

the ink provided by the embodiment of the invention contains inorganic nanoparticles and a block copolymer, and the block copolymer at least contains one terminal sulfydryl, so that the block copolymer modifier can be effectively combined with metal ions on the inorganic nanoparticles to form a stable ligand system. On the basis, the block copolymer modifier comprises a block chain A and a block chain B, wherein one block chain A has a hole transport characteristic, and the other block chain B is polystyrene and has a certain insulating property. The obtained inorganic nano-particles can effectively adjust the distance between the particles of the inorganic nano-particles, avoid energy transfer caused by too close distance between the particles of the inorganic nano-particles, reduce energy loss and improve quantum efficiency. And the structural unit in the block chain A is selected from at least one of structures shown in formulas I and II, the carbazolyl band gap energy in the block chain A is relatively large, and the highest occupied orbital (HOMO) energy is about-5.81 eV, so that the HOMO energy level of the quantum dot light emitting layer is increased, the energy barrier with the hole transport layer is reduced, and the HOMO energy level can be further regulated and controlled by regulating and controlling the introduced group on the N atom. Specifically, the butyl group has an electron donating ability, so that the HOMO energy level of the butyl group is further improved relative to carbazole, and the butyl group is matched with the charge transport layer, so that the butyl group has stronger hole transport ability, is convenient for hole transport, and enables the hole and electron transport of the device to be balanced and improved. Therefore, the block chain A with the hole transport property and the polystyrene without the charge transport property coexist to form the block copolymer modifier, the polystyrene chain segment has good solubility in the ink, the solubility and the film forming property of the ink can be enhanced, the block chain A and the polystyrene cooperate to adjust the charge transport property, the hole injection balance of inorganic nanoparticles such as quantum dots is improved, and the light emitting property of the inorganic nanoparticles is further improved. In addition, the inorganic nanoparticles are modified by the block copolymer modifier, so that the viscosity of the ink can be adjusted, the printing manufacturability and the film forming property are improved, the inorganic nanoparticle printing ink can meet the requirements of ink-jet printing, the ink is stably discharged, the ink is stably spread, the drying is uniform, and the film forming is uniform.

The block chain B for forming the block copolymer, namely polystyrene, has certain insulating property, and the polystyrene chain segment has certain flexibility relatively, so that the block chain B and the block chain A can form better micro-area uniform arrangement in the film.

Specifically, in the embodiment of the present invention, the block chain a and the block chain B constitute a block copolymer, and the block copolymer obtained thereby contains at least one terminal thiol group, so that the block copolymer is bonded to the inorganic nanoparticle such as a quantum dot. That is, it can be understood that the terminal mercapto group exists in three forms in the block copolymer. A, B represents a block chain A and a block chain B, respectively, and as one embodiment, the terminal mercapto group in the copolymer is located at one end of the block chain A, and the copolymer is abbreviated as SH-A-B; as a second embodiment, the terminal mercapto group in the copolymer is located at one end of the block chain B, the copolymer being abbreviated SH-B-a; as a third embodiment, both the block chain B and the block chain A of the copolymer contain a terminal mercapto group, and the copolymer is abbreviated as SH-B-A-SH.

Further preferably, the weight percentage of the block chain A is 10-90% based on the total weight of the block copolymer as 100%. The appropriate content of the block chain A can ensure that an inorganic nanoparticle film formed by ink-jet printing of the inorganic nanoparticle printing ink has high charge transfer performance, and meanwhile, the appropriate addition of polystyrene can avoid the over-high charge transfer performance to inhibit the generation of excitons, thereby ensuring good luminescence performance. In order to obtain better luminescence properties while ensuring suitable ink jet printing properties, the weight percentage of the block chain a is further preferably from 40% to 60%, based on 100% by weight of the total weight of the block copolymer.

In the embodiment of the invention, the block copolymer is added into the inorganic nanoparticle printing ink, so that the inorganic nanoparticles can be modified, the printing performance of the inorganic nanoparticle printing ink is improved, and the luminescence performance of the obtained inorganic nanoparticle printing film is improved. Preferably, the block copolymer in the composite particles accounts for 10-80% of the total weight of the composite particles, so that the inorganic nanoparticle printing ink has proper viscosity and is beneficial to obtaining an inorganic nanoparticle printing film with high quantum efficiency. More importantly, the appropriate block copolymer content allows the block copolymer to remain in dynamic equilibrium with the inorganic nanoparticles in dissociation and association. More preferably, the block copolymer in the composite particle comprises 20% to 50% of the total weight of the composite particle.

In the embodiment of the present invention, one or more inorganic nanoparticles may be used in the inorganic nanoparticle ink. In particular, the inorganic nano-particles are used as a matrix component of the inorganic nano-particle printing ink, the semiconductor material may be at least one of group IV, group II-VI, group II-V, group III-VI, group IV-VI, group I-III-VI, group II-IV-V binary or multiple single crystal semiconductor compounds, or at least one of group IV, group II-VI, group II-V, group III-VI, group IV-VI, group I-III-VI, group II-IV-V binary or multiple core-shell structure semiconductor compounds, or a mixture of a single crystal semiconductor compound and a core-shell structure semiconductor compound. Specifically, the inorganic nanoparticles may be selected from, but not limited to, at least one of CdSe, CdS, CdTe, ZnO, ZnSe, ZnS, ZnTe, HgS, HgSe, HgTe, CdZnSe; but is not limited to, InAs, InP, InN, GaN, InSb, InAsP, InGaAs, GaAs, GaP, GaSb, AlP, AlN, AlAs, AlSb, CdSeTe, ZnCdSe. In the embodiment of the present invention, the structure type of the inorganic nanoparticles is not limited, and a uniform mixing type, a gradient mixing type, a core-shell type, or a combination type may be used. Furthermore, the inorganic nanoparticles may also be perovskite nanoparticle materials, with luminescent perovskite nanoparticles, metal nanoparticle materials, metal oxide nanoparticle materials, and combinations thereof being particularly preferred.

The composition form of the inorganic nanoparticles is not limited, and the inorganic nanoparticles can be doped or undoped inorganic nanoparticles, wherein doping means that the inorganic nanoparticles also contain other doping elements inside. Specifically, the inorganic nanoparticles may be quantum dot materials. Wherein the ligand of the quantum dot comprises at least one of acid ligand, thiol ligand, amine ligand, (oxy) phosphine ligand, phospholipid, lecithin, polyvinyl pyridine and the like. As a specific embodiment, the acid ligand is at least one of deca acid, undecylenic acid, tetradecanoic acid, oleic acid and stearic acid; the mercaptan ligand is at least one of octaalkylmercaptan, dodecyl mercaptan and octadecyl mercaptan; the amine ligand comprises at least one of oleylamine, octadecylamine and octamine; the (oxy) phosphine ligand is at least one of trioctylphosphine and trioctylphosphine.

The inorganic nanoparticle printing provided by the embodiment of the invention is suitable for ink-jet printing of the quantum dot light-emitting layer, and when the water content in the inorganic nanoparticle printing ink is higher, water is difficult to volatilize or remove, and is easy to remain in the quantum dot ink, so that the performance of the formed quantum dot light-emitting layer is influenced. In view of this, the quantum dots according to the embodiments of the present invention are preferably oil-soluble quantum dots.

As a particularly preferred embodiment, the average size of the quantum dots is 1-20 nm.

In embodiments of the present invention, the inorganic nanoparticle printing ink further comprises at least one organic solvent. The organic solvent is selected from but not limited to chlorobenzene, o-dichlorobenzene, tetrahydrofuran, anisole, morpholine, toluene, o-xylene, m-xylene, p-xylene, n-hexane, dichloromethane, trichloromethane, 1, 4-dioxane, 1, 2-dichloroethane, 1,1, 1-trichloroethane, 1,1,2, 2-tetrachloroethane, tetrahydronaphthalene, at least one of decalin, phenoxytoluene, dodecane, 1-methoxynaphthalene, 1-butylnaphthalene, orthodimethoxybenzene, 1-methylnaphthalene, 1, 2-dimethylnaphthalene, cyclohexylbenzene, 1,2, 4-trimethoxybenzene, phenylhexane, tetradecane, 1, 2-dimethylnaphthalene, 4-isopropylbiphenyl, 2-isopropylnaphthalene, 1-ethylnaphthalene and 1,2,3, 4-tetrahydronaphthalene.

Further, the weight ratio of the total weight of the composite particles to the organic solvent is 0.01-20.0:80-99.9 by weight ratio to impart better viscosity to the inorganic nanoparticle printing ink. Further preferably, the weight ratio of the total weight of the composite particles to the organic solvent is 4.0-15.0:85.0-96.0 by weight ratio.

Preferably, the ink consists of the composite particles and the organic solvent, and the weight ratio of the total weight of the composite particles to the organic solvent is 4.0-15.0: 85.0-96.0. I.e. the inorganic nanoparticle printing ink does not contain any auxiliary agents other than the inorganic nanoparticles, the block copolymer and the organic solvent.

As another preferable mode, the ink contains the composite particles and the organic solvent, and the weight ratio of the total weight of the composite particles to the organic solvent is 4.0-15.0: 85.0-96.0. Further, in the present embodiment, the inorganic nanoparticle printing ink may further include an auxiliary agent, which includes but is not limited to: viscosity modifiers and dispersants.

In order to ensure that when the quantum dot ink is used for ink-jet printing, the ink is properly released from a nozzle of an ink-jet printing head without blockage, and simultaneously has better film-forming characteristics, a viscosity regulator can be added into the inorganic nanoparticle printing ink. The viscosity modifier is preferably at least one of a polyhydric alcohol, an alkyl glycol ether or trimethylolpropane, trimethylolethane, casein, carboxymethylcellulose. Specifically, the polyhydric alcohol is at least one of ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, hexylene glycol, 1, 3-butylene glycol, 1, 4-butylene glycol, 1, 5-pentanediol, 2-butene-1, 4-diol, 2-methyl-2-pentanediol, 1,2, 6-hexanetriol, glycerol, polyethylene glycol, dipropylene glycol and polyvinyl alcohol. The alkyl glycol ether is at least one of polyethylene glycol monobutyl ether, diethylene glycol monoethyl ether, dipropylene glycol monomethyl ether and propylene glycol n-propyl ether.

The addition of the dispersant to the ink is effective to uniformly disperse the quantum dots in the solvent and to stabilize the dispersion. In particular, the dispersant may be one or more surfactants. The surfactant may be an anionic, cationic, nonionic or amphoteric surfactant.

As specific examples, the nonionic surfactant includes, but is not limited to, at least one of linear or secondary alcohol ethoxylates, alkylphenol ethoxylates, fluorosurfactants, fatty acid polyoxyethylene esters, fatty amine polyoxyethylene ethers, polyoxyethylene block copolymers and propoxylated block copolymers, polyoxyethylene and propylsilicone oxide resin-based surfactants, alkyl polyglycosides, and acetylene polyethylene oxide surfactants. The anionic surfactant includes, but is not limited to, at least one of carboxylates (e.g., ether carboxylates and sulfosuccinates), sulfates (e.g., sodium lauryl sulfate), sulfonates (e.g., dodecylbenzene sulfonate, alpha-olefin sulfonate, alkyl diphenyl oxide disulfonate, fatty acid taurates, alkyl naphthalene sulfonates), phosphates (e.g., phosphate esters of alkyl and aryl alcohols), phosphonates and amine oxide surfactants, and anionic fluorinated surfactants. The amphoteric surfactant includes, but is not limited to, at least one of trimethylamine ethylester, sultaine, and aminopropionate. The cationic surfactant includes, but is not limited to, at least one of quaternary ammonium compounds, cationic amine oxides, ethoxylated fatty amines, and imidazoline surfactants.

The inorganic nanoparticle printing ink provided by the embodiment of the invention has a viscosity of 0.5-60.0mPa.s at 25-35 ℃, specifically 1mPa.s, 5mPa.s, 10mPa.s, 15mPa.s, 20mPa.s, 25mPa.s, 30mPa.s, 35mPa.s, 40mPa.s, 45mPa.s, 50mPa.s, 55mPa.s, 60 mPa.s; further, the viscosity of the quantum dot ink is preferably 1 to 30.0mpa.s at 25 ℃, and more preferably 1 to 15.0mpa.s at 25 to 35 ℃. The surface tension of the inorganic nanoparticle printing ink is 20.0-80.0mN/m, so that the inorganic nanoparticle printing ink can be smoothly released from a printing nozzle in an ink-jet printing process, and has a good film forming characteristic. Specifically, the inorganic nanoparticle printing ink may have a surface tension of 20.0, 30.0, 40.0, 50.0, 60.0, 70.0, 80.0 mN/m.

The inorganic nano-particle printing ink provided by the embodiment of the invention has the surface tension within the range of 20-80mN/m and the viscosity of 0.5-60.0mPa.s at the temperature of 25-35 ℃, can meet the requirements of the current ink-jet printer on the viscosity and the surface tension, realizes the ink-jet printing mode of an inorganic nano-particle layer, realizes stable ink discharge, stable spreading, high wettability, uniform drying and uniform film forming in the printing process, and obtains an inorganic nano-particle light-emitting layer with a pixel lattice, high resolution and electro-excitation. Meanwhile, according to the inorganic nanoparticle printing ink provided by the embodiment of the invention, the thickness of a film layer formed by the printed inorganic nanoparticles such as quantum dots and a block copolymer is uniform and flat, and the inorganic nanoparticles such as quantum dots are uniformly distributed in the block copolymer, so that the electron-charge injection of a quantum dot light-emitting layer is more balanced, the energy transfer loss among the quantum dots is reduced, and the light-emitting efficiency is improved.

Preparation method of printing ink

Another aspect of the present invention provides a method for preparing an ink, comprising the steps of:

s01, providing inorganic nano-particle particles, a block copolymer and an organic solvent;

s02, dispersing the block copolymer and the inorganic nano particles in an organic solvent to form the inorganic nano particle ink.

The preparation method of the ink provided by the embodiment of the invention only needs to disperse the inorganic nanoparticles in the organic solvent, is simple and easy to control in operation, does not need harsh conditions, and can realize mass production.

Specifically, in the step S01, the types and contents of the inorganic nanoparticles, the block copolymer, and the organic solvent are all stated above, and are not described herein again for the sake of brevity.

The block copolymer provided by the embodiment of the invention can be prepared by self, and is preferably synthesized by a reversible addition-fragmentation chain transfer (RAFT) polymerization-amine decomposition method.

The preparation method of the block copolymer comprises the following steps:

s011, providing at least one of functional structural monomers shown in a formula III and a formula IV, placing the functional structural monomer, a free radical initiator and an RAFT reagent in a solvent, and preparing the RAFT reagent of the functional block chain A through polymerization reaction;

specifically, in step S011, the structural monomers of the block chain a are functional structural monomers of formulae iii and iv (functional structural monomers of formulae i and ii, respectively), and the structural general formula of the functional structural monomers is represented as R¹CHCH₂Or R¹C(R’)CH₂Wherein, said R¹Is carbazolyl in functional structural monomers shown in formulas III and IV. The RAFT agent is represented by R²-S-CS-R³Is used for reacting with the terminal alkenyl of the functional structural monomer. Wherein R is²、R³Preferably aliphatic, aromatic groups of 3-10 carbon atoms, to provide better solubility and reactivity of the RAFT agent during the reaction. The free radical initiator is used for initiating the polymerization reaction of the functional structural monomer. Specifically, the free radical initiator is selected from one of a free radical thermal initiator and a free radical photoinitiator. Particularly preferably, the thermal radical initiator is selected from azo, peroxide, persulfate, oxygenAt least one of a redox initiator including, but not limited to, Azobisisobutyronitrile (AIBN); the free radical photoinitiator is selected from at least one of 2-hydroxy-2-methyl-1-phenyl-1-acetone, 2-dimethoxy-2-phenylacetophenone, 2-methyl-1- (4-methylthiophenyl) -2-morpholinyl-1-acetone, 1-hydroxycyclohexyl phenyl ketone, 2-dimethoxy-phenyl ketone, phenyl bis- (2,4, 6-trimethylbenzoyl) phosphine oxide, 2-phenylbenzyl-2-dimethylamine-1- (4-morpholinebenzylphenyl) butanone, 2, 4-dimethylthioxanthone and 2, 4-diethylthioxanthone. In the embodiment of the present invention, in the step S111 and the step S112, the solvent used for polymerization may be at least one selected from benzene and alkylbenzene, and may be at least one selected from tetrahydrofuran, dichloromethane, dichloroethane, chloroform, chlorobenzene, nitrobenzene, dioxane, and cyclohexane; can be selected from lipids; can be selected from ketones; may be selected from at least one of N-methylpyrrolidone, N-dimethylformamide, N-dimethylacetamide and dimethylsulfoxide, and may be any combination of the above solvents. More specifically, the alkylbenzene is selected from at least one of toluene, xylene, and other alkylbenzenes having a boiling point higher than that of the xylene; the esters are selected from at least one of but not limited to ethyl acetate, n-butyl acetate and 1-methoxy-2-propyl acetate; the ketone is selected from at least one of acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone. Further preferably, in the step S111 and the step S112 described below, the solvent used for the polymerization is a toluene, chloroform or tetrahydrofuran solvent.

The functional structural monomer, a free radical initiator and an RAFT (reversible addition-fragmentation chain) test are subjected to polymerization reaction to prepare the RAFT reagent of the functional block chain A, taking a formula III as an example, the reaction formula is as follows:

wherein the value of m in the RAFT reagent of the functionalized block chain A is determined by the type of the functional structural monomer participating in the reaction. When the functional structural monomer participating in the reaction is only the functional structural monomer shown in the formula III, the polymer with the structure shown in the formula I is obtained through polymerization reaction, and the value of m is the same as that of x; when the functional structural monomer participating in the reaction is only the functional structural monomer shown in the formula IV, the polymer with the structure shown in the formula II is obtained through polymerization reaction, and at the moment, the value of m is the same as that of y; when the functional structural monomer participating in the reaction contains the functional structural monomers shown in the formulas III and IV, the polymerization reaction obtains the polymer with the structures shown in the formulas I and II, and in this case, m is x + y.

Preferably, after the polymerization reaction is finished, the reaction product is placed into liquid nitrogen to be cooled for several seconds and then is precipitated by normal hexane to obtain the functionalized polymer chain macromolecule RAFT reagent.

S012, providing a styrene monomer, placing the RAFT reagent of the functionalized block chain A, the styrene monomer and a free radical initiator in a solvent, and carrying out polymerization reaction to prepare the diblock copolymer with at least one end of dithioester.

Specifically, in step S012, the radical initiator is selected in the same manner as in step S011, and the polymerization solvent is selected in the same manner as in step S011. Reacting the RAFT reagent of the functionalized block chain A with the styrene monomer and a free radical initiator in a solvent for polymerization to obtain a diblock copolymer with at least one end of dithioester, taking a formula III as an example, the reaction formula is as follows:

in the diblock copolymer with the dithioester at the tail end, n represents the number of structural units of styrene in polystyrene, and the value of n is a positive integer. The size of n influences the content of block chains B in the block copolymer.

S013, carrying out aminolysis reaction on the diblock copolymer with the tail end of dithioester and primary amine to prepare the block copolymer with the tail end of mercapto.

Specifically, in step S013, the diblock copolymer with dithioester end and the primary amine are aminolyzed to prepare a block copolymer with mercapto end, and the reaction formula is shown below, taking formula iii as an example:

wherein the primary amine is selected from at least one of ethylamine, propylamine, n-butylamine, n-hexylamine and cyclohexylamine.

Further, the block copolymer is dissolved and precipitated by adopting tetrahydrofuran and normal hexane, and after repeated for many times, the block copolymer with high purity is obtained by drying and is used for being added into the inorganic nano-particle ink to improve the performance of the ink.

In step S02, the inorganic nanoparticles and the block copolymer are dispersed in the organic solvent, and the dispersion form is not limited, and may be achieved by stirring. Preferably, the block copolymer is dispersed in an organic solvent, and the inorganic nanoparticles such as quantum dots are added after adjusting the viscosity of the solvent.

Film(s)

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

E01. providing the ink;

E02. and depositing the ink on a carrier, and drying to obtain a granular film.

The method for preparing the inorganic nanoparticle printing ink in step E01 is as described above, and will not be described herein for brevity.

In the step E02, the manner of depositing the ink on the carrier is not critical, and it is preferable to deposit the inorganic nano-printing ink on the carrier by inkjet printing with a suitable inkjet printer, and then dry the ink to volatilize the solvent. Specifically, the inkjet printing is preferably realized by piezoelectric inkjet printing or thermal inkjet printing. The drying is carried outThe treatment is at least one of heating drying, cooling drying and reduced pressure drying. In one embodiment, the drying treatment is performed by one of temperature-raising drying, temperature-lowering drying, and reduced-pressure drying alone. As another embodiment, the drying treatment is performed by drying at elevated temperature and drying under reduced pressure, or drying at reduced temperature and drying under reduced pressure. Preferably, the temperature for heating and drying is 60-180 ℃ and the time is 0-30 min; preferably, the temperature of the temperature reduction treatment is 0-20 ℃; preferably, the degree of vacuum of the reduced pressure treatment is 1X 10^-6The pressure is reduced to normal pressure. Drying to obtain inorganic nanometer particle film, such as quantum dot film.

And the proper drying treatment mode can effectively remove the organic solvent, ensure that the inorganic nano particles such as quantum dot materials and the block copolymer are not damaged and form a uniform and flat film.

The inorganic nano particle film dry film formed by ink-jet printing has the thickness of 10-100 nm; further, the dry film thickness of the inorganic nanoparticle film formed by ink-jet printing is 20-50 nm.

The following description will be given with reference to specific examples.

Example 1

A preparation method of a block polymer modifier SH-A-B (SH-I-B) comprises the following steps:

5g of functional monomer N-vinyl carbazole of a block chain shown in a formula I, 5mg of Azodiisobutyronitrile (AIBN) serving as a free radical initiator and 80mg of dithio-2-cyano-isopropanol benzoate are mixed and dispersed in 50mL of tetrahydrofuran, oxygen in the mixture is removed by vacuum-liquid nitrogen defoaming for several times, nitrogen is filled, the mixture is heated to 50 ℃, and polymerization is carried out for 48 hours. And (3) putting the reactant mixture into liquid nitrogen to cool for several seconds to terminate the chain transfer reaction, and then precipitating by using normal hexane to obtain 3.5g of the first-stage functional polymer chain macromolecular RAFT reagent.

Dispersing 3g of the functional polymer chain macromolecule RAFT reagent, 2g of styrene and 2mg of AIBN in 50mL of tetrahydrofuran, defoaming the mixture by vacuum-liquid nitrogen for several times to remove oxygen in the mixture, filling nitrogen, heating to 50 ℃, and polymerizing for 48 hours. The reaction mixture was cooled in liquid nitrogen for several seconds to terminate the chain transfer reaction, and then n-hexane was precipitated to obtain 4.2g of a diblock polymer having a dithioester terminal.

4g of the diblock polymer having a terminal dithioester was reacted with 10g of cyclohexylamine in 50mL of tetrahydrofuran at room temperature for 6 hours, and then n-hexane was precipitated to obtain 3.6g of the diblock polymer having a terminal mercapto group.

The block polymer is dissolved and precipitated by tetrahydrofuran and normal hexane for many times, and is dried in vacuum to constant weight, and then the block polymer can be added into quantum dot ink to improve the performance of the ink.

Example 2

A preparation method of an inorganic nanoparticle film comprises the following steps:

600mg of the polymer prepared in example 1 were mixed with 20g of dodecane, dissolved by heating at 100 ℃ for 30 minutes, and then filtered through a 1 μ filter to obtain a polymer solution ready for use. 1.5g of oleylamine stabilized red CdSe/ZnS quantum dots and 8.5g of the above polymer solution were mixed and stirred for 30 minutes, and filtered through a 0.45 μ filter to obtain quantum dot ink.

A layer of red quantum dots of 20 × 30um, resolution 200 × 200ppi was printed by an inkjet printer.

Heating to 100 ℃ on a hot plate, nitrogen flow and vacuum of 1X 10^-6And volatilizing and drying for 30min under the condition of Torr to obtain the monochromatic quantum dot luminescent layer.

Example 3

A preparation method of a block polymer modifier SH-A-B (SH-I-II-B) comprises the following steps:

3g of functional monomer N-vinyl carbazole of a block chain in a formula I, 3mg of Azodiisobutyronitrile (AIBN) serving as a free radical initiator and 60mg of phenethyl dithiobenzoate are mixed and dispersed in 50mL of tetrahydrofuran, oxygen in the mixture is removed by vacuum-liquid nitrogen defoaming for several times, nitrogen is filled, the mixture is heated to 50 ℃, and polymerization is carried out for 48 hours. Adding 2g of functional monomer 2- (9H-carbazole-9-yl) ethyl methacrylate of a block chain in the formula II, defoaming the mixture by vacuum-liquid nitrogen for several times to remove oxygen in the mixture, filling nitrogen, heating the mixture to 50 ℃, and polymerizing the mixture for 48 hours. And (3) cooling the reactant mixture in liquid nitrogen for several seconds to terminate the chain transfer reaction, and then precipitating by using normal hexane to obtain 3.3g of the first-stage functional polymer chain macromolecular RAFT reagent.

Dispersing 3g of the functional polymer chain macromolecule RAFT reagent, 2g of styrene and 2mg of AIBN in 50mL of tetrahydrofuran, defoaming the mixture by vacuum-liquid nitrogen for several times to remove oxygen in the mixture, filling nitrogen, heating to 50 ℃, and polymerizing for 48 hours. The reaction mixture was cooled in liquid nitrogen for several seconds to terminate the chain transfer reaction, and then n-hexane was precipitated to obtain 4.3g of a diblock polymer having a dithioester terminal.

4g of a diblock polymer having a dithioester terminal was reacted with 10g of cyclohexylamine in 50mL of tetrahydrofuran at room temperature for 6 hours, and then n-hexane was precipitated to obtain 3.4g of a diblock polymer having a mercapto group terminal.

Example 4

500mg of the polymer prepared in example 3 was mixed with 20g of tetradecane and 10g of cyclohexylbenzene, and dissolved by heating at 100 ℃ for 30 minutes, followed by filtration through a 1. mu. filter to obtain a polymer solution for use. 1.0g of oleylamine stabilized red CdSe/ZnS quantum dot and 9.0g of the polymer solution were mixed and stirred for 30 minutes, and filtered through a 0.45 μ filter to obtain a quantum dot ink.

Heating to 130 ℃ on a hotplate, nitrogen flow and vacuum of 1X 10^-6And volatilizing and drying for 30min under the condition of Torr to obtain the monochromatic quantum dot luminescent layer.

Example 5

4g of functional monomer N-vinyl carbazole of a block chain in a formula I, 2g of functional monomer N-vinyl butyl carbazole of a block chain in a type II, 3mg of Azodiisobutyronitrile (AIBN) as a free radical initiator and 60mg of phenethyl dithiobenzoate are mixed and dispersed in 50mL of tetrahydrofuran, oxygen in the mixture is removed by vacuum-liquid nitrogen defoaming for several times, nitrogen is filled, then the mixture is heated to 50 ℃, and polymerization is carried out for 48 hours. And (3) putting the reactant mixture into liquid nitrogen to cool for several seconds to terminate the chain transfer reaction, and then precipitating by using normal hexane to obtain 3.7g of the first-stage functional polymer chain macromolecular RAFT reagent.

Dispersing 3g of the functional polymer chain macromolecule RAFT reagent, 2g of styrene and 2mg of AIBN in 50mL of tetrahydrofuran, defoaming the mixture by vacuum-liquid nitrogen for several times to remove oxygen in the mixture, filling nitrogen, heating to 50 ℃, and polymerizing for 48 hours. The reaction mixture was cooled in liquid nitrogen for several seconds to terminate the chain transfer reaction, and then n-hexane was precipitated to obtain 3.8g of a diblock polymer having a dithioester terminal.

Example 6

500mg of the polymer prepared in example 5 was mixed with 20g of dodecane and 5g of decalin, dissolved by heating at 100 ℃ for 30 minutes, and then filtered through a 1 μ filter to obtain a polymer solution for use. 1.2g of oleylamine stabilized red CdSe/ZnS quantum dot and 8.8g of the above polymer solution were mixed and stirred for 30 minutes, and filtered through a 0.45 μ filter to obtain a quantum dot ink.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.

Claims

1. A composite particle comprising an inorganic nanoparticle and a block copolymer bonded to the surface of the inorganic nanoparticle, wherein the block copolymer is a block copolymer comprising a block chain A and a block chain B, the block chain A is a block chain having a hole transport property, the block chain B is polystyrene, the block copolymer contains at least one terminal mercapto group, and the block copolymer is bonded to the inorganic nanoparticle through the terminal mercapto group, wherein the structural unit in the block chain A is at least one selected from the structures represented by formula I and formula II,

2. the composite particle of claim 1, wherein said block copolymer comprises a mid-block chain, said mid-block chain comprising a block chain a and a block chain B, said mid-block chain having one end to which one of said terminal thiol groups is attached.

3. The composite particle according to claim 2, wherein the other end of the block copolymer connecting the middle block chain is an aliphatic group of 3 to 10 carbon atoms or an aromatic group of 3 to 10 carbon atoms.

4. The composite particle according to claim 3, wherein the block copolymer has a weight average molecular weight of 1000-50000.

5. The composite particle of claim 4, wherein the block copolymer has a weight average molecular weight of 5000-10000.

6. The composite particle of claim 1, wherein the weight percent of block chains a is from 10% to 90% based on the total weight of the block copolymer taken as 100%.

7. The composite particle of claim 6, wherein the weight percent of block chains A is from 40% to 60% based on the total weight of the block copolymer taken as 100%.

8. The composite particle of any one of claims 1-7, wherein the block copolymer is present in an amount from 10% to 80% by weight, based on 100% by weight of the total composite particle.

9. The composite particle of claim 8, wherein the block copolymer is present in an amount ranging from 20 to 50 weight percent, based on the total weight of the composite particle taken as 100 percent.

10. A block copolymer, which is characterized in that the block copolymer comprises a midblock chain, wherein the midblock chain consists of a block chain A and a block chain B, one end of the midblock chain is connected with a terminal sulfydryl, wherein the block chain A contains a carbazolyl structure, the block chain B is polystyrene, and the structural unit in the block chain A is selected from at least one of structures shown in formulas I and II,

11. the block copolymer of claim 10, wherein the other end of the block copolymer is an aliphatic group of 3 to 10 carbon atoms or an aromatic group of 3 to 10 carbon atoms.

12. The block copolymer of claim 10, wherein the block copolymer has a weight average molecular weight of 1000-50000.

13. The block copolymer of claim 12, wherein the block copolymer has a weight average molecular weight of 5000-10000.

14. The block copolymer of any one of claims 10 to 13, wherein the weight percent of block chain a is from 10% to 90%, based on 100% of the total weight of the block copolymer.

15. The block copolymer of claim 14, wherein the weight percent of block chain a is from 40% to 60% based on the total weight of the block copolymer taken as 100%.

16. An ink, comprising composite particles and a solvent, wherein the composite particles comprise inorganic nanoparticles and a block copolymer bonded on the surface of the inorganic nanoparticles, the block copolymer is a block copolymer comprising a block chain A and a block chain B, the block chain A is a block chain with hole transport property, the block chain B is polystyrene, the block copolymer modifier at least contains one terminal mercapto group, and the block copolymer is bonded to the inorganic nanoparticles through the terminal mercapto group, wherein the structural unit in the block chain A is selected from at least one of the structures shown in formula I and formula II,

17. the ink of claim 16, wherein the block copolymer comprises a mid-block chain, the mid-block chain comprising a block chain a and a block chain B, the mid-block chain having one end to which one of the terminal thiol groups is attached.

18. The ink according to claim 17, wherein the other end of the block copolymer to which the mid-block chain is connected is an aliphatic group having 3 to 10 carbon atoms or an aromatic group having 3 to 10 carbon atoms.

19. The ink of claim 18, wherein the weight average molecular weight of the block copolymer of formula (lb) is 1000-50000.

20. The ink according to claim 19, wherein the weight average molecular weight of the block copolymer is 5000-10000.

21. The ink according to any one of claims 16 to 20, wherein the block chain a is present in an amount of 10% to 90% by weight, based on 100% by weight of the total block copolymer.

22. The ink according to claim 21, wherein the weight percentage of the block chain a is from 40% to 60% based on the total weight of the block copolymer taken as 100%.

23. The ink according to any one of claims 16-20, wherein the block copolymer comprises 10% to 80% of the total weight of the inorganic nanoparticles and the block copolymer.

24. The ink of claim 23, wherein the block copolymer comprises 20% to 50% of the total weight of the inorganic nanoparticles and the block copolymer.

25. The ink of claim 16, wherein the ink comprises at least one organic solvent, and wherein the weight ratio of the combined weight of the inorganic nanoparticles and the block copolymer to the organic solvent is from 0.01 to 20.0:80 to 99.9.

26. The ink of claim 25, wherein a weight ratio of a total weight of the inorganic nanoparticles and the block copolymer to the organic solvent is 4.0-15.0:85.0-96.0, by weight ratio.

27. The ink of claim 26, wherein the ink consists of the inorganic nanoparticles, the block copolymer, and the organic solvent in a weight ratio of a total weight of the inorganic nanoparticles and the block copolymer to the organic solvent of 4.0-15.0: 85.0-96.0.

28. The preparation method of the ink is characterized by comprising the following steps of:

providing inorganic nanoparticles, a block copolymer, and a solvent;

29. The method of preparing an ink according to claim 28, wherein the method of preparing the block copolymer comprises the steps of:

providing at least one of functional structural monomers shown in formulas III and IV, placing the functional structural monomer, a free radical initiator and an RAFT reagent in a solvent, and preparing the RAFT reagent of the functional block chain A through polymerization reaction;

providing a styrene monomer, placing the RAFT reagent of the functionalized block chain A, the styrene monomer and a free radical initiator into a solvent, and carrying out polymerization reaction to prepare a diblock copolymer with at least one end being dithioester;

and carrying out aminolysis reaction on the diblock copolymer with the end of dithioester and primary amine to prepare the block copolymer with the end of sulfydryl.

30. A method for preparing a film, comprising the steps of:

providing the ink of any one of claims 16-27;

and depositing the printing ink on a carrier, and drying to obtain the film.