Semiconductor composite nanomaterial and its preparation method and use

Abstract

The present invention relates to a semiconductor composite nanomaterial, its preparation method, and use. The semiconductor composite nanomaterial comprises CdSe / CdS nanorods and nanoparticles grown on both ends of the CdSe / CdS nanorods; the nanoparticles comprise a core-shell structure; the core-shell structure comprises a nanogold core and a cobalt layer coating the outer surface of the nanogold core. The preparation method comprises mixing a CdSe / CdS nanorod solution with a gold precursor solution, performing a first reaction, then adding a cobalt source and performing a second reaction to obtain the semiconductor composite nanomaterial. The semiconductor composite nanomaterial provided by the present invention combines a fluorescent material with magnetic nanoparticles, can emit strong circularly polarized light under an external magnetic field, and has a simple preparation method and broad application prospects.

Description

Technical Field

[0001] The present invention relates to the technical field of composite nanomaterials, and in particular to a semiconductor composite nanomaterial and a preparation method and application thereof. Background Art

[0002] Circularly polarized luminescent materials, due to their unique chiral fluorescence properties, offer enormous application prospects and are a current research hotspot in the field of chiral materials. Circularly polarized luminescent materials have extremely important applications in quantum optical computing, information storage, three-dimensional displays, bio-encoded imaging, and spintronic devices. Currently, many chiral materials exhibit circularly polarized luminescence, including chiral organic molecules, chiral lanthanide complexes, chiral polymers, chiral perovskites, and chiral metal clusters.

[0003] Compared with chiral luminescent materials, non-chiral materials with magnetic effects can also induce chiral optical properties and can be used in spintronic devices to obtain spin-polarized current and circularly polarized light.

[0004] CN113178539A discloses an organic electro-induced circularly polarized light-emitting device based on an achiral polymer, comprising an anode, a hole injection layer, a light-emitting layer, an electron transport layer, an electron injection layer and a cathode stacked in sequence, wherein the material of the light-emitting layer is poly(9,9-dihexylfluorene-co-benzothiadiazole) induced by circularly polarized light.

[0005] CN111410953A discloses a circularly polarized luminescent supramolecular gel and a method for preparing the same. The method involves mixing a C2-symmetric chiral gelator and an achiral fluorescent molecule, adding the mixture to a solvent, heating until completely dissolved, and allowing the mixture to cool to room temperature to form a uniform circularly polarized luminescent supramolecular gel. These supramolecular gels exhibit a full spectrum of circularly polarized luminescence, from blue, green, yellow, to red, and possess a large g-factor. Furthermore, by co-assembling three achiral aromatic molecules and the chiral gelator, a circularly polarized luminescent supramolecular gel capable of emitting white light can be obtained.

[0006] However, the circularly polarized luminescence properties of achiral magnetic luminescent materials remain largely unstudied. When doped with paramagnetic substances, achiral luminescent materials can emit circularly polarized light in an external magnetic field, but are often limited by shortcomings such as difficulty in material preparation and insufficient magnetic response. Composite nanomaterials, obtained by combining strongly fluorescent semiconductor nanocrystals with magnetic nanoparticles through an interface, can endow semiconductor nanocrystals with unique magneto-optical properties, potentially enabling strong magnetic-responsive circularly polarized luminescence. However, the large lattice mismatch between different materials is not conducive to heterogeneous growth, and the electron transfer process can easily lead to fluorescence quenching.

[0007] Therefore, providing a semiconductor composite nanomaterial that combines semiconductor nanomaterials with fluorescent properties and magnetic nanoparticles and a preparation method thereof has important research value and application value. Summary of the Invention

[0008] To address the above issues, the present invention aims to provide a semiconductor composite nanomaterial, its preparation method, and its use. Compared with existing technologies, the semiconductor composite nanomaterial provided by the present invention has a heterogeneous structure, combining fluorescent and superparamagnetic properties. It can amplify the chiral luminescence properties of CdSe / CdS nanorods and emit strong circularly polarized light under an external magnetic field. The preparation method provided by the present invention is simple to operate and has broad application prospects.

[0009] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0010] In a first aspect, the present invention provides a semiconductor composite nanomaterial, which includes CdSe / CdS nanorods and nanoparticles grown on both ends of the CdSe / CdS nanorods; the nanoparticles include a core-shell structure; the core-shell structure includes a nanogold core and a cobalt layer coated on the outer surface of the nanogold core.

[0011] The semiconductor composite nanomaterial provided by the present invention uses CdSe / CdS nanorods as the luminescent material. The CdSe / CdS nanorods are a core-shell structure semiconductor nanomaterial in which CdSe quantum dots are coated by CdS nanorods, and the fluorescence wavelength thereof mainly depends on the diameter of the CdSe core. Furthermore, the present invention designs nanoparticles with a core-shell structure to be loaded on both ends of the CdSe / CdS nanorods: first, a nanogold core is designed to be selectively grown on both ends of the CdSe / CdS nanorods, and then a cobalt layer is designed to be grown on the outside of the nanogold core to obtain magnetic core-shell structure nanoparticles, thereby forming the semiconductor composite nanomaterial. The semiconductor composite nanomaterial provided by the present invention can amplify the chiral luminescence properties of the CdSe / CdS nanorods through the interaction between the fluorescent CdSe / CdS nanorods and the magnetic nanoparticles, and can emit strong circularly polarized light under an external magnetic field.

[0012] Preferably, the length of the CdSe / CdS nanorods is 20-150 nm, for example, it can be 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 110 nm, 120 nm, 130 nm, 140 nm or 150 nm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0013] The present invention preferably controls the length of the CdSe / CdS nanorods within a specific range, which can enhance the circularly polarized luminescence intensity and magnetism of the obtained semiconductor composite nanomaterial.

[0014] Preferably, the average particle size of the gold nanoparticle core is 2-5 nm, for example, 2 nm, 2.5 nm, 3 nm, 4 nm or 5 nm, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0015] The present invention preferably controls the average particle size of the nano-gold core within a specific range, which is more conducive to the growth of the cobalt layer on the nano-gold core, thereby improving the circularly polarized luminescence intensity of the semiconductor composite nanomaterial.

[0016] Preferably, the average particle size of the nanoparticles is 8-12 nm, for example, 8 nm, 9 nm, 10 nm, 11 nm or 12 nm, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0017] The present invention preferably controls the average particle size of the nanoparticles within a specific range, and can regulate the relative sizes of the nanoparticles containing the cobalt layer and the CdSe / CdS nanorods, thereby the two cooperate to enhance the circularly polarized luminescence intensity of the semiconductor composite nanomaterial.

[0018] In a second aspect, the present invention provides a method for preparing the semiconductor composite nanomaterial according to the first aspect of the present invention, the preparation method comprising the following steps:

[0019] (1) mixing a CdSe / CdS nanorod solution and a gold precursor solution to perform a first reaction to obtain a nanorod-gold composite material;

[0020] (2) Mixing the nanorod-gold composite material obtained in step (1) with a cobalt source, and performing a second reaction to obtain the semiconductor composite nanomaterial.

[0021] The method for preparing a semiconductor composite nanomaterial provided by the present invention involves subjecting a CdSe / CdS nanorod solution and a gold precursor solution to a first reaction, whereby a nanogold core selectively grows on both ends of the CdSe / CdS nanorod, thereby obtaining a nanorod-gold composite material. The nanorod-gold composite material is then mixed with a cobalt source and subjected to a second reaction, whereby a cobalt layer grows on the outer surface of the nanogold core, thereby obtaining the semiconductor composite nanomaterial. The preparation method provided by the present invention can combine a fluorescent material with magnetic nanoparticles to obtain a semiconductor composite nanomaterial having both fluorescent and superparamagnetic properties, capable of emitting strong circularly polarized light under an external magnetic field.

[0022] Preferably, the preparation of the CdSe / CdS nanorod solution in step (1) comprises: mixing CdSe / CdS nanorods and a first solvent to obtain the CdSe / CdS nanorod solution.

[0023] Preferably, the first solvent includes any one of toluene, dodecane, xylene or 1,4-dioxane, or a combination of at least two thereof, for example, a combination of toluene and dodecane or a combination of dodecane and xylene.

[0024] Preferably, the preparation of the gold precursor solution in step (1) comprises: mixing a gold source, a first surfactant and a reducing agent in a first solvent to obtain the gold precursor solution.

[0025] Preferably, the gold source includes any one of gold trichloride, chloroauric acid or goldous chloride, or a combination of at least two thereof, for example, a combination of gold trichloride and chloroauric acid or a combination of chloroauric acid and goldous chloride, preferably gold trichloride.

[0026] Preferably, the first surfactant includes any one of didodecyldimethylammonium bromide, dihexadecyldimethylammonium bromide, hexadecyltrimethylammonium bromide, hexadecylpyridinium chloride or hexadecylpyridinium bromide, or a combination of at least two thereof, for example, it can be a combination of didodecyldimethylammonium bromide and dihexadecyldimethylammonium bromide or a combination of dihexadecyldimethylammonium bromide and hexadecyltrimethylammonium bromide, preferably didodecyldimethylammonium bromide.

[0027] Preferably, the reducing agent includes any one of octadecylamine, hexadecylamine, laurylamine or oleylamine, or a combination of at least two thereof, for example, a combination of octadecylamine and hexadecylamine or a combination of hexadecylamine and laurylamine, preferably octadecylamine.

[0028] Preferably, the molar ratio of gold trichloride, didodecyldimethylammonium bromide and octadecylamine is 1:(2-20):(6-60), for example, it can be 1:2:6, 1:5:6, 1:8:6, 1:10:6, 1:12:6, 1:15:6, 1:18:6, 1:20:6, 1:2:10, 1:2:20, 1:2:30, 1:2:40, 1:2:50 or 1:2:60, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0029] Preferably, the molar ratio of the gold source to the CdSe / CdS nanorods is (500-2000):1, for example, it can be 500:1, 600:1, 700:1, 800:1, 900:1, 1000:1, 1200:1, 1400:1, 1600:1, 1800:1 or 2000:1, but is not limited to the listed values. Other unlisted values ​​within the numerical range are also applicable, preferably (500-1000):1.

[0030] The present invention preferably controls the molar ratio of the gold source to the CdSe / CdS nanorods within a specific range, thereby controlling the average particle size of the nano-gold core and thereby improving the circularly polarized luminescence intensity of the semiconductor composite nanomaterial.

[0031] Preferably, the temperature of the first reaction in step (1) is 40-100°C, for example, 40°C, 50°C, 60°C, 70°C, 80°C, 90°C or 100°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0032] Preferably, the time of the first reaction is 0.5-2 h, for example, 0.5 h, 0.6 h, 0.8 h, 1 h, 1.2 h, 1.4 h, 1.6 h, 1.8 h or 2 h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0033] In the present invention, after the first reaction is completed, the reaction product is precipitated, filtered, and washed to obtain the nanorod-gold composite material. The precipitant generally used for the precipitation is methanol.

[0034] Preferably, the mixing in step (2) comprises: mixing the nanorod-gold composite material and a cobalt source in a second solvent.

[0035] Preferably, the second solvent includes any one of octadecene, tetralin, diphenyl ether, n-tetracosane or trioctylamine, or a combination of at least two thereof, for example, a combination of octadecene and tetralin or a combination of tetralin and diphenyl ether.

[0036] Preferably, the second reaction is carried out under a protective atmosphere;

[0037] Preferably, the protective atmosphere comprises nitrogen and / or an inert gas.

[0038] Preferably, a second surfactant is also added to the mixing in step (2).

[0039] Preferably, the cobalt source includes any one of dicobalt octacarbonyl, cobalt acetate or cobalt chloride, or a combination of at least two thereof, for example, a combination of dicobalt octacarbonyl and cobalt acetate or a combination of cobalt acetate and cobalt chloride, preferably dicobalt octacarbonyl.

[0040] Preferably, the second surfactant includes any one of oleic acid, di-n-octylamine, n-octylamine, laurylamine or oleylamine, or a combination of at least two thereof, for example, a combination of oleic acid and di-n-octylamine or a combination of n-octylamine and laurylamine, preferably a combination of oleic acid and di-n-octylamine.

[0041] Preferably, the molar ratio of oleic acid, di-n-octylamine and dicobalt octacarbonyl is (15-150):(10-100):1, for example, 15:10:1, 20:10:1, 40:10:1, 60:10:1, 80:10:1, 100:10:1, 120:10:1, 150:10:1, 15:20:1, 15:40:1, 15:60:1, 15:80:1 or 15:100:1, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0042] Preferably, the molar ratio of the cobalt source to the nanorod-gold composite material is (10 4 -10 5 ):1, for example, it can be 1×10 4 :1, 2×10 4 :1, 4×10 4 :1, 6×10 4 :1, 8×10 4 :1 or 1×10 5 :1, but not limited to the listed values, other values ​​not listed in the numerical range are also applicable, preferably (4×10 4 -6×10 4 ):1.

[0043] The present invention preferably controls the molar ratio of the cobalt source to the nanorod-gold composite material within a specific range, thereby controlling the relative sizes of the nanoparticles and the CdSe / CdS nanorods, thereby increasing the circularly polarized luminescence intensity of the semiconductor composite nanomaterial.

[0044] Preferably, the temperature of the second reaction in step (2) is 150-220°C, for example, it can be 150°C, 160°C, 170°C, 180°C, 190°C, 200°C, 210°C or 220°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0045] Preferably, the time of the second reaction is 0.5-2 h, for example, 0.5 h, 0.8 h, 1 h, 1.2 h, 1.4 h, 1.6 h, 1.8 h or 2 h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0046] In the present invention, after the second reaction is completed, the reaction product is precipitated, filtered, and washed to obtain the semiconductor composite nanomaterial. The precipitant generally used for the precipitation is methanol.

[0047] As a preferred technical solution of the second aspect of the present invention, the preparation method comprises the following steps:

[0048] (1) mixing CdSe / CdS nanorods and a first solvent to obtain a CdSe / CdS nanorod solution;

[0049] A gold source, a first surfactant, and a reducing agent are mixed in a first solvent to obtain the gold precursor solution, wherein the gold source comprises any one or a combination of at least two of gold trichloride, chloroauric acid, or gold (II) chloride; the first surfactant comprises any one or a combination of at least two of didodecyldimethylammonium bromide, dihexadecyldimethylammonium bromide, hexadecyltrimethylammonium bromide, hexadecylpyridinium chloride, or hexadecylpyridinium bromide; the reducing agent comprises any one or a combination of at least two of octadecylamine, hexadecylamine, laurylamine, or oleylamine; and the molar ratio of the gold trichloride, didodecyldimethylammonium bromide, and octadecylamine is 1:(2-20):(6-60);

[0050] Mixing a CdSe / CdS nanorod solution and a gold precursor solution, wherein the molar ratio of the gold source to the CdSe / CdS nanorod is (500-2000):1, and performing a first reaction at 40-100° C. for 0.5-2 h to obtain a nanorod-gold composite material;

[0051] (2) mixing the nanorod-gold composite material obtained in step (1), a cobalt source, and a second surfactant in a second solvent, wherein the cobalt source comprises any one of octacarbonyl dicobalt, cobalt acetate, or cobalt chloride, or a combination of at least two thereof, and the second surfactant comprises any one of oleic acid, di-n-octylamine, n-octylamine, laurylamine, or oleylamine, or a combination of at least two thereof, and the molar ratio of oleic acid, di-n-octylamine, and octacarbonyl dicobalt is (15-150):(10-100):1; the molar ratio of the cobalt source to the nanorod-gold composite material is (10 4 -10 5 ):1, and then carry out a second reaction at 150-220° C. for 0.5-2 h to obtain the semiconductor composite nanomaterial.

[0052] In a third aspect, the present invention provides a use of the semiconductor composite nanomaterial as described in the first aspect of the present invention, wherein the semiconductor composite nanomaterial is used in the field of biological imaging, the field of electronic devices, or the field of information processing.

[0053] Compared with the prior art, the present invention has the following beneficial effects:

[0054] (1) The semiconductor composite nanomaterial provided by the present invention combines CdSe / CdS nanorods and magnetic nanoparticles, which can amplify the chiral luminescence properties of CdSe / CdS nanorods, concentrate the fluorescence properties and magnetism on a single nanoparticle, and emit strong circularly polarized light under an external magnetic field. Under optimal conditions, compared with CdSe / CdS nanorods, the semiconductor composite nanomaterial can amplify the intensity of circularly polarized light by more than 16 times, and can be used in fields such as bioimaging, electronic devices or information processing.

[0055] (2) The preparation method of the semiconductor composite nanomaterial provided by the present invention is simple to operate and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 is a transmission electron micrograph of the nanorod-gold composite material described in Example 1 of the present invention;

[0057] Figure 2 is a transmission electron microscope image of the semiconductor composite nanomaterial described in Example 1 of the present invention;

[0058] Figure 3 is a UV-visible absorption spectrum of the semiconductor composite nanomaterial described in Example 1 of the present invention;

[0059] Figure 4 is a fluorescence emission spectrum of the semiconductor composite nanomaterial described in Example 1 of the present invention;

[0060] Figure 5 is a hysteresis loop diagram of the semiconductor composite nanomaterial described in Example 1 of the present invention;

[0061] Figure 6 is a magnetic circularly polarized luminescence spectrum of the CdSe / CdS nanorods described in Example 1 of the present invention;

[0062] Figure 7 This is a magnetic circularly polarized luminescence spectrum of the semiconductor composite nanomaterial described in Example 1 of the present invention;

[0063] Figure 8 is a transmission electron microscope image of the nanorod-gold composite material described in Example 2 of the present invention;

[0064] Figure 9 This is a transmission electron microscope image of the semiconductor composite nanomaterial described in Example 2 of the present invention. DETAILED DESCRIPTION

[0065] The technical solution of the present invention is further described below by way of specific embodiments. It should be understood by those skilled in the art that the embodiments are merely to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0066] The method for preparing CdSe / CdS nanorods of the present invention comprises the following steps:

[0067] (a) tri-n-octylphosphine oxide, octadecylphosphonic acid and cadmium oxide are mixed in a molar ratio of (10-50):(2-20):1, heated to 100-180°C and then vacuumed for 0.5-2h, heated to 280-320°C under argon protection, and then 1-2g of tri-n-octylphosphine is added. After the temperature is raised to 330-380°C, a tri-n-octylphosphine solution of selenium is injected, reacted for 5-350s, cooled to room temperature, and precipitated with methanol to obtain CdSe nanocrystals;

[0068] The selenium tri-n-octylphosphine solution is obtained by mixing selenium powder and tri-n-octylphosphine in a molar ratio of 1:(1-10);

[0069] (b) mixing tri-n-octylphosphine oxide, octadecylphosphonic acid, hexylphosphonic acid and cadmium oxide in a molar ratio of (10-50):(2-20):(5-50):1, evacuating at 100-180° C. for 0.5-2 h, heating to 300-380° C. under argon protection, then adding 1-2 g of tri-n-octylphosphine, injecting a mixed solution of sulfur powder and CdSe nanocrystals after the temperature is restored, reacting for 3-20 min, and cooling to room temperature to obtain the CdSe / CdS nanorods;

[0070] The mixed solution of sulfur powder and CdSe nanocrystals is composed of sulfur powder, tri-n-octylphosphine and CdSe nanocrystals in a molar ratio of (10 6 -10 4 ):(10 6 -10 4 ):1 mixed to obtain.

[0071] Preparation Example 1

[0072] This preparation example provides a method for preparing CdSe / CdS nanorods, which comprises the following steps:

[0073] (a) In a 50 mL three-necked flask, 3 g of tri-n-octylphosphine oxide, 0.3 g of octadecylphosphonic acid, and 0.06 g of cadmium oxide were mixed, heated to 150°C, and evacuated for 1 h. The temperature was then raised to 300°C under argon protection, and 1.5 g of tri-n-octylphosphine was added. The temperature was raised to 360°C, and a tri-n-octylphosphine solution of selenium was injected. The mixture was reacted for 30 s, cooled to room temperature, and precipitated with methanol to obtain CdSe nanocrystals.

[0074] The selenium tri-n-octylphosphine solution is obtained by mixing 0.06g of selenium powder and 0.36g of tri-n-octylphosphine;

[0075] (b) In a 50 mL three-necked flask, 3 g of tri-n-octylphosphine oxide, 0.3 g of octadecylphosphonic acid, 0.08 g of hexylphosphonic acid, and 0.06 g of cadmium oxide were mixed, and the mixture was evacuated at 150° C. for 1 h. The temperature was raised to 350° C. under argon protection, and then 1.5 g of tri-n-octylphosphine was added. After the temperature was restored, a mixed solution of sulfur powder and CdSe nanocrystals was injected, and the mixture was reacted for 6 min. The mixture was cooled to room temperature to obtain the CdSe / CdS nanorods;

[0076] The mixed solution of sulfur powder and CdSe nanocrystals is obtained by mixing 0.12 g of sulfur powder, 1.5 g of tri-n-octylphosphine and 80 nmol of CdSe nanocrystals.

[0077] The length of the CdSe / CdS nanorods obtained in this preparation example is 80 nm.

[0078] Preparation Example 2

[0079] This preparation example provides a method for preparing CdSe / CdS nanorods, which comprises the following steps:

[0080] (a) In a 50 mL three-necked flask, 3 g of tri-n-octylphosphine oxide, 0.3 g of octadecylphosphonic acid, and 0.06 g of cadmium oxide were mixed, heated to 150°C, and evacuated for 1 h. The temperature was then raised to 300°C under argon protection, and 1.5 g of tri-n-octylphosphine was added. The temperature was raised to 360°C, and a tri-n-octylphosphine solution of selenium was injected. The mixture was reacted for 30 s, cooled to room temperature, and precipitated with methanol to obtain CdSe nanocrystals.

[0081] The selenium tri-n-octylphosphine solution is obtained by mixing 0.06g of selenium powder and 0.36g of tri-n-octylphosphine;

[0082] (b) In a 50 mL three-necked flask, 3 g of tri-n-octylphosphine oxide, 0.3 g of octadecylphosphonic acid, 0.08 g of hexylphosphonic acid, and 0.06 g of cadmium oxide were mixed, and the mixture was evacuated at 150° C. for 1 h. The temperature was raised to 350° C. under argon protection, and then 1.5 g of tri-n-octylphosphine was added. After the temperature was restored, a mixed solution of sulfur powder and CdSe nanocrystals was injected, and the mixture was reacted for 6 min. The mixture was cooled to room temperature to obtain the CdSe / CdS nanorods;

[0083] The mixed solution of sulfur powder and CdSe nanocrystals is obtained by mixing 0.06 g of sulfur powder, 1.5 g of tri-n-octylphosphine and 80 nmol of CdSe nanocrystals.

[0084] The length of the CdSe / CdS nanorods obtained in this preparation example is 40 nm.

[0085] Preparation Example 3

[0086] This preparation example provides a method for preparing CdSe / CdS nanorods, which comprises the following steps:

[0087] (a) In a 50 mL three-necked flask, 3 g of tri-n-octylphosphine oxide, 0.3 g of octadecylphosphonic acid, and 0.06 g of cadmium oxide were mixed, heated to 150°C, and evacuated for 1 h. The temperature was then raised to 300°C under argon protection, and 1.5 g of tri-n-octylphosphine was added. The temperature was raised to 360°C, and a tri-n-octylphosphine solution of selenium was injected. The mixture was reacted for 30 s, cooled to room temperature, and precipitated with methanol to obtain CdSe nanocrystals.

[0088] The selenium tri-n-octylphosphine solution is obtained by mixing 0.06g of selenium powder and 0.36g of tri-n-octylphosphine;

[0089] (b) In a 50 mL three-necked flask, 3 g of tri-n-octylphosphine oxide, 0.3 g of octadecylphosphonic acid, 0.08 g of hexylphosphonic acid, and 0.06 g of cadmium oxide were mixed, and the mixture was evacuated at 150° C. for 1 h. The temperature was raised to 350° C. under argon protection, and then 1.5 g of tri-n-octylphosphine was added. After the temperature was restored, a mixed solution of sulfur powder and CdSe nanocrystals was injected, and the mixture was reacted for 12 min. The mixture was cooled to room temperature to obtain the CdSe / CdS nanorods.

[0090] The mixed solution of sulfur powder and CdSe nanocrystals is obtained by mixing 0.16 g of sulfur powder, 2 g of trioctylphosphine and 10 nmol of CdSe nanocrystals.

[0091] The length of the CdSe / CdS nanorods obtained in this preparation example is 150 nm.

[0092] Example 1

[0093] This embodiment provides a method for preparing a semiconductor composite nanomaterial, the preparation method comprising the following steps:

[0094] (1) mixing CdSe / CdS nanorods with 0.5 mL of toluene solution and diluting the mixture to 20 mL to obtain a CdSe / CdS nanorod solution; the CdSe / CdS nanorods were obtained by the method described in Preparation Example 1;

[0095] Mixing gold trichloride, didodecyldimethylammonium bromide, and octadecylamine in 5 mL of toluene solution to obtain a gold precursor solution, wherein the molar ratio of gold trichloride, didodecyldimethylammonium bromide, and octadecylamine is 1:11:33;

[0096] Mixing a CdSe / CdS nanorod solution and 0.5 mL of a gold precursor solution, wherein the molar ratio of gold trichloride to CdSe / CdS nanorods is 1000:1, and then performing a first reaction at 80° C. for 1 hour to obtain a nanorod-gold composite material;

[0097] (2) Mixing the nanorod-gold composite material obtained in step (1) with 15 mL of octadecene, and then adding dicobalt octacarbonyl, oleic acid, and dioctylamine, wherein the molar ratio of oleic acid, dioctylamine, and dicobalt octacarbonyl is 82:55:1; and the molar ratio of dicobalt octacarbonyl to the nanorod-gold composite material is 4×10 4 :1, and then a second reaction is carried out at 200° C. for 1 hour to obtain the semiconductor composite nanomaterial.

[0098] This embodiment also provides a semiconductor composite nanomaterial obtained by the above preparation method, wherein the semiconductor composite nanomaterial includes CdSe / CdS nanorods and nanoparticles grown on both ends of the CdSe / CdS nanorods, and the nanoparticles include a nanogold core and a cobalt layer coated on the outer surface of the nanogold core.

[0099] The transmission electron microscopy images of the nanorod-gold composite material and the semiconductor composite nanomaterial in this embodiment are shown in FIG. Figure 1 and Figure 2 As shown, from Figure 1 It can be seen that the length of the CdSe / CdS nanorods is 80nm, and the nanogold cores are selectively grown on both ends of the CdSe / CdS nanorods, with a size of about 2.5nm. Figure 2 It can be seen that the cobalt layer selectively grows on the gold nanocore at both ends of the nanorod to form nanoparticles with a core-shell structure. The size of the nanoparticles is about 8 nm.

[0100] The semiconductor composite nanomaterials in this embodiment were analyzed by UV-visible absorption spectrum, and the results were as follows: Figure 3 As shown, from Figure 3 It can be seen that in the long wavelength region, the absorption of cobalt nanoparticles masks the first absorption characteristic peak of the CdSe core, while in the short wavelength region there is still an obvious CdS absorption characteristic peak.

[0101] The semiconductor composite nanomaterials in this embodiment were subjected to fluorescence emission spectrum analysis (the solvent was hexane and the fluorescence test excitation wavelength was 400 nm). The results are as follows: Figure 4 As shown, from Figure 4 It can be seen that the semiconductor composite nanomaterial still retains the fluorescence properties of CdSe / CdS nanorods.

[0102] The hysteresis loop of the semiconductor composite nanomaterial in this embodiment is shown in FIG. Figure 5 As shown, from Figure 5 It can be seen that the semiconductor composite nanomaterial exhibits superparamagnetism and can be magnetized under an external magnetic field.

[0103] The magnetic circularly polarized luminescence spectra of CdSe / CdS nanorods and semiconductor composite nanomaterials in this embodiment under an external magnetic field of 1.0 T are shown in FIG. Figure 6 and Figure 7 As shown, it can be seen that the circularly polarized light intensity of the semiconductor composite nanomaterial reaches more than 160mdeg, while the luminescence intensity of CdSe / CdS nanorods can only reach about 10mdeg. It can be seen that the semiconductor composite nanomaterial can amplify the circularly polarized luminescence intensity by about 16 times compared with CdSe / CdS nanorods.

[0104] Example 2

[0105] This embodiment provides a method for preparing a semiconductor composite nanomaterial, the preparation method comprising the following steps:

[0106] (1) mixing CdSe / CdS nanorods with 0.5 mL of toluene solution and diluting the mixture to 20 mL to obtain a CdSe / CdS nanorod solution; the CdSe / CdS nanorods were obtained by the method described in Preparation Example 2;

[0107] Mixing gold trichloride, didodecyldimethylammonium bromide, and octadecylamine in 5 mL of toluene solution to obtain a gold precursor solution, wherein the molar ratio of gold trichloride, didodecyldimethylammonium bromide, and octadecylamine is 1:2:6;

[0108] Mixing a CdSe / CdS nanorod solution and 0.5 mL of a gold precursor solution, wherein the molar ratio of gold trichloride to CdSe / CdS nanorods is 500:1, and then performing a first reaction at 100° C. for 0.5 h to obtain a nanorod-gold composite material;

[0109] (2) Mixing the nanorod-gold composite material obtained in step (1) with 15 mL of octadecene, and then adding dicobalt octacarbonyl, oleic acid, and dioctylamine, wherein the molar ratio of oleic acid, dioctylamine, and dicobalt octacarbonyl is 15:10:1; and the molar ratio of dicobalt octacarbonyl to the nanorod-gold composite material is 5×10 4 :1, and then a second reaction is carried out at 150° C. for 2 h to obtain the semiconductor composite nanomaterial.

[0110] This embodiment also provides a semiconductor composite nanomaterial obtained by the above preparation method, wherein the semiconductor composite nanomaterial includes CdSe / CdS nanorods and nanoparticles grown on both ends of the CdSe / CdS nanorods, and the nanoparticles include a nanogold core and a cobalt layer coated on the outer surface of the nanogold core.

[0111] The transmission electron microscopy images of the nanorod-gold composite material and the semiconductor composite nanomaterial obtained in this example are shown in FIG. Figure 8 and Figure 9 As shown, from Figure 8It can be seen that the length of CdSe / CdS nanorods is 40nm, and the nanogold cores are selectively grown on both ends of the CdSe / CdS nanorods, with a size of about 2.5nm. Figure 9 It can be seen that the cobalt layer selectively grows on the gold nanocore at both ends of the nanorod to form nanoparticles with a core-shell structure. The size of the nanoparticles is about 10 nm.

[0112] Example 3

[0113] This embodiment provides a method for preparing a semiconductor composite nanomaterial, the preparation method comprising the following steps:

[0114] (1) mixing CdSe / CdS nanorods with 0.5 mL of toluene solution and diluting the mixture to 20 mL to obtain a CdSe / CdS nanorod solution; the CdSe / CdS nanorods were obtained by the method described in Preparation Example 3;

[0115] Mixing gold trichloride, didodecyldimethylammonium bromide, and octadecylamine in 5 mL of toluene solution to obtain a gold precursor solution, wherein the molar ratio of gold trichloride, didodecyldimethylammonium bromide, and octadecylamine is 1:20:60;

[0116] Mixing a CdSe / CdS nanorod solution and 0.5 mL of a gold precursor solution, wherein the molar ratio of gold trichloride to CdSe / CdS nanorods is 700:1, and then performing a first reaction at 40° C. for 2 h to obtain a nanorod-gold composite material;

[0117] (2) Mixing the nanorod-gold composite material obtained in step (1) with 15 mL of octadecene, and then adding dicobalt octacarbonyl, oleic acid, and dioctylamine, wherein the molar ratio of oleic acid, dioctylamine, and dicobalt octacarbonyl is 150:100:1, and the molar ratio of dicobalt octacarbonyl to the nanorod-gold composite material is 6×10 4 :1, and then a second reaction is carried out at 220°C for 0.5h to obtain the semiconductor composite nanomaterial.

[0118] This embodiment also provides a semiconductor composite nanomaterial obtained by the above preparation method, wherein the semiconductor composite nanomaterial includes CdSe / CdS nanorods and nanoparticles grown on both ends of the CdSe / CdS nanorods, wherein the nanoparticles include a nanogold core and a cobalt layer coated on the outer surface of the nanogold core, the average particle size of the nanogold core is 2.5 nm, and the average particle size of the nanoparticles is 12 nm.

[0119] Example 4

[0120] This embodiment provides a method for preparing a semiconductor composite nanomaterial. The only difference from Example 1 is that in step (1), the molar ratio of gold trichloride to CdSe / CdS nanorods is 2000:1.

[0121] Example 5

[0122] This embodiment provides a method for preparing a semiconductor composite nanomaterial. The only difference from Example 1 is that the molar ratio of the octacarbonyl dicobalt to the nanorod-gold composite material in step (2) is 10 5 :1.

[0123] Comparative Example 1

[0124] This comparative example provides a method for preparing a nanomaterial. The only difference from Example 1 is that the CdSe / CdS nanorod solution is not mixed with the gold precursor solution, but the CdSe / CdS nanorod solution is directly mixed with the cobalt source and the second surfactant. Specifically,

[0125] Octacarbonyl dicobalt, oleic acid and di-n-octylamine were added to the CdSe / CdS nanorod solution, and then a second reaction was carried out at 200° C. for 1 hour to obtain the nanomaterial. The added amounts of the CdSe / CdS nanorod solution and octacarbonyl dicobalt, oleic acid and di-n-octylamine were the same as those in Example 1.

[0126] In this comparative example, cobalt elements cannot grow on CdSe / CdS nanorods, so CdSe / CdS nanorods loaded with nanoparticles at both ends cannot be obtained, and thus do not have superparamagnetism, and the circularly polarized luminescence intensity of CdSe / CdS nanorods cannot be amplified.

[0127] The structures of the semiconductor composite nanomaterials prepared in Examples 1-5 and Comparative Example 1 were tested using transmission electron microscopy to obtain the gold nanoparticle core, the average particle size of the nanoparticles, and the length of the CdSe / CdS nanorods. The results are shown in Table 1.

[0128] The magnetic properties of the semiconductor composite nanomaterials prepared in Examples 1-5 and Comparative Example 1 were measured using hysteresis loops. The results are shown in Table 1.

[0129] The circularly polarized luminescence intensity of the semiconductor composite nanomaterials prepared in Examples 1-5 and Comparative Example 1 was measured using circularly polarized luminescence spectroscopy, and the circularly polarized luminescence magnification of the obtained semiconductor composite nanomaterials compared to that of CdSe / CdS nanorods was calculated. Circularly polarized luminescence magnification = circularly polarized luminescence intensity of semiconductor composite nanomaterial ÷ circularly polarized luminescence intensity of CdSe / CdS nanorods. The results are shown in Table 1.

[0130] Table 1

[0131]

[0132] In Table 1, “-” indicates that the property could not be measured.

[0133] From Table 1, we can see the following points:

[0134] (1) From the data of Examples 1-5, it can be seen that the semiconductor composite nanomaterial provided by the present invention has a composite structure composed of CdSe / CdS nanorods and nanoparticles, has superparamagnetism and can amplify circularly polarized light. Under optimal conditions, the semiconductor composite nanomaterial can amplify the circularly polarized luminescence intensity by more than 16 times compared with CdSe / CdS nanorods.

[0135] (2) A comprehensive comparison of the data of Example 1 and Example 4 shows that the molar ratio of gold trichloride to CdSe / CdS nanorods in Example 1 is 1000:1, compared with 2000:1 in Example 4. The average particle size of the gold nanoparticles in Example 1 is 2.5 nm, which can amplify the circularly polarized light intensity by 16 times, while the average particle size of the gold nanoparticles in Example 4 is 6 nm, and the circularly polarized light intensity is weak and cannot be amplified. It can be seen that the present invention preferably controls the molar ratio of the gold source to the CdSe / CdS nanorods, which can control the size of the gold nanoparticles, and further enhance the circularly polarized light intensity of the semiconductor composite nanomaterial.

[0136] (3) Comprehensive comparison of the data of Example 1 and Example 5 shows that the molar ratio of dicobalt octacarbonyl to the nanorod-gold composite material in Example 1 is 4×10 4 :1, compared to 10 in Example 5 5 :1, the average particle size of the nanoparticles in Example 1 is 8 nm, which can amplify the circularly polarized luminescence intensity by 16 times, while the average particle size of the nanoparticles in Example 5 is 16 nm, and the circularly polarized luminescence intensity is weak and cannot be amplified. It can be seen that the present invention preferably controls the molar ratio of the cobalt source and the nanorod-gold composite material, which can control the relative size of the nanoparticles and the CdSe / CdS nanorods, and thus can enhance the circularly polarized luminescence intensity of the semiconductor composite nanomaterial.

[0137] (4) A comprehensive comparison of the data of Example 1 and Comparative Example 1 shows that the only difference between Comparative Example 1 and Example 1 is that the CdSe / CdS nanorod solution is not mixed with the gold precursor solution. In Comparative Example 1, the cobalt element cannot grow on the CdSe / CdS nanorods, and the nanorods do not have superparamagnetism. The circularly polarized luminescence is weak, approximately equal to the luminescence intensity of the CdSe / CdS nanorods, and therefore the circularly polarized luminescence intensity of the CdSe / CdS nanorods cannot be amplified. Therefore, the preparation method provided by the present invention can combine the CdSe / CdS nanorods and the magnetic cobalt nanoparticles by mixing the CdSe / CdS nanorod solution and the gold precursor solution, performing the first reaction, and then adding the cobalt source and performing the second reaction, thereby amplifying the circularly polarized luminescence intensity.

[0138] In summary, the semiconductor composite nanomaterial provided by the present invention can amplify the intensity of circularly polarized light by combining CdSe / CdS nanorods and magnetic nanoparticles, and the preparation method is simple, and can be used in fields such as bioimaging, electronic devices or information processing.

[0139] The applicant declares that the above is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention fall within the scope of protection and disclosure of the present invention.

Claims

1. A semiconductor composite nanomaterial, characterized in that: The semiconductor composite nanomaterial includes CdSe / CdS nanorods and nanoparticles grown on both ends of the CdSe / CdS nanorods; The nanoparticles include a core-shell structure; The core-shell structure comprises a nano-gold core and a cobalt layer coated on the outer surface of the nano-gold core; The average particle size of the gold nanoparticles is 2-5 nm. The average particle size of the nanoparticles is 8-12 nm The semiconductor composite nanomaterial can emit circularly polarized light under an external magnetic field; Compared with CdSe / CdS nanorods, the semiconductor composite nanomaterial amplifies the intensity of circularly polarized light by more than 16 times.

2. The semiconductor composite nanomaterial according to claim 1, characterized in that The length of the CdSe / CdS nanorods is 20-150 nm.

3. A method for preparing the semiconductor composite nanomaterial according to claim 1 or 2, characterized in that: The preparation method comprises the following steps: (1) mixing a CdSe / CdS nanorod solution and a gold precursor solution to perform a first reaction to obtain a nanorod-gold composite material; (2) Mixing the nanorod-gold composite material obtained in step (1) with a cobalt source, and performing a second reaction to obtain the semiconductor composite nanomaterial.

4. The preparation method according to claim 3, characterized in that The preparation of the CdSe / CdS nanorod solution in step (1) includes: mixing CdSe / CdS nanorods and a first solvent to obtain the CdSe / CdS nanorod solution.

5. The preparation method according to claim 4, characterized in that The first solvent includes any one of toluene, dodecane, xylene or 1,4-dioxane, or a combination of at least two thereof.

6. The preparation method according to claim 3, characterized in that The preparation of the gold precursor solution in step (1) includes: mixing a gold source, a first surfactant and a reducing agent in a first solvent to obtain the gold precursor solution.

7. The preparation method according to claim 6, characterized in that The gold source includes any one of gold trichloride, chloroauric acid or gold(II) chloride, or a combination of at least two of them.

8. The preparation method according to claim 7, characterized in that The gold source is gold trichloride.

9. The preparation method according to claim 8, characterized in that The first surfactant includes any one of didodecyldimethylammonium bromide, dihexadecyldimethylammonium bromide, hexadecyltrimethylammonium bromide, hexadecylpyridinium chloride or hexadecylpyridinium bromide, or a combination of at least two thereof.

10. The preparation method according to claim 9, characterized in that The first surfactant is didodecyldimethylammonium bromide.

11. The preparation method according to claim 10, characterized in that: The reducing agent includes any one of octadecylamine, hexadecylamine, laurylamine or oleylamine, or a combination of at least two thereof.

12. The preparation method according to claim 11, characterized in that The reducing agent is octadecylamine.

13. The preparation method according to claim 12, characterized in that The molar ratio of gold trichloride, didodecyldimethylammonium bromide and octadecylamine is 1:(2-20):(6-60).

14. The preparation method according to claim 6, characterized in that The molar ratio of the gold source to the CdSe / CdS nanorods is (500-2000):

1.

15. The preparation method according to claim 14, characterized in that The molar ratio of the gold source to the CdSe / CdS nanorods is (500-1000):

1.

16. The preparation method according to claim 3, characterized in that The temperature of the first reaction in step (1) is 40-100°C.

17. The preparation method according to claim 3, characterized in that The first reaction time is 0.5-2h.

18. The preparation method according to claim 3, characterized in that The mixing in step (2) includes: mixing the nanorod-gold composite material and a cobalt source in a second solvent.

19. The preparation method according to claim 18, characterized in that The second solvent includes any one of octadecene, tetralin, diphenyl ether, n-tetracosane or trioctylamine, or a combination of at least two thereof.

20. The preparation method according to claim 3, characterized in that The second reaction is carried out under a protective atmosphere.

21. The preparation method according to claim 20, characterized in that The protective atmosphere includes nitrogen and / or an inert gas.

22. The preparation method according to claim 3, characterized in that A second surfactant is also added to the mixing in step (2).

23. The preparation method according to claim 22, characterized in that The cobalt source includes any one of dicobalt octacarbonyl, cobalt acetate or cobalt chloride, or a combination of at least two of them.

24. The preparation method according to claim 23, characterized in that The cobalt source is dicobalt octacarbonyl.

25. The preparation method according to claim 24, characterized in that The second surfactant includes any one of oleic acid, di-n-octylamine, n-octylamine, laurylamine or oleylamine, or a combination of at least two thereof.

26. The preparation method according to claim 25, characterized in that The second surfactant is a combination of oleic acid and di-n-octylamine.

27. The preparation method according to claim 26, characterized in that The molar ratio of the second surfactant, the oleic acid, di-n-octylamine and dicobalt octacarbonyl is (15-150):(10-100):

1.

28. The preparation method according to claim 3, characterized in that The molar ratio of the cobalt source to the nanorod-gold composite material is (10 4 -10 5 ):

1.

29. The preparation method according to claim 28, characterized in that The molar ratio of the cobalt source to the nanorod-gold composite material is (4×10 4 -6×10 4 ):

1.

30. The preparation method according to claim 3, characterized in that The temperature of the second reaction in step (2) is 150-220°C.

31. The preparation method according to claim 3, characterized in that The second reaction time is 0.5-2h.

32. A use of the semiconductor composite nanomaterial according to claim 1 or 2, characterized in that: The semiconductor composite nanomaterial is used in the fields of biological imaging, electronic devices or information processing.

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