阅读说明：本技术 一种氧化锌量子点的合成方法 (Synthesis method of zinc oxide quantum dots ) 是由 苗拯宁 武永军 潘明月 夏义文 于 2021-02-19 设计创作，主要内容包括：本发明公开一种氧化锌量子点的合成方法,涉及无机金属材料技术领域,包括以下步骤：S1、称取醋酸锌置于三口烧瓶中,用量筒量取的醇类有机溶剂加入至三口烧瓶中；S2、将三口烧瓶置于磁力搅拌器中搅拌,在65-80℃中加热回流,将三口烧瓶自然冷却至室温；S3、称取强碱在超声环境下溶解在醇类有机溶剂中；S4、将强碱溶液缓慢倒入S2中醋酸锌醇溶液中,持续搅拌,反应30分钟,S5、取0.2～0.4ml硅烷偶联剂与1.5～2ml水混合后逐滴加入S4溶液中,溶液浑浊后终止反应,用离心机离心过滤,得到的沉淀物用乙无水醇洗涤、离心、沉淀,最后将沉淀放入烘箱中烘干制得氧化锌量子点粉末,本发明合成方法简单,条件可控,制备的氧化锌尺寸均一、纯度高具有优异的发光性能。(The invention discloses a synthesis method of zinc oxide quantum dots, which relates to the technical field of inorganic metal materials and comprises the following steps: s1, weighing zinc acetate, placing the zinc acetate into a three-neck flask, and adding an alcohol organic solvent measured by a measuring cylinder into the three-neck flask; s2, placing the three-neck flask into a magnetic stirrer for stirring, heating and refluxing at 65-80 ℃, and naturally cooling the three-neck flask to room temperature; s3, weighing strong base, and dissolving the strong base in an alcohol organic solvent under an ultrasonic environment; s4, slowly pouring the strong base solution into the zinc acetate alcoholic solution in the S2, continuously stirring, reacting for 30 minutes, S5, mixing 0.2-0.4 ml of silane coupling agent with 1.5-2 ml of water, dropwise adding the mixture into the S4 solution, terminating the reaction after the solution is turbid, centrifugally filtering the mixture by using a centrifugal machine, washing the obtained precipitate by using anhydrous ethanol, centrifuging and precipitating the precipitate, and finally drying the precipitate in an oven to obtain the zinc oxide quantum dot powder.)

1. A method of synthesizing zinc oxide quantum dots, the method comprising the steps of:

s1, weighing 0.5-0.8 g of zinc acetate, placing the zinc acetate into a three-neck flask, measuring 20ml of alcohol organic solvent by using a measuring cylinder, and adding the alcohol organic solvent into the three-neck flask, so that the concentration of a zinc acetate solution is 0.04-0.15 mol/L;

s2, placing the three-neck flask in a magnetic stirring temperature-control electric heating jacket, stirring at high speed, heating and refluxing at 65-80 ℃, stirring until clear and transparent, taking down the three-neck flask, and naturally cooling to room temperature;

s3, weighing 0.18-0.41 g of strong base, and dissolving the strong base in a certain amount of alcohol organic solvent in an ultrasonic environment;

s4, slowly pouring the S3 strong alkali solution into the zinc acetate alcoholic solution in the S2, continuously stirring, and reacting for 30 min.

S5, mixing 0.2-0.4 ml of silane coupling agent with 2ml of water, dropwise adding the solution S4, stopping the reaction after the solution is turbid, centrifuging for 5min at 4100r/min by using a centrifuge, carefully pouring supernatant, washing precipitate by using anhydrous ethanol, centrifuging and precipitating, repeating the operations to remove unreacted precursors and byproducts, finally placing the precipitate in an oven, and baking for 2h at the temperature of 70 ℃ to obtain the zinc oxide quantum dot powder.

2. The method for synthesizing the zinc oxide quantum dot according to claim 1, wherein the molar ratio of the zinc acetate to the strong base is 1 (1.2-3.5).

3. The method of claim 1, wherein the alcoholic organic solvent in step S1 is absolute ethanol or methanol, and the absolute ethanol and the methanol are both analytically pure.

4. The method of claim 1, wherein the strong base in S3 is sodium methoxide, and the concentration of the sodium methoxide in the solution is 0.11-0.42 mol/L.

Background

In recent years, nanometer semiconductor particles (quantum dots, QDs) with particle diameters not larger than the self-exciton bohr diameter in three dimensions attract people to pay attention, and through changing the size of the quantum dots, people can adjust the energy gap of the quantum dots, so that the quantum dots have different photoelectric properties. Zinc oxide quantum dots (ZnOQDs) have a wide forbidden band (3.37eV) and a large exciton binding energy (60meV), are easy to prepare, have excellent ultraviolet absorption and photoluminescence properties, good biocompatibility, adjustable band gap, environmental protection, high quantum efficiency, and are easy to synthesize. Has potential application prospect in the fields of biological fluorescent marking, biological imaging, anti-counterfeiting identification, antibacterial catalysis, health illumination and the like.

At present, there are many methods for synthesizing zinc oxide quantum dots, which are roughly divided into two physical methods and two chemical methods, and the physical methods generally include a vapor transport method, a metal-organic vapor deposition method, an electrochemical deposition method and the like. But compared with a chemical method, a physical method has expensive equipment and wider particle size distribution, and the application of the method in the preparation of nano materials is limited; on the contrary, the chemical synthesis method for preparing the nano material has low cost and simple operation, the synthesized quantum dots have good purity, and the size of the quantum dots can be accurately regulated and controlled through reaction conditions. The common chemical method for preparing the zinc oxide quantum dots comprises the following steps: sol-gel method, microemulsion method, and solvothermal method. For the preparation of zinc oxide quantum dots by the sol-gel method, zinc acetate dihydrate is generally hydrolyzed in an organic solution system under an alkaline environment, and the common alkali source is alkali metal hydroxide, organic amine and the like. The technology is based on the traditional sol-gel method, and sodium methoxide is used as an alkali source for synthesizing the zinc oxide quantum dots.

Disclosure of Invention

In view of the defects in the prior art, the present invention aims to provide a method for synthesizing zinc oxide quantum dots, so as to solve the problems in the background art.

The purpose of the invention can be realized by the following technical scheme: a method for synthesizing zinc oxide quantum dots comprises the following steps:

s1, weighing 0.5-0.8 g of zinc acetate, placing the zinc acetate into a three-neck flask, measuring 20ml of alcohol organic solvent by using a measuring cylinder, and adding the alcohol organic solvent into the three-neck flask, so that the concentration of a zinc acetate solution is 0.04-0.15 mol/L;

s2, placing the three-neck flask in a magnetic stirring temperature-control electric heating jacket, stirring at high speed, heating and refluxing at 65-80 ℃, stirring until clear and transparent, taking down the three-neck flask, and naturally cooling to room temperature;

s3, weighing 0.18-0.41 g of strong base, and dissolving the strong base in a certain amount of alcohol organic solvent in an ultrasonic environment;

s4, slowly pouring the S3 strong alkali solution into the zinc acetate alcoholic solution in the S2, continuously stirring, and reacting for 30 min.

S5, mixing 0.2-0.4 ml of silane coupling agent with 2ml of water, dropwise adding the solution S4, stopping the reaction after the solution is turbid, centrifuging for 5min at 4100r/min by using a centrifuge, carefully pouring supernatant, washing precipitate by using anhydrous ethanol, centrifuging and precipitating, repeating the operations to remove unreacted precursors and byproducts, finally placing the precipitate in an oven, and baking for 2h at the temperature of 70 ℃ to obtain the zinc oxide quantum dot powder.

In a further embodiment of the invention, the molar ratio of the zinc acetate to the strong base is 1 (1.2-3.5).

As a further embodiment of the present invention, the alcoholic organic solvent in step S1 is absolute ethanol or methanol, and the absolute ethanol and the methanol are both analytically pure.

In a further embodiment of the present invention, the strong base in S3 is sodium methoxide, and the concentration of the sodium methoxide in the solution is 0.11 to 0.42 mol/L.

The invention has the beneficial effects that: the method has the advantages that sodium methoxide is used as an alkali source for the first time to synthesize the zinc oxide quantum dots, the cost is low, the method is simple, the conditions are controllable, and the prepared zinc oxide has uniform size, high purity and excellent luminous performance.

The method has low operation energy consumption at room temperature, is environment-friendly, and can be used for large-scale synthesis of the zinc oxide quantum dots.

Drawings

In order to more clearly illustrate the embodiments or technical solutions in the prior art of the present invention, the drawings used in the description of the embodiments or prior art will be briefly described below, and it is obvious for those skilled in the art that other drawings can be obtained based on these drawings without creative efforts.

FIG. 1 is an XRD spectrogram of zinc oxide quantum dots prepared by the invention

FIG. 2 is the ultraviolet-visible absorption spectrum of zinc oxide quantum dots prepared by the invention

FIG. 3 is a TEM image of zinc oxide quantum dots prepared by the invention

FIG. 4 is a photoluminescence spectrum of zinc oxide quantum dots prepared by the invention

FIG. 5 is a flow chart of the preparation of the present invention

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 1 to 5, a specific embodiment of the method for synthesizing zinc oxide quantum dots of the present invention is as follows:

example 1

S1, weighing 0.5g of zinc acetate, placing the zinc acetate into a three-neck flask, weighing 20ml of ethanol by using a measuring cylinder, and adding the ethanol into the three-neck flask;

s2, placing the three-neck flask on a magnetic stirring temperature-control electric heating jacket, stirring at high speed, heating and refluxing at 65 ℃, taking down the three-neck flask after the zinc acetate is completely dissolved and the solution is clarified, and naturally cooling to room temperature;

s3, weighing 0.18g of sodium methoxide, dissolving the sodium methoxide in 20ml of ethanol, ultrasonically mixing for 20min, taking out, placing in cold water, and cooling to room temperature;

s4, slowly pouring the sodium methoxide ethanol solution into the zinc acetate ethanol solution, continuously stirring, and reacting for 30 min.

S5, mixing 0.2ml of silane coupling agent with 2ml of water, dropwise adding the mixture into the solution prepared in the S4, stopping the reaction after the solution is turbid, centrifuging the mixture for 5min at 4100r/min by using a centrifuge, carefully pouring supernatant, washing precipitates by using anhydrous ethanol, centrifuging and precipitating, repeating the operations to remove unreacted precursors and byproducts, finally putting the precipitates into an oven, and drying the precipitates for 2h at 70 ℃ to obtain zinc oxide quantum dot powder.

XRD test is carried out on the obtained product, as shown in figure 1, Zn2 +/OH-5: 7, the crystal form is a hexagonal wurtzite structure; the obtained sample is subjected to ultraviolet visible absorption spectrum test, and the absorption starting wavelength of the sample is 358nm as shown in FIG. 2; TEM test results show that the sample has uniform size and approximately spherical particles as shown in FIG. 3 a; photoluminescence spectrum test results the sample shown in fig. 4 has a luminescence peak near 510 nm.

Example 2

S1, weighing 0.8g of zinc acetate, placing the zinc acetate into a three-neck flask, weighing 20ml of ethanol by using a measuring cylinder, and adding the ethanol into the three-neck flask;

s2, placing the three-neck flask on a magnetic stirring temperature-control electric heating jacket, stirring at high speed, heating and refluxing at 80 ℃, taking down the three-neck flask after the zinc acetate is completely dissolved and the solution is clarified, and naturally cooling to room temperature;

s3, weighing 0.25g of sodium methoxide, dissolving the sodium methoxide in 20ml of ethanol, performing ultrasonic treatment for 20min, taking out, placing in cold water, and cooling to room temperature;

s4, slowly pouring the sodium methoxide ethanol solution into the zinc acetate ethanol solution, continuously stirring, and reacting for 30 min.

S5, 0.3ml of silane coupling agent is mixed with 2ml of water and then the mixture is added into the S4 solution dropwise. Stopping the reaction after the solution is turbid, centrifuging for 5min at 4100r/min by using a centrifuge, carefully pouring the supernatant, washing the precipitate by using anhydrous ethanol, centrifuging and precipitating, repeating the operations to remove unreacted precursors and byproducts, and finally putting the precipitate into an oven and drying for 2h at 70 ℃ to obtain the zinc oxide quantum dot powder.

XRD test is carried out on the obtained product, as shown in figure 1, Zn2+/OH < -1: 2, the crystal form is a hexagonal wurtzite structure; the obtained sample was subjected to ultraviolet-visible absorption spectrum measurement, and the absorption initiation wavelength of the sample was 366nm as shown in FIG. 2; TEM test results show that the sample has uniform size and approximately spherical particles as shown in FIG. 3 b; photoluminescence spectrum test results the sample shown in fig. 4 has a luminescence peak near 510 nm.

Example 3

S1, weighing 0.5g of zinc acetate, placing the zinc acetate into a three-neck flask, weighing 20ml of ethanol by using a measuring cylinder, and adding the ethanol into the three-neck flask;

s2, placing the three-neck flask on a magnetic stirring temperature-control electric heating jacket, stirring at high speed, heating and refluxing at 70 ℃, taking down the three-neck flask after the zinc acetate is completely dissolved and the solution is clarified, and naturally cooling to room temperature;

s3, weighing 0.31g of sodium methoxide, dissolving the sodium methoxide in 20ml of ethanol, performing ultrasonic treatment for 20min, taking out, placing in cold water, and cooling to room temperature;

s4, slowly pouring the sodium methoxide ethanol solution into the zinc acetate ethanol solution, continuously stirring, and reacting for 30 min.

S5, 0.4ml of silane coupling agent is mixed with 2ml of water and then the mixture is added into the S4 solution dropwise. Stopping the reaction after the solution is turbid, centrifuging for 5min at 4100r/min by using a centrifuge, carefully pouring the supernatant, washing the precipitate by using anhydrous ethanol, centrifuging and precipitating, repeating the operations to remove unreacted precursors and byproducts, and finally putting the precipitate into an oven and drying for 2h at 70 ℃ to obtain the zinc oxide quantum dot powder.

XRD test is carried out on the obtained product, as shown in figure 1, Zn2+/OH < -1: 2.5, the crystal form is a hexagonal wurtzite structure; the obtained sample was subjected to ultraviolet-visible absorption spectrum measurement, and the absorption initiation wavelength of the sample was 356nm as shown in fig. 2; TEM test results show that the sample has uniform size and approximately spherical particles as shown in FIG. 3 c; photoluminescence spectrum test results the sample shown in fig. 4 has a luminescence peak near 510 nm.

Example 4

S1, weighing 0.5g of zinc acetate, placing the zinc acetate into a three-neck flask, weighing 20ml of ethanol by using a measuring cylinder, and adding the ethanol into the three-neck flask;

s2, placing the three-neck flask on a magnetic stirring temperature-control electric heating jacket, stirring at high speed, heating and refluxing at 80 ℃, taking down the three-neck flask after the zinc acetate is completely dissolved and the solution is clarified, and naturally cooling to room temperature;

s3, weighing 0.41g of sodium methoxide, dissolving the sodium methoxide in 20ml of ethanol, performing ultrasonic treatment for 20min, taking out, placing in cold water, and cooling to room temperature;

s4, slowly pouring the sodium methoxide ethanol solution into the zinc acetate ethanol solution, continuously stirring, and reacting for 30 min.

S5, 0.25ml of silane coupling agent is mixed with 2ml of water and then the mixture is added into the S4 solution dropwise. Stopping the reaction after the solution is turbid, centrifuging for 5min at 4100r/min by using a centrifuge, carefully pouring the supernatant, washing the precipitate by using anhydrous ethanol, centrifuging and precipitating, repeating the operations to remove unreacted precursors and byproducts, and finally putting the precipitate into an oven and drying for 2h at 70 ℃ to obtain the zinc oxide quantum dot powder.

XRD test is carried out on the obtained product, as shown in figure 1, Zn2 +/OH-3: 10, the crystal form is a hexagonal wurtzite structure; the obtained sample is subjected to ultraviolet visible absorption spectrum test, and the absorption starting wavelength of the sample is 358nm as shown in FIG. 2; TEM test results are shown in FIG. 3d, the sample size is uniform, and the particles are approximately spherical; photoluminescence spectrum test results the sample shown in fig. 4 has a luminescence peak near 510 nm.

It will be appreciated by those skilled in the art that various changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the spirit and scope of the invention, and any equivalents thereto, such as those skilled in the art, are intended to be embraced therein.