KR102578817B1 - Transfer printing method for polar ligand treated quantum dot, polar ligand treated quantum dot layer prepared by the method and electronic device - Google Patents

Abstract

The present invention discloses a transfer printing method for quantum dots surface-treated with a polar ligand, and a quantum dot thin film and electronic device surface-treated with a polar ligand produced by the method. The present invention includes the steps of forming a quantum dot thin film including quantum dots surface-treated with a ligand having a first polarity on a first substrate; Picking up the quantum dot thin film using a stamp; and transferring the quantum dot thin film to a second substrate using the stamp, wherein the stamp is surface-treated with a self-assembled monomolecular film having a second polarity.

Description

Transfer printing method of quantum dots surface-treated with a polar ligand, quantum dot thin film and electronic device surface-treated with a polar ligand produced by the method {TRANSFER PRINTING METHOD FOR POLAR LIGAND TREATED QUANTUM DOT, POLAR LIGAND TREATED QUANTUM DOT LAYER PREPARED BY THE METHOD AND ELECTRONIC DEVICE}

The present invention relates to a transfer printing method of quantum dots surface-treated with a polar ligand, a quantum dot thin film surface-treated with a polar ligand produced by the method, and an electronic device, and more specifically, to a stamp surface with a polarity. Transfer printing of quantum dots surface-treated with polarized ligands, which enables high-resolution patterning of a quantum dot thin film containing quantum dots surface-treated with a polarized ligand by Coulomb attraction by treating the surface as a self-assembled monomolecular film, with a width ranging from hundreds of nanometers to several millimeters. It relates to a method, a quantum dot thin film and an electronic device surface-treated with a polar ligand prepared by the method.

Recently, quantum dots have been applied to the display field by using the photoluminescence and electroluminescence phenomena of various types of quantum dot materials, and are especially being applied to and commercialized in products for the purpose of color conversion and brightness improvement using photoluminescence.

In addition, quantum dots are being applied to a wide range of fields, such as the light absorption layer of solar cells, biosensors, optical sensors, and lighting, and active research is being conducted, and the results in the display field are greatly noticeable.

Conventionally, a thin film of quantum dot nanoparticles coated on a donor substrate is picked up with an embossed stamp or a front stamp and transferred to the final substrate. When forming a quantum dot pattern, polydimethylsiloxane (PDMS; 19.8 mJm ^-2 ), a silicone rubber, is used. do.

Quantum dots for general light-emitting devices are surrounded by long carbon chain organic ligands, and the quantum dot thin film is quickly picked up from the donor substrate using an embossed stamp or front stamp and transferred to the final substrate.

Quantum dot thin films surrounded by organic ligands consisting of long carbon chains are easy to transfer using PDMS stamps with low surface energy, but in the case of quantum dot thin films surrounded by ligands with polarity of positive or negative charge, Van der Waals force Transfer is not possible using PDMS only because it is not picked up from the donor substrate.

Therefore, research on methods for transfer printing quantum dot thin films surrounded by polar ligands is required.

Republic of Korea Patent No. 2010-0093858, “Quantum dot layer manufacturing method and quantum dot light-emitting device manufactured by applying the same”

Tae-Ho Kim et al. 13, “Full-color quantum dot displays fabricated by transfer printing”, Nature Photon. 2011, 5, 176-182. Moon Kee Choi et al. 11"Wearable red-green-blue quantum dot light-emitting diode array using high-resolution intaglio transfer printing", Nature Commun. 2015, 6, 7149.

In an embodiment of the present invention, quantum dots surface-treated with a polar ligand are formed by forming the surface of a stamp into a short self-assembled material with a charge (e.g., C ₂ -C ₁₈ carbon chain + polar functional group such as NH ₃ , SH, OH, Cl, etc.) treated with silane) to increase the Coulombic attraction between the stamp and the quantum dots surface-treated with a polar ligand, which can pattern high-resolution nanoparticle thin films with a width of hundreds of nanometers to several millimeters. The aim is to provide a transfer printing method for quantum dots.

In addition, by increasing the Coulomb attraction between quantum dots surface-treated with polar ligands, high-resolution micropixel-based light emitting devices can be created using quantum dots surface-treated with polar ligands patterned at high resolution from hundreds of nanometers to several millimeters wide. We would like to provide

An embodiment of the present invention involves the transfer printing of quantum dots surface-treated with a polar ligand that can facilitate high-resolution patterning by changing the surface energy by treating the surface of a viscoelastic stamp with a self-assembled monolayer of a short polar organic ligand. We would like to provide a method.

A transfer printing method of quantum dots surface-treated with a ligand having a polarity according to an embodiment of the present invention includes forming a quantum dot thin film including quantum dots surface-treated with a ligand having a first polarity on a first substrate; Picking up the quantum dot thin film using a stamp; and transferring the quantum dot thin film to a second substrate using the stamp, wherein the stamp is surface treated with a self-assembled monolayer having a second polarity.

In the step of picking up the quantum dot thin film using a stamp, the quantum dot thin film may be picked up by Coulomb attraction.

The ligand having the first polarity may include at least one of an inorganic ligand and a two-functional ligand.

The inorganic ligands include metal-chalcogenide compounds, metal-halide compounds, metal-oxide compounds, chalcogenides, halides, and pseudohalides. (pseudohalide), and may contain at least one of hydroxy ions.

The two-functional ligand may include a ligand in which at least two functional groups of a carboxylic acid group, a phosphorous acid group, a hydroxyl group, a thiol group, an amine group, a phosphine group, and a phosphine oxide group are bonded to a C ₁ -C ₂₄ hydrocarbon.

The self-assembled monolayer is a C ₂ to C group containing at least one of an amine group (-NH ₃ ), a thiol group (-SH), a Teflon group (-CF ₃ ), an epoxy group, and a linear and branched alkyl group (-R). It may contain a silane group consisting of a backbone of ₁₈ hydrocarbons.

The stamp may include an embossed pattern.

Transferring the quantum dot thin film to the second substrate using the stamp, then separating the stamp from the second substrate to pick up the quantum dot pattern; and transferring the quantum dot pattern to a third substrate using the stamp.

The quantum dot thin film may include a quantum dot pattern.

The second substrate may include an engraved trench.

Transferring the quantum dot thin film to the second substrate using the stamp, then separating the stamp from the second substrate to pick up the quantum dot pattern; and transferring the quantum dot pattern to a third substrate using the stamp.

The second substrate may have a recessed area recessed from the surface.

When the stamp is separated from the second substrate, a portion of the quantum dot thin film in contact with the second substrate remains on the second substrate, and a portion corresponding to the recess area may be picked up by the stamp.

The width of the quantum dot pattern may be 20 nm to 100 mm.

A quantum dot thin film including quantum dots surface-treated with a polarized ligand according to an embodiment of the present invention includes quantum dots surface-treated with at least one of an inorganic ligand and two functional group ligands.

A quantum dot thin film including quantum dots surface-treated with a ligand having the polarity may include a pattern.

An electronic device according to an embodiment of the present invention includes an electronic device including a quantum dot thin film including quantum dots surface-treated with a polarized ligand according to an embodiment of the present invention.

The electronic device may be any one of a light emitting device, a photo detector, a transistor, a solar cell, and a memory device.

According to an embodiment of the present invention, quantum dots surface-treated with a polar ligand are formed by forming the surface of the stamp into a short self-assembled material with a charge (e.g., C ₂ -C ₁₈ carbon chain + NH ₃ , SH, OH, Cl, F). A polar ligand capable of patterning high-resolution nanoparticle thin films with a width of hundreds of nanometers to several millimeters by increasing the Coulombic attraction between the stamp and quantum dots surface-treated with a polar ligand (silane with a polar functional group, such as a silane). A transfer printing method of surface-treated quantum dots can be provided.

In addition, by increasing the Coulomb attraction between quantum dots surface-treated with polar ligands, high-resolution micropixel-based light emitting devices can be created using quantum dots surface-treated with polar ligands patterned at high resolution from hundreds of nanometers to several millimeters wide. can be provided.

According to an embodiment of the present invention, the surface of a viscoelastic stamp is treated with a self-assembled monomolecular film of a short organic ligand having a polarity to change the surface energy of quantum dots surface-treated with a polarizing ligand that can facilitate high-resolution patterning. A transfer printing method may be provided.

Figure 1 is a cross-sectional view showing a first substrate on which a quantum dot thin film including quantum dots surface-treated with a polar ligand is formed.
Figure 2 is a cross-sectional view showing an embossed stamp placed on a first substrate on which quantum dots surface-treated with a ligand having a first polarity are formed.
Figure 3 is a cross-sectional view showing a stamp used in the transfer printing method of quantum dots surface-treated with a ligand having polarity according to an embodiment of the present invention, and Figure 4 is a transfer printing method of quantum dots surface-treated with a ligand having a first polarity. This is an image showing the chemical formula of the self-assembled monomolecular film used in the method.
Figure 5 is a cross-sectional view showing a quantum dot pattern including quantum dots surface-treated with a ligand having a first polarity picked up on an embossed stamp, and Figure 6 is a coulomb diagram of quantum dots surface-treated with a ligand having a first polarity and a self-assembled monomolecular film. This is a cross-sectional view detailing the workforce.
Figure 7 is a cross-sectional view showing a second substrate onto which a quantum dot pattern including quantum dots surface-treated with a ligand having a first polarity is transferred.
Figure 8 is a cross-sectional view showing a front stamp disposed on a first substrate on which a quantum dot thin film including quantum dots surface-treated with a ligand having a first polarity is formed, and Figure 9 is a quantum dot surface-treated with a ligand having a first polarity. It is a cross-sectional view showing a front stamp that picks up a quantum dot thin film containing, and Figure 10 is a cross-sectional view showing a second substrate onto which a quantum dot thin film containing quantum dots surface-treated with a ligand having the first polarity is transferred.
Figure 11 is a cross-sectional view showing a second substrate including a front stamp and an engraved pattern on which a quantum dot thin film containing quantum dots surface-treated with a ligand having a first polarity is picked up, and Figure 12 is a cross-sectional view showing the first substrate in contact with the second substrate. It is a cross-sectional view showing a front stamp picking up a quantum dot thin film including quantum dots surface-treated with a polarized ligand, and Figure 13 shows a quantum dot pattern including quantum dots surface-treated with a first polarized ligand being picked up from a second substrate. It is a cross-sectional view showing one front stamp, and Figure 14 is a cross-sectional view showing a third substrate onto which a quantum dot pattern including quantum dots surface-treated with a ligand having the first polarity is transferred.
Figure 15 is a cross-sectional view showing an electronic device according to an embodiment of the present invention.
Figure 16 is an optical image showing a quantum dot surface-treated with an inorganic ligand that is entirely transferred using a transfer printing method of a quantum dot surface-treated with a polarized ligand according to an embodiment of the present invention.
Figure 17 is an optical image showing a quantum dot surface-treated with an inorganic ligand that has been patterned and transferred using a transfer printing method of a quantum dot surface-treated with a polarized ligand according to an embodiment of the present invention.
Figure 18 is an electron microscope image showing a quantum dot surface-treated with an inorganic ligand that was patterned and transferred using a transfer printing method of a quantum dot surface-treated with a polarized ligand according to an embodiment of the present invention.
Figure 19 is an image showing an electronic device including quantum dots surface-treated with a polarized ligand according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings and the contents described in the accompanying drawings, but the present invention is not limited or limited by the embodiments.

The terminology used herein is for describing embodiments and is not intended to limit the invention. As used herein, singular forms also include plural forms, unless specifically stated otherwise in the context. As used in the specification, “comprises” and/or “comprising” does not exclude the presence or addition of one or more other components or steps.

As used herein, “embodiment,” “example,” “aspect,” “example,” etc. should be construed to mean that any aspect or design described is better or advantageous than other aspects or designs. It's not like that.

Additionally, the term 'or' means an inclusive OR 'inclusive or' rather than an exclusive OR 'exclusive or'. That is, unless otherwise stated or clear from the context, the expression 'x uses a or b' means any of the natural inclusive permutations.

Additionally, as used in this specification and claims, the singular expressions “a” or “an” generally mean “one or more,” unless otherwise indicated or it is clear from the context that the singular refers to singular forms. It should be interpreted as

The terms used in the description below have been selected as general and universal in the related technical field, but there may be different terms depending on technological developments and/or changes, customs, technicians' preferences, etc. Accordingly, the terms used in the description below should not be understood as limiting the technical idea, but should be understood as illustrative terms for describing embodiments.

In addition, in certain cases, there are terms arbitrarily selected by the applicant, and in this case, the detailed meaning will be described in the relevant description. Therefore, the terms used in the description below should be understood based on the meaning of the term and the overall content of the specification, not just the name of the term.

Unless otherwise defined, all terms (including technical and scientific terms) used in this specification may be used with meanings that can be commonly understood by those skilled in the art to which the present invention pertains. Additionally, terms defined in commonly used dictionaries are not interpreted ideally or excessively unless clearly specifically defined.

Meanwhile, in describing the present invention, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the gist of the present invention, the detailed description will be omitted. In addition, the terminology used in this specification is a term used to appropriately express the embodiments of the present invention, and may vary depending on the intention of the user or operator or the customs of the field to which the present invention belongs. Therefore, definitions of these terms should be made based on the content throughout this specification.

The transfer printing method of quantum dots surface-treated with a ligand having a polarity according to an embodiment of the present invention includes forming a quantum dot thin film including quantum dots surface-treated with a ligand having a first polarity on a first substrate (S110); It includes picking up the quantum dot thin film using a stamp (S120) and transferring the quantum dot thin film to a second substrate using the stamp (S130), wherein the stamp has a second polarity. The surface is treated with a self-assembled monolayer (SAM).

Therefore, the conventional stamp was optimized for the transfer of quantum dots and nanoparticles surface-treated with organic ligands, especially ligands with long carbon chains, so it was impossible to transfer quantum dots and nanoparticles surface-treated with polar ligands. Quantum dots surface-treated with a polar ligand according to an embodiment of the present invention are made by forming the surface of the stamp into a short self-assembled material with a charge (e.g., C ₂ -C ₁₈ carbon chain + NH ₃ , SH, OH, Cl, etc.) By increasing the Coulombic attraction between the stamp and the quantum dots surface-treated with a polar ligand by treatment with a functional silane), high-resolution nanoparticle thin films with a width of hundreds of nanometers to several millimeters can be patterned.

In addition, in the transfer printing method of quantum dots surface-treated with a polar ligand according to an embodiment of the present invention, a quantum dot pattern can be formed by performing transfer printing using an embossed stamp including an embossed pattern on the surface, and the surface If transfer printing is performed using this conformal front stamp, a front quantum dot thin film can be formed, and if transfer printing is performed using a second substrate containing a front stamp and an intaglio pattern, a quantum dot pattern can be formed. can be formed.

Hereinafter, with reference to FIGS. 1 to 7, a transfer printing method of quantum dots surface-treated with a polar ligand according to an embodiment of the present invention using an embossed stamp will be described, and with reference to FIGS. 8 to 10, a front stamping method will be described. A transfer printing method of quantum dots surface-treated with a polarized ligand according to an embodiment of the present invention using is described. Referring to FIGS. 11 to 14, the present invention uses a second substrate including a front stamp and an engraved pattern. A method for transfer printing quantum dots surface-treated with a polarized ligand according to an example will be described.

Figure 1 is a cross-sectional view showing a first substrate on which a quantum dot thin film including quantum dots surface-treated with a polar ligand is formed.

The transfer printing method of quantum dots surface-treated with a polar ligand according to an embodiment of the present invention includes forming a quantum dot thin film 120 including quantum dots surface-treated with a polar ligand on a first substrate 111. Proceed with (S110).

The quantum dot thin film 120 containing quantum dots surface-treated with a polar ligand may be formed of a colloidal nanocrystal material containing quantum dots.

Quantum dots may be group II-VI, group III-V, group I-III-VI, group IV-VI semiconductor compounds, or mixtures thereof. The quantum dots include at least one of CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, HgS, HgSe, HgTe, GaN, GaP, GaAs, InP, InAs, CuInS ₂ , CuInSe ₂ , CuInTe ₂ , PbS, PbSe, and PbTe. , but is not limited to this. In some cases, a mixture of two or more of the listed quantum dots may be used. For example, a quantum dot mixture in which two or more types of quantum dots exist in a simple mixed state, or two or more types of compounds in the same crystal, such as a crystal with a core-shell structure or a crystal with a gradient structure. Mixed crystals, in which crystals are partially divided, or two or more types of nanocrystal compounds may be used. For example, quantum dots may have a core structure that allows holes to easily escape to the outside, or may have a core/shell structure including a core and a shell covering the core.

The core may be a group II-VI, group III-V, group I-III-VI, group IV-VI semiconductor compound or a mixture thereof, preferably CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, HgS. , HgSe, HgTe, GaN, GaP, GaAs, InP, InAs, CuInS ₂ , CuInSe ₂ , CuInTe ₂ , PbS, PbSe, and PbTe, but is not limited thereto. The shell may include at least one of CdSe, ZnSe, ZnS, ZnTe, CdTe, PbS, TiO, SrSe, and HgSe, but is not limited thereto.

Quantum dots used in the transfer printing method of quantum dots surface-treated with a polar ligand according to an embodiment of the present invention may include any one of spherical, linear, and plate shapes, but are not limited thereto.

Depending on the embodiment, the transfer printing method of quantum dots surface-treated with a ligand having a polarity according to an embodiment of the present invention may be used to transfer metal, spherical, surface-treated quantum dots with a ligand having a first polarity (an inorganic ligand or a bi-functional ligand) in addition to the quantum dots. It may include, but is not limited to, inorganic nanocrystals of metal oxide, linear metal oxide, and plate-shaped metal oxide.

For example, gold nanoparticles may include, but are not limited to, nanowires.

In addition, the nanocrystal material may include nanocrystals of at least one of spherical oxide, linear oxide, plate-shaped oxide, and polygonal oxide, and preferably, at least one of ITO, ZnO, TiO ₂ , CeOx, and FeOx. It may include nanoparticles, but is not limited thereto.

Quantum dots may be surface treated with a ligand having a first polarity, and the ligand having a second polarity may be an inorganic ligand or a bifunctional ligand.

Inorganic ligands include metal-chalcogenide compounds, metal-halide compounds, metal-oxide compounds, chalcogenides, halides and pseudohalides ( pseudohalide), and may contain at least one of hydroxy ions, and the pseudo halide may include at least one of O ^2- , C ^N- , N ^3- , SCN- ^, and ^OCN- , but is not limited thereto.

Preferably, the inorganic ligand may be a metal-chalcogenide compound, and the metal-chalcogenide compound is AsS ₄ ^2- , NH ₄ S ^2- , MoS ₄ ^2- , WS ₄ ^2- , Zn ₂ S ₂ , Zn ₂ Se ₂ , Zn ₂ Te ₂ , Cu ₂ S ₂ , Cu ₂ Se ₂ , Cu ₂ Te ₂ , Mn ₂ S ₂ , Mn ₂ Se ₂ , Mn ₂ Te ₂ , Fe ₂ S ₂ , Fe ₂ Se ₂ , Fe ₂ Te ₂ , Co ₂ S ₂ , Co ₂ Se ₂ , Co ₂ Te ₂ , Sn ₂ S ₆ , Sn ₂ Se6, In ₂ Se ₄ , In ₂ Te ₃ , Ga ₂ Se ₃ , CuInSe ₂ , Cu ₇ S ₄ , Hg ₃ Se ₄ , Ge ₂ S, Sb ₂ S ₃ , Sb ₂ Se ₃ , Sb ₂ Te ₃ , and hydrazine hydrate of ZnTe, but is not limited thereto.

As for the two-functional ligand, one functional group may be bound to the surface of the quantum dot, and the remaining functional group may be polar, thereby imparting first polarity to the quantum dot.

The two-functional ligand may include a ligand in which at least two functional groups of a carboxylic acid group, a phosphorous acid group, a hydroxyl group, a thiol group, an amine group, a phosphine group, and a phosphine oxide group are bonded to a C ₁ -C ₂₄ hydrocarbon.

Preferably, the two functional group ligands are cysteamine, amino-octanethiol, amino-dodecanethiol, mercaptopropionic acid, mercaptoundeca. mercaptoundecanoic acid, mercaptohexadecanoic acid, ethanol amine, methanol amine, propanol amine, butanol amine, diaminooctane , may include at least one of diaminohexane, hexanedioic acid, pentanedioic acid, butanedioic acid, and propanedioic acid, but It is not limited.

The first polarity can be positive or negative; if the first polarity is positive, the second polarity is negative, and if the first polarity is negative, the second polarity is positive.

For example, quantum dots surface-treated with a ligand having a first polarity may be quantum dots surface-treated with a cation to have a positive charge, and quantum dots surface-treated with a cation may be surface-treated with a cationic inorganic ligand on the surface of the quantum dot.

The cationic inorganic ligand may be a cationic metal-chalcogenide compound. For example, the cationic inorganic ligand may be Zn ₂ S ₂ , Zn ₂ Se ₂ , Zn ₂ Te ₂ , Cu ₂ S ₂ , Cu ₂ Se ₂ , Cu ₂ Te ₂ , Mn ₂ S ₂ , Mn ₂ Se ₂ , Mn ₂ Te ₂ , Fe ₂ S ₂ , Fe 2 Se 2 , Fe ₂ Te ₂ , Co ₂ S ₂ , Co _{2 Se 2} , _{Co 2 Te} It may include at least one of ₂ and Sn ₂ S ₆ , but is not limited thereto.

In cationic metal-chalcogenide compounds, the metal atoms have a positive charge. For example, in the case of Zn ₂ S ₂ , which has a bonding structure of Zn-SS-Zn, one of the outermost electrons of Zn is covalently bonded to S, but the other electron is not bonded to S. Zn is a group 2 element and has the property of easily donating electrons. Accordingly, Zn loses its outermost electrons that are not bonded to S in solution.

Accordingly, Zn in the bonding structure of Zn-S-S-Zn has a positive charge in the solution. By this mechanism or a similar mechanism, the cationic metal-chalcogenide compound becomes cationic in solution.

Since the Zn atom of Zn ₂ Se ₂ is bound to the surface of the quantum dot in the form of a positive ion and the Zn atom has a positive charge, it is bound to the anion component of the quantum dot (for example, the Se atom of the CdSe quantum dot) or in the form of an orbital. It can be.

Quantum dots surface-treated with a ligand having a first polarity may be quantum dots surface-treated with anions to have a negative charge, and quantum dots surface-treated with anions may be surface-treated with an anionic inorganic ligand on the surface of the quantum dots.

The anionic inorganic ligand may be an anionic metal-chalcogenide compound. For example, the anionic inorganic ligand may be AsS ₄ ^2- , NH ₄ S ^2- , MoS ₄ ^2- , WS ₄ ^2- , Sn ₂ S ₆ , Sn ₂ Se6, In ₂ Se ₄ , In ₂ Te ₃ , Ga ₂ Se ₃ , CuInSe ₂ , Cu ₇ S ₄ , Hg ₃ Se ₄ , Ge ₂ S, Sb ₂ S ₃ , Sb ₂ Se ₃ , Sb ₂ It may include at least one of Te ₃ and hydrazine hydrate of ZnTe, S ^2- , and OH ^- , but is not limited thereto.

Quantum dots can be manufactured using known quantum dot synthesis methods. For example, the quantum dots of the present invention may include all quantum dots manufactured by a chemical wet method using a metal precursor. In addition, quantum dots can be manufactured by injecting a predetermined metal precursor into an organic solution in the presence of a dispersant, if necessary, and growing crystals at a constant temperature, but are not limited thereto. Also, when manufacturing quantum dots, the size of the quantum dots can be adjusted to absorb or emit light of red, green, and blue wavelengths.

The first substrate 111 may be surface treated with ODTS (octadecyltrichlorosilane) or the like before forming the quantum dot thin film 120. By surface treatment, the interaction between the first substrate 111 and the colloidal nanocrystal material is weakened, so that the colloidal nanocrystal material can actively spread on the surface of the first substrate 111, and the nanoparticles in the colloidal nanocrystal material They can stick together and grow uniformly.

In addition, pick-up of the quantum dot thin film 120 by stamping can be performed more effectively.

Quantum dots surface-treated with a ligand having a first polarity are coated on the first substrate 111 by a liquid process (solution process), for example, spin coating, dip coating, printing, or spray coating, to form a quantum dot thin film 120. This can be formed.

The first substrate is glass, quartz, Al ₂ O ₃ , SiC, polydimethlysiloxane (PDMS), ecoflex (Polybutylene adipate terephthalate, PBAT), polyurethane (PU), polyurethane acrylate ( PUA), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polysilane, polysiloxane, polysilazane, polycarbosilane, cyclic olefin copolymer ( Cyclic olefin copolymer (COC), Cyclic olefin polymer (COP), polyethylene (PE), polypropylene (PP), polyimide (PI), polytetrafluoroethylene (PTFE), polyvinyl chloride (PVC) ), polycarbonate (PC), polyvinylidene fluoride (PVDF), polyethylene naphthalate (PEN), perfluoroalkyl polymer (PFA), and styrene acryl nitrile copolymer (SAN). It can be done, but it is not limited to this.

Figure 2 is a cross-sectional view showing an embossed stamp placed on a first substrate on which quantum dots surface-treated with a ligand having a first polarity are formed.

The stamp may be a siloxane-based, acryl-based, epoxy-based elastomer or a composite thereof, or may be formed by mixing other reinforcing materials to adjust the strength of the material. For example, the stamp may be formed from polydimethylsiloxane (PDMS).

Additionally, the stamp may be an embossed stamp including an embossed pattern 131 on the surface, or a full-face stamp not including a pattern.

The transfer printing method of quantum dots surface-treated with a ligand having a first polarity according to an embodiment of the present invention uses an embossed stamp 131 including an embossed pattern on the surface to form a quantum dot thin film 120 on a second substrate. It can be formed into a pattern.

The stamp used in the transfer printing method of quantum dots surface-treated with a polarized ligand according to an embodiment of the present invention may be surface treated with a self-assembled monomolecular film 140 having a second polarity.

The self-assembled monolayer 140 may have a second polarity, and the second polarity is formed to be different from the first polarity of the quantum dot thin film 120, and the step of picking up the quantum dot thin film 120 using a stamp (S120) When proceeding, the quantum dot thin film 120 can be picked up by Coulomb attraction.

The self-assembled monolayer 140 having a second polarity surface treated on the stamp will be described in more detail with reference to FIGS. 3 and 4.

Figure 3 is a cross-sectional view showing a stamp used in the transfer printing method of quantum dots surface-treated with a ligand having polarity according to an embodiment of the present invention, and Figure 4 is a transfer printing method of quantum dots surface-treated with a ligand having a first polarity. This is an image showing the chemical formula of the self-assembled monomolecular film used in the method.

The self-assembled monolayer 140 may include a silane-based compound linked to a C ₂ to C ₁₈ hydrocarbon, and the silane-based compound is a polar functional group including at least one of NH ₃ , SH, OH, F, Cl, and an epoxy group. It is terminated.

Preferably, the self-assembled monolayer 140 contains at least one of an amine group (-NH ₃ ), a thiol group (-SH), a Teflon group (-CF ₃ ), an epoxy group, and a linear and branched alkyl group (-R). It may include a silane group composed of a C ₂ to C ₁₈ hydrocarbon backbone.

Moreover, preferably, the self-assembled monolayer 140 is made of (3-Aminopropyl)triethoxysilane, (3-Mercaptopropyl)triethoxysilane ), (3-Chloropropyl)triethoxysilane, (3-Glycidyloxypropyl)triethoxysilane, 3-[bis(2- At least one of 3-[Bis(2-hydroxyethyl)amino]propyl-triethoxysilane) and 4-Chlorophenyltriethoxysilane ((4-Chlorophenyl)triethoxysilane) It may include, but is not limited to this.

Figure 5 is a cross-sectional view showing a quantum dot pattern including quantum dots surface-treated with a ligand having a first polarity picked up on an embossed stamp, and Figure 6 is a coulomb diagram of quantum dots surface-treated with a ligand having a first polarity and a self-assembled monomolecular film. This is a cross-sectional view detailing the workforce.

The transfer printing method of quantum dots surface-treated with a polar ligand according to an embodiment of the present invention proceeds with the step (S120) of picking up the quantum dot thin film 120 using a stamp.

More specifically, the quantum dot thin film 120 including a stamp surface-treated with a self-assembled monomolecular film 140 having a second polarity and a quantum dot (Q) surface-treated with a ligand (L) having a first polarity exhibits electrostatic attraction. , ionic bonds, or van der Waals forces. Therefore, there is strong adhesion at the interface of the quantum dot thin film 120 including the stamp surface-treated with the self-assembled monomolecular film 140 having a second polarity and the quantum dot (Q) surface-treated with the ligand (L) having the first polarity. It can be easily picked up and have very good mechanical strength at the same time.

At this time, when the quantum dots (Q) surface-treated with the ligand (L) having the first polarity are picked up on the stamp surface-treated with the self-assembled monomolecular film 140 having the second polarity and then transferred to the final substrate, the surface of the stamp The combination of the ligand (L) having the first polarity of the quantum dot thin film 120 and the self-assembled monomolecular film 140 having the second polarity of the stamp surface can be adjusted so that the quantum dot thin film 120 can be easily separated without residue. .

The quantum dot thin film 120 can be picked up by being separated from the first substrate 111 by a stamp, and when the stamp is brought into contact with the quantum dot thin film 120 and then separated at a speed of about 10 cm/s, it contacts the lower surface of the stamp. The quantum dot thin film 121 may be separated from the first substrate 111 and picked up.

In the transfer printing method of quantum dots surface-treated with a polar ligand according to an embodiment of the present invention, when using the embossed stamp 131, as shown in FIG. 5, among the quantum dot thin film 120, the embossed stamp 131 and The quantum dot thin film 121 that is in contact is picked up by the self-assembled monomolecular film 140 surface-treated on the embossed stamp 131, and the quantum dot thin film 122 that is not in contact with the embossed stamp 131 is picked up on the first substrate 111. A quantum dot pattern 121 having a shape corresponding to the embossed pattern of the embossed stamp 131 may be picked up in the embossed stamp 131 .

Referring to FIG. 6, for example, when a quantum dot thin film 120 including quantum dots surface ^- treated with an inorganic ligand having an OH- functional group is formed on a first substrate, it is terminated with an amine group (-NH ₃₊ ). When transfer printing is performed using a stamp (131 in the case of an embossed stamp) surface-treated with the self-assembled monomolecular film (140), the surface is treated with an inorganic ligand due to Coulomb attraction by the OH- functional group and amine group (-NH ₃ ⁺ ). The quantum dot thin film 120 containing the quantum dots can be easily transferred from the first substrate 111 to a stamp (131 in the case of an embossed stamp).

Figure 7 is a cross-sectional view showing a second substrate onto which a quantum dot pattern including quantum dots surface-treated with a ligand having a first polarity is transferred.

The transfer printing method of quantum dots surface-treated with a polar ligand according to an embodiment of the present invention proceeds with the step (S130) of transferring the quantum dot thin film to a second substrate using a stamp.

The second substrate 112 may be made of at least one of metal, metal oxide, semiconductor, and insulator, but is not limited thereto. Specifically, depending on the purpose, it may be made of gold, palladium, platinum, glass, ceramic, germanium, silicon, plastic, etc.

For example, when the quantum dot pattern 121 is used in an electroluminescent device, the second substrate 112 is an organic charge transfer layer stacked on at least one of a transparent and flat surface glass substrate, a transparent plastic substrate, and transparent silicon. layer or an inorganic charge transport layer (hole transport layer or electron transport layer).

The second substrate 112 can be used after ultrasonic cleaning with a solvent such as isopropyl alcohol, acetone, or methanol to remove contaminants and UV-ozone treatment.

The transfer printing method of quantum dots surface-treated with a ligand having a polarity according to an embodiment of the present invention includes quantum dots surface-treated with a ligand having a first polarity on a second substrate 112 when using an embossed stamp. The quantum dot pattern 121 may be transferred to the quantum dot thin film.

The width of the quantum dot pattern 121 may be 20 nm to 100 mm. If the width of the quantum dot pattern 121 is less than 20 nm, there is a limitation in that the shape of the pattern becomes non-uniform, and if it exceeds 100 mm, there is a problem in that the thickness becomes non-uniform.

The thickness of the quantum dot pattern 121 may be from 6 nm to about 1,000 nm. If the thickness of the quantum dot pattern 121 is less than 6 nm, there is a problem of insufficient attraction between the quantum dots because the quantum dots are a single layer, and if the thickness of the quantum dot pattern 121 exceeds 1,000 nm, there is a problem of insufficient attraction between the quantum dots. If so, there is a problem that the quantum dot pattern 121 collapses during the transfer process.

Therefore, the transfer printing method of quantum dots surface-treated with a polar ligand according to an embodiment of the present invention is to treat the surface of a viscoelastic stamp with a self-assembled monolayer of a short polar organic ligand to change the surface energy to enable high-resolution patterning. It can be performed easily.

Therefore, the transfer printing method of quantum dots surface-treated with a ligand having a polarity according to an embodiment of the present invention is a high-resolution nanoparticle based on quantum dots surface-treated with a ligand having a first polarity (e.g., an inorganic ligand or a bifunctional ligand). Patterning can be used to manufacture various electronic devices such as light emitting devices, transistors, memories, or photo detectors.

According to an embodiment, the transfer printing method of quantum dots surface-treated with a polarized ligand according to an embodiment of the present invention proceeds with the step (S140) of transferring the quantum dot thin film to the second substrate 112 using a stamp. , a step of separating the stamp from the second substrate 112 to pick up the quantum dot pattern 121, and a step of transferring the quantum dot pattern 121 to the third substrate using the stamp.

At this time, the stamp used in the step (S110) of forming a quantum dot thin film including quantum dots surface-treated with a ligand having a first polarity on the first substrate may be a front stamp, and the quantum dot pattern 121 is formed using the stamp. ) The stamp used in the step of transferring to the third substrate may be an embossed stamp including an embossed pattern.

Therefore, in the step of transferring the quantum dot pattern 121 to the third substrate using a stamp, the quantum dot thin film can be transferred and printed as the quantum dot pattern 121 on the third substrate by using an embossed stamp.

The step of separating the stamp from the second substrate 112 to pick up the quantum dot pattern and the step of transferring the quantum dot pattern 121 to the third substrate using the stamp are steps S140 and A quantum dot pattern can be formed from the second substrate 112 to the third substrate using the same method.

Hereinafter, with reference to FIGS. 8 to 10, a method for transfer printing quantum dots surface-treated with a polar ligand according to an embodiment of the present invention using a front stamp will be described.

Since the stamp includes the same components as those in FIGS. 1 to 7 except that a conformal front stamp is used, the description of the same components will be omitted.

Figure 8 is a cross-sectional view showing a front stamp disposed on a first substrate on which a quantum dot thin film including quantum dots surface-treated with a ligand having a first polarity is formed, and Figure 9 is a quantum dot surface-treated with a ligand having a first polarity. It is a cross-sectional view showing a front stamp that picks up a quantum dot thin film containing, and Figure 10 is a cross-sectional view showing a second substrate onto which a quantum dot thin film containing quantum dots surface-treated with a ligand having the first polarity is transferred.

In the transfer printing method of quantum dots surface-treated with a polar ligand according to an embodiment of the present invention, the quantum dot thin film 120 can be transferred to the entire surface of the second substrate 112 by using the front stamp 132.

When using the front stamp 132, it is possible to transfer while applying uniform pressure to all surfaces of the front stamp 132 regardless of the density, spacing, or size of the quantum dot pattern, making it possible to transfer the quantum dot thin film 120 over a larger area. You can.

On the other hand, when using an embossed stamp, if the spacing is wide compared to the size of the quantum dot pattern, unnecessary parts may be transferred together due to leaning of the embossed stamp, and if the size of the quantum dot pattern varies, the pressure distribution is not uniform, making it difficult to form the pattern. This may be uneven.

The thickness of the quantum dot pattern 121 may be from 6 nm to about 1,000 ㎛, and if the thickness of the quantum dot pattern 121 is less than 6 nm, the quantum dot pattern 121 is a single layer, so there is a problem of insufficient attraction between individual quantum dots, If it exceeds 1,000 ㎛, there is a problem that the quantum dot pattern 121 collapses during the transfer process.

Hereinafter, with reference to FIGS. 11 to 14, a transfer printing method of quantum dots surface-treated with a polarized ligand according to an embodiment of the present invention using a second substrate including a front stamp and an engraved pattern will be described. Do this.

Since it includes the same components as those in FIGS. 1 to 10 except for using a second substrate including a front stamp and an engraved pattern, description of the same components will be omitted.

Figure 11 is a cross-sectional view showing a second substrate including a front stamp and an engraved pattern on which a quantum dot thin film containing quantum dots surface-treated with a ligand having a first polarity is picked up, and Figure 12 is a cross-sectional view showing the first substrate in contact with the second substrate. It is a cross-sectional view showing a front stamp picking up a quantum dot thin film including quantum dots surface-treated with a polarized ligand, and Figure 13 shows a quantum dot pattern including quantum dots surface-treated with a first polarized ligand being picked up from a second substrate. It is a cross-sectional view showing one front stamp, and Figure 14 is a cross-sectional view showing a third substrate onto which a quantum dot pattern including quantum dots surface-treated with a ligand having the first polarity is transferred.

According to an embodiment, the transfer printing method of quantum dots surface-treated with a polarized ligand according to an embodiment of the present invention includes the step (S130) of transferring the quantum dot thin film 120 to the second substrate 112 using a stamp. Next, separate the stamp from the second substrate 120 to pick up the quantum dot pattern 121 (S140) and transfer the quantum dot pattern 121 to the third substrate 113 using the stamp (S150). ) may include.

The second substrate 112 may include a concave trench. For example, the second substrate 112 may have a recessed region R recessed from the surface.

More specifically, the front stamp 132 on which the quantum dot thin film 120 is formed may be arranged to be aligned on the second substrate 112 including the engraved trench, and the second substrate 112 has the surface of the front stamp 132. Energy (the surface energy of the PDMS stamp is 19.8 mJ/㎡) can be formed of a material with a surface energy greater than that of silicon, polymer, glass, organic material, oxide, etc.

A slight pressure may be applied overall to the front stamp 132 so that the quantum dot thin film 120 is in uniform contact with the second substrate 112, and at this time, the quantum dot thin film 120 is in the recess area of the second substrate 112. Portions other than (R) contact the second substrate 112, and portions corresponding to the recess region (R) do not contact the second substrate 112.

Since the surface energy of the second substrate 112 is greater than the surface energy of the front stamp 132, the portion of the quantum dot thin film 120 in contact with the second substrate 112 is separated from the front stamp and is attached to the front stamp 132. It remains on the surface, and the portion corresponding to the recess region (R) can be picked up while still being adhered to the front stamp 132 to form the quantum dot pattern 121. Substances remaining on the second substrate 112 may be removed with pyranha solution or the like.

Therefore, when the front stamp is separated from the second substrate 112, the portion 122 of the quantum dot thin film 120 that is in contact with the second substrate 112 remains in the second substrate 112, and the recess region (R) The portion 121 corresponding to can be picked up by the front stamp 132.

The front stamp 132 may be aligned on the third substrate 113, and the quantum dot pattern 121 may be transferred to the third substrate 113. The quantum dot pattern 121 may be transferred from the front stamp 132 to the third substrate 113 by bringing the front stamp 132 on which the quantum dot pattern 121 is formed into contact with the third substrate 113 and then separating it.

The width of the quantum dot pattern 121 may be 20 nm to 100 mm. If the width of the quantum dot pattern 121 is less than 20 nm, there is a limitation in that the shape of the pattern becomes non-uniform, and if it exceeds 100 mm, there is a problem in that the thickness becomes non-uniform.

The thickness of the quantum dot pattern 121 may be from 6 nm to about 1,000 nm. If the thickness of the quantum dot pattern 121 is less than 6 nm, there is a problem of insufficient attraction between the quantum dots because the quantum dots are a single layer, and if the thickness of the quantum dot pattern 121 exceeds 1,000 nm, there is a problem of insufficient attraction between the quantum dots. If so, there is a problem that the quantum dot pattern 121 collapses during the transfer process.

The third substrate 113 may be a wearable substrate, a flexible substrate, or a plastic substrate, and the portion of the third substrate 113 that is in contact with the quantum dot pattern is made of a material having a surface energy greater than that of the front stamp 232. It is desirable to form

Therefore, the transfer printing method of the quantum dot thin film 120 according to an embodiment of the present invention can form a quantum dot pattern 121 with various densities and resolutions.

In addition, the transfer printing method of quantum dots surface-treated with a polar ligand according to an embodiment of the present invention involves treating the surface of a viscoelastic stamp with a self-assembled monolayer of a short polar organic ligand to change the surface energy to enable high-resolution patterning. It can be performed easily.

In addition, the transfer printing method of quantum dots surface-treated with a ligand having a polarity according to an embodiment of the present invention is a high-resolution nanoparticle based on quantum dots surface-treated with a ligand having a first polarity (e.g., an inorganic ligand or a bifunctional ligand). Patterning can be used to manufacture various electronic devices such as light emitting devices, transistors, memories, or photo detectors.

Figure 15 is a cross-sectional view showing an electronic device according to an embodiment of the present invention.

Electronic devices including quantum dots surface-treated with a polarized ligand according to an embodiment of the present invention may include, but are not limited to, any one of a light emitting device, a photo detector, a transistor, a solar cell, and a memory device.

Preferably, the electronic device including quantum dots surface-treated with a polarized ligand according to an embodiment of the present invention may be a self-luminous quantum dot device.

The quantum dot device includes a hole transport layer 220 formed on the first electrode 210, a photoactive layer 230 formed on the hole transport layer 220, and an electron transport layer 240 formed on the quantum dot light emitting layer 230. ) and a second electrode 250 formed on the electron transport layer 240.

The first electrode 210 is an electrode that provides holes to the device, and the second electrode 250 is an electrode that provides electrons to the device.

The hole transport layer 220 is a layer that moves holes to the quantum dot light-emitting layer 230, allowing holes to be effectively transferred to the quantum dot light-emitting layer 230, and balancing the densities of holes and electrons in the quantum dot light-emitting layer 230 to emit light. Efficiency can be increased.

In addition, electrons injected from the first electrode 210 into the quantum dot light-emitting layer 230 are trapped in the quantum dot light-emitting layer 230 by the energy barrier existing at the hole transport layer 220/quantum dot light-emitting layer 230 interface, so that electrons and holes are trapped in the quantum dot light-emitting layer 230. As the recombination probability increases, luminous efficiency can be improved.

The electronic device according to an embodiment of the present invention may include, as a quantum dot light-emitting layer 230, a quantum dot thin film manufactured by a transfer printing method of quantum dots surface-treated with a ligand having a polarity according to an embodiment of the present invention.

Since the quantum dot thin film used as the quantum dot light-emitting layer 230 includes the same components as the transfer printing method of quantum dots surface-treated with a polar ligand according to an embodiment of the present invention, the same components will be omitted.

The electron transport layer 240 can improve the efficiency of the device by transporting electrons generated from the second electrode 250 to the quantum dot light-emitting layer 230.

Figure 16 is an optical image showing a quantum dot surface-treated with an inorganic ligand that is entirely transferred using a transfer printing method of a quantum dot surface-treated with a polarized ligand according to an embodiment of the present invention.

Referring to FIG. 16, it can be seen that quantum dots surface-treated with an inorganic ligand are conformally well transferred using the transfer printing method of quantum dots surface-treated with a polar ligand according to an embodiment of the present invention.

Figure 17 is an optical image showing a quantum dot surface-treated with an inorganic ligand that has been patterned and transferred using a transfer printing method of a quantum dot surface-treated with a polarized ligand according to an embodiment of the present invention.

Referring to FIG. 17, it can be seen that quantum dots surface-treated with an inorganic ligand are well transferred into a quantum dot pattern using the transfer printing method of quantum dots surface-treated with a polar ligand according to an embodiment of the present invention.

Figure 18 is an electron microscope image showing a quantum dot surface-treated with an inorganic ligand that was patterned and transferred using a transfer printing method of a quantum dot surface-treated with a polarized ligand according to an embodiment of the present invention.

In Figure 18, the pattern of quantum dots surface-treated with the transferred inorganic ligand is 3㎛.

Referring to FIG. 18, it can be seen that quantum dots surface-treated with an inorganic ligand are formed into a super-resolution pattern using the transfer printing method of quantum dots surface-treated with a polar ligand according to an embodiment of the present invention.

Figure 19 is an image showing an electronic device including quantum dots surface-treated with a polarized ligand according to an embodiment of the present invention.

Referring to FIG. 19, it can be seen that a self-luminous quantum dot device is manufactured using a quantum dot thin film surface-treated with a polarized ligand according to an embodiment of the present invention, thereby exhibiting high luminous efficiency.

As described above, although the present invention has been described with reference to limited embodiments and drawings, the present invention is not limited to the above embodiments, and various modifications and variations can be made from these descriptions by those skilled in the art. This is possible. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be determined by the claims and equivalents thereof as well as the claims described later.

111: first substrate 112: second substrate
113: Third substrate 120: Quantum dot thin film
121: Quantum dot pattern 131: Embossed stamp
132: front stamp 140: self-assembled monolayer
210: first electrode 220: hole transport layer
230: Quantum dot emitting layer 240: Electron transport layer
250: second electrode

Claims (18)

Forming a quantum dot thin film including quantum dots surface-treated with a ligand having a first polarity on a first substrate;
Picking up the quantum dot thin film using a stamp; and
Transferring the quantum dot thin film to a second substrate using the stamp;
Including,
A transfer printing method for quantum dots surface-treated with a polar ligand, wherein the stamp is surface-treated with a self-assembled monolayer having a second polarity.
According to paragraph 1,
The step of picking up the quantum dot thin film using a stamp is a transfer printing method of quantum dots surface-treated with a polar ligand, characterized in that the quantum dot thin film is picked up by Coulomb attraction.
According to paragraph 1,
A method for transferring and printing quantum dots surface-treated with a polarized ligand, wherein the first polarized ligand includes at least one of an inorganic ligand and a two-functional ligand.
According to paragraph 3,
The inorganic ligands include metal-chalcogenide compounds, metal-halide compounds, metal-oxide compounds, chalcogenides, halides, and pseudohalides. (pseudohalide), a lamination transfer printing method of a quantum dot multilayer thin film, characterized in that it contains at least one of hydroxy ions.
According to paragraph 3,
The two-functional ligand is characterized in that it includes a ligand in which at least two functional groups of a carboxyl group, a phosphorous acid group, a hydroxyl group, a thiol group, an amine group, a phosphine group, and a phosphine oxide group are bonded to a C ₁ -C ₂₄ hydrocarbon. Laminated transfer printing method for quantum dot multilayer thin films.
According to paragraph 1,
The self-assembled monolayer is a C ₂ to C group containing at least one of an amine group (-NH ₃ ), a thiol group (-SH), a Teflon group (-CF ₃ ), an epoxy group, and a linear and branched alkyl group (-R). A transfer printing method for quantum dots surface-treated with a polar ligand, characterized in that it contains a silane group consisting of a backbone of ₁₈ hydrocarbons.
According to paragraph 1,
A transfer printing method for quantum dots surface-treated with a polarized ligand, wherein the stamp includes an embossed pattern.
In clause 7,
After transferring the quantum dot thin film to the second substrate using the stamp,
Separating the stamp from the second substrate and picking up a quantum dot pattern; and
Transferring the quantum dot pattern to a third substrate using the stamp;
A transfer printing method for quantum dots surface-treated with a polarized ligand, comprising:
In clause 7,
A transfer printing method for quantum dots surface-treated with a polarized ligand, wherein the quantum dot thin film includes a quantum dot pattern.
According to paragraph 1,
The transfer printing method of quantum dots surface-treated with a polarized ligand, wherein the second substrate includes an engraved trench.
According to clause 10,
After transferring the quantum dot thin film to the second substrate using the stamp,
Separating the stamp from the second substrate and picking up a quantum dot pattern; and
Transferring the quantum dot pattern to a third substrate using the stamp;
A transfer printing method for quantum dots surface-treated with a polarized ligand, comprising:
According to clause 10,
A transfer printing method of quantum dots surface-treated with a polar ligand, wherein the second substrate has a recessed area recessed from the surface.
According to clause 12,
When the stamp is separated from the second substrate, the portion of the quantum dot thin film in contact with the second substrate remains on the second substrate, and the portion corresponding to the recess area is picked up by the stamp. Transfer printing method for quantum dots surface-treated with polar ligands.
According to claim 8 or 11,
A transfer printing method for quantum dots surface-treated with a polar ligand, characterized in that the width of the quantum dot pattern is 20 nm to 100 mm.

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