Synthesis method of selenium-doped mercury telluride colloidal quantum dots and application thereof

Abstract

The application relates to a synthesis method of selenium-doped mercury telluride colloidal quantum dots and application thereof, and the synthesis method comprises the following steps: adding mercury halide into oleylamine to obtain an oleylamine complex solution of the mercury halide; rapidly injecting a mixed precursor solution of tri-n-octyl tellurium phosphine and oleylamine selenium urea into the solution, so that the mixed precursor reacts with the mercury halide to generate selenium-doped mercury telluride colloidal quantum dots. The synthesis method synthesizes the selenium-doped mercury telluride colloidal quantum dots through a simple one-step method, greatly simplifies a synthesis threshold of the mercury telluride colloidal quantum dots, and makes the mercury telluride colloidal quantum dots more controllable, faster and cheaper.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of new semiconductor materials and infrared detection technology, and particularly relates to a synthesis method of selenium-doped mercury telluride colloidal quantum dots and application thereof. BACKGROUND

[0002] Infrared light detection has been widely used in the fields of self-driving cars, security systems, atmospheric monitoring, etc. So far, commercial infrared detectors mainly rely on single-crystal inorganic semiconductors, such as epitaxially grown InGaAs and HgCdTe. The high manufacturing threshold and subsequent complex flip-chip bonding process of single-crystal materials have brought high cost burden to the technology. Colloidal quantum dots are particularly attractive candidates for infrared photodetectors because of their tunable bandgap size, low-cost manufacturing, and excellent solution processability, which can be directly integrated with Si electronic devices.

[0003] Due to the bulk exciton Bohr radius of 39.3 nm and the zero bulk bandgap, the absorption band edge of mercury telluride colloidal quantum dots can be extended from the short-wave infrared to the long-wave infrared or even the terahertz region, which is a very potential infrared detection material. Although many efforts have been made in the growth kinetics adjustment during the synthesis process or the ligand engineering after the synthesis to break through the performance of mercury telluride colloidal quantum dot infrared detectors, the chemical stability of mercury telluride colloidal quantum dots has not been fully valued. Telluride compounds are notorious for being easily oxidized, especially in the nanometer size range. We believe that uncontrolled oxidation can lead to newly formed trap states and p-type self-doping, which poses new challenges to the adjustment of the performance of the material itself. At the same time, the mercury telluride colloidal quantum dots synthesized based on the traditional method have poor stability and are not easy to preserve, which makes it difficult to mass-produce industrially. Therefore, it is urgent to develop a new process to stabilize the oxidation resistance and colloidal stability of mercury telluride colloidal quantum dots. SUMMARY

[0004] The technical problem to be solved by the present application is that the existing synthesis method for synthesizing mercury telluride colloidal quantum dots has various deficiencies, and a synthesis method of selenium-doped mercury telluride colloidal quantum dots is provided.

[0005] In order to solve the above technical problems, the embodiment of the present application provides a synthesis method of selenium-doped mercury telluride colloidal quantum dots, comprising the following steps:

[0006] S1: adding mercury halide into oleylamine to obtain an oleylamine complex solution of mercury halide;

[0007] S2: adding selenium urea into the oleylamine solution and heating to obtain an oleylamine selenium urea solution;

[0008] S3: adding tellurium powder into tri-n-octylphosphine to obtain a tri-n-octylphosphine telluride solution by heating; mixing the tri-n-octylphosphine telluride solution and the oleylamine selenourea solution to form a mixed precursor solution;

[0009] S4: injecting the mixed precursor solution into the oleylamine complex solution of the mercury halide to make the mixed precursor react with the mercury halide to generate a selenium-doped mercury telluride colloidal quantum dot solution;

[0010] S5: injecting a quenching agent into the selenium-doped mercury telluride colloidal quantum dot solution to stop the reaction, and adding a certain amount of an anti-solvent after stirring for a period of time to obtain a colloidal quantum dot powder;

[0011] The concentration of the oleylamine selenourea solution is 0.1-2 mmol / mL, and the concentration of the tri-n-octylphosphine telluride solution is 0.1-1 mmol / mL.

[0012] The steps S1-S5 are all carried out in anhydrous and oxygen-free environment.

[0013] Preferably, the concentration of the mercury halide in the oleylamine solution of the mercury halide is 0.1-2 mol / L; and the mercury halide includes any one or any combination of mercury chloride, mercury bromide and mercury iodide.

[0014] Preferably, the step S1 is carried out at a temperature of 50-120°C.

[0015] Preferably, the step S2 is carried out at a temperature of 150-210°C, and the step S3 is carried out at a temperature of 120-160°C.

[0016] Preferably, the ratio of the tri-n-octylphosphine telluride solution to the oleylamine selenourea solution in the mixed precursor solution in the step S3 is 1:1-1:10.

[0017] Preferably, the quenching agent in the step S5 includes any one or any combination of n-hexane, n-octane, toluene, tetrachloroethylene and chloroform.

[0018] Preferably, the volume of the anti-solvent added in the step S5 is 1-5 times the volume of the selenium-doped mercury telluride colloidal quantum dot solution.

[0019] Preferably, the anti-solvent is any one or any combination of ethanol, methanol, isopropyl alcohol, acetone and acetonitrile.

[0020] Preferably, the stirring time in the step S5 is 1-60 min.

[0021] The application further provides a selenium-doped mercury telluride colloidal quantum dot prepared by the above synthesis method.

[0022] The application further provides an application of the selenium-doped mercury telluride colloidal quantum dot.

[0023] The embodiment of the application has the following beneficial effects:

[0024] (1) The selenium-doped mercury telluride colloidal quantum dot is synthesized by a simple one-step method, which greatly simplifies the synthesis threshold of the mercury telluride colloidal quantum dot, makes it more controllable, faster and cheaper, and has higher potential for industrial production.

[0025] (2) The selenium-doped mercury telluride colloidal quantum dot solution has improved processability and oxidation resistance by introducing a certain proportion of selenium urea precursor into the mixed precursor solution, so that the selenium-doped mercury telluride colloidal quantum dot solution is easier to make the selenium-doped mercury telluride colloidal quantum dot.

[0026] (3) The selenium-doped colloidal quantum dot prepared by the embodiment of the application has adjustable size, controllable morphology, and good monodispersity, high crystallinity, good photoelectric properties, high technical reliability, and good processability.

[0027] (4) The selenium-doped mercury telluride colloidal quantum dot prepared by the embodiment of the application can be stably dispersed in a conventional organic solvent for a long time, and can be stored for more than one year. BRIEF DESCRIPTION OF DRAWINGS

[0028] In order to more clearly illustrate the technical solutions of the embodiments of the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiment or prior art description. Obviously, the drawings in the following description are only some embodiments of the application, and other drawings can be obtained by those skilled in the art without creative labor.

[0029] Figure 1 is a synthesis method flow chart of the selenium-doped mercury telluride colloidal quantum dot provided by the application;

[0030] Figure 2 is an anti-oxidation comparison diagram of the selenium-doped mercury telluride colloidal quantum dot and the mercury telluride colloidal quantum dot prepared by the application;

[0031] Figure 3A is a transmission electron microscope image of the selenium-doped mercury telluride colloidal quantum dot prepared by the application;

[0032] Figure 3B is a transmission electron microscope image of the mercury telluride colloidal quantum dot obtained without adding the oleylamine selenium urea solution in the application;

[0033] Figure 4is an element mapping and linear scanning element distribution diagram of the prepared selenium-doped mercury telluride colloidal quantum dots of the present application;

[0034] Figure 5 is a colloidal dispersion photo of the prepared mercury telluride colloidal quantum dots after anti-solvent purification, which are obtained by adding no oleylamine selenium urea solution to the synthesized selenium-doped mercury telluride of the present application;

[0035] Figure 6 is an application effect diagram of the prepared selenium-doped mercury telluride colloidal quantum dots in an infrared detector of the present application. DETAILED DESCRIPTION

[0036] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the present application.

[0037] Please refer to Figure 1 The present application discloses a synthesis method of selenium-doped mercury telluride colloidal quantum dots. The synthesis method mainly comprises the following steps:

[0038] S1: adding mercury halide into oleylamine to obtain an oleylamine complex solution of mercury halide;

[0039] S2: adding selenium urea into the oleylamine solution and heating to obtain an oleylamine selenium urea solution;

[0040] S3: adding tellurium powder into tri-n-octyl phosphine and heating to obtain a tri-n-octyl tellurium phosphine solution; mixing the tri-n-octyl tellurium phosphine solution and the oleylamine selenium urea solution to form a mixed precursor solution;

[0041] S4: injecting the mixed precursor solution into the oleylamine complex solution of mercury halide to make the mixed precursor react with the mercury halide to generate a selenium-doped mercury telluride colloidal quantum dot solution;

[0042] S5: injecting a quenching agent into the selenium-doped mercury telluride colloidal quantum dot solution to stop the reaction, and after stirring for a period of time, adding a certain amount of anti-solvent to obtain a colloidal quantum dot powder.

[0043] The concentration of the oleylamine selenium urea solution is 0.1-2 mmol / mL, and the concentration of the tri-n-octyl tellurium phosphine solution is 0.1-1 mmol / mL. The concentration of mercury halide in the oleylamine solution of mercury halide is 0.1-2 mol / L; the mercury halide includes any one or any combination of mercury chloride, mercury bromide and mercury iodide. The steps S1-S5 are all carried out in anhydrous and anaerobic environment.

[0044] The injection time of the mixed precursor solution into the oleylamine complex solution of the mercury halide in step S4 should be less than 30 s. The injection time of the quenching agent into the selenium-doped mercury telluride colloidal quantum dot solution to stop the reaction in step S5 should be less than 30 s.

[0045] The synthesis method of the selenium-doped mercury telluride colloidal quantum dot synthesizes the selenium-doped mercury telluride colloidal quantum dot through a simple one-step method, greatly simplifies the synthesis threshold of the mercury telluride colloidal quantum dot, makes it more controllable, faster, cheaper, and has higher potential for industrial production.

[0046] Referring to Figure 2 The selenium-doped mercury telluride colloidal quantum dot prepared by the synthesis method of the selenium-doped mercury telluride colloidal quantum dot has excellent oxidation resistance compared with the mercury telluride colloidal quantum dot. The selenium-doped mercury telluride colloidal quantum dot prepared by the synthesis method of the selenium-doped mercury telluride colloidal quantum dot has a layer of selenium-mercury covering layer on the surface. The selenium-mercury covering layer does not react with O2, so the selenium-doped mercury telluride colloidal quantum dot has extremely high resistance to O2. Therefore, the selenium-doped mercury telluride colloidal quantum dot has excellent oxidation resistance.

[0047] In some embodiments, the step S1 is carried out at a temperature of 50-120°C. The step S2 is carried out at a temperature of 150-210°C. The step S3 is carried out at a temperature of 120-160°C.

[0048] In some embodiments, the volume of the anti-solvent added in step S5 is 1-5 times the volume of the selenium-doped mercury telluride colloidal quantum dot solution.

[0049] In some embodiments, the mercury halide is any one or any combination of mercury chloride, mercury bromide and mercury iodide.

[0050] In some embodiments, the ratio of the n-octyl tellurium phosphine solution to the oleylamine selenium urea solution in the mixed precursor solution is 1:1-1:10.

[0051] In some embodiments, the quenching agent includes any one or any combination of n-hexane, n-octane, toluene, tetrachloroethylene, chloroform.

[0052] In some embodiments, the anti-solvent is any one or any combination of ethanol, methanol, isopropyl alcohol, acetone, acetonitrile.

[0053] In some embodiments, the stirring time in step S5 is 1-60 min.

[0054] Embodiment 1

[0055] In some embodiments, the synthesis method of the selenium-doped mercury telluride colloidal quantum dot comprises the following specific steps:

[0056] (1) Preparation of mercury precursor: 276 mg of mercury chloride was weighed in a three-necked flask, 15 mL of oleylamine was measured, and the mixture was heated to 80°C under an inert atmosphere for 1 h to obtain a mercury precursor solution;

[0057] (2) Preparation of tri-n-octylphosphine telluride: 2.54 g of tellurium powder was dissolved in 20 mL of tri-n-octylphosphine solution, heated to 160°C under a nitrogen atmosphere for 4 hours until the tellurium powder was completely dissolved, and cooled to room temperature to obtain a 1 mmol / mL tri-n-octylphosphine telluride solution;

[0058] (3) Preparation of oleylamine selenourea: 126 mg of selenourea powder was dissolved in 1 mL of oleylamine solution, heated to 210°C under a nitrogen atmosphere for 2 hours until the selenourea powder was completely dissolved, and cooled to room temperature to obtain a 1 mmol / mL oleylamine selenourea solution;

[0059] (4) Preparation of mixed precursor of tri-n-octylphosphine telluride and oleylamine selenourea: 0.5 mL of 1 mmol / mL tri-n-octylphosphine telluride and 1 mmol / mL oleylamine selenourea solution were taken respectively, and shaken for 3 min until the solution was uniformly mixed;

[0060] (5) 1 mL of the mixed precursor of tri-n-octylphosphine telluride and oleylamine selenourea was injected into the mercury precursor solution of (1), and the reaction was started, and stopped after 3 min;

[0061] (6) Then 10 mL of tetrachloroethylene solvent was quickly injected to quench the reaction and cooled to room temperature in an ice bath;

[0062] (7) The quenched solution was poured into a centrifuge tube, 25 mL of anhydrous ethanol was added to the centrifuge tube for precipitation, and the black powder obtained was the selenium-doped mercury telluride colloidal quantum dots.

[0063] Example 2

[0064] The example 2 is based on the example 1, and the reaction temperature of the step S1 is changed to 120°C. The synthesis method of the selenium-doped mercury telluride colloidal quantum dots is specifically as follows:

[0065] (1) Preparation of mercury precursor: 276 mg of mercury chloride was weighed in a three-necked flask, 15 mL of oleylamine was measured, and the mixture was heated to 120°C under an inert atmosphere for 1 h to obtain a mercury precursor solution;

[0066] (2) Preparation of tri-n-octylphosphine telluride: 2.54 g of tellurium powder was dissolved in 20 mL of tri-n-octylphosphine solution, heated to 160°C under a nitrogen atmosphere for 4 hours until the tellurium powder was completely dissolved, and cooled to room temperature to obtain a 1 mmol / mL tri-n-octylphosphine telluride solution;

[0067] (3) Preparation of oleylamine selenourea: 126 mg of selenourea powder was dissolved in 1 mL of oleylamine solution, heated to 210°C under nitrogen atmosphere and maintained for 2 hours until the selenourea powder was completely dissolved, and cooled to room temperature to obtain a 1 mmol / mL oleylamine selenourea solution;

[0068] (4) Preparation of mixed precursors of tri-n-octylphosphine telluride and oleylamine selenourea: 0.5 mL of 1 mmol / mL tri-n-octylphosphine telluride and 1 mmol / mL oleylamine selenourea solutions were taken respectively and shaken for 3 min until the solutions were uniformly mixed;

[0069] (5) 1 mL of mixed precursors of tri-n-octylphosphine telluride and oleylamine selenourea was injected into the mercury precursor solution in (1), and timing was started, and the reaction was stopped after 3 min;

[0070] (6) Then 10 mL of tetrachloroethylene solvent was rapidly injected to quench the reaction and cooled to room temperature in an ice bath;

[0071] (7) The quenched solution was poured into a centrifuge tube, 25 mL of anhydrous ethanol was added to the centrifuge tube for precipitation, and the obtained black powder was the selenium-doped mercury telluride colloidal quantum dots.

[0072] Example 3

[0073] The example 3 changed the ratio of tri-n-octylphosphine telluride solution and oleylamine selenourea solution in the mixed precursors on the basis of example 2. The specific steps of the synthesis method of the selenium-doped mercury telluride colloidal quantum dots are as follows:

[0074] (1) Preparation of mercury precursor: 276 mg of mercury chloride was weighed in a three-necked flask, 15 mL of oleylamine was measured, and the mixture was heated to 120°C under inert atmosphere for 1 h to obtain a mercury precursor solution;

[0075] (2) Preparation of tri-n-octylphosphine telluride: 2.54 g of tellurium powder was dissolved in 20 mL of tri-n-octylphosphine solution, heated to 160°C under nitrogen atmosphere and maintained for 4 hours until the tellurium powder was completely dissolved, and cooled to room temperature to obtain a 1 mmol / mL tri-n-octylphosphine telluride solution;

[0076] (3) Preparation of oleylamine selenourea: 126 mg of selenourea powder was dissolved in 1 mL of oleylamine solution, heated to 210°C under nitrogen atmosphere and maintained for 2 hours until the selenourea powder was completely dissolved, and cooled to room temperature to obtain a 1 mmol / mL oleylamine selenourea solution;

[0077] (4) Preparation of mixed precursors of tri-n-octylphosphine telluride and oleylamine selenourea: 0.3 and 0.7 mL of 1 mmol / mL tri-n-octylphosphine telluride and 1 mmol / mL oleylamine selenourea solutions were taken respectively and shaken for 3 min until the solutions were uniformly mixed;

[0078] (5) Inject 1 mL of the mixed precursor of tri-n-octylphosphine telluride and oleylamine selenourea into the mercury precursor solution (1) and start timing, stop the reaction after 3 min;

[0079] (6) Subsequently, inject 10 mL of tetrachloroethylene solvent to quench the reaction and cool to room temperature in an ice bath;

[0080] (7) Pour the quenched solution into a centrifuge tube, add 25 mL of anhydrous ethanol to the centrifuge tube for precipitation, and the black powder obtained is the selenium-doped mercury telluride colloidal quantum dots.

[0081] Example 4

[0082] The example 4 is based on the example 2, and the mercury chloride in the step S1 is replaced by mercury bromide. The specific steps of the synthesis method of the selenium-doped mercury telluride colloidal quantum dots are as follows:

[0083] (1) Preparation of mercury precursor: weigh 276 mg of mercury bromide in a three-necked flask, and weigh 15 mL of oleylamine. The mixture is heated to 120°C under an inert atmosphere and maintained for 1 h;

[0084] (2) Preparation of tri-n-octylphosphine telluride: weigh 2.54 g of tellurium powder and dissolve it in 20 mL of tri-n-octylphosphine solution. Heat to 160°C under a nitrogen atmosphere and maintain for 4 hours until the tellurium powder is completely dissolved. Cool to room temperature to obtain a 1 mmol / mL solution of tri-n-octylphosphine telluride;

[0085] (3) Preparation of oleylamine selenourea: weigh 126 mg of selenourea powder and dissolve it in 1 mL of oleylamine solution. Heat to 210°C under a nitrogen atmosphere and maintain for 2 hours until the selenourea powder is completely dissolved. Cool to room temperature to obtain a 1 mmol / mL solution of oleylamine selenourea;

[0086] (4) Preparation of mixed precursor of tri-n-octylphosphine telluride and oleylamine selenourea: take 0.3 mL and 0.7 mL of 1 mmol / mL tri-n-octylphosphine telluride and 1 mmol / mL oleylamine selenourea solutions respectively, and shake for 3 min until the solution is uniformly mixed;

[0087] (5) Inject 1 mL of the mixed precursor of tri-n-octylphosphine telluride and oleylamine selenourea into the mercury precursor solution (1) and start timing, stop the reaction after 3 min;

[0088] (6) Subsequently, inject 15 mL of n-hexane solvent to quench the reaction and cool to room temperature in an ice bath;

[0089] (7) Pour the quenched solution into a centrifuge tube, add 25 mL of anhydrous ethanol to the centrifuge tube for precipitation, and the black powder obtained is the selenium-doped mercury telluride colloidal quantum dots.

[0090] Example 5

[0091] The embodiment 5 is based on the embodiment 2, and the tetrachloroethylene solvent in the step S5 is replaced by n-hexane solvent. The specific steps of the synthesis method of the selenium-doped mercury telluride colloidal quantum dots are as follows:

[0092] (1) Preparation of mercury precursor: 276 mg of mercury chloride was weighed in a three-necked flask, 15 mL of oleylamine was measured, and the mixture was heated to 120°C under an inert atmosphere for 1 h;

[0093] (2) Preparation of tri-n-octyl tellurium phosphine: 2.54 g of tellurium powder was dissolved in 20 mL of tri-n-octyl phosphine solution, heated to 160°C under a nitrogen atmosphere for 4 h until the tellurium powder was completely dissolved, and cooled to room temperature to obtain a 1 mmol / mL tri-n-octyl tellurium phosphine solution;

[0094] (3) Preparation of oleylamine selenourea: 126 mg of selenourea powder was dissolved in 1 mL of oleylamine solution, heated to 210°C under a nitrogen atmosphere for 2 h until the selenourea powder was completely dissolved, and cooled to room temperature to obtain a 1 mmol / mL oleylamine selenourea solution;

[0095] (4) Preparation of mixed precursor of tri-n-octyl tellurium phosphine and oleylamine selenourea: 0.3 mL and 0.7 mL of 1 mmol / mL tri-n-octyl tellurium phosphine and 1 mmol / mL oleylamine selenourea solutions, respectively, were shaken for 3 min until the solution was uniformly mixed;

[0096] (5) 1 mL of the mixed precursor of tri-n-octyl tellurium phosphine and oleylamine selenourea was injected into the mercury precursor solution, and the timing was started, and the reaction was stopped after 3 min;

[0097] (6) Then, 15 mL of n-hexane solvent was rapidly injected to quench the reaction and cooled to room temperature in an ice bath;

[0098] (7) The quenched solution was poured into a centrifuge tube, 25 mL of anhydrous ethanol was added to the centrifuge tube for precipitation, and the obtained black powder was the selenium-doped mercury telluride colloidal quantum dots.

[0099] Embodiment 6

[0100] The embodiment 6 is based on the embodiment 2, and the anhydrous ethanol in the step S5 is replaced by acetone. The specific steps of the synthesis method of the selenium-doped mercury telluride colloidal quantum dots are as follows:

[0101] (1) Preparation of mercury precursor: 276 mg of mercury chloride was weighed in a three-necked flask, 15 mL of oleylamine was measured, and the mixture was heated to 120°C under an inert atmosphere for 1 h;

[0102] (2) Preparation of tri-n-octylphosphine telluride: 2.54 g of tellurium powder was dissolved in 20 mL of tri-n-octylphosphine solution, heated to 160°C under nitrogen atmosphere for 4 hours until the tellurium powder was completely dissolved, and cooled to room temperature to obtain a 1 mmol / mL tri-n-octylphosphine telluride solution;

[0103] (3) Preparation of oleylamine selenourea: 126 mg of selenourea powder was dissolved in 1 mL of oleylamine solution, heated to 210°C under nitrogen atmosphere for 2 hours until the selenourea powder was completely dissolved, and cooled to room temperature to obtain a 1 mmol / mL oleylamine selenourea solution;

[0104] (4) Preparation of mixed precursor of tri-n-octylphosphine telluride and oleylamine selenourea: 0.3 mL and 0.7 mL of 1 mmol / mL tri-n-octylphosphine telluride and 1 mmol / mL oleylamine selenourea solutions, respectively, were shaken for 3 min until the solutions were uniformly mixed;

[0105] (5) 1 mL of the mixed precursor of tri-n-octylphosphine telluride and oleylamine selenourea was injected into the mercury precursor solution of (1), and the reaction was stopped after 3 min;

[0106] (6) Subsequently, 10 mL of tetrachloroethylene solvent was rapidly injected to quench the reaction and cooled to room temperature in an ice bath;

[0107] (7) The quenched solution was poured into a centrifuge tube, 40 mL of acetone was added to the centrifuge tube for precipitation, and the obtained black powder was the mercury telluride colloidal quantum dots obtained without adding oleylamine selenourea solution.

[0108] Comparative Example 1

[0109] The comparative example 1 is a synthesis method opposite to the above-mentioned example, i.e., a synthesis method of mercury telluride colloidal quantum dots obtained without adding oleylamine selenourea solution. The specific synthesis method of the mercury telluride colloidal quantum dots obtained without adding oleylamine selenourea solution has the following specific steps:

[0110] (1) Preparation of mercury precursor: 276 mg of mercury chloride was weighed in a three-necked flask, 15 mL of oleylamine was measured, and the mixture was heated to 120°C under an inert atmosphere for 1 h to obtain a mercury precursor solution;

[0111] (2) Preparation of tri-n-octylphosphine telluride: 2.54 g of tellurium powder was dissolved in 20 mL of tri-n-octylphosphine solution, heated to 160°C under nitrogen atmosphere for 4 hours until the tellurium powder was completely dissolved, and cooled to room temperature to obtain a 1 mmol / mL tri-n-octylphosphine telluride solution;

[0112] (3) 1 mL of the tri-n-octylphosphine telluride precursor was injected into the mercury precursor solution of (1), and the reaction was stopped after 3 min;

[0113] (4) Then, 10 mL of tetrachloroethylene solvent was quickly injected to quench the reaction and the mixture was cooled to room temperature in an ice bath;

[0114] (5) The quenched solution was poured into a centrifuge tube, and 25 mL of anhydrous ethanol was added to the centrifuge tube for precipitation. The resulting black powder was selenium-doped mercury telluride colloidal quantum dots.

[0115] See also Figure 3A 、 3B , Figure 3A This is a transmission electron microscope image of a typical selenium-doped mercury telluride colloidal quantum dots prepared by the above synthesis method. By controlling factors such as reaction temperature, mercury halide, quenching agent and anti-solvent, the selenium-doped mercury telluride colloidal quantum dots have good monodispersity and good processability. Figure 3B This is a transmission electron micrograph of mercury telluride colloidal quantum dots obtained without adding oleylamine selenourea solution, i.e., the transmission electron micrograph of Comparative Example 1. The mercury telluride colloidal quantum dots obtained without adding oleylamine selenourea solution have poor dispersion and severe quantum dot agglomeration.

[0116] See also Figure 4 , Figure 4 The elemental mapping and linear scan elemental distribution diagrams of typical selenium-doped mercury telluride colloidal quantum dots produced in Examples 2-3 are shown. By controlling factors such as reaction temperature, mercury halide, quenching agent, and antisolvent, the elements in the selenium-doped mercury telluride colloidal quantum dots are uniformly dispersed, demonstrating the controllable and uniform nature of selenium doping.

[0117] See also Figure 5 , Figure 5 The colloidal dispersion of the selenium-doped mercury telluride colloidal quantum dots prepared in Example 4 and the mercury telluride colloidal quantum dots prepared in Comparative Example 1 during the purification process after adding an antisolvent is shown. This demonstrates the high stability and solution processability of the selenium-doped mercury telluride colloidal quantum dots prepared in Example 4.

[0118] See also Figure 6 , Figure 6 Different applications of selenium-doped mercury telluride colloidal quantum dots prepared in Example 6 of the present invention in infrared detectors. Figure 6 a in the figure is the broad spectrum external quantum efficiency of the selenium-doped mercury telluride colloidal quantum dot infrared detector, and the detector response cutoff wavelength is 2.2 μm; Figure 6 b in the figure is the light-dark state current-voltage characteristic curve of the selenium-doped mercury telluride colloidal quantum dot infrared detector; Figure 6 The c in the figure is the noise power density curve of the selenium-doped mercury telluride colloidal quantum dot infrared detector as a function of frequency. The noise power density of the device at 500 Hz is 2.13×10 -13 AHz -1 / 2 ; ​The d in the formula is a wide-spectrum specific detectivity of the selenium-doped mercury telluride colloidal quantum dot infrared detector, and the peak specific detectivity of the infrared detector is 5.17*10 11 Jones.

[0119] In conclusion, the selenium-doped mercury telluride colloidal quantum dots are synthesized by using a one-step method, and by adjusting the mercury halide, quenching agent, anti-solvent and reaction temperature, the synthesized selenium-doped mercury telluride colloidal quantum dots have the characteristics of size-adjustable, controllable morphology, good monodispersity, high crystallinity, good photoelectric properties, high technical reliability and processability.

[0120] The above only discloses a preferred embodiment of the present application, of course, cannot limit the scope of the present application, those skilled in the art can understand that the implementation of all or part of the above-mentioned embodiments, and the equivalent changes made by the present application claims, still belong to the scope of the present application.

Claims

1. A method for synthesizing selenium-doped mercury telluride colloidal quantum dots, characterized in that, The method comprises the following steps: S1: adding mercury halide into oleylamine to obtain an oleylamine complex solution of mercury halide; S2: adding selenourea into the oleylamine solution and heating to obtain an oleylamine selenourea solution; S3: adding tellurium powder into tri-n-octylphosphine and heating to obtain a tri-n-octylphosphine tellurium solution; mixing the tri-n-octylphosphine tellurium solution and the oleylamine selenourea solution to form a mixed precursor solution; S4: injecting the mixed precursor solution into the oleylamine complex solution of mercury halide to make the mixed precursor react with the mercury halide to generate a selenium-doped mercury telluride colloidal quantum dot solution; S5: injecting a quenching agent into the selenium-doped mercury telluride colloidal quantum dot solution to stop the reaction, adding a certain amount of an anti-solvent after stirring for a period of time to obtain a colloidal quantum dot powder; The concentration of the oleylamine selenourea solution is 0.1-2 mmol / mL, and the concentration of the tri-n-octylphosphine tellurium solution is 0.1-1 mmol / mL; The steps S1-S5 are all carried out in anhydrous and oxygen-free environment.

2. The method according to claim 1, wherein the concentration of mercury halide in the oleylamine solution of mercury halide is 0.1-2 mol / L; and the mercury halide comprises any one or any combination of mercury chloride, mercury bromide and mercury iodide.

3. The method for synthesizing selenium-doped mercury telluride colloidal quantum dots according to claim 1, wherein: The step S1 is carried out at a temperature of 50-120°C.

4. The method for synthesizing selenium-doped mercury telluride colloidal quantum dots according to claim 1, wherein: The step S2 is carried out at a temperature of 150-210°C, and the step S3 is carried out at a temperature of 120-160°C.

5. The method for synthesizing selenium-doped mercury telluride colloidal quantum dots according to claim 1, wherein: The ratio of the tri-n-octylphosphine tellurium solution to the oleylamine selenourea solution in the mixed precursor solution in the step S3 is 1:1-1:

10.

6. The method of claim 1, wherein the selenium-doped mercury telluride colloidal quantum dots are synthesized by the following steps: The quenching agent in the step S5 comprises any one or any combination of n-hexane, n-octane, toluene, tetrachloroethylene and chloroform.

7. The method for synthesizing selenium-doped mercury telluride colloidal quantum dots according to claim 1, wherein: The volume of the anti-solvent added in the step S5 is 1-5 times the volume of the selenium-doped mercury telluride colloidal quantum dot solution. The anti-solvent is any one or any combination of ethanol, methanol, isopropyl alcohol, acetone and acetonitrile.

8. The method of claim 1, wherein the selenium-doped mercury telluride colloidal quantum dots are synthesized by the method comprising: The stirring time in the step S5 is 1-60 min.

9. A selenium-doped mercury telluride colloidal quantum dot, wherein, The selenium-doped mercury telluride colloidal quantum dot is prepared by any one of the synthesis methods in claims 1-8.

10. Use of the selenium-doped mercury telluride colloidal quantum dots according to any one of claims 1-8, characterized in that, The selenium-doped mercury telluride colloidal quantum dot is applied to infrared photoelectric devices.

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