Preparation method of monodisperse indium antimonide colloidal quantum dots with controllable size

Abstract

The invention discloses a preparation method of size-controllable monodisperse indium antimonide colloidal quantum dots, which comprises the following steps: (1) preparing a precursor solution containing an indium precursor and an antimony precursor, and heating the precursor solution at 50-300 DEG C for 1-20 minutes; (2) in an inert atmosphere, raising the temperature of a solvent to a reaction temperature, injecting a reducing agent, then injecting the heated precursor solution, maintaining the reaction temperature for 10s-30min, and then stopping the reaction to obtain monodisperse indium antimonide colloidal quantum dots; the reaction temperature is 250 to 300 DEG C; in the reaction system in the step (2), the concentration of the indium precursor and the concentration of the antimony precursor are independently 0.4-8 mmol / L; the size of the monodisperse indium antimonide colloidal quantum dot is regulated and controlled by regulating and controlling the concentration of a precursor in a reaction system, the injection mode of a precursor solution and the growth time. According to the preparation method disclosed by the invention, accurate regulation and control on the size of the indium antimonide colloidal quantum dot can be realized without the help of a complex size selective precipitation technology.

Description

Technical Field

[0001] The present invention relates to the field of cutting-edge new material technology, and in particular to a method for preparing size-controllable monodisperse indium antimonide colloidal quantum dots. Background Art

[0002] InSb colloidal quantum dots have shown excellent application potential in the short-wave to mid-wave infrared spectral region due to their unique narrow bandgap characteristics (only 0.17 eV at 300K), large exciton Bohr radius (up to 60nm) and the absence of toxic heavy metal elements such as lead and mercury, thus arousing widespread research interest. However, due to the high covalent bond characteristics of InSb materials, it is in sharp contrast to traditional II-VI or V-VI compound semiconductors in terms of synthesis conditions. Specifically, the synthesis of InSb often requires the use of highly reactive precursors and the addition of strong reducing agents, and is carried out in a high temperature environment.

[0003] In 2012, the Talapin group developed the first successful synthesis protocol for InSb colloidal quantum dots with size tunability (3.4-6.5 nm) and narrow polydispersity (reduced to about 15% by post-synthesis size-selective precipitation techniques) by using lithium triethylborohydride (LiEt 3 BH, also known as superhydride), silyl amide antimony (Sb[N(Si(Me) 3 ) 2 ] 3 ) and InCl 3 Co-reduction at room temperature, and then heated to the growth temperature (240-260°C) (Liu, W.; Chang, AY; Schaller, RD; Talapin, DV, Colloidal InSb Nanocrystals. Journal of the American Chemical Society 2012, 134 (50), 20258-20261.). However, on the one hand, the size range of the obtained quantum dot product is small, which cannot meet the needs of longer wavelength response; on the other hand, the monodispersity of the obtained quantum dot product is extremely poor, and complex size-selective precipitation technology is required before it can be used.

[0004] In 2020, the Donega team successfully constructed InSb complexes using commercially available compounds, namely indium trichloride (InCl3), tris(dimethylamino)antimony (Sb[NMe2]3) and primary alkylamines, through in situ reactions at room temperature. Furthermore, with the help of these carefully prepared complexes, the team successfully synthesized InSb colloidal quantum dots with diameters ranging from 2.8 to 18.2nm by a rapid co-reduction method at temperatures above 230°C (Busatto, S.; de Ruiter, M.; Jastrzebski, JT; Albrecht, W.; Pinchetti, V.; Brovelli, S.; Bals, S.; Moret, M.-E.; de Mello Donega, CJ An, Luminescent colloidal InSb quantum dots from In situ generated single-source precursor. 2020, 14(10), 13146-13160.). Although Donega's team has increased the size control range to 2.8nm to 18.2nm, the size polydispersity of the resulting quantum dot product samples still requires the use of complex size-selective precipitation technology to be reduced to below 10%, which increases the difficulty of synthesis, limits the accuracy and flexibility of quantum dot size control, and is not easy to apply and prepare on a large scale.

[0005] This patented technology successfully overcomes the size control problem existing in the existing synthesis method, expands the size control range to 5.8nm to 22.4nm, and all products are not obtained through size selective precipitation technology. In this patent, technical parameters such as precursor activity, concentration and growth temperature work together to achieve precise control of the size of InSb colloidal quantum dots, thereby achieving the response of InSb quantum dots in the near-infrared to mid-wave infrared light region, laying the foundation for key core materials for InSb colloidal quantum dots in the fields of infrared spectroscopy detection and optoelectronic devices. Summary of the invention

[0006] The present invention provides a method for preparing size-controllable monodisperse indium antimonide colloidal quantum dots. The preparation method of the present invention can achieve precise control of the size of the indium antimonide colloidal quantum dots without the need for complex size-selective precipitation technology.

[0007] The technical solution of the present invention is as follows:

[0008] A method for preparing size-controllable monodisperse indium antimonide colloidal quantum dots comprises the following steps:

[0009] (1) preparing a precursor solution containing an indium precursor and an antimony precursor, and heating the precursor solution at 50 to 300° C. for 1 to 20 minutes;

[0010] (2) In an inert atmosphere, the solvent is heated to a reaction temperature, a reducing agent is injected, and then the heated precursor solution is injected, and the reaction temperature is maintained for 10 seconds to 30 minutes before stopping the reaction to obtain monodisperse indium antimonide colloidal quantum dots;

[0011] The reaction temperature is 250-300°C;

[0012] In the reaction system of step (2), the concentrations of the indium precursor and the antimony precursor are independently 0.4 to 8 mmol / L;

[0013] The size of monodisperse indium antimonide colloidal quantum dots is controlled by regulating the concentration of the precursor in the reaction system, the injection method of the precursor solution, and the growth time.

[0014] Preferably, before injecting the precursor solution, the precursor solution is heated at 60-120° C. for 5-15 min.

[0015] The present invention heats the precursor solution before injecting it to enhance its reaction activity, so that the prepared indium antimonide colloidal quantum dots have a larger size and good monodispersity. The size and distribution of the quantum dot product synthesized by heating the precursor solution at a high temperature of 60 to 120°C are significantly better than the result of heating the precursor solution below 60°C.

[0016] Preferably, in step (2), the reaction temperature is 250-280° C. When the synthesis temperature is lower than 250° C., a large amount of by-product Sb single substance will be generated, and the by-product is difficult to separate; when the temperature is raised to above 250° C., the crystallinity is enhanced, and the Sb single substance almost completely disappears.

[0017] Preferably, in step (2), the reaction time is 30s to 30min. As the reaction time increases, the size of the quantum dots increases, but if the reaction time is too long, the monodispersity of the quantum dots deteriorates. When the reaction time is 30s to 30min, the size of the quantum dots obtained is moderate and the monodispersity is excellent.

[0018] Preferably, in the reaction system of step (2), the concentrations of the indium precursor and the antimony precursor are independently 0.04 to 0.8 mmol / L.

[0019] More preferably, in the reaction system of step (2), the concentrations of the indium precursor and the antimony precursor are independently 0.2 to 0.8 mmol / L.

[0020] The higher the precursor concentration, the larger the size of the obtained quantum dots and the better the monodispersity of the quantum dots. When the concentrations of the indium precursor and the antimony precursor are independently 0.2 to 0.8 mmol / L, the obtained quantum dots are of moderate size and have better monodispersity.

[0021] Preferably, in step (2), the precursor solution is injected by rapid injection or dropwise addition; rapid injection means adding the precursor solution all at once within 0.1 to 1 second. Rapid injection can obtain larger-sized InSb colloidal quantum dots, while dropwise addition can obtain smaller-sized InSb colloidal quantum dots.

[0022] Preferably, the indium precursor and antimony precursor are at least one of indium chloride, indium bromide, indium iodide, indium acetate, and indium fatty carboxylate; the antimony precursor is at least one of antimony chloride, antimony bromide, antimony iodide, and tris(dimethylamino)antimony.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] Through the preparation method of the present invention, the controllable preparation of InSb colloidal quantum dots with adjustable sizes in a wide range of 5nm to 22.4nm is successfully achieved, and without the use of complex size-selective precipitation technology, the InSb colloidal quantum dots show extremely narrow size distribution, reflecting excellent monodispersity. The present invention realizes the response of InSb colloidal quantum dots in the near-infrared to mid-wave infrared spectral region. This result opens up a new prospect for the application of InSb colloidal quantum dots in the fields of infrared spectral detection, optoelectronic devices, etc., marking a major breakthrough in the development of semiconductor material science and technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The transmission electron microscope (TEM) image (a) and size distribution image (b) of InSb colloidal quantum dots prepared in Example 1 of the present invention;

[0026] Figure 2 The transmission electron microscope (TEM) image (a) and size distribution image (b) of InSb colloidal quantum dots prepared in Example 2 of the present invention;

[0027] Figure 3 The transmission electron microscope (TEM) image (a) and size distribution image (b) of InSb colloidal quantum dots prepared in Example 3 of the present invention;

[0028] Figure 4 The transmission electron microscope TEM image (a) and size distribution diagram (b) of InSb colloidal quantum dots prepared in Example 4 of the present invention;

[0029] Figure 5The transmission electron microscope (TEM) image (a) and size distribution image (b) of InSb colloidal quantum dots prepared in Example 5 of the present invention;

[0030] Figure 6 The transmission electron microscope TEM image (a) and size distribution diagram (b) of InSb colloidal quantum dots prepared in Example 6 of the present invention;

[0031] Figure 7 The transmission electron microscope TEM image (a) and size distribution diagram (b) of InSb colloidal quantum dots prepared in Example 7 of the present invention;

[0032] Figure 8 The transmission electron microscope TEM image (a) and size distribution diagram (b) of InSb colloidal quantum dots prepared in Example 8 of the present invention;

[0033] Fig. 9 The transmission electron microscope (TEM) image (a) and size distribution image (b) of InSb colloidal quantum dots prepared in Example 9 of the present invention;

[0034] Fig.10 The Fourier infrared absorption spectrum of the 12.0 nm-sized InSb colloidal quantum dots prepared in Example 4 of the present invention (a) and the relationship between the characteristic absorption peak position of the InSb colloidal quantum dots and the size d (nm) (b);

[0035] Fig.11 The Fourier infrared absorption spectrum of the 17.8 nm InSb colloidal quantum dots prepared in Example 8 of the present invention (a) and the relationship between the characteristic absorption peak position of the InSb colloidal quantum dots and the size d (nm) (b);

[0036] Fig.12 TEM image (a) of the InSb colloidal quantum dots prepared in Example 10 of the present invention and TEM image (b) of the InSb colloidal quantum dots prepared in Example 11;

[0037] Fig.13 1 is the XRD diffraction spectrum of InSb colloidal quantum dots prepared in Examples 10, 12-14 of the present invention. DETAILED DESCRIPTION

[0038] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be pointed out that the embodiments described below are intended to facilitate the understanding of the present invention and do not have any limiting effect on the present invention.

[0039] Embodiment 1:

[0040] A method for preparing monodisperse InSb colloidal quantum dots with large-scale size control:

[0041] (1) Take 10 mL of lithium triethylborohydride reducing agent solution (LiEt 3 BH) and 10 mL of n-octyl ether solvent were mixed into a pre-prepared container and stirred to ensure uniform mixing of the solution.

[0042] (2) Weigh 0.78 mmol of indium chloride precursor powder and antimony chloride precursor powder respectively, pour them into a mixture of 2 ml of toluene and 0.6 ml of oleylamine (or other fatty amine), and stir to mix well.

[0043] (3) heating the precursor solution prepared in step (2) at 75° C. until the precursor powder and particles are completely dissolved to form a clear solution;

[0044] (4) Place 5 mL of oleylamine in a 25 mL three-necked flask, introduce argon and stir, exhaust, heat to 270°C, inject 1.5 mL of the lithium triethylborohydride solution prepared in step (1), heat the precursor solution obtained in step (3) at 100°C for 10 min, then quickly inject 10 μL of the heated precursor solution as quickly as possible (within 0.5 s) to maintain growth at the reaction temperature.

[0045] (5) After growing for 5 min and reaching the target growth time, the reaction solution obtained in step (4) is quickly stopped by using cold water, cooled to room temperature, purified by using toluene and methanol solvents, and dispersed and stored in toluene or tetrachloroethylene solution.

[0046] The TEM image of InSb colloidal quantum dots synthesized in Example 1 is as follows: Figure 1 As shown in (a), its size distribution histogram is as follows Figure 1 As shown in (b), the InSb colloidal quantum dots synthesized in Example 1 have an average size of 5.8 nm and a monodispersity coefficient of about 12.8% (the monodispersity coefficient is the ratio of the standard deviation to the average diameter).

[0047] Embodiment 2:

[0048] A method for preparing monodisperse InSb colloidal quantum dots with large-scale size control:

[0049] (1) Take 10 mL of lithium triethylborohydride reducing agent solution (LiEt 3 BH) and 10 mL of n-octyl ether solvent were mixed into a pre-prepared container and stirred to ensure uniform mixing of the solution.

[0050] (2) Weigh 0.78 mmol of indium chloride precursor powder and antimony chloride precursor powder respectively, pour them into a mixture of 2 ml of toluene and 0.6 ml of oleylamine (or other fatty amine), and stir to mix well.

[0051] (3) heating the precursor solution prepared in step (2) at 75° C. until the precursor powder and particles are completely dissolved to form a clear solution;

[0052] (4) Place 5 mL of oleylamine in a 25 mL three-necked flask, introduce argon and stir, exhaust, heat to 270°C, inject 1.5 mL of the lithium triethylborohydride solution prepared in step (1), heat the precursor solution obtained in step (3) at 100°C for 10 min, then quickly inject 12 μL of the heated precursor solution as quickly as possible (within 0.5 s) to maintain growth at the reaction temperature.

[0053] (5) After growing for 5 min and reaching the target growth time, the reaction solution obtained in step (4) is quickly stopped by using cold water, cooled to room temperature, purified by using toluene and methanol solvents, and dispersed and stored in toluene or tetrachloroethylene solution.

[0054] The TEM image of InSb colloidal quantum dots synthesized in Example 2 is as follows: Figure 2 As shown in (a), its size distribution histogram is as follows Figure 2 As shown in (b), the InSb colloidal quantum dots synthesized in Example 2 have an average size of 7.8 nm and a monodispersity of about 20.5% (the monodispersity coefficient is the ratio of the standard deviation to the average diameter).

[0055] Embodiment 3:

[0056] A method for preparing monodisperse InSb colloidal quantum dots with large-scale size control:

[0057] (1) Take 10 mL of lithium triethylborohydride reducing agent solution (LiEt 3 BH) and 10 mL of n-octyl ether solvent were mixed into a pre-prepared container and stirred to ensure uniform mixing of the solution.

[0058] (2) 0.78 mmol of indium chloride precursor and antimony chloride precursor powders were weighed and poured into a mixture of 2 ml of toluene and 0.6 ml of oleylamine (or other fatty amines), and stirred to mix well.

[0059] (3) heating the precursor solution prepared in step (2) at 75° C. until the precursor powder and particles are completely dissolved to form a clear solution;

[0060] (4) Place 5 mL of oleylamine in a 25 mL three-necked flask, introduce argon and stir, exhaust, heat to 270°C, inject 1.5 mL of the lithium triethylborohydride solution prepared in step (1), heat the precursor solution obtained in step (3) at 100°C for 10 min, then quickly inject 12 μL of the heated precursor solution as quickly as possible (within 0.5 s) to maintain growth at the reaction temperature.

[0061] (5) After growing for 30 minutes and reaching the target growth time, the reaction solution obtained in step (4) is quickly stopped by using cold water, cooled to room temperature, purified by using toluene and methanol solvents, and dispersed and stored in toluene or tetrachloroethylene solution.

[0062] TEM images of InSb colloidal quantum dots synthesized in Example 3 are shown in Figure 3 As shown in (a), its size distribution histogram is as follows Figure 3 As shown in (b) in the figure, the InSb colloidal quantum dots synthesized in Example 3 have an average size of 11.5 nm and a monodispersity of about 12.4% (the monodispersity coefficient is the ratio of the standard deviation to the average diameter).

[0063] Embodiment 4:

[0064] A method for preparing monodisperse InSb colloidal quantum dots with large-scale size control:

[0065] (1) Take 10 mL of lithium triethylborohydride reducing agent solution (LiEt 3 BH) and 10 mL of n-octyl ether solvent were mixed into a pre-prepared container and stirred to ensure uniform mixing of the solution.

[0066] (2) 0.78 mmol of indium chloride precursor and antimony chloride precursor powders were weighed and poured into a mixture of 2 ml of toluene and 0.6 ml of oleylamine (or other fatty amines), and stirred to mix well.

[0067] (3) heating the precursor solution prepared in step (2) at 75° C. until the precursor powder and particles are completely dissolved to form a clear solution;

[0068] (4) Place 5 mL of oleylamine in a 25 mL three-necked flask, introduce argon gas and stir, exhaust, heat to 270°C, inject 1.5 mL of the lithium triethylborohydride solution prepared in step (1), heat the precursor solution obtained in step (3) at 100°C for 10 min, then slowly inject 60 μL of the heated precursor solution dropwise to maintain the growth at the reaction temperature.

[0069] (5) After growing for 5 min and reaching the target growth time, the reaction solution obtained in step (4) is quickly stopped by using cold water, cooled to room temperature, purified by using toluene and methanol solvents, and dispersed and stored in toluene or tetrachloroethylene solution.

[0070] TEM images of InSb colloidal quantum dots synthesized in Example 4 are shown in Figure 4 As shown in (a), its size distribution histogram is as follows Figure 4As shown in (b) in the figure, the InSb colloidal quantum dots synthesized in Example 4 have an average size of 12.0 nm and a monodispersity of about 14.2% (the monodispersity coefficient is the ratio of the standard deviation to the average diameter).

[0071] Embodiment 5:

[0072] A method for preparing monodisperse InSb colloidal quantum dots with large-scale size control:

[0073] (1) Take 10 mL of lithium triethylborohydride reducing agent solution (LiEt 3 BH) and 10 mL of n-octyl ether solvent were mixed into a pre-prepared container and stirred to ensure uniform mixing of the solution.

[0074] (2) 0.78 mmol of indium chloride precursor and antimony chloride precursor powders were weighed and poured into a mixture of 2 ml of toluene and 0.6 ml of oleylamine (or other fatty amines), and stirred to mix well.

[0075] (3) heating the precursor solution prepared in step (2) at 75° C. until the precursor powder and particles are completely dissolved to form a clear solution;

[0076] (4) Place 5 mL of oleylamine in a 25 mL three-necked flask, introduce argon and stir, exhaust, heat to 270°C, inject 1.5 mL of the lithium triethylborohydride solution prepared in step (1), heat the precursor solution obtained in step (3) at 100°C for 10 min, then quickly inject 120 μL of the heated precursor solution as quickly as possible (within 0.5 s) to maintain growth at the reaction temperature.

[0077] (5) After growing for 60 seconds and reaching the target growth time, the reaction solution obtained in step (4) is quickly stopped by using cold water, cooled to room temperature, purified using toluene and methanol solvents, and dispersed and stored in toluene or tetrachloroethylene solution.

[0078] TEM images of InSb colloidal quantum dots synthesized in Example 5 are shown in Figure 5 As shown in (a), its size distribution histogram is as follows Figure 5 As shown in (b) in the figure, the average size of the InSb colloidal quantum dots synthesized in Example 5 is 14.7 nm, and the monodispersity coefficient is about 10.5% (the monodispersity coefficient is the ratio of the standard deviation to the average diameter).

[0079] Embodiment 6:

[0080] A method for preparing monodisperse InSb colloidal quantum dots with large-scale size control:

[0081] (1) Take 10 mL of lithium triethylborohydride reducing agent solution (LiEt 3BH) and 10 mL of n-octyl ether solvent were mixed into a pre-prepared container and stirred to ensure uniform mixing of the solution.

[0082] (2) 0.78 mmol of indium chloride precursor and antimony chloride precursor powders are weighed and poured into a mixture of 2 ml of toluene and 0.6 ml of oleylamine (or other fatty amines), and stirred to mix evenly.

[0083] (3) heating the precursor solution prepared in step (2) at 75° C. until the precursor powder and particles are completely dissolved to form a clear solution;

[0084] (4) Place 5 mL of oleylamine in a 25 mL three-necked flask, introduce argon and stir, exhaust, heat to 270°C, inject 1.5 mL of the lithium triethylborohydride solution prepared in step (1), heat the precursor solution obtained in step (3) at 100°C for 10 min, then quickly inject 160 μL of the heated precursor solution as quickly as possible (within 0.5 s) to maintain growth at the reaction temperature.

[0085] (5) After growing for 60 seconds and reaching the target growth time, the reaction solution obtained in step (4) is quickly stopped by using cold water, cooled to room temperature, purified using toluene and methanol solvents, and dispersed and stored in toluene or tetrachloroethylene solution.

[0086] TEM images of InSb colloidal quantum dots synthesized in Example 6 are shown in Figure 6 As shown in (a), its size distribution histogram is as follows Figure 6 As shown in (b) in the figure, the average size of the InSb colloidal quantum dots synthesized in Example 6 is 15.3 nm, and the monodispersity coefficient is about 9.2% (the monodispersity coefficient is the ratio of the standard deviation to the average diameter).

[0087] Embodiment 7:

[0088] A method for preparing monodisperse InSb colloidal quantum dots with large-scale size control:

[0089] (1) Take 10 mL of lithium triethylborohydride reducing agent solution (LiEt 3 BH) and 10 mL of n-octyl ether solvent were mixed into a pre-prepared container and stirred to ensure uniform mixing of the solution.

[0090] (2) 0.78 mmol of indium chloride precursor and antimony chloride precursor powders were weighed and poured into a mixture of 2 ml of toluene and 0.6 ml of oleylamine (or other fatty amines), and stirred to mix well.

[0091] (3) heating the precursor solution prepared in step (2) at 75° C. until the precursor powder and particles are completely dissolved to form a clear solution;

[0092] (4) Place 5 mL of oleylamine in a 25 mL three-necked flask, introduce argon and stir, exhaust, heat to 270°C, inject 1.5 mL of the lithium triethylborohydride solution prepared in step (1), heat the precursor solution obtained in step (3) at 100°C for 10 min, then quickly inject 100 μL of the heated precursor solution as quickly as possible (within 0.5 s) to maintain growth at the reaction temperature.

[0093] (5) After growing for 40 seconds and reaching the target growth time, the reaction solution obtained in step (4) is quickly stopped by using cold water, cooled to room temperature, purified using toluene and methanol solvents, and dispersed and stored in toluene or tetrachloroethylene solution.

[0094] TEM images of InSb colloidal quantum dots synthesized in Example 7 are shown in Figure 7 As shown in (a), its size distribution histogram is as follows Figure 7 As shown in (b), the average size of the InSb colloidal quantum dots synthesized in Example 7 is 17.1 nm, and the monodispersity coefficient is about 8.3% (the monodispersity coefficient is the ratio of the standard deviation to the average diameter).

[0095] Embodiment 8:

[0096] A method for preparing monodisperse InSb colloidal quantum dots with large-scale size control

[0097] (1) Take 10 mL of lithium triethylborohydride reducing agent solution (LiEt 3 BH) and 10 mL of n-octyl ether solvent were mixed into a pre-prepared container and stirred to ensure uniform mixing of the solution.

[0098] (2) 0.78 mmol of indium chloride precursor and antimony chloride precursor powders were weighed and poured into a mixture of 2 ml of toluene and 0.6 ml of oleylamine (or other fatty amines), and stirred to mix well.

[0099] (3) heating the precursor solution prepared in step (2) at 75° C. until the precursor powder and particles are completely dissolved to form a clear solution;

[0100] (4) Place 5 mL of oleylamine in a 25 mL three-necked flask, introduce argon and stir, exhaust, heat to 270°C, inject 1.5 mL of the lithium triethylborohydride solution prepared in step (1), heat the precursor solution obtained in step (3) at 100°C for 10 min, then quickly inject 100 μL of the heated precursor solution as quickly as possible (within 0.5 s) to maintain growth at the reaction temperature.

[0101] (5) After growing for 60 seconds and reaching the target growth time, the reaction solution obtained in step (4) is quickly stopped by using cold water, cooled to room temperature, purified using toluene and methanol solvents, and dispersed and stored in toluene or tetrachloroethylene solution.

[0102] TEM images of InSb colloidal quantum dots synthesized in Example 8 are as follows: Figure 8 As shown in (a), its size distribution histogram is as follows Figure 8 As shown in (b), the average size of the InSb colloidal quantum dots synthesized in Example 8 is 17.8 nm, and the monodispersity coefficient is about 9.1% (the monodispersity coefficient is the ratio of the standard deviation to the average diameter).

[0103] Embodiment 9:

[0104] A method for preparing monodisperse InSb colloidal quantum dots with large-scale size control:

[0105] (1) Take 10 mL of lithium triethylborohydride reducing agent solution (LiEt 3 BH) and 10 mL of n-octyl ether solvent were mixed into a pre-prepared container and stirred to ensure uniform mixing of the solution.

[0106] (2) 0.78 mmol of indium chloride precursor and antimony chloride precursor powders were weighed and poured into a mixture of 2 ml of toluene and 0.6 ml of oleylamine (or other fatty amines), and stirred to mix well.

[0107] (3) heating the precursor solution prepared in step (2) at 75° C. until the precursor powder and particles are completely dissolved to form a clear solution;

[0108] (4) Place 5 mL of oleylamine in a 25 mL three-necked flask, introduce argon and stir, exhaust, heat to 270°C, inject 1.5 mL of the lithium triethylborohydride solution prepared in step (1), heat the precursor solution obtained in step (3) at 100°C for 10 min, then quickly inject 60 μL of the heated precursor solution as quickly as possible (within 0.5 s) to maintain growth at the reaction temperature.

[0109] (5) After growing for 5 min and reaching the target growth time, the reaction solution obtained in step (4) is quickly stopped by using cold water, cooled to room temperature, purified by using toluene and methanol solvents, and dispersed and stored in toluene or tetrachloroethylene solution.

[0110] TEM images of InSb colloidal quantum dots synthesized in Example 9 are as follows: Fig. 9 As shown in (a), its size distribution histogram is as follows Fig. 9As shown in (b), the average size of the InSb colloidal quantum dots synthesized in Example 9 is 22.4 nm, and the monodispersity coefficient is about 5.6% (the monodispersity coefficient is the ratio of the standard deviation to the average diameter).

[0111] Embodiment 10:

[0112] Preparation of InSb colloidal quantum dots at different precursor solution preheating temperatures:

[0113] (1) Take 10 mL of lithium triethylborohydride reducing agent solution (LiEt 3 BH) and 10 mL of n-octyl ether solvent were mixed into a pre-prepared container and stirred to ensure uniform mixing of the solution.

[0114] (2) 0.78 mmol of indium chloride precursor and antimony chloride precursor powders were weighed and poured into a mixture of 2 ml of toluene and 0.6 ml of oleylamine (or other fatty amines), and stirred to mix well.

[0115] (3) heating the precursor solution prepared in step (2) at 75° C. until the precursor powder and particles are completely dissolved to form a clear solution;

[0116] (4) Place 5 mL of oleylamine in a 25 mL three-necked flask, introduce argon and stir, exhaust, heat to 270°C, inject 1.5 mL of the lithium triethylborohydride solution prepared in step (1), heat the precursor solution obtained in step (3) at 50°C for 10 min, then quickly inject 120 μL of the heated precursor solution as quickly as possible (within 0.5 s) to maintain growth at the reaction temperature.

[0117] (5) After growing for 10 minutes and reaching the target growth time, the reaction solution obtained in step (4) is quickly stopped by using cold water, cooled to room temperature, purified using toluene and methanol solvents, and dispersed and stored in toluene or tetrachloroethylene solution.

[0118] Example 10 The precursor solution was heated at 50°C for 10 minutes to synthesize the InSb colloidal quantum dots. Fig.12 As shown in (a).

[0119] Embodiment 11:

[0120] Preparation of InSb colloidal quantum dots at different precursor solution preheating temperatures:

[0121] (1) Take 10 mL of lithium triethylborohydride reducing agent solution (LiEt 3 BH) and 10 mL of n-octyl ether solvent were mixed into a pre-prepared container and stirred to ensure uniform mixing of the solution.

[0122] (2) 0.78 mmol of indium chloride precursor and antimony chloride precursor powders were weighed and poured into a mixture of 2 ml of toluene and 0.6 ml of oleylamine (or other fatty amines), and stirred to mix well.

[0123] (3) heating the precursor solution prepared in step (2) at 75° C. until the precursor powder and particles are completely dissolved to form a clear solution;

[0124] (4) Place 5 mL of oleylamine in a 25 mL three-necked flask, introduce argon and stir, exhaust, heat to 270°C, inject 1.5 mL of the lithium triethylborohydride solution prepared in step (1), heat the precursor solution obtained in step (3) at 100°C for 10 min, then quickly inject 120 μL of the heated precursor solution as quickly as possible (within 0.5 s) to maintain growth at the reaction temperature.

[0125] (5) After growing for 10 minutes and reaching the target growth time, the reaction solution obtained in step (4) is quickly stopped by using cold water, cooled to room temperature, purified using toluene and methanol solvents, and dispersed and stored in toluene or tetrachloroethylene solution.

[0126] Example 11 The precursor solution was heated at 100°C for 10 minutes to synthesize the InSb colloidal quantum dots. Fig.12 As shown in (b). Fig.12 It can be seen from the transmission electron microscope TEM images (a) and (b) that when the synthesis temperature is 270°C, the size and distribution of the quantum dot products synthesized by heating the precursor at 100°C are significantly better than those obtained by heating the precursor at 50°C.

[0127] Embodiment 12-14:

[0128] Preparation of InSb colloidal quantum dot samples at different synthesis temperatures:

[0129] (1) Take 10 mL of lithium triethylborohydride reducing agent solution (LiEt 3 BH) and 10 mL of n-octyl ether solvent were mixed into a pre-prepared container and stirred to ensure uniform mixing of the solution.

[0130] (2) 0.78 mmol of indium chloride precursor and antimony chloride precursor powders were weighed and poured into a mixture of 2 ml of toluene and 0.6 ml of oleylamine (or other fatty amines), and stirred to mix well.

[0131] (3) heating the precursor solution prepared in step (2) at 75° C. until the precursor powder and particles are completely dissolved to form a clear solution;

[0132] (4) Place 5 mL of oleylamine in a 25 mL three-necked flask, introduce argon and stir, then exhaust. Heat the samples of Examples 12-14 to 240°C, 250°C, and 260°C, respectively, and inject 1.5 mL of the lithium triethylborohydride solution prepared in step (1). Heat the precursor solution obtained in step (3) at 50°C for 10 min, then quickly inject 120 μL of the heated precursor solution as quickly as possible (within 0.5 s) to maintain growth at the reaction temperature.

[0133] (5) After growing for 10 minutes and reaching the target growth time, the reaction solution obtained in step (4) is quickly stopped by using cold water, cooled to room temperature, purified using toluene and methanol solvents, and dispersed and stored in toluene or tetrachloroethylene solution.

[0134] The XRD diffraction spectra of InSb colloidal quantum dots synthesized in Examples 12-14 and Example 10 at synthesis temperatures of 240°C, 250°C, 260°C, and 270°C are shown in FIG. Fig.13 As shown in the attached Fig.13 From the XRD spectrum results, it can be seen that when the synthesis temperature is lower than 250°C, a large amount of by-product Sb single substance will be generated, and the by-product is difficult to separate; when the temperature is increased to 270°C, the crystallinity is enhanced and the Sb single substance almost completely disappears.

[0135] Comparison of embodiments:

[0136] (1) Different concentration conditions, other conditions are the same:

[0137] i. Under the rapid injection mode with a growth time of 5 min and a volume of 10 μl of the injected precursor solution, the average size of the quantum dots was 5.8 nm (Example 1).

[0138] ii. Under the rapid injection mode with a growth time of 5 min, when the volume of the injected precursor solution is 12 μl, the average size of the quantum dots is 7.8 nm (Example 2).

[0139] iii. Under the rapid injection mode with a growth time of 5 min, when the volume of the injected precursor solution is 60 μl, the average size of the quantum dots is 22.4 nm (Example 9).

[0140] iv. When the growth time is 60 s and the injection mode is rapid injection, when the volume of the injected precursor solution is 120 μL, the average size of the quantum dots is 14.7 nm (Example 5).

[0141] v. When the growth time is 60 s and the injection mode is rapid injection, when the volume of the injected precursor solution is 160 μL, the average size of the quantum dots is 15.3 nm (Example 6).

[0142] (2) Different injection methods, other conditions are the same:

[0143] i. The volume of the injected precursor solution is 60 μL, and the growth time is 5 min. When the slow injection method is selected, the average size of the quantum dots is 12.0 nm (Example 4).

[0144] ii. The volume of the injected precursor solution is 60 μL, and the growth time is 5 min. When the rapid injection method is selected, the average size of the quantum dots is 22.4 nm (Example 9).

[0145] (3) Different growth times, other conditions are the same:

[0146] i. The volume of the injected precursor solution was 12 μL. Under the rapid injection mode, when the growth time was 5 min, the average size of the quantum dots was 7.8 nm (Example 2).

[0147] ii. When the volume of the injected precursor solution is 12 μL and the growth time is 30 min under the rapid injection mode, the average size of the quantum dots is 11.5 nm (Example 3).

[0148] iii. When the volume of the injected precursor solution is 100 μL and the injection mode is rapid injection and the growth time is 40 s, the average size of the quantum dots is 17.1 nm (Example 7).

[0149] iv. The volume of the injected precursor solution is 100 μL. Under the rapid injection mode, when the growth time is 60 s, the average size of the quantum dots is 17.8 nm (Example 8).

[0150] (4) The preheating temperature of the precursor solution is different, and other conditions are the same:

[0151] i. The precursor solution was preheated at 50° C., and the average size of the quantum dots was small and the shape was irregular (Example 10).

[0152] ii. The precursor solution was preheated at 100° C., and the average size of the quantum dots was larger and the shape was relatively regular (Example 11).

[0153] (5) Synthesis temperature is different, other conditions are the same:

[0154] When the synthesis temperature was increased to 270°C, the crystallinity was enhanced and the Sb single substance almost completely disappeared, which was the optimal synthesis temperature (Examples 10, 12-14).

[0155] InSb colloidal quantum dots absorption spectrum test:

[0156] The absorption spectra of InSb colloidal quantum dots of different sizes prepared in Example 4 and Example 8 were tested by using an ultraviolet-visible infrared spectrometer and a Fourier transform infrared spectrometer. Fig.10 and Fig.11 As shown. The infrared absorption spectrum with characteristic absorption peaks at 2500nm and 3100nm and absorption range of 1-5μm was obtained. This achievement realizes the light response of InSb colloidal quantum dots from short-wave infrared to medium-wave infrared, fills the gap of InSb quantum dots prepared by existing technology in response in this band, and provides strong support for the technical development of related fields.

[0157] The embodiments described above provide a detailed description of the technical solutions and beneficial effects of the present invention. It should be understood that the above are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, supplements and equivalent substitutions made within the scope of the principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing size-controllable monodisperse indium antimonide colloidal quantum dots, characterized in that: The following steps are involved: (1) preparing a precursor solution containing an indium precursor and an antimony precursor, and heating the precursor solution at 50 to 300° C. for 1 to 20 minutes; (2) In an inert atmosphere, the solvent is heated to a reaction temperature, a reducing agent is injected, and then the heated precursor solution is injected, and the reaction temperature is maintained for 10 seconds to 30 minutes before stopping the reaction to obtain monodisperse indium antimonide colloidal quantum dots; The reaction temperature is 250-300°C; In the reaction system of step (2), the concentrations of the indium precursor and the antimony precursor are independently 0.4 to 8 mmol / L; The size of monodisperse indium antimonide colloidal quantum dots is controlled by regulating the concentration of the precursor in the reaction system, the injection method of the precursor solution, and the growth time.

2. The method for preparing size-controllable monodisperse indium antimonide colloidal quantum dots according to claim 1, characterized in that: Before injecting the precursor solution, the precursor solution is heated at 60 to 120° C. for 5 to 15 minutes.

3. The method for preparing size-controllable monodisperse indium antimonide colloidal quantum dots according to claim 1, characterized in that: In step (2), the reaction temperature is 250-280°C.

4. The method for preparing size-controllable monodisperse indium antimonide colloidal quantum dots according to claim 1, characterized in that: In step (2), the reaction time is 30s to 30min.

5. The method for preparing size-controllable monodisperse indium antimonide colloidal quantum dots according to claim 1, characterized in that: In the reaction system of step (2), the concentrations of the indium precursor and the antimony precursor are independently 0.04 to 0.8 mmol / L.

6. The method for preparing size-controllable monodisperse indium antimonide colloidal quantum dots according to claim 5, characterized in that: In the reaction system of step (2), the concentrations of the indium precursor and the antimony precursor are independently 0.2 to 0.8 mmol / L.

7. The method for preparing size-controllable monodisperse indium antimonide colloidal quantum dots according to claim 1, characterized in that: In step (2), the precursor solution is injected in a rapid manner or dropwise manner; rapid injection means adding the precursor solution all at once within 0.1 to 1 second.

8. The method for preparing size-controllable monodisperse indium antimonide colloidal quantum dots according to claim 1, characterized in that: The indium precursor and antimony precursor are at least one of indium chloride, indium bromide, indium iodide, indium acetate, and indium carboxylate; the antimony precursor is at least one of antimony chloride, antimony bromide, antimony iodide, and tris(dimethylamino)antimony.

Images