Etching method of lead sulfide quantum dots

Abstract

The invention provides an etching method of lead sulfide quantum dots. A tetrahydrofuran (THF) organic solution has a certain etching effect on lead sulfide (PbS) solid quantum dots at room temperature. The quantum dots used in the method are PbS quantum dots which are synthesized through a cation exchange method or a thermal injection method and have the absorption peak value within the range of 880-1700 nm, a series of quantum dots with different sizes can be obtained by adjusting the concentration of the PbS quantum dots in THF, the more the amount of THF solvent is, the more remarkable the etching effect of the PbS quantum dots is, and the higher the etching efficiency of the PbS quantum dots is. Specifically, the absorption wavelength of the quantum dots is shorter than that before etching. The condition for etching the quantum dots by the THF solution is mild, the operation is simple, and the smaller the absorption peak position is, the more sensitive the THF etching effect is.

Description

Technical Field

[0001] This invention relates to the field of PbS colloidal quantum dot post-processing, and specifically to an etching method for lead sulfide quantum dots. Background Technology

[0002] Short-wave infrared (SWIR) refers to infrared light with wavelengths in the range of 800-2500 nm. It effectively avoids strong light interference from the visible light band while possessing extremely high optical penetration and signal identification capabilities, enabling signal transmission and detection over longer distances and at deeper levels. Due to these unique capabilities, SWIR imaging technology is widely used in civilian and military fields such as night vision devices, component identification, biological detection, remote sensing mapping, and photovoltaic and photoelectric detection. Compared to longer wavelength infrared light, short-wave infrared light around 1000 nm has advantages such as lower manufacturing costs, compatibility with silicon-based photodetectors, and no need for expensive cooling components.

[0003] Materials used in the short-wave infrared optical window include traditional inorganic nanomaterials and organic dyes. Among them, PbS quantum dots, as a typical group IV-VI colloidal semiconductor material, can have their particle size precisely controlled by adjusting the reaction time and precursor concentration during synthesis, achieving accurate positioning of the absorption peak at around 1000 nm, thus possessing unique optical and electrical properties. However, the current mature synthesis reaction conditions for PbS quantum dots are harsh and the process is complex; moreover, the preparation of quantum dots of different sizes requires repeated synthesis experiments, resulting in high costs. In addition, it is difficult to achieve precise control of quantum dot size during actual synthesis, making it difficult to meet the application requirements of some precision scenarios.

[0004] In view of this, it is indeed necessary to provide a simple and efficient method to adjust the size distribution of PbS quantum dots in order to solve the above problems. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention provides an etching method for lead sulfide quantum dots (PbS) quantum dots. This method can be performed directly under ambient conditions by mixing PbS quantum dots with a THF organic solution, thereby controlling the absorption peak position of the PbS quantum dots. This method can yield a series of quantum dots of different sizes, and the absorption wavelength of the etched PbS quantum dots exhibits a blue shift compared to before etching. This method is simple to operate, operates under mild experimental conditions, and quantum dots with smaller absorption peak positions are more sensitive to the etching effect of THF.

[0006] To achieve the above objectives, the first aspect of the present invention provides a method for etching lead sulfide quantum dots, the specific technical solution of which is as follows: A method for etching lead sulfide quantum dots includes the following steps: PbS quantum dots were dissolved in a THF organic solution and etched to obtain a uniform quantum dot solution, wherein the absorption peak of the PbS quantum dots was located in the range of 880-1700 nm. An antisolvent was added to the homogeneous quantum dot solution, and the solution was centrifuged and dried to obtain etched PbS quantum dot solids.

[0007] Furthermore, in the quantum dot solution, the concentration of the PbS quantum dots in the THF organic solution is 0.5-50 mg / mL.

[0008] Furthermore, in the quantum dot solution, the concentration of the PbS quantum dots in the THF organic solution is 1-25 mg / mL.

[0009] Furthermore, the mixing and dissolution of the PbS quantum dots with the THF organic solution is carried out at room temperature.

[0010] Furthermore, the volume of the antisolvent is 4-9 times that of the THF organic solution.

[0011] Furthermore, the antisolvent is ethanol, acetone, or acetonitrile.

[0012] To achieve the above objectives, a second aspect of the present invention provides a lead sulfide quantum dot, the specific technical solution of which is as follows: A lead sulfide quantum dot, wherein the lead sulfide quantum dot is prepared by the etching method described above for lead sulfide quantum dots.

[0013] In summary, the beneficial effects of this invention are as follows: the THF organic solvent etching method of this invention is simple to operate and does not require anhydrous or oxygen-free conditions, and its operating efficiency is extremely high compared with existing chemical synthesis methods. By adjusting the solubility concentration of quantum dots in THF, a series of PbS quantum dots with different size distributions can be effectively obtained in air, and quantum dots with smaller absorption peak positions are more sensitive to the etching effect of THF. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in the embodiments or prior art, the drawings used in the description of the embodiments or prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 A schematic flowchart of an etching method for lead sulfide quantum dots proposed in this invention is shown. Figure 2 The absorption spectra of PbS quantum dots before and after etching in Examples 1-3 of the present invention are shown; Figure 3 The absorption spectra of PbS quantum dots before and after etching in Example 4 of the present invention are shown. Figure 4 The absorption spectra of PbS quantum dots before and after etching in Example 5 of the present invention are shown. Figure 5 The absorption spectra of PbS quantum dots before and after etching in Example 6 of the present invention are shown. Figure 6 The absorption spectra of PbS quantum dots before and after etching in Example 7 of the present invention are shown. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0017] This invention provides a method for etching lead sulfide quantum dots, see reference. Figure 1 As shown, the method includes the following steps: (1) Etching PbS quantum dots with THF organic solvent; Specifically, PbS (lead sulfide) quantum dots are dissolved in THF (tetrahydrofuran) organic solution at room temperature until the PbS quantum dots are completely dissolved to form a homogeneous mixed solution with a concentration of 0.5-50 mg / mL, preferably in the range of 1-25 mg / mL.

[0018] The absorption peak of the PbS quantum dots is located in the range of 880-1700 nm. Depending on the actual situation, the absorption peak of the PbS quantum dots can be set to 880 nm, 996 nm, 1090 nm, 1326 nm or 1684 nm. The PbS quantum dots are synthesized by cation exchange or thermal injection.

[0019] (2) Cleaning and separation of PbS quantum dots.

[0020] Specifically, an antisolvent is added to the mixed solution, and then centrifuged to separate the solid and liquid phases. After removing all the organic solution, the remaining quantum dot solid is placed in a vacuum drying oven and dried at room temperature for 5-10 minutes to obtain the etched PbS quantum dot solid. The volume of the antisolvent is 4-9 times that of the THF organic solution, and the antisolvent is ethanol, acetone, or acetonitrile, etc.

[0021] It should be noted that both solid quantum dots and quantum dot solutions can be etched by long-chain organic solvents containing double bonds. Therefore, THF organic solution can also be added to quantum dot solutions for etching.

[0022] The following section will provide further explanation of this scheme in conjunction with specific experimental values. Example 1 A method for etching lead sulfide quantum dots includes the following steps: (1) Etching of PbS quantum dots mixed with THF organic solvent; PbS quantum dots with an absorption peak of 996 nm, synthesized by cation exchange, were dissolved in THF organic solution at room temperature. The PbS quantum dots needed to be completely dissolved to prepare a homogeneous solution of 25 mg / mL quantum dots.

[0023] (2) Cleaning and separation of PbS quantum dots.

[0024] Nine times the volume of ethanol solution was added to the homogeneous quantum dot solution, and then the solution was centrifuged at high speed in a centrifuge to wash and obtain solid quantum dots. After removing all organic solutions, the remaining quantum dot solid was placed in a vacuum drying oven for drying to obtain etched quantum dot solid.

[0025] Results representation: See Figure 2 The image shown is the absorption diagram of PbS quantum dots after etching, with an absorption peak of 996 nm.

[0026] Example 2 A method for etching lead sulfide quantum dots includes the following steps: (1) Etching of PbS quantum dots mixed with THF organic solvent; PbS quantum dots with an absorption peak of 996 nm, synthesized by cation exchange, were dissolved in THF organic solution at room temperature. The PbS quantum dots needed to be completely dissolved to prepare a homogeneous solution of 5 mg / mL quantum dots.

[0027] (2) Cleaning and separation of PbS quantum dots.

[0028] Add 7 times the volume of acetonitrile solution to the homogeneous quantum dot solution, then centrifuge at high speed in a centrifuge to wash and obtain solid quantum dots. After removing all organic solutions, place the remaining quantum dot solid in a vacuum drying oven to dry, and the etched quantum dot solid can be obtained.

[0029] Results representation: See Figure 2 The image shown is the absorption diagram of PbS quantum dots after etching, with an absorption peak of 996 nm.

[0030] Example 3 A method for etching lead sulfide quantum dots includes the following steps: (1) Etching of PbS quantum dots mixed with THF organic solvent; PbS quantum dots with an absorption peak of 996 nm, synthesized by cation exchange, were dissolved in THF organic solution at room temperature. The PbS quantum dots needed to be completely dissolved to prepare a homogeneous solution of 1 mg / mL quantum dots.

[0031] (2) Cleaning and separation of PbS quantum dots Add 4 times the volume of acetone solution to the quantum dot homogeneous solution, then centrifuge at high speed in a centrifuge to wash and obtain solid quantum dots. After removing all organic solutions, place the remaining quantum dot solid in a vacuum drying oven to dry, and you can obtain the etched quantum dot solid.

[0032] Results representation: See Figure 2 The image shown is the absorption spectrum of PbS quantum dots after etching, with an absorption peak at 996 nm. Absorption spectra of PbS quantum dots with other concentrations after etching are also shown. Figure 2 As shown.

[0033] Example 4 A method for etching lead sulfide quantum dots includes the following steps: (1) Etching of PbS quantum dots mixed with THF organic solvent; PbS quantum dots with an absorption peak of 1090 nm, synthesized by cation exchange, were dissolved in THF organic solution at room temperature. The PbS quantum dots needed to be completely dissolved to prepare a homogeneous solution of 5 mg / mL quantum dots.

[0034] (2) Cleaning and separation of PbS quantum dots.

[0035] Nine volumes of ethanol solution were added to a uniform quantum dot solution, and then the solution was centrifuged at high speed in a centrifuge. After washing, solid quantum dots were obtained. After removing all organic solutions, the remaining quantum dot solids were placed in a vacuum drying oven for drying to obtain etched quantum dot solids.

[0036] Results representation: See Figure 3 The image shown is an absorption diagram of the PbS quantum dots before and after etching in this embodiment.

[0037] Example 5 A method for etching lead sulfide quantum dots includes the following steps: (1) Etching of PbS quantum dots mixed with THF organic solvent; PbS quantum dots with an absorption peak of 1326 nm, synthesized by cation exchange, were dissolved in THF organic solution at room temperature. The PbS quantum dots needed to be completely dissolved to prepare a homogeneous solution of 5 mg / mL quantum dots.

[0038] (2) Cleaning and separation of PbS quantum dots.

[0039] Nine volumes of ethanol solution were added to a uniform quantum dot solution, and then the solution was centrifuged at high speed in a centrifuge. After washing, solid quantum dots were obtained. After removing all organic solutions, the remaining quantum dot solids were placed in a vacuum drying oven for drying to obtain etched quantum dot solids.

[0040] Results representation: See Figure 4 The image shown is an absorption diagram of the PbS quantum dots before and after etching in this embodiment.

[0041] Example 6 A method for etching lead sulfide quantum dots includes the following steps: (1) Etching of PbS quantum dots with THF organic solvent PbS quantum dots with an absorption peak of 1700 nm, synthesized by cation exchange, were dissolved in THF organic solution at room temperature. The PbS quantum dots needed to be completely dissolved to obtain a homogeneous solution of 5 mg / mL quantum dots.

[0042] (2) Cleaning and separation of PbS quantum dots.

[0043] Add 4 times the volume of acetone solution to the quantum dot homogeneous solution, then centrifuge at high speed in a centrifuge to wash and obtain solid quantum dots. After removing all organic solutions, place the remaining quantum dot solid in a vacuum drying oven to dry, and you can obtain the etched quantum dot solid.

[0044] Results representation: See Figure 5 The image shown is an absorption diagram of the PbS quantum dots before and after etching in this embodiment.

[0045] Example 7 A method for etching lead sulfide quantum dots includes the following steps: (1) Etching of PbS quantum dots mixed with THF organic solvent; PbS quantum dots with an absorption peak of 880 nm, synthesized in one step by hot injection, were dissolved in THF organic solution at room temperature. The PbS quantum dots needed to be completely dissolved to obtain a homogeneous solution of 5 mg / mL quantum dots.

[0046] (2) Cleaning and separation of PbS quantum dots.

[0047] Add 7 times the volume of acetonitrile solution to the homogeneous quantum dot solution, then centrifuge at high speed in a centrifuge to wash and obtain solid quantum dots. After removing all organic solutions, place the remaining quantum dot solid in a vacuum drying oven to dry, and the etched quantum dot solid can be obtained.

[0048] Results representation: See Figure 6The image shown is an absorption diagram of the PbS quantum dots before and after etching in this embodiment.

[0049] From the above Figures 2-6 It can be seen that quantum dots can be etched in THF organic solutions with a concentration range of 0.5-50 mg / mL. The lower the concentration of quantum dots, the more significant the etching effect, specifically manifested in the greater difference in the absorption wavelength of quantum dots before and after etching.

[0050] In summary, this invention proposes an etching method for lead sulfide quantum dots. By adjusting the solubility concentration of PbS quantum dots in a THF organic solution, different degrees of etching can be achieved. Then, an excess of antisolvent is added to the homogeneous quantum dot solution, followed by centrifugation and drying to obtain a series of PbS quantum dot solids with different size distributions. Compared to traditional chemical synthesis methods for quantum dots, such as cation exchange or thermal injection, THF solvent etching is simpler to operate, has milder experimental conditions, and exhibits greater etching effect for quantum dots with smaller absorption peaks.

[0051] It should be noted that although the present invention has been disclosed above with specific embodiments, the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Those skilled in the art can make various modifications and refinements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the scope defined in the claims.

Claims

1. A method for etching lead sulfide quantum dots, characterized in that, Includes the following steps: PbS quantum dots were dissolved in a THF organic solution and etched to obtain a uniform quantum dot solution, wherein the absorption peak of the PbS quantum dots was located in the range of 880-1700 nm. An antisolvent was added to the homogeneous quantum dot solution, and the solution was centrifuged and dried to obtain etched PbS quantum dot solids.

2. The etching method for lead sulfide quantum dots according to claim 1, characterized in that, In the quantum dot solution, the concentration of the PbS quantum dots in the THF organic solution is 0.5-50 mg / mL.

3. The etching method for lead sulfide quantum dots according to claim 2, characterized in that, In the quantum dot solution, the concentration of the PbS quantum dots in the THF organic solution is 1-25 mg / mL.

4. The etching method for lead sulfide quantum dots according to claim 1, characterized in that, The PbS quantum dots were mixed and dissolved with the THF organic solution at room temperature.

5. The etching method for lead sulfide quantum dots according to any one of claims 1-4, characterized in that, The volume of the antisolvent is 4-9 times that of the THF organic solution.

6. The etching method for lead sulfide quantum dots according to claim 5, characterized in that, The antisolvent is ethanol, acetone, or acetonitrile.

7. A lead sulfide quantum dot, characterized in that, The lead sulfide quantum dots are prepared by the etching method for lead sulfide quantum dots according to any one of claims 1-7.

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