A cadmium selenide quantum dot and a preparation method and application thereof
By preparing a cadmium source solution and reducing agent in an atmospheric environment and adjusting the pH value, cadmium selenide quantum dots with good water solubility and stability were prepared, solving the problems of complex operation and poor water solubility in the existing technology, and realizing the simplified synthesis and excellent performance application of cadmium selenide quantum dots.
Patent Information
- Application Number
- CN202311179068.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-09-13
- Publication Date
- 2025-11-18
- Estimated Expiration
- 2043-09-13
AI Technical Summary
Existing methods for synthesizing cadmium selenide quantum dots require an inert atmosphere, are complex to operate, and produce products with poor water solubility.
Cadmium selenide quantum dots were prepared by preparing a cadmium source solution, adding surface modifiers and reducing agents, adjusting the pH to 7-9, mixing and heating under atmospheric conditions. By using a specific molar ratio of reducing agent and cadmium source, dissolved oxygen in water was consumed, resulting in the preparation of cadmium selenide quantum dots with good water solubility and high stability.
We successfully prepared cadmium selenide quantum dots with good water solubility and stability in an atmospheric environment, which simplified the operation process and showed good fluorescence and photoelectric properties, and can be applied to the construction of micro optoelectronic devices.
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Figure CN117285013B_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of quantum dot synthesis method, and in particular to a kind of cadmium selenide quantum dots and preparation method and application thereof. BACKGROUND
[0002] Quantum dots are a kind of new nanomaterials, with its extremely small size and many unique physical and chemical properties that macroscopic materials do not have, which injects new vitality into the basic research of material field. At the same time, quantum dots usually have satisfactory light stability, strong fluorescence effect, photoelectric conversion effect and good biocompatibility, which makes quantum dots become a research hotspot in many fields.
[0003] Cadmium selenide quantum dots are a common Cd quantum dot, and currently a variety of shape and size of quantum dot synthesis paths have been developed. According to the difference of synthesis solution phase, it can be divided into three categories: oil phase hot injection synthesis method, oil phase thermal cracking synthesis method and aqueous phase synthesis method.
[0004] The organic phase synthesis method such as oil phase hot injection method and oil phase thermal cracking method can obtain quantum dots with uniform size and uniform distribution. However, this kind of reaction usually also needs high reaction temperature (at least 150-350℃) to reach the reaction activity condition, and there are problems of high cost of raw materials, great toxicity, instability and so on, which require high quality of experimental equipment and operating personnel. The synthesis method of aqueous phase method is not so harsh in reaction condition, but inert gas needs to be used to protect the precursor from oxidation during operation process, which also requires high instrument equipment, and the synthesis process error is large.
[0005] From the existing literature reports, the synthesis of cadmium selenide quantum dots still cannot leave the protection of inert atmosphere, which requires high quality of experimental personnel and is not conducive to the operation of beginners. SUMMARY
[0006] The purpose of the present application is to overcome the deficiencies of the prior art and provide a kind of cadmium selenide quantum dots and preparation method and application thereof. The present application solves the problem that the synthesis method of cadmium selenide quantum dots in the prior art cannot leave the protection of nitrogen atmosphere, and the water solubility of the product is poor.
[0007] In order to achieve the above purpose, the technical scheme adopted by the present application is as follows:
[0008] In the first aspect, the present application provides a preparation method of cadmium selenide quantum dots, comprising the following steps:
[0009] (1) configure cadmium source solution, then add surface modifier, adjust the pH of the solution to 7-9 with strong alkali solution, then add reducing agent, and mix uniformly to obtain precursor solution A;
[0010] (2) configure selenium source solution as precursor liquid B;
[0011] (3) mix the precursor liquid B and the precursor liquid A uniformly and heat to 80-100℃ for 1-24h, to obtain cadmium selenide quantum dots;
[0012] The surface modifier in the step (1) is at least one of mercaptopropionic acid, mercaptoethylamine, mercaptopropylamine and dodecyl acetic acid.
[0013] The molar ratio of the reducing agent to the cadmium element in the cadmium source in the step (1) is (1-7):(1-4.5).
[0014] The present application can successfully prepare cadmium selenide quantum dots in the atmospheric environment by adding an excess of reducing agent to consume the dissolved oxygen in water without additional protection in a nitrogen atmosphere, solves the problems of complicated operation and complex instruments in the synthesis process of quantum dots, and the cadmium selenide quantum dots have good water solubility and high stability by using a specific molar ratio of reducing agent to cadmium source.
[0015] Preferably, the volume ratio of the precursor liquid A to the precursor liquid B in the step (3) is 1:(0.25-2).
[0016] More preferably, the volume ratio of the precursor liquid A to the precursor liquid B in the step (3) is 1:0.5.
[0017] Preferably, the cadmium source in the step (1) is at least one of cadmium nitrate and cadmium acetate.
[0018] Preferably, the surface modifier in the step (1) is mercaptopropionic acid.
[0019] Preferably, the strong alkali solution in the step (1) is at least one of sodium hydroxide solution and ammonia water.
[0020] Preferably, the reducing agent in the step (1) is at least one of mercaptoethanol and sodium borohydride.
[0021] Preferably, the selenium source in the step (2) is at least one of sodium selenite and sodium selenate.
[0022] Preferably, the concentration of the cadmium source solution in the step (1) is 4-8mMol / L, the concentration of the surface modifier is 10-100mMol / L, and the concentration of the reducing agent is 50-200mMol / L.
[0023] Preferably, the concentration of the selenium source solution in the step (2) is 2-16mMol / L.
[0024] In the second aspect, the present application also provides a cadmium selenide quantum dot prepared by the above method.
[0025] The prepared cadmium selenide quantum dots have good fluorescence performance and photoelectric performance.
[0026] Preferably, the molar ratio of the cadmium source to the selenium source in the cadmium selenide quantum dots is (0.25-4):1.
[0027] More preferably, the molar ratio of the cadmium source to the selenium source in the cadmium selenide quantum dots is (0.8-2):1.
[0028] In a third aspect, the present application further provides a photoelectrochemical device comprising the cadmium selenide quantum dots.
[0029] Preferably, the preparation method of the photoelectrochemical device comprises the following steps:
[0030] S1: configuring a polydiallyldimethylammonium chloride solution with a molar concentration of 1-5%, adding 0.1-1 mol / L of sodium chloride to obtain a precursor solution C;
[0031] S2: diluting the cadmium selenide quantum dot solution by 2-4 times to obtain a precursor solution D;
[0032] S3: immersing the optical fiber microelectrode in the precursor solution C and the precursor solution D for 3-6 min, and circulating 3-6 times, and then washing and drying.
[0033] Since the polydiallyldimethylammonium chloride is a strong cationic polyelectrolyte with positive charge, the cadmium selenide quantum dots synthesized by the method of the present application have negative groups on the surface, and the optical fiber microelectrode is immersed in the precursor solution C and the precursor solution D, washed and dried, so that a uniform and stable conductive photosensitive layer is formed on the surface of the optical fiber microelectrode through electrostatic force, and the construction of the photoelectric device is realized.
[0034] Compared with the prior art, the present application has the following beneficial effects:
[0035] (1) The present application successfully prepares cadmium selenide quantum dots with good water solubility and stability in an atmospheric environment, solving the problems of complicated operation and complex instruments in the synthesis process of quantum dots.
[0036] (2) The cadmium selenide quantum dots synthesized in the present application exhibit good fluorescence performance and photoelectric performance, and are successfully applied to the construction of micro photoelectric devices. BRIEF DESCRIPTION OF DRAWINGS
[0037] Figure 1 is the ultraviolet absorption spectrum of the cadmium selenide quantum dots in the present application at different pH values.
[0038] Figure 2 is the fluorescence emission spectrum of the cadmium selenide quantum dots in the present application at different pH values.
[0039] Figure 3is the ultraviolet absorption spectrum diagram of cadmium selenide quantum dots in the present application under different Cd:Se molar ratios.
[0040] Figure 4 is the fluorescence emission spectrum diagram of cadmium selenide quantum dots in the present application under different Cd:Se molar ratios.
[0041] Figure 5 is the photocurrent response diagram of cadmium selenide quantum dots in the present application on a fiber micro-optoelectronic device (in the figure, 2, 4, 6, 8 represent the deposition circle number).
[0042] Figure 6 is the fluorescence emission spectrum diagram of cadmium selenide quantum dots in the present application under different molar ratios of reducing agent and cadmium source (in which, 1 represents Comparative Example 1, 2 represents Comparative Example 2, and 3 represents Example 1). DETAILED DESCRIPTION
[0043] In order to better illustrate the purpose, technical scheme and advantages of the present application, the present application will be further described below in combination with specific examples, but the protection scope and implementation mode of the present application are not limited thereto.
[0044] The materials, reagents and the like used in the following examples are commercially available reagents and materials unless otherwise specified.
[0045] Example 1
[0046] A preparation method of cadmium selenide quantum dots, comprising the following steps:
[0047] (1) 10 mL of cadmium nitrate solution is configured, the concentration of the cadmium nitrate solution is 4 mMol / L, then 50 μL of mercaptopropionic acid is added, the concentration of the mercaptopropionic acid is 40 mMol / L, the pH of the solution is adjusted to 7 by sodium hydroxide, and finally 45 μL of mercaptoethanol is added, the concentration of the mercaptoethanol is 200 mMol / L, and the mixture is uniformly mixed to obtain precursor solution A;
[0048] (2) 5 mL of sodium selenite solution is configured, the concentration of the sodium selenite solution is 4 mMol / L, and the mixture is uniformly mixed to obtain precursor solution B;
[0049] (3) The precursor solution B is quickly added to the precursor solution A, the temperature is raised to 80℃, and the reaction time is 2 h, thereby obtaining cadmium selenide quantum dots.
[0050] In this embodiment, the molar ratio of mercaptoethanol to cadmium nitrate solution in step (1) is 1:4.5; the molar ratio of cadmium nitrate to sodium selenite is 2:1.
[0051] An application of cadmium selenide quantum dots in a photoelectrochemical device, comprising the following steps:
[0052] S1: Prepare a 2% polydiallyldimethylammonium chloride solution, add 0.1 mol / L sodium chloride to obtain precursor solution C;
[0053] S2: Dilute the cadmium selenide quantum dot stock solution 3 times to obtain precursor solution D;
[0054] S3: Immerse the fiber microelectrode in precursor solution C and precursor solution D for 5 minutes in sequence, cycle 5 times, wash and dry. Then, a uniform and stable conductive photosensitive layer can be formed on the surface of the fiber microelectrode through electrostatic force, thus realizing the construction of optoelectronic devices.
[0055] Example 2
[0056] A method for preparing cadmium selenide quantum dots includes the following steps:
[0057] (1) Prepare 10 mL of cadmium nitrate solution with a concentration of 8 mmol / L, then add 50 μL of mercaptopropionic acid with a concentration of 10 mmol / L, adjust the pH of the reaction solution to 7 with sodium hydroxide, and finally add 2.8 mL of mercaptoethanol with a concentration of 200 mmol / L. After mixing evenly, the precursor solution A is obtained.
[0058] (2) Prepare 5 mL of sodium selenite solution with a concentration of 8 mmol / L. After mixing evenly, the precursor solution B is obtained.
[0059] (3) Add precursor solution B to precursor solution A quickly, heat to 100℃, and react for 12 hours to obtain cadmium selenide quantum dots.
[0060] In this embodiment, the molar ratio of mercaptoethanol to cadmium nitrate solution in step (1) is 7:1; the molar ratio of cadmium nitrate to sodium selenite is 2:1.
[0061] An application of cadmium selenide quantum dots in optochemical devices includes the following steps:
[0062] S1: Prepare a 1% polydiallyldimethylammonium chloride solution, add 0.5 mol / L sodium chloride to obtain precursor solution C;
[0063] S2: Dilute the cadmium selenide quantum dot stock solution 4 times to obtain precursor solution D;
[0064] S3: Immerse the fiber microelectrode in precursor solution C and precursor solution D for 3 minutes in sequence, cycle 5 times, wash and dry. Then, a uniform and stable conductive photosensitive layer can be formed on the surface of the fiber microelectrode through electrostatic force, thus realizing the construction of optoelectronic devices.
[0065] Example 3
[0066] A method for preparing cadmium selenide quantum dots includes the following steps:
[0067] (1) Prepare 5 mL of cadmium nitrate solution with a molar concentration of 8 mMol / L, then add 50 μL of mercaptopropionic acid with a molar concentration of 100 mMol / L, adjust the pH of the solution to 7 with sodium hydroxide, and finally add 0.4 mL of mercaptoethanol with a concentration of 200 mMol / L. After mixing evenly, the precursor solution A is obtained.
[0068] (2) Prepare 10 mL of sodium selenite solution with a molar concentration of 2 mmol / L. After mixing evenly, the precursor solution B is obtained.
[0069] (3) Add precursor solution B to precursor solution A quickly, heat to 100℃, and react for 24 hours to obtain cadmium selenide quantum dots.
[0070] In this embodiment, the molar ratio of mercaptoethanol to cadmium nitrate solution in step (1) is 2:1; the molar ratio of cadmium nitrate to sodium selenite is 2:1.
[0071] An application of cadmium selenide quantum dots in optochemical devices includes the following steps:
[0072] S1: Prepare a 5% polydiallyldimethylammonium chloride solution, add 1 mol / L sodium chloride to obtain precursor solution C;
[0073] S2: Dilute the cadmium selenide quantum dot stock solution by 2 times to obtain precursor solution D;
[0074] S3: Immerse the fiber microelectrode in precursor solution C and precursor solution D for 2 minutes in sequence, cycle 5 times, wash and dry. Then, a uniform and stable conductive photosensitive layer can be formed on the surface of the fiber microelectrode through electrostatic force, thus realizing the construction of optoelectronic devices.
[0075] Example 4
[0076] The difference from Example 1 is that in step (1), the pH of the reaction solution is adjusted to 8 with sodium hydroxide, while the other steps are the same as in Example 1.
[0077] Example 5
[0078] The difference from Example 1 is that in step (1), the pH of the reaction solution is adjusted to 9 with sodium hydroxide, while the other steps are the same as in Example 1.
[0079] Examples 4-5 investigated the effect of pH in precursor solution A on the synthesis of cadmium selenide quantum dots. The ultraviolet absorption and fluorescence properties of the cadmium selenide quantum dots synthesized by the method of this invention were characterized by ultraviolet-visible spectrophotometry and fluorescence spectrophotometry. Their ultraviolet absorption and fluorescence emission spectra are shown below.Figure 1 and Figure 2 As shown.
[0080] pass Figure 1 and Figure 2 It can be seen that when the pH of the reaction solution is adjusted to 7 with sodium hydroxide in step (1), the fluorescence intensity is the highest, indicating that the fluorescence performance of the cadmium selenide quantum dots synthesized in this invention is the best.
[0081] Example 6
[0082] The difference from Example 1 is that the molar ratio of cadmium nitrate to sodium selenite in the cadmium selenide quantum dots is 1:1.5, while the other steps are the same as in Example 1.
[0083] Example 7
[0084] The difference from Example 1 is that the molar ratio of cadmium nitrate to sodium selenite in the cadmium selenide quantum dots is 1:1.25, while the other steps are the same as in Example 1.
[0085] Example 8
[0086] The difference from Example 1 is that the molar ratio of cadmium nitrate to sodium selenite in the cadmium selenide quantum dots is 4:1, while the other steps are the same as in Example 1.
[0087] Examples 6-8 investigate the effect of the molar ratio of cadmium nitrate to sodium selenite on the synthesis of cadmium selenide quantum dots. The UV absorption and fluorescence emission spectra of the cadmium selenide quantum dots synthesized in this invention are shown below. Figure 3 and Figure 4 As shown.
[0088] pass Figure 3 and Figure 4 It can be seen that as the Cd:Se molar ratio increases, the formation rate of cadmium selenide quantum dots increases significantly, and the color change can be observed earlier during the reaction. Furthermore, when the Cd:Se molar ratio exceeds 1:1, significant precipitation of quantum dots occurs, indicating an excess of Se. The fluorescence intensity is highest when the Cd:Se molar ratio is 2:1, indicating that the synthesized cadmium selenide quantum dots exhibit the best fluorescence performance.
[0089] Comparative Example 1
[0090] The difference from Example 1 is that the molar ratio of mercaptoethanol to cadmium nitrate solution in step (1) is 1:10, while the other steps are the same as in Example 1.
[0091] Comparative Example 2
[0092] The difference from Example 1 is that the molar ratio of mercaptoethanol to cadmium nitrate solution in step (1) is 8:1, while the other steps are the same as in Example 1.
[0093] according to Figure 6 It is known that when the molar ratio of mercaptoethanol to cadmium nitrate solution is outside the range specified in this application, the fluorescence performance of cadmium selenide quantum dots is poor. When the molar ratio of mercaptoethanol to cadmium nitrate solution is within the range specified in this application, the fluorescence performance of cadmium selenide quantum dots is significantly improved.
[0094] Comparative Example 3
[0095] The difference from Example 1 is that the molar ratio of cadmium nitrate to sodium selenite in the cadmium selenide quantum dots is 0.1:1.
[0096] Comparative Example 4
[0097] The difference from Example 1 is that the molar ratio of cadmium nitrate to sodium selenite in the cadmium selenide quantum dots is 8:1.
[0098] according to Figure 4 It is known that when the molar ratio of cadmium nitrate to sodium selenite is not within the range specified in this application, the fluorescence performance of cadmium selenide quantum dots is poor.
[0099] Comparative Example 5
[0100] The difference from Example 1 is that in step (1), the pH of the reaction solution is adjusted to 6 with sodium hydroxide, while the other steps are the same as in Example 1.
[0101] according to Figure 2 It can be seen that the fluorescence performance of cadmium selenide quantum dots is poor when the pH of the reaction solution is 6.
[0102] Comparative Example 6
[0103] The difference from Example 1 is that in step (1), the pH of the reaction solution is adjusted to 11 with sodium hydroxide, while the other steps are the same as in Example 1.
[0104] according to Figure 2 It can be seen that the fluorescence performance of cadmium selenide quantum dots is poor when the pH of the reaction solution is 11.
[0105] Photoelectric performance testing of cadmium selenide quantum dot micro-optoelectronic devices:
[0106] A three-electrode system was used for testing. This system consisted of a silver / silver chloride electrode as the reference electrode, a platinum wire electrode as the counter electrode, and fiber microelectrodes (prepared in Example 1) deposited on optical fibers with different numbers of turns as the working electrode. A time-current method was then employed for detection. The light source wavelength was set to 410 nm, and the detection solution was 0.1 mol / L tris(hydroxymethyl)aminomethane hydrochloride buffer (pH 7.4) with 0.1 mol / L ascorbic acid added. After the detection device was set up, light irradiation was alternately provided at 20-second intervals, and the photocurrent change curve of the cadmium selenide fiber microelectrode was recorded. The test results were then obtained. Figure 5 As shown.
[0107] according to Figure 5 It can be seen that as the number of deposition cycles increases, the photocurrent gradually increases, indicating that when the pH of the reaction solution is adjusted to 7 with sodium hydroxide in step (1) and the molar ratio of cadmium nitrate solution to sodium selenite solution is 2:1, the cadmium selenide quantum dots synthesized in this invention have the best photoelectric properties.
[0108] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.
Claims
1. A method for preparing cadmium selenide quantum dots, characterized in that, Includes the following steps: (1) Prepare a cadmium source solution, then add a surface modifier, adjust the pH of the solution to 7 with a strong alkaline solution, add a reducing agent, mix well to obtain precursor solution A; (2) Prepare a selenium source solution as precursor solution B; (3) Mix precursor solution B and precursor solution A evenly and heat to 80-100℃ and keep warm for 1-24h to obtain cadmium selenide quantum dots. In step (1), the surface modifier is at least one of mercaptopropionic acid, mercaptoethylamine, mercaptopropylamine, and dodecyl acetic acid. In step (1), the molar ratio of the reducing agent to the cadmium element in the cadmium source is 1:4.5; The reducing agent in step (1) is mercaptoethanol.
2. The method for preparing cadmium selenide quantum dots as described in claim 1, characterized in that, In step (3), the volume ratio of precursor solution A to precursor solution B is 1:(0.25-2).
3. The method for preparing cadmium selenide quantum dots as described in claim 1, characterized in that, In step (1), the cadmium source is at least one of cadmium nitrate and cadmium acetate.
4. The method for preparing cadmium selenide quantum dots as described in claim 1, characterized in that, The surface modifier in step (1) is mercaptopropionic acid.
5. The method for preparing cadmium selenide quantum dots as described in claim 1, characterized in that, The strong alkaline solution in step (1) is a sodium hydroxide solution.
6. The method for preparing cadmium selenide quantum dots as described in claim 1, characterized in that, In step (2), the selenium source is at least one of sodium selenite and sodium selenate.
7. A cadmium selenide quantum dot, characterized in that, It is prepared by the method for preparing cadmium selenide quantum dots according to any one of claims 1-6.
8. The cadmium selenide quantum dot as described in claim 7, characterized in that, The molar ratio of cadmium source to selenium source in the cadmium selenide quantum dots is (0.25-4):
1.
9. A photoelectrochemical device, characterized in that, Including cadmium selenide quantum dots as described in claim 7 or 8.
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