Composite material, preparation method thereof, thin film and electronic equipment

Abstract

The invention relates to the technical field of light-emitting devices, in particular to a composite material, a preparation method thereof, a thin film and electronic equipment. The composite material provided by the invention comprises a quantum rod body; the hydrophobic ligand is connected to the surface of the quantum rod body; the hydrophilic ligand is connected to the surface of the quantum rod body. The quantum rods are induced to be arranged orderly through the hydrophilic ligand and the hydrophobic ligand, self-assembly of the quantum rods is achieved, the anisotropic light-emitting layer thin film is obtained, and then the light source utilization rate is effectively increased.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of light-emitting devices, in particular to a composite material, a preparation method thereof, a thin film and an electronic device. BACKGROUND

[0002] Compared with organic light-emitting diode (OLED) displays, self-luminous devices using inorganic quantum dots as electroluminescent materials have the advantages of wide color gamut coverage, high color purity, ultra-thin and light, and bendable and curlable, and thus have attracted extensive attention.

[0003] Semiconductor quantum rods are one-dimensional nanomaterials with high aspect ratio. In addition to having similar quantum confinement effects and narrow emission peaks as 0-dimensional inorganic quantum dots, semiconductor quantum rods also have anisotropic light absorption and emission characteristics. The dipole moment of a semiconductor quantum rod is parallel to the long axis direction, and the corresponding emitted light direction is perpendicular to the long axis, which can improve the light-emitting efficiency and avoid light source loss. However, after the quantum rods are formed into a film, the arrangement uniformity is poor, which is not conducive to forming a relatively concentrated light source. SUMMARY

[0004] Based on this, the present application provides a composite material, a preparation method thereof, a thin film and an electronic device.

[0005] In a first aspect of the present application, a composite material is provided, comprising:

[0006] a quantum rod body;

[0007] a hydrophobic ligand connected to the surface of the quantum rod body;

[0008] a hydrophilic ligand connected to the surface of the quantum rod body.

[0009] In a second aspect of the present application, a preparation method of a composite material is provided, comprising the following steps:

[0010] mixing a quantum rod body and a hydrophobic ligand in a first organic solvent to perform a first heating reaction to obtain a quantum rod precursor;

[0011] mixing the quantum rod precursor and a hydrophilic ligand in a second organic solvent to perform a second heating reaction to obtain the composite material.

[0012] In a third aspect of the present application, a thin film is provided, comprising the composite material of the first aspect of the present application or the composite material prepared by the preparation method of the second aspect of the present application; the thin film has one or more of the following characteristics:

[0013] (1) the thin film has anisotropy;

[0014] (2) the length direction of the quantum rod body is parallel to the extension direction of the film, and a plurality of the quantum rod bodies are arranged in parallel;

[0015] (3) the length direction of the quantum rod body intersects the extension direction of the film, and a plurality of the quantum rod bodies are arranged in parallel.

[0016] In a fourth aspect of the present application, an electronic device is provided, which comprises the composite material of the first aspect of the present application, or the composite material prepared by the preparation method of the second aspect of the present application, or the film of the third aspect of the present application.

[0017] The composite material provided by the present application has at least the following beneficial effects:

[0018] The present application induces the ordered arrangement of quantum rods by hydrophilic ligands and hydrophobic ligands, realizes the self-assembly of quantum rods, and obtains an anisotropic light-emitting layer film, thereby effectively improving the light source utilization rate. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 A structure schematic diagram of the composite material provided by the present application is shown in the figure;

[0020] Figure 2 A structure schematic diagram of the self-assembly arrangement of the composite material provided by the present application on (a) an oleophilic substrate and (b) a hydrophilic substrate is shown in the figure;

[0021] Figure 3 A schematic diagram of the second heating reaction of the quantum rod precursor and the hydrophilic ligand of the present application is shown in the figure;

[0022] Figure 4 A schematic diagram of the angle-dependent PL spectrum test setup of the present application is shown in the figure.

[0023] In the figure, 101 is an optical film sample, 102 is a sample substrate, 103 is a rotatable sample stage, 104 is an excitation light source, and 105 is a spectrometer. DETAILED DESCRIPTION

[0024] The composite material, the preparation method thereof, the film, and the light-emitting device of the present application will be further and completely described below in combination with specific embodiments. The present application can be realized in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0025] In the present application, "carboxyl" refers to -COOH. "Mercapto" refers to -SH. "Phosphonic acid group" refers to -PO3H2. "Amine group" refers to -NH2.

[0026] In the present application, represents a connection site, and is represented by The number of occurrences indicates the number of connection sites.

[0027] In this application, when no linking site is specified in the group, it means that any linkable site in the group is selected as the linking site.

[0028] In this application, "substitution" means that the hydrogen atom in the substituent is replaced by the substituent. In this application, when the same substituent appears multiple times, it can be independently selected from different groups.

[0029] In this application, "substituted or unsubstituted" means that the defined group may or may not be substituted. When the defined group is substituted, it should be understood that it may be substituted by a group acceptable in the art, including but not limited to: -OH, halogen, -CN, -NC, -NO2, -CF3, -CHO, -COOH, -OC≡N, -N=C=O, -SC≡N, -N=C=S, Cl~C 20 Alkyl, C1-C 20 Heteroalkyl, C1-C 20 Acyloxy group, C1-C 20 Alkoxycarbonyl group.

[0030] In this application, "alkyl" can refer to straight-chain, branched, and / or cyclic alkyl groups. In this application, "C1-C2" refers to... 10 "Straight-chain alkyl" refers to a straight-chain alkyl group comprising 1 to 10 carbon atoms. Non-limiting examples of alkyl groups include: methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, isobutyl, 2-ethylbutyl, 3,3-dimethylbutyl, n-pentyl, isopentyl, neopentyl, tert-pentyl, cyclopentyl, 1-methylpentyl, 3-methylpentyl, 2-ethylpentyl, 4-methyl-2-pentyl, n-hexyl, 1-methylhexyl, 2-ethylhexyl, 2-butylhexyl, cyclohexyl, 4 -Methylcyclohexyl, 4-tert-butylcyclohexyl, n-heptyl, 1-methylheptyl, 2-butyldodecyl, 2-hexyldodecyl, 2-octyldodecyl, n-hexadecyl, 2-ethylhexadecyl, 2-butylhexadecyl, 2-hexylhexadecyl, 2-octylhexadecyl, n-nonadecanyl, 2-ethyleicosyl, 2-butyleicosyl, 2-hexyleicosyl, 2-octyleicosyl, n-trisyl, n-heptadecyl, n-triadecyl, and adamantane, etc.

[0031] "Alkenyl" refers to a group containing at least one unsaturated site, i.e., carbon-carbon sp. 2 Hydrocarbons with a double bond consisting of a positive, secondary, tertiary, or cyclic carbon atom. Non-limiting examples of alkenyl groups include, but are not limited to, vinyl (-CH=CH2), allyl (-CH2CH=CH2), cyclopentenyl (-C5H7), and 5-hexenyl (-CH2CH2CH2CH2CH=CH2).

[0032] In this application, "ring atom number" refers to the number of atoms in the ring itself of a structural compound (e.g., a monocyclic compound, a fused-ring compound, a cross-linked compound, a carbocyclic compound, or a heterocyclic compound) obtained by atomic bonding to form a ring. When the ring is substituted by a substituent, the atoms contained in the substituent are not included in the ring-forming atoms. The same applies to the "ring atom number" described below unless otherwise specified. For example, a benzene ring has 6 ring atoms, a naphthalene ring has 10 ring atoms, and a thiophene group has 5 ring atoms.

[0033] In this application, "aryl" refers to an aromatic hydrocarbon group derived from an aromatic ring compound by removing one hydrogen atom. It can be a monocyclic aryl, a fused-ring aryl, or a polycyclic aryl; for polycyclic rings, at least one is an aromatic ring system. Phrases containing this term include, for example, "C6-C6...". 12 "Aryl" refers to an aryl group containing 6 to 12 carbon atoms. Each time it appears, the number of carbon atoms can be 6, 7, 8, 9, 10, 11, or 12. Suitable examples include, but are not limited to, benzene, biphenyl, and naphthalene.

[0034] In this application, "heteroaryl" refers to an aryl or cyclopentadienyl group in which at least one carbon atom is replaced by a non-carbon atom, which can be an N atom, an O atom, an S atom, etc. Suitable examples of "heteroaryl" include, but are not limited to: furan, benzofuran, thiophene, benzothiophene, pyrrole, pyrazole, triazole, imidazole, oxazole, oxadiazole, thiazole, tetrazolium, indole, carbazole, pyrroloimidazol, pyrrolopyrrole, thiophenolopyrrole, thiophenolothiophene, furanolopyrrole, furanolofuran, thiophenolofuran, benzoisoxazole, benzoisothiazolium, benzimidazole, pyridine, pyrazine, pyridazine, pyrimidine, triazine, quinoline, isoquinoline, o-diazonyl, quinoxaline, phenanthridine, primidine, quinazoline, and quinazolineone.

[0035] In this application, "anisotropy" refers to the variation of certain physicochemical properties of a material with changing orientation, exhibiting differences in different directions. In this application, the quantum rod, as a semiconductor material, has a large aspect ratio, which causes the distribution of its dipole moment along the extended axis during transitions between the ground and excited states, and the directions of its photon absorption and photon emission are perpendicular to the long axis. Therefore, when the quantum rod is arranged in an ordered manner in a thin film or bulk phase, it can absorb and emit light in a specific direction, simultaneously forming linearly polarized light.

[0036] In this application, "hydrophilic" and "hydrophobic" refer to the affinity for water; "hydrophilic" means that when water is placed on a material surface, the contact angle θ < 90°. "Hydrophobic" means that when water is placed on a material surface, the contact angle θ > 90°.

[0037] In the light emitting process, the direction of the transition dipole moment plays a key role in the emission and absorption of light. If the quantum rods are arranged in a disordered manner, the direction of light emission is also random, and the light loss rate is high. When the quantum rods are arranged in an aligned manner, the direction of the optical transition dipole moment can be more regular. At this time, the aligned quantum rods can concentrate the light emission direction, and more light can be effectively emitted from the device, thereby improving the light emitting efficiency.

[0038] Currently, to align the quantum rods, a method of applying a magnetic field or a method of manufacturing micro grooves on the surface of the substrate is usually used. However, the application of an electric field requires the additional insertion of an electrode, and a high magnetic field is required. Manufacturing micro grooves on the surface of the substrate has the disadvantage that the alignment degree of the quantum rod orientation is not enough, and the micro grooves manufactured on the surface of the substrate will damage the substrate, which may reduce the optical properties. Based on this, the present application provides a quantum rod material capable of self-assembly arrangement.

[0039] In a first aspect of the present application, a quantum rod is provided, comprising:

[0040] a quantum rod body;

[0041] a hydrophobic ligand connected to the surface of the quantum rod body;

[0042] a hydrophilic ligand connected to the surface of the quantum rod body.

[0043] In one example, the quantum rod body comprises a middle part and first and second end parts respectively arranged at both ends of the middle part, and the first and second end parts respectively have an arc segment abutting the middle part. The hydrophobic ligand is connected to the middle part of the quantum rod body. The hydrophilic ligand is connected to the arc segment of the quantum rod body. In one example, the middle part of the quantum rod body is a cylinder.

[0044] It can be understood that the middle part of the quantum rod body is relatively flat, and therefore has a low curvature. For example, the curvature of the middle part of the quantum rod body is -0.01 to 0.01.

[0045] In one example, the hydrophobic ligand comprises a non-polar hydrophobic chain segment and a first polar group at the end of the non-polar hydrophobic chain segment.

[0046] The hydrophilic ligand comprises a hydrophilic chain segment and a second polar group at the end of the hydrophilic chain segment.

[0047] The first and second polar groups are each independently selected from metal coordination groups.

[0048] It can be understood that the quantum rod body has a one-dimensional linear structure, and the two end surfaces with relatively large curvature along the long axis direction of the quantum rod body are the arc surface sections of the quantum rod body. Along the long axis direction of the quantum rod body, the outer side surface with relatively small curvature is the middle part of the quantum rod body. The structure of the quantum rod provided in the present application is shown in Figure 1 , wherein the hydrophobic ligand is modified on the middle part of the quantum rod body, and the hydrophilic ligand is modified on the arc surface section. Because the hydrophilic and hydrophobic effects of the ligands located on the arc surface section and the middle part are different, the arrangement mode of the quantum rod is different on the surface of different substrates.

[0049] For example, as shown in Figure 2 , when the surface of the substrate has oleophilic properties, the composite material tends to be arranged parallel to the substrate to ensure the contact area of the hydrophobic ligand with the oleophilic substrate and reduce the contact area of the hydrophilic ligand with the oleophilic substrate. That is, on the surface of the hydrophobic substrate, the contact area of the hydrophobic ligand with the hydrophobic substrate in the composite material is greater than the contact area of the hydrophilic ligand with the hydrophobic substrate.

[0050] For example, as shown in Figure 2 , when the surface of the substrate has hydrophilic properties, the composite material tends to be arranged perpendicular to the substrate to ensure the contact area of the hydrophilic ligand with the hydrophilic substrate and reduce the contact area of the hydrophobic ligand with the oleophilic substrate. That is, on the surface of the hydrophilic substrate, the contact area of the hydrophilic ligand with the hydrophilic substrate in the composite material is greater than the contact area of the hydrophobic ligand with the hydrophilic substrate.

[0051] Therefore, the composite material provided in the present application has excellent substrate sensitivity, so that the ordered arrangement of the composite material can be induced by the hydrophilic and oleophilic properties of the surface of the substrate, and the self-assembly of the composite material can be realized to obtain an anisotropic light-emitting layer film, thereby effectively improving the light source utilization rate.

[0052] The hydrophobic ligand comprises a non-polar hydrophobic chain segment and a first polar group at the end of the non-polar hydrophobic chain segment. The non-polar hydrophobic chain segment can endow the hydrophobic ligand with hydrophobic properties, and the first polar group has excellent metal ligand ability, so it can coordinate with the metal atoms in the quantum rod body to realize the modification of the hydrophobic ligand.

[0053] In one example, the metal coordination group comprises one or more of carboxyl, mercapto, phosphonic acid, and amine.

[0054] In one example, the non-polar hydrophobic chain segment is selected from C 10 -C 20 linear alkyl, C 10 -C 20 branched alkyl, C 10 -C 20cyclic alkyl, C 10 ~C 20 linear alkenyl, C 10 ~C 20 branched alkenyl, and C 10 ~C 20 cyclic alkenyl.

[0055] Exemplarily, the non-polar hydrophobic segment includes, but is not limited to: CH3-(CH2)9-, CH3-(CH2) 10 -, CH3-(CH2) 11 -, CH3-(CH2) 12 -, CH3-(CH2) 13 -, CH3-(CH2) 14 -, CH3-(CH2) 15 -, CH3-(CH2) 16 -, CH3-(CH2) 17 -, CH3-(CH2) 18 -, CH3-(CH2) 19 -, CH2=CH-(CH2)8-, CH2=CH-(CH2)9-, CH2=CH-(CH2) 10 -, CH2=CH-(CH2) 11 -, CH2=CH-(CH2) 12 -, CH2=CH-(CH2) 13 -, CH2=CH-(CH2) 14 -, CH2=CH-(CH2) 15 -, CH2=CH-(CH2) 16 -, CH2=CH-(CH2) 17 -, or CH2=CH-(CH2) 18 -.

[0056] Preferably, the non-polar hydrophobic segment is selected from C 10 ~C 20 linear alkyl. Linear alkyl has strong hydrophobicity, while having small steric hindrance. In addition, linear alkyls mainly interact with each other through van der Waals forces, which has strong structural stability, thus having excellent adaptability to subsequent quantum rod ink film forming process.

[0057] In one example, the hydrophobic ligand includes one or more of the compounds having the structure of formula (I):

[0058] wherein n is selected from any integer between 9 and 19. It can be appreciated that n is selected from 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, or 19. Illustratively, the hydrophobic ligand includes, but is not limited to

[0059]

[0060] Compared with other polar groups, the phosphorus atom in phosphonic acid group has an empty d orbital, which can form a stronger coordination bond with metal ions on the surface of quantum rods. And phosphonic acid group has more extensive coordination adaptability, which can be modified on the surface of quantum rod main body through monodentate coordination, bidentate coordination or even polydentate coordination. The above-mentioned various coordination modes enable phosphonic acid group to better adapt to different structures and chemical environments on the surface of quantum rods, thereby realizing more effective coordination.

[0061] In one example, the hydrophilic ligand includes one or more of the compounds having the structure of formula (II):

[0062]

[0063] wherein, is the hydrophilic segment; R1includes an ether bond. n is any integer between 1 and 5. Illustratively, n is 1, 2, 3, 4, or 5.

[0064] The present application confers hydrophilic properties to the ligand by selecting R1group including an ether bond. In addition, the substitution site of R1on the phenyl group is at least 3, i.e. the hydrophilic ligand provided by the present application has a dendritic structure. The dendritic hydrophilic ligand can better modify the end with larger curvature, and the hydrophilic interaction site of the dendritic hydrophilic segment is more, which can confer excellent hydrophilic properties to the quantum rod.

[0065] In one example, R1is independently selected from

[0066] wherein R 11 and R 12 are each independently selected from a single bond, a C1-C5 linear alkylene group, or a C3-C5 branched alkylene group.

[0067] R 13 is each independently selected from x and z are each independently selected from any integer between 0 and 5; y is selected from any integer between 1 and 4; m is selected from any integer between 1 and 10.

[0068] R 13The inclusion of multiple ether linkages can improve hydrophilic properties. It can be appreciated that x, z can be selected from 0, 1, 2, 3, 4, or 5. y can be selected from 1, 2, 3, or 4. m can be selected from 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10. R 13 Suitable examples include, but are not limited to:

[0069] wherein, is the second polar group.

[0070] Further, is selected from -PO3H2.

[0071] wherein, is a linking group.

[0072] Further, is selected from a single bond, a C1-C5straight-chain alkylene, 10 a C3-C6straight-chain alkylene, a C3-C6branched alkylene, a C6-C12aryl, 10 a C5-C10heteroaryl having from 5 to 10 ring atoms, which is unsubstituted or substituted by at least one R'; wherein the heteroatoms in the heteroaryl are nitrogen, oxygen, or sulfur. R' is at each occurrence independently selected from C1-C6straight-chain alkyl.

[0073] Further, is selected from a single bond, a C1-C5straight-chain alkylene, wherein X1is at each occurrence independently selected from C, N, or S, and at least one X1is N; R 14 and R 15 is at each occurrence independently selected from C1-C5straight-chain alkylene. 14 and R 15 is at each occurrence independently selected from C1-C5straight-chain alkylene.

[0074] In one example, the hydrophilic ligand comprises one or more of

[0075]

[0076]

[0077] Further, the hydrophilic ligand comprises one or more of

[0078]

[0079] ​The hydrophilic ligand is relatively stable and simple to prepare. The hydrophilic ligand has a dendritic structure. When the polar group phosphonic acid group is coordinated with the arc segment of the quantum rod body, one polar group is coordinated with the quantum rod body, and multiple hydrophilic sites can be brought, which enables the hydrophilic polyether bond segment on the outside to better modify the arc segment, so as to improve the hydrophilic performance of the arc segment of the quantum rod.

[0080] wherein q1, q2, q3 and q4 are each independently selected from any integer from 1 to 5. Illustratively, q1, q2, q3 and q4 are each independently selected from 1, 2, 3, 4 or 5.

[0081] In one example, the quantum rod body is a single-structure quantum rod or a core-shell quantum rod. The material of the single-structure quantum rod, the core material of the core-shell quantum rod, and the shell material of the core-shell quantum rod are each selected from one or more of II-VI compound, IV-VI compound, III-V compound, I-III-VI compound, and perovskite nanoparticle material, wherein the II-VI compound includes one or more of CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, and HgZnSTe, the IV-VI compound includes one or more of SnS, SnSe, SnTe, PbS, PbSe, PbTe, SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, SnPbSSe, SnPbSeTe, and SnPbSTe, the III-V compound includes one or more of GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InNP, InNAs, InNSb, InPAs, InPSb, GaAlNP, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, and InAlPSb, and the I-III-VI compound includes one or more of CuInS2, CuInSe2, and AgInS2.

[0082] The perovskite nanoparticle material is one or more of inorganic perovskite quantum dot, organic perovskite quantum dot, and organic-inorganic hybrid perovskite quantum dot, wherein the inorganic perovskite quantum dot has a general structure of AMX3, wherein A is Cs + ion, and M is a divalent metal cation selected from Pb2+ Sn 2+ Cu 2+ Ni 2+ Cd 2+ Cr 2+ Mn 2+ Co 2+ Fe 2+ Ge 2+ Yb 2+ and Eu 2+ one or more of Sn, Cu, Ni, Cd, Cr, Mn, Co, Fe, Ge, Yb, and Eu, X is a halide anion; the structure general formula of the organic perovskite quantum dot is CMX3, C is formamidinium; the structure general formula of the organic-inorganic hybrid perovskite quantum dot is BMX3, B is selected from organic amine cations.

[0083] In one example, the length of the quantum rod body is 20 nm to 200 nm. It is understood that the length of the quantum rod body includes, but is not limited to, 20 nm, 25 nm, 30 nm, 40 nm, 45 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 110 nm, 120 nm, 130 nm, 140 nm, 150 nm, 160 nm, 170 nm, 180 nm, 190 nm, or 200 nm.

[0084] In one example, the cross-sectional diameter of the middle portion of the quantum rod body is 4 nm to 20 nm. It is understood that the cross-sectional diameter of the middle portion of the quantum rod body includes, but is not limited to, 4 nm, 5 nm, 7 nm, 9 nm, 10 nm, 12 nm, 14 nm, 15 nm, 16 nm, 18 nm, or 20 nm.

[0085] In one example, the ratio of the length of the quantum rod body to the cross-sectional diameter of the middle portion of the quantum rod body is (5-10): 1. It is understood that the ratio of the length of the quantum rod body to the cross-sectional diameter of the middle portion of the quantum rod body includes, but is not limited to, 5: 1, 5.5: 1, 6: 1, 6.5: 1, 7: 1, 7.5: 1, 8: 1, 9: 1, or 10: 1.

[0086] In one example, the mass ratio of the quantum rod body to the hydrophobic ligand is (0.5-5): 1. Illustratively, the mass ratio of the quantum rod body to the hydrophobic ligand includes, but is not limited to, 0.5: 1, 0.8: 1, 1: 1, 1.2: 1, 1.5: 1, 1.8: 1, 2: 1, 2.5: 1, 3: 1, 3.5: 1, 3.8: 1, 4: 1, 4.2: 1, 4.5: 1, 4.8: 1, or 5: 1.

[0087] In one example, the mass ratio of the quantum rod body and the hydrophilic ligand is (0.5-5):1. For example, the mass ratio of the quantum rod body and the hydrophilic ligand includes, but is not limited to, 0.5:1, 0.8:1, 1:1, 1.2:1, 1.5:1, 1.8:1, 2:1, 2.5:1, 3:1, 3.5:1, 3.8:1, 4:1, 4.2:1, 4.5:1, 4.8:1 or 5:1.

[0088] In one example, the ratio of the length of the middle part of the quantum rod body to the length of the first end part of the quantum rod body is (8-20):1. For example, the ratio of the length of the middle part of the quantum rod body to the length of the first end part of the quantum rod body includes, but is not limited to, 8:1, 9:1, 10:1, 12:1, 15:1, 18:1 or 20:1.

[0089] In one example, the ratio of the length of the middle part of the quantum rod body to the length of the second end part of the quantum rod body is (8-20):1. For example, the ratio of the length of the middle part of the quantum rod body to the length of the second end part of the quantum rod body includes, but is not limited to, 8:1, 9:1, 10:1, 12:1, 15:1, 18:1 or 20:1.

[0090] In a second aspect of the present application, a preparation method of the composite material according to any one of the examples of the first aspect of the present application is provided, including the following steps:

[0091] S10, mixing the quantum rod body and the hydrophobic ligand in a first organic solvent to perform a first heating reaction to obtain a quantum rod precursor.

[0092] S20, mixing the quantum rod precursor and the hydrophilic ligand in a second organic solvent to perform a second heating reaction to prepare the quantum rod.

[0093] The quantum rod body includes a middle part and first and second end parts respectively arranged at both ends of the middle part, and the first and second end parts respectively have arc segments abutting the two ends of the middle part. In step S10, after the first heating reaction, the hydrophobic ligand is modified on the middle part and the arc segments of the quantum rod body in the quantum rod precursor prepared at this time. In step S20, the second heating reaction can replace the hydrophobic ligand modified on the arc segments with the hydrophilic ligand. For example, in step S20, a schematic diagram of the second heating reaction of the quantum rod precursor and the hydrophilic ligand is as shown in Figure 3The quantum rod preparation method provided in the present application first modifies the middle part and the curved surface segment of the quantum rod body by using a hydrophobic ligand with small steric hindrance. At this time, the curvature of the middle part is relatively low, so the hydrophobic ligands are arranged closely in the middle part of the quantum rod body. Then the quantum rod precursor is mixed with a hydrophilic ligand. At this time, the high curvature of the curved surface segment causes the original hydrophobic ligands to be relatively dispersed. At this time, the hydrophilic ligand with large steric hindrance can overcome the relatively weak ligand-ligand interaction of the curved surface segment, and then replace the hydrophobic ligand, so as to realize the preparation of the composite material of the present application. Further, the preparation method provided in the present application has mild reaction conditions, which can avoid corrosion of the core-shell structure of the quantum rod body, thereby ensuring the luminescent properties of the quantum rod.

[0094] In one example, the temperature of the first heating reaction is 170-190°C.

[0095] It can be understood that the heating temperature in step S10 can be selected from any value between 170-190°C. For example, the heating temperature includes but is not limited to 170°C, 173°C, 175°C, 178°C, 180°C, 183°C, 185°C, 188°C or 190°C. Further, in step S10, the time of the first heating reaction is 3-8h. For example, the time of the first heating reaction includes but is not limited to 3h, 4h, 5h, 6h, 7h or 8h.

[0096] In one example, in step S10, the mass ratio of the quantum rod body and the hydrophobic ligand mixed is (0.5-5):1. For example, the mass ratio of the quantum rod body and the hydrophobic ligand mixed includes but is not limited to 0.5:1, 0.8:1, 1:1, 1.2:1, 1.5:1, 1.8:1, 2:1, 2.5:1, 3:1, 3.5:1, 3.8:1, 4:1, 4.2:1, 4.5:1, 4.8:1 or 5:1.

[0097] In one example, in step S10, the mass ratio of the quantum rod precursor and the hydrophilic ligand mixed is (1-5):1. For example, the mass ratio of the quantum rod precursor and the hydrophilic ligand mixed includes but is not limited to 1:1, 1.5:1, 2:1, 2.2:1, 2.5:1, 2.8:1, 3:1, 3.5:1, 4:1, 4.5:1 or 5:1.

[0098] In one example, in step S10, the first organic solvent includes one or more of chain alkanes, cyclic alkanes, halogenated alkanes and aromatic compounds.

[0099] Further, the first organic solvent includes one or more of xylene, chlorobenzene, phenylcyclohexane and methyl benzoate.

[0100] In one example, the mass-to-volume ratio of the quantum rod bodies and the first organic solvent in step S10 is (40-60) mg:(1-5) mL. For example, the mass-to-volume ratio of the quantum rod bodies and the first organic solvent includes, but is not limited to, 40 mg:2 mL, 45 mg:2 mL, 48 mg:2 mL, 50 mg:2 mL, 52 mg:2 mL, 55 mg:2 mL, 58 mg:2 mL, 60 mg:2 mL, 40 mg:2.5 mL, 45 mg:2.5 mL, 48 mg:2.5 mL, 50 mg:2.5 mL, 52 mg:2.5 mL, 55 mg:2.5 mL, 58 mg:2.5 mL, 60 mg:2.5 mL, 40 mg:3 mL, 45 mg:3 mL, 48 mg:3 mL, 50 mg:3 mL, 52 mg:3 mL, 55 mg:3 mL, 58 mg:3 mL, or 60 mg:3 mL.

[0101] In one example, the temperature of the second heating reaction in step S20 is 150-200 °C. It is understood that the temperature of the second heating reaction in step S20 can be any value selected from the range of 150-200 °C. For example, the temperature of the second heating reaction includes, but is not limited to, 150 °C, 160 °C, 170 °C, 180 °C, 190 °C, or 200 °C. Further, the time of the second heating reaction in step S20 is 3-8 h. For example, the time of the second heating reaction includes, but is not limited to, 3 h, 4 h, 5 h, 6 h, 7 h, or 8 h.

[0102] In one example, the second organic solvent in step S20 has a boiling point higher than the temperature of the second heating reaction. The second organic solvent having a boiling point higher than the temperature of the second heating reaction is beneficial for dispersing the quantum rod precursor and the hydrophilic ligand, and provides sufficient reaction medium for the ligand exchange reaction.

[0103] In one example, the second organic solvent in step S20 includes one or more of a chain alkane, a cyclic alkane, a halogenated alkane, and an aromatic compound.

[0104] Further, the second organic solvent includes one or more of dimethylbenzene, chlorobenzene, phenylcyclohexane, and methyl benzoate.

[0105] In one example, the mass volume ratio of the quantum rod precursor and the second organic solvent in step S20 is (40-60) mg:(1-5) mL. For example, the mass volume ratio of the quantum rod precursor and the second organic solvent includes, but is not limited to, 40 mg:2 mL, 45 mg:2 mL, 48 mg:2 mL, 50 mg:2 mL, 52 mg:2 mL, 55 mg:2 mL, 58 mg:2 mL, 60 mg:2 mL, 40 mg:2.5 mL, 45 mg:2.5 mL, 48 mg:2.5 mL, 50 mg:2.5 mL, 52 mg:2.5 mL, 55 mg:2.5 mL, 58 mg:2.5 mL, 60 mg:2.5 mL, 40 mg:3 mL, 45 mg:3 mL, 48 mg:3 mL, 50 mg:3 mL, 52 mg:3 mL, 55 mg:3 mL, 58 mg:3 mL, or 60 mg:3 mL.

[0106] It is understood that the present application does not limit the source of the hydrophilic ligand and the hydrophobic ligand, and any hydrophilic ligand and hydrophobic ligand having the structure described above can be obtained.

[0107] For example, R 11 selected from a single bond, R 12 selected from a methyl group, R 13 selected from selected from R 15 selected from a methyl group, the present application further provides a method for preparing a hydrophilic ligand, comprising the following steps:

[0108] P10, mixing the aromatic compound, the brominated polyether compound, the pH regulator and the catalyst in the first dispersant to carry out a substitution reaction to prepare an aromatic polyether compound.

[0109] The aromatic compound is selected from The brominated polyether compound is selected from Each of x is independently selected from any integer from 0 to 5; y is selected from any integer from 1 to 4; and m is selected from any integer from 1 to 10. The pH regulator includes, but is not limited to, potassium carbonate. The catalyst includes, but is not limited to, potassium iodide.

[0110] The aromatic polyether compound is selected from R 13 selected from each x is independently selected from any integer between 0 and 5; y is selected from any integer between 1 and 4; m is selected from any integer between 1 and 10. In step P10, the process parameters for the substitution reaction include: a reaction temperature between 70 °C and 100 °C, and a reaction time between 16 h and 48 h. In step P10, the first dispersant includes, but is not limited to, N,N-dimethylformamide.

[0111] P20, mixing the aromatic polyether compound, a reducing agent, and a second dispersant to perform a reduction reaction to produce a reduction product.

[0112] wherein the reduction product is selected from In step P20, the process parameters for the reduction reaction include: a reaction temperature between 70 °C and 100 °C, and a reaction time between 2 h and 8 h. Further, in step P20, the reducing agent includes, but is not limited to, lithium aluminum hydride (LiAlH4). The second dispersant includes, but is not limited to, tetrahydrofuran (THF).

[0113] P30, mixing the reduction product, a pyridine compound, and thionyl chloride in a third dispersant to perform a chlorination reaction to produce a chlorination product.

[0114] In step P30, the pyridine compound includes, but is not limited to, 2,6-di-tert-butyl-4-methylpyridine (DTBMP). The third dispersant includes, but is not limited to, dichloromethane. The process parameters for the chlorination reaction include: a reaction temperature between 15 °C and 30 °C, and a reaction time between 2 h and 4 h. The chlorination product is selected from

[0115] P40, mixing the chlorination product, an ester aromatic compound, an acid-base regulator, and a reaction promoter in a fourth dispersant to perform a reaction to produce an ester aromatic polyether compound. The ester aromatic compound is selected from In step P40, the process parameters for the reaction include: a reaction temperature between 70 °C and 100 °C, and a reaction time between 16 h and 48 h. In step P40, the fourth dispersant includes, but is not limited to, N,N-dimethylformamide. The acid-base regulator includes, but is not limited to, potassium carbonate. The reaction promoter includes, but is not limited to, potassium iodide.

[0116] The ester aromatic polyether compound is selected from R 13 selected from each x is independently selected from any integer between 0 and 5; y is selected from any integer between 1 and 4; m is selected from any integer between 1 and 10.

[0117] P50, mixing the ester aromatic polyether compound, a second reducing agent, and a fifth dispersing agent to perform a second reduction reaction to produce a second reduction product. In step P50, the process parameters for performing the second reduction reaction include a reaction temperature of 70-100°C and a reaction time of 2-8 hours. Further, in step P50, the second reducing agent includes, but is not limited to, lithium aluminum hydride (LiAlH4). The fifth dispersing agent includes, but is not limited to, tetrahydrofuran (THF). The second reduction product is selected from

[0118] P60, mixing the second reduction product, a second pyridine compound, and thionyl chloride in a sixth dispersing agent to perform a second chlorination reaction to produce a second chlorination product.

[0119] In step P60, the second pyridine compound includes, but is not limited to, 2,6-di-tert-butyl-4-methylpyridine (DTBMP). The sixth dispersing agent includes, but is not limited to, dichloromethane. The process parameters for performing the second chlorination reaction include a reaction temperature of 15-30°C and a reaction time of 2-4 hours. The second chlorination product is selected from

[0120] P70, mixing the second chlorination product and sodium azide in a seventh dispersing agent to produce an azido compound.

[0121] The seventh dispersing agent includes, but is not limited to, N,N-dimethylformamide. The process parameters for producing the azido compound include a reaction temperature of 60-80°C and a reaction time of 12-20 hours. The azido compound is selected from

[0122] P80, mixing the azido compound, an unsaturated phosphoric acid compound, copper sulfate pentahydrate, and sodium ascorbate in a mixed dispersing agent to perform a cyclization reaction to produce a hydrophilic ligand.

[0123] In step P80, the unsaturated phosphoric acid compound is selected from C≡C-R 14 -PO3H2. R 14 is selected from C1-C6 linear alkyl. The mixed dispersing agent includes tetrahydrofuran and water. The process parameters for performing the cyclization reaction include a reaction temperature of 65-85°C and a reaction time of 10-14 hours.

[0124] The hydrophilic ligand is selected from R 13 is selected from x is each independently selected from any integer from 0 to 5; y is selected from any integer from 1 to 4; and m is selected from any integer from 1 to 10. 14 is selected from C1-C6 linear alkyl.

[0125] In a third aspect of the present application, a film is provided, comprising the composite material according to any one of the embodiments of the first aspect of the present application, or prepared by the method according to the second aspect of the present application.

[0126] In some examples, the film has anisotropy.

[0127] In one example, the length direction of the quantum rod body is parallel to the extension direction of the film, and a plurality of the quantum rod bodies are arranged in parallel. For example, as shown in FIG. a, when the substrate surface has oleophilic properties, the quantum rod bodies of the composite material in the film tend to be arranged in parallel to the extension direction of the film, so as to ensure the contact area of the hydrophobic ligand with the oleophilic substrate and reduce the contact area of the hydrophilic ligand with the oleophilic substrate. In this case, when the film is on the hydrophobic substrate surface, the contact area of the hydrophobic ligand in the composite material with the hydrophobic substrate is greater than the contact area of the hydrophilic ligand with the hydrophobic substrate. Figure 2 In another example, the length direction of the quantum rod body intersects the extension direction of the film, and a plurality of the quantum rod bodies are arranged in parallel. For example, when the film is on the hydrophilic substrate surface, the length direction of the quantum rod body of the composite material in the film intersects the extension direction of the film, and a plurality of the quantum rod bodies are arranged in parallel, so as to increase the contact area of the hydrophilic ligand with the hydrophilic substrate. In this case, the contact area of the hydrophilic ligand with the hydrophilic substrate is greater than the contact area of the hydrophobic ligand with the hydrophilic substrate. The above examples illustrate that the film provided by the present application has anisotropy, thereby effectively improving the light source utilization rate.

[0128] The present application also provides a quantum rod ink, comprising quantum rods and an organic solvent; wherein the quantum rods are the composite material according to any one of the examples of the first aspect of the present application.

[0129] The present application also provides a method for preparing an ink, comprising the following steps:

[0130] Mixing the composite material and the organic solvent to prepare the ink.

[0131] In one example, the mass-volume ratio of the composite material and the organic solvent is (15-30) mg: 1 mL. Further, the mass-volume ratio of the composite material and the organic solvent includes, but is not limited to, 15 mg: 1 mL, 18 mg: 1 mL, 19 mg: 1 mL, 20 mg: 1 mL, 21 mg: 1 mL, 22 mg: 1 mL, 25 mg: 1 mL, 28 mg: 1 mL, or 30 mg: 1 mL. The boiling point of the organic solvent is ≥ 100°C.

[0132]

[0133] ​In one example, the organic solvent includes hexadecane and cyclohexylbenzene in a volume ratio of (6-8) : (2-4).

[0134] The application also provides a method for preparing a light-emitting layer, comprising the following steps:

[0135] R10, applying the ink on a surface of a substrate to prepare a liquid film;

[0136] R20, evaporating the organic solvent in the liquid film to prepare a light-emitting layer.

[0137] In one example, the method for applying the ink on a surface of a substrate in step R10 includes, but is not limited to, spin coating, blade coating or inkjet printing. In one example, the method for evaporating the organic solvent in the liquid film in step R20 includes, but is not limited to, drying or annealing. In one example, the method for drying includes, but is not limited to, reduced pressure or heating treatment. In one example, the process parameters for drying include a drying temperature of 30-80°C. In one example, the process parameters for annealing include an annealing temperature of 50-100°C.

[0138] The application also provides a light-emitting device, comprising:

[0139] a cathode and an anode arranged oppositely; and

[0140] a light-emitting layer arranged between the cathode and the anode, wherein the light-emitting layer comprises the composite material according to the first aspect of the application.

[0141] It can be understood that the light-emitting layer according to the application contains the composite material according to the first aspect of the application. Therefore, the light-emitting layer has a certain affinity or repulsion to the substrate. In one example, the light-emitting layer according to the application can be a composite layer comprising a substrate.

[0142] In one example, the material of the anode layer and / or the cathode layer includes one or more of a metal, a carbon material and a metal oxide. In one example, the metal includes one or more of Al, Ag, Cu, Mo, Au, Ba, Ca, Yb and Mg; the carbon material includes one or more of graphite, carbon nanotube, graphene and carbon fiber; and the metal oxide includes a doped or undoped metal oxide, and the metal oxide includes one or more of ITO, FTO, ATO, AZO, GZO, IZO, MZO and AMO.

[0143] In another example, the anode layer and / or the cathode layer is a composite electrode. Optionally, the composite electrode comprises one or more of AZO / Ag / AZO, AZO / Al / AZO, ITO / Ag / ITO, ITO / Al / ITO, ZnO / Ag / ZnO, ZnO / Al / ZnO, ZnS / Ag / ZnS, ZnS / Al / ZnS, TiO2 / Ag / TiO2, and TiO2 / Al / TiO2.

[0144] In one example, the light emitting device further comprises an electron functional layer disposed between the cathode and the light emitting layer.

[0145] In one example, the electron functional layer comprises an inorganic material. The inorganic material is selected from one or more of doped or undoped zinc oxide, barium oxide, aluminum oxide, nickel oxide, titanium oxide, tin oxide, tantalum oxide, zirconium oxide, nickel oxide, lithium titanium oxide, zinc aluminum oxide, zinc manganese oxide, zinc tin oxide, zinc lithium oxide, indium tin oxide, cadmium sulfide, zinc sulfide, molybdenum sulfide, tungsten sulfide, copper sulfide, zinc stannate, indium phosphide, gallium phosphide, copper indium sulfide, copper gallium sulfide, barium titanate, and the doping element comprises one or more of aluminum, magnesium, lithium, manganese, yttrium, lanthanum, copper, nickel, zirconium, cerium, gadolinium.

[0146] In one example, the light emitting device further comprises a hole functional layer disposed between the anode and the light emitting layer.

[0147] Optionally, the hole functional layer comprises a hole injection layer and / or a hole transport layer.

[0148] The material of the hole transport layer and / or the hole injection layer comprises one or more of TFB, CuPc, PVK, Poly-TPD, PFB, DNTPD, TCATA, TCCA, CBP, TPD, NPB, NPD, PEDOT:PSS, TAPC, MCC, F4-TCNQ, HATCN, 4,4',4'-tris(N-3-methylphenyl-N phenylamino)triphenylamine, polyaniline, transition metal oxide, transition metal sulfide, transition metal stannate, doped graphene, undoped graphene, and C60.

[0149] The present application also provides an electronic device comprising the composite material as described above, or the composite material prepared by the method as described above, or the film as described above. The electronic device can be any electronic product with display function, such as a smartphone, a tablet personal computer, a mobile phone, a video phone, an e-book reader, a laptop PC, a netbook computer, a workstation, a server, a personal digital assistant, a portable multimedia player, an MP3 player, a mobile medical machine, a camera, a game machine, a digital camera, a car navigation device, an electronic billboard, an automatic teller machine, a smart bracelet, a smart watch, a virtual reality (VR) device, or a wearable device.

[0150] The following are specific examples. Unless otherwise specified, the raw materials used in the examples are commercially available.

[0151] Preparation Example 1

[0152] Preparation Example 1 provides a hydrophilic ligand L2 and a method for preparing the same, wherein the structure of the hydrophilic ligand L2 is:

[0153]

[0154] The specific preparation steps include:

[0155] (1) 1-bromo-2-(2-methoxyethoxy)ethane (2.196 g, 12.0 mmol), 3,4,5-trihydroxybenzoic acid methyl ester (0.736 g, 4.0 mmol), K2CO3(2.208 g, 16 mmol), KI (0.100 g, 0.60 mmol) and 100 mL of DMF were added to a reaction bottle, stirred and heated to 80°C for 20 h. After the reaction was completed, the mixture was cooled to room temperature, diluted with 300 mL of chloroform, washed with 100 mL of water twice and 100 mL of 1M hydrochloric acid twice, respectively. The washed organic solution was dried with sodium sulfate, filtered to remove the drying agent, the solvent was removed under reduced pressure, and finally purified by silica gel column chromatography with n-hexane / ethyl acetate as the eluent. After drying, white solid M1 (1.47 g, 75%) was obtained.

[0156] wherein the 1H NMR spectrum of M1 is as follows: 1H NMR (CDC13) δ 7.23 (s, 2H), 4.22 (t, 6H), 3.85 (s, 3H), 3.77 (t, 6H), 3.50-3.60 (m, 12H), 3.40 (s, 9H).

[0157]

[0158] (2) LiAlH4(0.425 g, 11.2 mmol) and 100 mL THF were mixed in a flask under nitrogen protection and cooled to 0 °C, and M1 (1.372 g, 2.8 mmol) was slowly added thereto. After the addition was completed, the reaction mixture was warmed to 70 °C and reacted for 4 h. The reaction completed mixture was concentrated under reduced pressure, then diluted with 100 mL chloroform, and washed with 50 mL 1M hydrochloric acid twice, respectively. The washed organic solution was dried by adding sodium sulfate, the drying agent was removed by filtration, the solvent was removed under reduced pressure, and a white solid M2 (1.07 g, 83%) was obtained after drying.

[0159] wherein the 1H NMR spectrum of M2 is as follows: 1H NMR (CDC13) δ 6.67 (s, 2H), 5.14 (t, 1H), 4.65 (d, 2H), 4.20 (t, 6H), 3.72 (t, 6H), 3.50-3.60 (m, 12H), 3.40 (s, 9H).

[0160]

[0161] (3) M2 (0.970 g, 2.1 mmol) was dissolved in 100 mL dichloromethane in a flask under nitrogen protection, and 2,6-di-tert-butyl-4-methylpyridine (1.291 g, 6.3 mmol) and thionyl chloride (0.46 mL, 6.3 mmol) were sequentially added after cooling to 0 °C. The reaction mixture was warmed to room temperature and reacted for 3 h, then diluted with 300 mL chloroform, and washed with 100 mL 1M hydrochloric acid twice, respectively. The washed organic solution was dried by adding sodium sulfate, the drying agent was removed by filtration, the solvent was removed under reduced pressure, and a yellow solid M3 (0.90 g, 89%) was obtained after drying.

[0162] wherein the 1H NMR spectrum of M3 is as follows: 1H NMR (CDC13) δ 6.63 (s, 2H), 4.62 (d, 2H), 4.20 (t, 6H), 3.70 (t, 6H), 3.45-3.55 (m, 12H), 3.35 (s, 9H).

[0163]

[0164] (4) Into a reaction flask was added M3 (0.792 g, 1.65 mmol), 3,4,5-trihydroxybenzoic acid methyl ester (0.101 g, 0.55 mmol), K2CO3 (0.304 g, 2.2 mmol), KI (0.0014 g, 0.08 mmol) and 25 mL of DMF, stirred and heated to 80 °C for 20 h. After the reaction was completed, the mixture was cooled to room temperature, diluted with 300 mL of chloroform, and washed with 100 mL of water twice and 100 mL of 1 M hydrochloric acid twice, respectively. The washed organic solution was dried by adding sodium sulfate, the drying agent was removed by filtration, the solvent was removed under reduced pressure, and finally purified by silica gel column chromatography using n-hexane / ethyl acetate as the eluent, and dried to obtain white solid M4 (0.60 g, 72%).

[0165] wherein the 1H NMR spectrum of M4 is as follows: 1H NMR (CDCI3) δ 7.12 (s, 2H), 6.65 (s, 6H), 5.13 (s, 6H), 4.23 (t, 18H), 3.81 (s, 3H), 3.75 (t, 18H), 3.50-3.60 (m, 36H), 3.38 (s, 27H).

[0166]

[0167] (5) LiAlH4 (0.054 g, 1.44 mmol) and 25 mL of THF were mixed in a three-necked flask under nitrogen protection and cooled to 0 °C, and M4 (0.546 g, 0.36 mmol) was slowly added thereto. After the addition was completed, the reaction mixture was warmed to 70 °C for 4 h. The reaction completed mixture was concentrated under reduced pressure, then diluted with 100 mL of chloroform, and washed with 50 mL of 1 M hydrochloric acid twice, respectively. The washed organic solution was dried by adding sodium sulfate, the drying agent was removed by filtration, the solvent was removed under reduced pressure, and dried to obtain white solid M5 (0.47 g, 88%).

[0168] wherein the 1H NMR spectrum of M5 is as follows: 1H NMR (CDCI3) δ 6.72 (s, 2H), 6.63 (s, 6H), 5.20 (t, 1H), 5.12 (s, 6H), 4.60 (d, 2H), 4.19 (t, 18H), 3.74 (t, 18H), 3.47-3.58 (m, 36H), 3.34 (s, 27H).

[0169]

[0170] (6) In a nitrogen-protected three-necked flask, M5 (0.447 g, 0.30 mmol) was dissolved in 20 mL of dichloromethane. After cooling to 0 °C, 2,6-di-tert-butyl-4-methylpyridine (0.185 g, 0.90 mmol) and thionyl chloride (0.065 mL, 0.90 mmol) were added sequentially. The reaction mixture was heated to room temperature and reacted for 3 h. Then, it was diluted with 300 mL of chloroform and washed twice with 100 mL of 1 M hydrochloric acid. Sodium sulfate was added to the washed organic solution for drying. The drying agent was removed by filtration, and the solvent was removed under reduced pressure. After drying, a yellow solid M6 (0.41 g, 91%) was obtained.

[0171] The 1H NMR spectrum of M6 is as follows: 1H NMR (CDCl3) δ 6.75 (s, 2H), 6.61 (s, 6H), 5.14 (s, 6H), 4.62 (d, 2H), 4.22 (t, 18H), 3.68 (t, 18H), 3.45-3.55 (m, 36H), 3.40 (s, 27H).

[0172]

[0173] (7) M6 (0.377 g, 0.25 mmol) and NaN3 (0.049 g, 0.75 mmol) were dissolved in 15 mL of DMF and heated to 70 °C for 16 h. After the reaction was complete, the mixture was cooled to room temperature, diluted with 30 mL of chloroform, and washed twice with 20 mL of water. Sodium sulfate was added to the washed organic solution for drying, the drying agent was removed by filtration, the solution was concentrated under reduced pressure, and finally precipitated in methanol in an ice bath to obtain a yellow solid M7 (0.34 g, 90%).

[0174] The 1H NMR spectrum of M7 is as follows: 1H NMR (CDCl3) δ 6.63 (s, 6H), 6.50 (s, 2H), 5.11 (s, 6H), 4.18 (t, 18H), 3.71 (t, 18H), 3.46–3.60 (m, 36H), 3.30 (s, 27H), 2.64 (s, 2H).

[0175]

[0176] (8) In a nitrogen-protected three-necked flask, M7 (0.303 g, 0.20 mmol), 5-hexynyl phosphate (0.036 g, 0.22 mmol), copper sulfate pentahydrate (5 mg, 0.02 mmol), and sodium vitamin C (4 mg, 0.02 mmol) were mixed with 2 mL THF and 0.4 mL water, stirred, and heated to 75 °C for 12 h. After the reaction mixture was cooled to room temperature, it was diluted with 20 mL chloroform and washed three times with 1 M hydrochloric acid. Sodium sulfate was added to the washed organic solution for drying, the drying agent was removed by filtration, the solution was concentrated under reduced pressure, and finally, a white solid L2 (0.19 g, 57%) was precipitated in methanol in an ice bath.

[0177] The 1H NMR spectrum of L2 is as follows: 1H NMR (CDCl3) δ 7.73 (s, 1H), 6.66 (s, 6H), 6.54 (s, 2H), 5.51 (s, 2H), 5.17 (s, 6H), 4.80 (s, 2H), 4.25 (t, 18H), 3.76 (t, 18H), 3.50-3.60 (m, 36H), 3.36 (s, 27H), 2.45 (t, 2H), 1.60 (m, 4H), 1.25 (m, 2H).

[0178]

[0179] Example 1

[0180] Example 1 provides a quantum rod and its preparation method, including the following steps:

[0181] Preparation of the quantum rod body: (1) CdO (135 mg), octadecyl phosphate HDPA (648 mg) and tri-n-octylphosphine oxide TOPO (5.0 g) were dried by vacuum stirring at 150 °C for 1 h, and then heated to 380 °C under argon protection and stirred until CdO was completely dissolved. The temperature was lowered to 350 °C and 2 mL of a tri-n-octylphosphine TOP preparative solution of Se (110 mg) was quickly added, and the mixture was stirred at 350 °C for 5 min. The reaction mixture was then rapidly cooled to room temperature, 10 mL of toluene was added, and the mixture was poured into a large amount of methanol for precipitation. After centrifugation, the supernatant was removed, and the precipitate was dissolved in 15 mL of toluene. The insoluble matter was removed by centrifugation. The toluene solution was concentrated to 10 mL and poured into a large amount of methanol for precipitation again. After centrifugation, the supernatant was removed, and the precipitate was dried under nitrogen purging to obtain CdSe rod-shaped nanocrystal nuclei (85 mg).

[0182] (2) The above-mentioned CdSe rod-shaped nanocrystals (50 mg) and sulfur (60 mg) were dissolved in pre-ventilated TOP (1.5 g). In another reaction flask, CdO (90 mg), HDPA (265 mg), n-hexyl phosphate HPA (80 mg), and TOPO (3.0 g) were dried under vacuum at 150 °C for 1 h, and then heated to 370 °C under argon protection and stirred until CdO was completely dissolved. While maintaining the temperature at 370 °C, 1 mL of TOP and the above-prepared TOP solution of CdSe and S were quickly added, and the reaction was continued to be stirred for 8 min. The reaction mixture was then rapidly cooled to room temperature, 10 mL of toluene was added, and the mixture was poured into a large amount of ethanol for precipitation. After centrifugation, the supernatant was removed, and the precipitate was dissolved in 15 mL of toluene. The insoluble matter was removed by centrifugation. The toluene solution was concentrated to 10 mL and poured into a large amount of ethanol for precipitation again. After centrifugation, the supernatant was removed, and the precipitate was dried under nitrogen purging to obtain the quantum rod body (80 mg). The quantum rod body includes a CdSe rod-shaped nanocrystal core and a CdS shell. The quantum rod body includes a central section and a first end and a second end respectively disposed at both ends of the central section. The first end and the second end each have an arc-shaped segment that aligns with the central section. The length of the quantum rod body is 20 nm, the cross-sectional diameter of the central section is 4 nm, the ratio of the length of the quantum rod body to the cross-sectional diameter of the central section is 5:1, and the ratio of the length of the central section, the length of the first end, and the length of the second end is approximately 15:1:1.

[0183] Preparation of the quantum rod precursor: 50 mg of quantum rod host material and 20 mg of hexadecyl phosphate were dissolved in 2.5 mL of 1,2-dichlorobenzene and heated to 180 °C for 8 h. After cooling, the mixture was poured into a large amount of ethanol for precipitation. After centrifugation, the supernatant was removed, and the precipitate was dissolved in 10 mL of toluene and poured into a large amount of ethanol for further precipitation. After centrifugation, the supernatant was removed, and the precipitate was dried under nitrogen purging to obtain the quantum rod precursor (50 mg). In the quantum rod precursor, the hexadecyl phosphate ligand was modified in the middle part and the arc segment of the quantum rod host.

[0184] Preparation of quantum rods: A quantum rod precursor (40 mg) and a hydrophilic ligand L2 (20 mg) were dissolved in 2.5 mL of 1,2-dichlorobenzene and heated to 160 °C for 8 h. After cooling, the mixture was poured into a large volume of ethanol for precipitation. After centrifugation, the supernatant was removed, and the precipitate was dissolved in 10 mL of toluene and poured into a large volume of ethanol for further precipitation. After centrifugation, the supernatant was removed, and the precipitate was dried under nitrogen purging to obtain quantum rods (40 mg). The central portion of the quantum rod body was modified with a hexadecyl phosphate ligand, and the arc segments of the quantum rod body were modified with the hydrophilic ligand L2.

[0185] Comparative Example 1

[0186] Preparation of CdSe / CdS quantum dots modified with oleic acid ligands: (1) First, TOPO (15 mL) was vacuum dried at 180 °C for 1 h, and then cooled to 120 °C. Under argon protection, 2 mL of a TOP preparative solution containing 160 mg of Se was added. After heating to 300 °C, 2.5 mL of a TOP preparative solution containing 115 mg of Cd(OAc)₂ was rapidly added with rapid stirring. The reaction was then continued at 260 °C for 1 h to form CdSe nanocrystals.

[0187] (2) In another reaction flask, 1-octadecene ODE (2 mL), oleic acid (0.5 mL), and Cd(OAc)₂ (115 mg) were mixed and dried under vacuum at 150 °C for 10 min. Then, under nitrogen protection, the above-mentioned ODE pre-dispersion of CdSe nanocrystals (1 mL) was added. The mixture was heated to 260 °C, and a sulfur (16 mg) ODE solution (3 mL) was slowly added dropwise. After the addition was complete, the reaction was continued for 1 h. Subsequently, the reaction mixture was rapidly cooled to room temperature, 10 mL of toluene was added, and the mixture was poured into a large amount of methanol for precipitation. After centrifugation, the supernatant was removed, and the precipitate was dissolved in 15 mL of toluene. The insoluble matter was removed by centrifugation. The toluene solution was concentrated to 10 mL and poured into a large amount of ethanol for precipitation again. After centrifugation, the supernatant was removed, and the precipitate was dried under nitrogen purging to obtain oleic acid ligand-modified CdSe / CdS quantum dots (120 mg). Among them, the nanometer diameter of CdSe / CdS quantum dots modified with oleic acid ligands is about 10 nm.

[0188] Comparative Example 2

[0189] Comparative Example 2 is basically the same as Example 1, except that Comparative Example 2 uses the quantum rod precursor prepared in Example 1.

[0190] Test case

[0191] (1) Preparation of ink: The materials of the above examples and comparative examples were dispersed in a mixed solvent of hexadecane and cyclohexylbenzene (volume ratio 7:3) to form a dispersion of 20 mg / mL, and ink was prepared.

[0192] (2) Preparation of hydrophilic substrate: The glass substrate was ultrasonically cleaned in acetone, isopropanol and deionized water for 10 min in sequence, then dried with high-purity nitrogen and baked at 150℃ for 30 min, and then treated in an ultraviolet ozone cleaner for 15 min.

[0193] (3) Preparation of the oleophilic substrate: The glass substrate was ultrasonically cleaned in acetone solution for 3 min, then acid-washed in Piranha solution (volume ratio of concentrated sulfuric acid:hydrogen peroxide = 3:7) at 80°C for 30 min. After rinsing with distilled water, it was transferred to RCA standard cleaning solution (volume ratio of concentrated ammonia:hydrogen peroxide = 1:1) and cleaned at 65°C for 5 min. After cleaning, the glass substrate was rinsed with deionized water and then dried with high-purity nitrogen to obtain a clean and hydroxylated glass substrate. The above glass substrate was immersed in 0.005 mol / L octadecyltrichlorosilane OTS bicyclohexane solution for 1 h, then removed and cured in an oven at 120°C for 1.5 h. It was then rinsed sequentially with large amounts of toluene, ethanol, and distilled water, and dried with high-purity nitrogen to obtain the oleophilic substrate.

[0194] (3) Spin-coating the ink onto either a hydrophilic or oleophilic substrate to form a liquid film. After allowing the liquid film to stand for 15 minutes, it was dried under vacuum and then annealed by baking at 120°C for 10 minutes to obtain an optical thin film. The thicknesses of the optical thin films prepared on the hydrophilic and oleophilic substrates in the examples and comparative examples are shown in Table 1.

[0195] Table 1

[0196]

[0197] The angle-dependent photoluminescence (PL) spectra of the optical thin film samples prepared in the above embodiments and comparative examples were tested respectively. In each case, a 385 nm excitation light was held at a 45° angle to the sample substrate, and the excitation light was directed onto the optical thin film sample. The spectrometer received the emission spectra at specific angles θ perpendicular to the substrate. Figure 4 As shown in Table 2, 101 is the optical thin film sample, 102 is the sample substrate, 103 is the rotatable sample stage, 104 is the excitation light source, and 105 is the spectrometer. For each sample, the peak emission intensity at different θ angles was compared, and normalized to the peak emission intensity measured at θ = 0°.

[0198] Table 2

[0199]

[0200] Table 2 shows that the angle-dependent PL spectral intensity data reveal significant differences in the optical films formed on hydrophilic and oleophilic substrates using the quantum rod material of Example 1. Specifically, the film on the hydrophilic substrate exhibits higher emission intensity at 80°, indicating that the quantum rods are stacked perpendicular to the substrate, thus forming a dipole moment perpendicular to the substrate and emitted light parallel to the substrate. Conversely, the film on the oleophilic substrate shows higher emission intensity at 0°, indicating that the quantum rods are stacked parallel to the substrate, thus forming a dipole moment parallel to the substrate and emitted light perpendicular to the substrate. These data demonstrate that the quantum rod material of this example possesses controllable self-assembly capabilities induced by substrate characteristics.

[0201] The optical thin films formed on hydrophilic or oleophilic substrates by the materials of Comparative Example 1 and Comparative Example 2 showed no significant difference, indicating that they do not possess controllable self-assembly properties. Specifically, the thin film of Comparative Example 1 exhibited higher emission intensity at 60°. This is because the quantum dot material of Comparative Example 1 is a completely isotropic material, with its dipole moments evenly distributed in all directions. The superposition effect resulted in the most concentrated emission at θ = 67°. However, due to the influence of the refractive indices of the thin film, substrate, and sample stage, the measured emission light at θ = 60° was stronger. The thin film of Comparative Example 2 also showed high emission intensity at 60°, but with low angle dependence. This is because the quantum rod material of Comparative Example 2 exhibited a certain degree of tendency to align parallel to the substrate. This tendency is not affected by the properties of the substrate, which is significantly different from the controllable self-assembly capability shown in Example 1.

[0202] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0203] The embodiments described above are merely illustrative of several implementation methods of this application, intended to facilitate a detailed understanding of the technical solutions of this application, but should not be construed as limiting the scope of protection of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the scope of protection of this application. It should be understood that technical solutions obtained by those skilled in the art based on the technical solutions provided in this application through logical analysis, reasoning, or limited experimentation are all within the scope of protection of the appended claims. Therefore, the scope of protection of this patent application should be determined by the content of the appended claims, and the specification can be used to interpret the content of the claims.

Claims

1. A composite material, characterized in that, include: Quantum rod body; A hydrophobic ligand is attached to the surface of the quantum rod body; A hydrophilic ligand is attached to the surface of the quantum rod body.

2. The composite material according to claim 1, characterized in that, The quantum rod body includes a middle portion and first end portions and second end portions respectively disposed at both ends of the middle portion. The first end portions and second end portions each have an arc-shaped segment that abuts against the middle portion. The composite material has one or more of the following characteristics: (1) The hydrophobic ligand is connected to the middle part of the quantum rod body; (2) The hydrophilic ligand is connected to the arc segment of the quantum rod body.

3. The composite material according to claim 1 or 2, characterized in that, The hydrophobic ligand comprises a nonpolar hydrophobic segment and a first polar group located at the end of the nonpolar hydrophobic segment; The hydrophilic ligand comprises a hydrophilic segment and a second polar group located at the end of the hydrophilic segment; The first polar group and the second polar group are each independently selected from metal coordinating groups.

4. The composite material according to claim 3, characterized in that, The metal coordinating group includes one or more of carboxyl, mercapto, phosphonic acid, and amino groups; and / or The nonpolar hydrophobic segments are selected from C. 10 ~C 20 straight-chain alkyl, C 10 ~C 20 Branched alkyl, C 10 ~C 20 Cycloalkyl, C 10 ~C 20 Straight-chain alkenyl, C 10 ~C 20 Branched alkenyl and C 10 ~C 20 One or more of the cyclic alkenyl groups.

5. The composite material according to claim 3, characterized in that, The hydrophobic ligand comprises one or more compounds having the structure of formula (I): Where n is selected from any integer from 9 to 19.

6. The composite material according to claim 3, characterized in that, The hydrophilic ligand comprises one or more compounds having the structure of formula (II): in, The hydrophilic segment; R1 includes an ether bond; n is any integer from 1 to 5; It is the second polar group; It is a linking group; Selected from single bonds, C1 to C 10 Straight-chain alkylene, C3-C 10 The heteroaryl group comprises a branched alkylene group, an aryl group having 6 to 12 unsubstituted or at least substituted ring atoms, and a heteroaryl group having 5 to 10 unsubstituted or at least substituted ring atoms, wherein the heteroatom in the heteroaryl group is nitrogen, oxygen or sulfur, and each occurrence of R' is independently selected from C1 to C6 straight-chain alkyl groups.

7. The composite material according to claim 6, characterized in that, The composite material has one or more of the following characteristics: (1) Each time R1 appears, it is independently selected from... Among them, R 11 and R 12 Each is independently selected from single bonds, C1-C5 straight-chain alkylene groups, or C3-C5 branched alkylene groups; R 13 Each time it appears, it is selected independently. x and z are each independently selected from any integer from 0 to 5; y is selected from any integer from 1 to 4; m is selected from any integer from 1 to 10; (2) Selected from single bonds, C1-C5 straight-chain alkylene groups, Each time X1 appears, it is independently selected from C, N, or S, and at least one X1 is N; R 14 and R 15 Each time it appears, R 14 and R 15 Each is independently selected from C1 to C5 straight-chain alkylene groups; (3) Selected from -PO3H2.

8. The composite material according to claim 6, characterized in that, The hydrophilic ligands include One or more of the following; Among them, q1, q2, q3 and q4 are each independently selected from any integer from 1 to 5.

9. The composite material according to claim 1 or 2, characterized in that, The composite material has one or more of the following characteristics: (1) The quantum rod body is a single-structure quantum rod or a core-shell structure quantum rod; optionally, the material of the single-structure quantum rod, the core material of the core-shell structure quantum rod, and the shell material of the core-shell structure quantum rod are selected from one or more of group II-VI compounds, group IV-VI compounds, group III-V compounds, group I-III-VI compounds, and perovskite nanoparticle materials, wherein group II-VI compounds include CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, and ZnS. One or more of the following compounds: Te, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, and HgZnSTe; and group IV-VI compounds including SnS, SnSe, SnTe, PbS, PbSe, PbTe, SnSeS, SnSeTe, SnSTe, PbSeS, and PbS. One or more of eTe, PbSTe, SnPbS, SnPbSe, SnPbTe, SnPbSSe, SnPbSeTe, and SnPbSTe, and III-V compounds including GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InNP, InNAs, InNSb, InPAs, InPSb, GaAlNP, GaAlNAs, Ga One or more of AlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, and InAlPSb are used, and Group I-III-VI compounds include one or more of CuInS2, CuInSe2, and AgInS2 are used; the perovskite nanoparticle material is one or more of inorganic perovskite quantum dots, organic perovskite quantum dots, and organic-inorganic hybrid perovskite quantum dots, wherein the general structural formula of the inorganic perovskite quantum dots is AMX3, where A is Cs. + Ion, M is a divalent metal cation, M is selected from Pb 2+ Sn 2+ Cu 2+ Ni 2 + Cd 2+ Cr 2+ Mn 2+ Co 2+ Fe 2+ 、Ge 2+ Yb 2+ and Eu 2+ One or more of the following, where X is a halide anion; the general structural formula of the organic perovskite quantum dots is CMX3, where C is formamidinyl; the general structural formula of the organic-inorganic hybrid perovskite quantum dots is BMX3, where B is selected from organic amine cations; (2) The length of the quantum rod body is 20nm to 200nm; (3) The cross-sectional diameter of the middle part of the quantum rod body is 4nm to 20nm; (4) The ratio of the length of the quantum rod body to the cross-sectional diameter of the middle part of the quantum rod body is (5~10):1; (5) The mass ratio of the quantum rod body to the hydrophobic ligand is (0.5-5):1; (6) The mass ratio of the quantum rod body to the hydrophilic ligand is (0.5-5):1; (7) The ratio of the length of the middle part of the quantum rod body to the length of the first end of the quantum rod body is (8~20):1; (8) The ratio of the length of the middle part of the quantum rod body to the length of the second end of the quantum rod body is (8~20):

1.

10. A method for preparing a composite material, characterized in that, Includes the following steps: The quantum rod bulk and hydrophobic ligand are mixed in a first organic solvent and subjected to a first heating reaction to obtain a quantum rod precursor. The quantum rod precursor and the hydrophilic ligand are mixed in a second organic solvent and subjected to a second heating reaction to obtain the composite material.

11. The method for preparing the composite material according to claim 10, characterized in that, The quantum rod body includes a middle portion and a first end portion and a second end portion respectively disposed at both ends of the middle portion, wherein the first end portion and the second end portion each have an arc surface segment that abuts against both ends of the middle portion; the preparation method has one or more of the following characteristics: (1) The mass ratio of the quantum rod body and the hydrophobic ligand is (0.5-5):1; (2) The mass ratio of the quantum rod precursor to the hydrophilic ligand is (1-5):1; (3) The boiling point of the second organic solvent is higher than the temperature of the second heating reaction; (4) In the quantum rod precursor, the hydrophobic ligand is modified in the middle part and the arc section of the quantum rod body; (5) The temperature of the first heating reaction is 170℃~190℃, and the time of the first heating reaction is 3h~8h; (6) The temperature of the second heating reaction is 150℃~200℃, and the time of the first heating reaction is 3h~8h; (7) The first organic solvent includes one or more of chain alkanes, cycloalkanes, haloalkanes and aromatic compounds; optionally, the first organic solvent includes one or more of xylene, chlorobenzene, phenylcyclohexane and methyl benzoate; (8) The second organic solvent includes one or more of chain alkanes, cycloalkanes, haloalkanes and aromatic compounds; optionally, the second organic solvent includes one or more of xylene, chlorobenzene, phenylcyclohexane and methyl benzoate; (9) In the composite material, the hydrophobic ligand is connected to the middle part of the quantum rod body; the hydrophilic ligand is connected to the arc segment of the quantum rod body.

12. A thin film, characterized in that, The film includes the composite material according to any one of claims 1 to 9, or the composite material prepared by the preparation method according to claim 10 or 11; the film has one or more of the following characteristics: (1) The film is anisotropic; (2) The length direction of the quantum rod body is parallel to the extension direction of the thin film, and multiple quantum rod bodies are arranged in parallel; (3) The length direction of the quantum rod body intersects with the extension direction of the thin film, and multiple quantum rod bodies are arranged in parallel.

13. An electronic device, characterized in that, It includes the composite material according to any one of claims 1 to 9, or the composite material prepared by the preparation method according to claim 10 or 11, or the film according to claim 12.

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