Large-size indium arsenide core-shell quantum dots with short-wave near-infrared emission, preparation method, and application thereof

Abstract

The present invention provides a large-sized indium arsenide quantum dot with a core-shell structure that emits short-wavelength near-infrared light, as well as a preparation method and application thereof. The quantum dot includes an indium arsenide quantum dot core and multiple shell structures with matching band gaps. The present invention controls the size of the indium arsenide quantum dot core by injecting indium arsenide nanoclusters into an indium arsenide seed solution, overcoming the Oswald ripening phenomenon. The injection rate of the indium arsenide nanoclusters is 0.1-5 ml / h, the injection time is 60-600 minutes, and the system reaction temperature is 260-300°C. After that, the precursor required for the shell is injected into the indium arsenide quantum dot core, and finally the large-sized indium arsenide quantum dot with a core-shell structure is completed. The fluorescence emission wavelength of the quantum dot is continuously adjustable within 1300-3000 nanometers, the particle size is uniform, and the peak-to-valley ratio of the absorption spectrum is greater than 1.2. The near-infrared light-emitting diode prepared based on indium arsenide quantum dots has a light-on voltage of less than 3V. Therefore, it has great practical application potential in the fields of near-infrared light-emitting devices, photodetectors or fluorescence detectors.

Description

Technical Field

[0001] The present invention relates to the fields of semiconductor devices and bioimaging technology, and in particular to large-sized indium arsenide core-shell quantum dots with short-wave near-infrared emission light, and a preparation method and application thereof. Background Art

[0002] Colloidal quantum dots (QDs) are materials synthesized using wet chemistry whose optical and physical properties are controlled by their size and shape due to quantum confinement effects. In particular, free-standing CQDs allow for solution-based chemical post-processing and solution-processable thin-film assembly. Consequently, CQDs have attracted attention in various optoelectronic fields, including bioimaging, displays, and flexible and stretchable devices.

[0003] To date, the most studied near-infrared (NIR) and short-wave infrared emitting NC compounds are Hg-based (II-VI) or Pb-based (IV-VI) semiconductors, whose synthesis and optical properties have been optimized over the past decades. However, due to the EU's "Restriction of Hazardous Substances" (RoHS) directive, the presence of mercury or lead has severely limited the use of such compounds in commercial applications, prompting the search for alternative lead-free and mercury-free RoHS-compliant materials.

[0004] Among these III-V semiconductors, indium arsenide quantum dots (InAs) have been identified as the most attractive alternative. Besides meeting RoHS requirements, another key reason for choosing InAs QDs is that their absorption and photoluminescence (PL) can be tuned from 750 to 1500 nm, thus covering a significant portion of the NIR range with a single material. However, the synthesis of InAs is significantly more complex than that of the more widely studied II-VI and IV-VI QDs. This is primarily due to two factors: (i) the limited selection of suitable precursor materials; and (ii) the covalent nature of the InAs lattice leads to poor crystallinity under the growth conditions of colloidal synthesis methods. One of the pioneering process designs commonly used to achieve monodisperse colloidal QDs is the hot injection method. Rapid precursor injection provides a supersaturated burst of monomers, resulting in uniform nucleation. However, rapid depletion of the As precursor during synthesis limits further QD growth. Consequently, the growth of large-scale InAs QDs is extremely challenging. Summary of the Invention

[0005] To address the above technical problems, the present invention provides large-sized indium arsenide core-shell quantum dots (IAs) emitting short-wavelength near-infrared light, as well as methods for their preparation and application. The present invention provides a method for growing large-sized IAs quantum dots, enabling continuously tunable emission wavelengths within the short-wavelength near-infrared range, enabling applications across diverse near-infrared bands. Near-infrared light-emitting diodes (NIDs) are also produced. In this context, large-sized refers to an emission wavelength exceeding 1300 nanometers.

[0006] The present invention is achieved through the following technical solutions:

[0007] The first object of the present invention is to provide a large-sized indium arsenide core-shell quantum dot with short-wave near-infrared emission light, wherein the large-sized indium arsenide core-shell quantum dot has a core-shell structure, with an indium arsenide quantum dot as the core and multiple shell layers wrapped around the surface of the indium arsenide quantum dot, wherein the multiple shell layers include two or more of InP shell, InZnP shell, GaP shell, ZnSe shell, ZnS shell, CdSe shell, and CdS shell;

[0008] The fluorescence emission wavelength of the large-sized indium arsenide core-shell quantum dots exceeds 1500 nanometers.

[0009] Furthermore, the shell layer is a phosphoindium zinc layer, a gallium phosphide layer, a zinc selenide layer, and a zinc sulfide layer. The shell layer is the preferred option. First, the selected materials are all environmentally friendly materials that comply with the EU HoRS. Second, the band gap of the selected materials matches the band gap of indium arsenide, specifically, the band gap of indium arsenide is 0.35eV, the band gap of phosphoindium zinc is 1.35eV, the band gap of gallium phosphide is 2.27eV, the band gap of zinc selenide is 2.36eV, and the band gap of zinc sulfide is 3.54eV. Through band gap matching, the current density can be increased, and the lighting voltage can be lowered, thereby improving the electrical performance of electrical devices in later applications.

[0010] In some embodiments of the present invention, the materials of the indium arsenide quantum dot core and shell are selected from environmentally friendly materials that meet the EU HoRS standard, which is in line with my country's concept of green development.

[0011] In some embodiments of the present invention, the particle size of the large-sized indium arsenide core-shell quantum dots is 3 to 20 nanometers.

[0012] In some embodiments of the present invention, the fluorescence emission peak of the large-sized indium arsenide core-shell quantum dots is located between 1300 and 3000 nanometers.

[0013] In some embodiments of the present invention, the peak-to-valley ratio of the absorption spectrum of the large-sized indium arsenide core-shell quantum dots is greater than 1.2.

[0014] A second object of the present invention is to provide a method for preparing large-sized indium arsenide core-shell quantum dots with short-wave near-infrared emission, comprising the following steps:

[0015] dissolving an indium source in an organic solvent to obtain an indium source solution;

[0016] An arsenic source is added to the indium source solution to react, and acid is used for etching (the main purpose of etching is to remove the oxide layer on the surface of the quantum dots, which is conducive to the attachment of indium arsenide nanoclusters to the surface of indium arsenide seeds) to obtain indium arsenide;

[0017] The metal precursor of the shell layer wrapped on the surface of the indium arsenide quantum dots is added to a mixed solution containing indium arsenide quantum dots, and heated to react to obtain the large-sized indium arsenide core-shell quantum dots with short-wave near-infrared emission light.

[0018] In some embodiments of the present invention, the organic solvent is selected from one or more of oleic acid, oleylamine, heptadecane, octylamine, dioctylamine, trioctylamine, tri-n-octylphosphine, dodecanethiol, octadecene and eicosene, and the organic solvent is degassed;

[0019] Preferably, the conditions for the heating reaction are: heating temperature of 100-300° C., and heating time of 10-200 minutes.

[0020] In some embodiments of the present invention, the indium source is one or more of anhydrous indium acetate, indium chloride, indium bromide, and indium iodide;

[0021] Preferably, the arsenic source is selected from one or more of tris(trimethylsilyl)arsenic, tris(trimethylgermanyl)arsenic, and aminoarsenic;

[0022] Preferably, the molar ratio of the indium source to the arsenic source is 1 to 5:1;

[0023] Preferably, the acid is selected from hydrobromic acid and / or hydrofluoric acid.

[0024] In some embodiments of the present invention, the phosphorus source is selected from TMS-P and / or TMGe-P (tris(trimethylgermanyl)phosphorus);

[0025] In some embodiments of the present invention, the metal precursor of the shell layer includes two or more of a zinc source, a phosphorus source, a selenium source, a sulfur source, a gallium source, and a cadmium source.

[0026] Preferably, the zinc source is selected from one or more of anhydrous zinc acetate, zinc stearate, and zinc palmitate;

[0027] Preferably, the gallium source is gallium chloride or gallium oleate;

[0028] Preferably, the selenium source is selenium powder;

[0029] Preferably, the sulfur source is sulfur powder.

[0030] Preferably, the phosphorus source is selected from one or more of TMS-P and tris(trimethylgermanyl)phosphine;

[0031] Preferably, the cadmium source is selected from dimethylcadmium and / or cadmium oxide.

[0032] In some embodiments of the present invention, the reaction temperatures and times required for the indium zinc phosphide layer, gallium phosphide layer, zinc selenide layer, and zinc sulfide layer wrapped on the surface of the indium arsenide quantum dots are:

[0033] The reaction temperature for preparing the phosphorus indium zinc shell is 180 to 310° C., and the reaction time is 30 to 240 minutes;

[0034] The reaction temperature for preparing the gallium phosphide shell is 180-310° C., and the reaction time is 30-240 minutes;

[0035] The reaction temperature for preparing the zinc selenide shell is 180-310° C., and the reaction time is 30-240 minutes;

[0036] The reaction temperature for preparing the zinc sulfide shell is 180-310° C., and the reaction time is 30-240 minutes;

[0037] The reaction temperature for preparing the cadmium selenide shell is 180-310° C., and the reaction time is 30-240 minutes;

[0038] The reaction temperature for preparing the cadmium sulfide shell is 180-310° C., and the reaction time is 30-240 minutes;

[0039] The reaction temperature for preparing the indium phosphide shell is 180-310° C., and the reaction time is 30-240 minutes.

[0040] In an embodiment of the present invention, the indium arsenide nanoclusters are prepared by the following method:

[0041] The indium source is dissolved in an organic solvent and degassed under heating. Then, an inert gas is filled in and the temperature is lowered. An arsenic source is dripped into the indium source system in a glove box to form indium arsenide nanoclusters. Finally, the indium arsenide nanoclusters are etched with acid.

[0042] Furthermore, the heating conditions are: the heating temperature is 90 to 120°C;

[0043] Cool down to 30-50℃;

[0044] The reaction time for forming the nanoclusters is 5 to 30 minutes;

[0045] The inert gas is nitrogen.

[0046] In some embodiments of the present invention, the indium arsenide quantum dot core is prepared by the following method:

[0047] An indium source is dissolved in an organic solvent and degassed while heated. An inert gas is then introduced and the temperature is increased. Once a predetermined temperature is reached, an arsenic source is rapidly injected. After the nucleation reaction is complete, the indium arsenide nanoclusters are continuously injected. The size of the indium arsenide quantum dots is controlled by adjusting the injection rate, injection time, and reaction temperature. The indium arsenide quantum dot cores are then purified and mixed with an organic solvent. The solvent is again degassed while heated, and then an inert gas is introduced and acid-etched. The reaction temperature is then increased, and the indium arsenide nanoclusters are continuously injected. The size of the indium arsenide quantum dots is controlled by adjusting the injection rate, injection time, and reaction temperature to obtain the indium arsenide quantum dot cores.

[0048] In an embodiment of the present invention, the inert gas is nitrogen;

[0049] In an embodiment of the present invention, the conditions for the vacuum heating reaction are: a heating temperature of 90 to 120° C.;

[0050] In an embodiment of the present invention, the reaction temperature of the nucleation reaction is 250-310°C;

[0051] In an embodiment of the present invention, the reaction time of the nucleation reaction is 1 to 30 minutes.

[0052] In an embodiment of the present invention, the injection rate of the indium arsenide nanoclusters is: 0.1 to 5 ml / hour;

[0053] In an embodiment of the present invention, the injection time of the indium arsenide nanoclusters is: 60 to 600 minutes;

[0054] In an embodiment of the present invention, the reaction temperature of the system for injecting indium arsenide nanoclusters is 270-310°C.

[0055] The third object of the present invention is to provide an application of the large-sized indium arsenide core-shell quantum dots with short-wave near-infrared emission in light-emitting devices, photodetectors or fluorescence detectors.

[0056] Furthermore, the light emitting device includes a near-infrared light emitting diode.

[0057] The light-emitting device is prepared by the following method, wherein the infrared light-emitting device structure includes an anode, a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer, an electron injection layer and a cathode;

[0058] The following steps are involved:

[0059] providing an electron injection layer and an electron transport layer on the pretreated substrate;

[0060] Spin coating an indium arsenide quantum dot dispersion on the obtained electron transport layer to form an indium arsenide quantum dot film, i.e., a light-emitting layer;

[0061] A hole transport layer, a hole injection layer and an anode are sequentially provided on the surface of the obtained light-emitting layer by vacuum evaporation method.

[0062] In one embodiment of the present invention, the hole injection layer is selected from one or more of poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid, nickel oxide, and molybdenum oxide.

[0063] In one embodiment of the present invention, the hole transport layer is selected from one or more of poly[bis(4-phenyl)(4-butylphenyl)amine], poly(9-vinylcarbazole) and polytriphenylamine.

[0064] In one embodiment of the present invention, the electron transport layer is selected from one or more of 2,4,6-tris[3-(diphenylphosphinoyl)phenyl]-1,3,5-triazole, 3,3'-[5'-[3-(3-pyridyl)phenyl][1,1':3',1"-terphenyl]-3,3"-diyl]dipyridine, 2,2',2"-(1,3,5-phenyl)triazine-3,3',3"-triylbenzene, nano zinc oxide, and nano tin oxide.

[0065] The above technical solution of the present invention has the following advantages over the prior art:

[0066] The present invention effectively avoids Oswald ripening during the growth process through a multi-step growth method, obtains near-infrared emission exceeding 1500 nanometers, and the peak-to-valley ratio of the absorption spectrum is greater than 1.2, realizing the preparation of ultra-large-sized indium arsenide quantum dots. In addition, a shell material with a high lattice match with indium arsenide is selected and successfully encapsulated, achieving a breakthrough in the preparation of ultra-large-sized (emission wavelength>1300 nanometers) core-shell structured indium arsenide quantum dots. The near-infrared light-emitting diodes prepared based on indium arsenide quantum dots effectively reduce device leakage current and effectively improve charge injection and transmission capabilities due to the low defect density and high uniformity of indium arsenide quantum dots themselves; the lighting voltage is only 3V. The materials used in the present invention are all easily available and highly reproducible, which is conducive to the preparation of large-area flexible devices and promotes the progress of large-scale industrialization. BRIEF DESCRIPTION OF THE DRAWINGS

[0067] In order to make the content of the present invention more clearly understood, the present invention is further described in detail below based on specific embodiments of the present invention in conjunction with the accompanying drawings, wherein

[0068] Figure 1 Schematic diagram of the principle of preparing large-sized indium arsenide quantum dots in Example 1;

[0069] Figure 2The fluorescence emission spectra of the indium arsenide quantum dots measured after equal sampling at different reaction time stages during the continuous injection in step (4) of Example 2;

[0070] Figure 3 The absorption spectra of indium arsenide quantum dots measured after equal sampling at different reaction time stages during continuous injection in step (4) of Example 2;

[0071] Figure 4 This is a transmission electron microscope photograph of aliquots taken at 80 minutes of reaction during the continuous injection in step (4) of Example 1;

[0072] Figure 5 This is a transmission electron microscope photograph of aliquots taken at 480 minutes of reaction time during the continuous injection in step (4) of Example 1;

[0073] Figure 6 The fluorescence emission spectra of indium arsenide quantum dots measured after equal sampling at different encapsulation stages in Example 3;

[0074] Figure 7 The absorption spectra of indium arsenide quantum dots measured after equal sampling at different encapsulation stages in Example 3;

[0075] Figure 8 Schematic diagram of the steps for preparing an indium arsenide quantum dot near-infrared light-emitting diode in Example 4;

[0076] Figure 9 The structural formula of the raw material for preparing the hole transport layer in the indium arsenide quantum dot near-infrared light-emitting diode in Example 4;

[0077] Figure 10 This is a graph showing the relationship between current density, voltage, and luminous brightness of the indium arsenide quantum dot near-infrared light-emitting diode prepared in Example 4; line A corresponds to the relationship between current density and voltage, and line B corresponds to the relationship between irradiance and voltage.

[0078] Figure 11 The fluorescence emission spectra of indium arsenide quantum dots measured after equal sampling at different reaction time stages in Comparative Example 1.

[0079] Figure 12 This is a transmission electron microscope photograph of an aliquot sample taken after 280 minutes of reaction in Comparative Example 1. DETAILED DESCRIPTION

[0080] The present invention will be further described below with reference to the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it. However, the embodiments are not intended to limit the present invention.

[0081] Example 1

[0082] This embodiment provides a method for preparing indium arsenide nanoclusters, the steps of which are as follows:

[0083] Step (12), preparing an arsenic source: in a glove box, 0.42 ml of tris(trimethylsilyl)arsenic, 0.6 ml of dioctylamine and 2.5 ml of heptadecane were mixed to obtain an arsenic-containing solution.

[0084] Step (2), preparing etching acid: dissolving 40 μL of hydrobromic acid in 2 mL of acetone to obtain a hydrobromic acid solution.

[0085] Step (3), preparation of indium source and indium arsenide nanoclusters: 0.8759 g of indium acetate, 3.0 ml of oleic acid and 15 ml of heptadecane were mixed to obtain an indium source solution. The indium source solution was degassed at 110°C for 90 minutes, and then nitrogen was introduced into the entire system and the temperature was lowered to 40°C. The solution was transferred to a glove box, and the arsenic-containing solution prepared in step (1) was then dripped into the reaction system and stirred continuously for 10 minutes. 360 μl of the hydrobromic acid solution prepared in step (2) was then dripped into the reaction system and stirred continuously for 10 minutes to obtain the etched indium arsenide nanoclusters.

[0086] Example 2

[0087] Indium arsenide quantum dots are prepared by continuous injection method in the embodiment of the present invention:

[0088] Step (1), preparing an arsenic source: in a glove box, 54 μL of tris(trimethylsilyl)arsenic, 170 μL of dioctylamine and 1 mL of heptadecane were mixed to obtain an arsenic source solution.

[0089] Step (2), 0.1168 g of indium acetate, 0.5 ml of oleic acid and 6 ml of heptadecane were mixed, and the whole system was degassed at 110 ° C for 90 minutes, and then nitrogen was introduced into the whole system and the system reaction temperature was set to 295 ° C. When it reached 290 ° C, the arsenic source solution prepared in step (1) was quickly injected into the reaction system and maintained for 15 minutes, and then the indium arsenide nanoclusters prepared in Example 1 were continuously dripped into the reaction system through a syringe pump, wherein the process of continuous dripping of indium arsenide nanoclusters was as follows: the whole reaction system was injected at 287 ° C, the injection rate was 2.4 ml / h for 60 minutes, and about 100 microliters of indium arsenide solution were extracted from the reaction system at 20 minutes, 40 minutes and 60 minutes of the reaction for spectral and absorption spectrum tests; then the temperature of the whole reaction system was set to 288.5 ° C, the injection rate was 2.3 The reaction mixture was continuously injected at a rate of 5 ml / h for 60 minutes, and approximately 100 microliters of indium arsenide solution were extracted from the reaction system at the 80th and 120th minutes of the reaction for spectral and absorption spectrum tests. The temperature of the entire reaction system was then set to 290° C., the injection rate was 2.30 ml / h for continuous injection for 60 minutes, and approximately 100 microliters of indium arsenide solution were extracted from the reaction system at the 160th minute of the reaction for spectral and absorption spectrum tests. The temperature of the entire reaction system was then set to 290° C., the injection rate was 2.20 ml / h for continuous injection for 100 minutes, and then the injection was stopped. The entire reaction system was maintained at 290° C. for 10 minutes, and approximately 100 microliters of indium arsenide solution were extracted from the reaction system at the 200th minute of the reaction for spectral and absorption spectrum tests. Finally, the heating source was removed and the mixture was naturally cooled to room temperature to obtain an indium arsenide quantum dot stock solution.

[0090] Step (3), purifying the indium arsenide quantum dot stock solution in step (2) in a glove box, specifically as follows: mixing the indium arsenide quantum dot stock solution, hexane and an alcohol mixed solvent in a volume ratio of 1:1:5 to obtain a mixed solution, fully shaking, centrifuging at 7800 rpm for 5 minutes, separating to obtain a solid precipitate, and redispersing the solid precipitate in n-hexane to prepare a 30 mg / ml indium arsenide quantum dot solution; wherein the alcohol mixed solvent is ethanol and isopropanol mixed in a volume ratio of 2.5:6.

[0091] Step (4): 2 ml of the indium arsenide quantum dot solution from step (3) was mixed with 4 ml of heptadecane. The entire system was degassed at 100°C for 30 minutes. After switching to nitrogen, 50 μl of diluted hydrobromic acid solution (40 μl of hydrobromic acid dissolved in 2 ml of acetone) was injected into the system and reacted for 10 minutes. The entire system was then heated to 290°C, and the indium arsenide nanoclusters obtained in Example 1 were continuously dripped into the reaction system through a syringe pump. The process of continuous dripping of the indium arsenide nanoclusters was as follows: the entire reaction system was injected at a rate of 0.58 ml / h at 290°C for 180 minutes and then the injection was stopped. Approximately 100 microliters of indium arsenide solution were extracted from the reaction system at 300 minutes, 320 minutes, 340 minutes and 480 minutes of reaction for spectral and absorption spectrum testing (the sampling time calculation at this time was consistent with that in step (2), and its calculation time was immediately the time in step 2 (2)). The entire reaction system was kept at 290°C for 10 minutes, and finally the heating source was removed and the reaction system was naturally cooled to room temperature to obtain an indium arsenide core quantum dot solution with a fluorescence peak wavelength of 1510 nm and a peak-to-valley ratio of 1.25. The absorption spectrum and fluorescence emission spectrum of the indium arsenide quantum dots measured after equal sampling at different time periods were detected. The experimental results are shown in FIG. Figure 2 and Figure 3 ,Depend on Figure 2 It can be seen that the emission wavelength of InAs quantum dots continues to redshift with the increase of reaction time, and finally achieves near-infrared emission of 1510 nm; Figure 3 It can be clearly seen that the absorption peak wavelength of InAs quantum dots continues to redshift with the increase of reaction time, and the peak-to-valley ratio shows a trend of first increasing and then decreasing, but in the final stage, the peak-to-valley ratio of InAs quantum dots is still greater than 1.2. Transmission electron microscopy images of InAs core quantum dots with reaction times of 80 minutes and 480 minutes were taken, and the results are shown in Figure 2. Figure 4 、 Figure 5 and Figure 12 ,Depend on Figure 4 It can be seen that the average size of the obtained indium arsenide core quantum dots is about 2.98 nanometers, and the wavelength corresponding to the reaction time of 80 minutes is 1000 nanometers. At this time, the indium arsenide quantum dots are small, but the size distribution is relatively uniform. Figure 5 It can be seen that the transmission electron microscope photos of equal samples taken after 480 minutes of reaction have an average size of about 6.53 nanometers. It can be clearly seen that with the red shift of the emission wavelength, the size of the indium arsenide quantum dots is gradually increasing, and the size of the quantum dots is uniform without any signs of ripening.

[0092] Comparative Example 1

[0093] Indium arsenide quantum dots were prepared by the following steps (one-pot method):

[0094] Step (1), preparing the arsenic source: in a glove box, mix 1.5 μL of tris(trimethylsilyl)arsenic, 10 μL of octylamine and 1 mL of octadecene.

[0095] Step (2), preparation of indium source: In a three-necked flask with a specification of 100 ml, 3 mg of indium acetate, 13.2 μl of oleic acid and 4 ml of 18-Schiff are mixed to obtain a mixed solution. The mixed solution is degassed at 60°C for 0.5 hours, then nitrogen is introduced and heated to 210°C and stirred for 15 minutes. The arsenic source prepared in step (1) is then injected into the system within 10 seconds and continuously stirred for 280 minutes. Indium arsenide quantum dots are obtained by a one-pot method. About 100 μl of indium arsenide solution is extracted from the reaction system at 5 minutes, 10 minutes, 20 minutes, 40 minutes, 80 minutes, 200 minutes and 280 minutes of reaction, respectively, for spectral and absorption spectrum testing. The fluorescence emission spectra of the indium arsenide quantum dots obtained at different time points in this comparative example are tested, and the results are shown in FIG. Figure 11 and Figure 12 ,Depend on Figure 11 It can be clearly seen that the emission wavelength of InAs quantum dots continues to redshift with the increase of reaction time, but its peak shape also gradually deteriorates and the half-peak width becomes wider, which means that the size of quantum dots is not uniform. Figure 12 It can also be proved that the size of indium arsenide quantum dots is not uniform and ripening phenomenon occurs.

[0096] Example 3

[0097] In this example, core-shell indium arsenide quantum dots were prepared by the following steps:

[0098] Step (1), preparing a phosphorus source: mixing 190 μL of tris(trimethylsilyl)phosphine and 1 mL of tri-n-octylphosphine in a glove box.

[0099] Step (2), preparing a phosphorus indium zinc precursor: 0.2919 g of indium acetate, 0.0917 g of zinc acetate, 1.27 ml of oleic acid and 8 ml of 18-Schiffonite were mixed to obtain a mixed solution, the mixed solution was degassed at 110° C. for 4 hours, then nitrogen was introduced and the temperature was cooled to room temperature, and the phosphorus source prepared in step (1) was added, and the mixture was stirred for 60 minutes to obtain a phosphorus indium zinc precursor solution.

[0100] Step (3), preparing a gallium phosphide precursor: 0.0528 g of gallium chloride, 0.0917 g of zinc acetate, 0.38 ml of oleic acid and 2 ml of 18-Schiff are mixed to obtain a mixed solution, the mixed solution is heated at 100° C. for 30 minutes, then cooled to room temperature, and the phosphorus source prepared in step (1) is added, and stirring is continued for 60 minutes to obtain a gallium phosphide precursor solution.

[0101] Step (4), preparing a zinc stearate precursor solution: 0.25 g of zinc stearate was mixed with 1 ml of 18 SDS, and stirred vigorously to obtain a zinc stearate precursor solution.

[0102] Step (5), preparing a zinc oleate precursor: 0.091 g of zinc acetate, 0.4 ml of oleic acid, and 5 ml of 18-Schiff are mixed to obtain a mixed solution. The mixed solution is degassed at 80° C. for 30 minutes, then nitrogen is introduced and the temperature is raised to 160° C. for 1 hour, and then the temperature is lowered to 80° C. to obtain a zinc oleate precursor solution.

[0103] Step (6), preparing a selenium precursor mixture: 1.78 g of selenium powder was mixed with 10 ml of tri-n-octylphosphine, and stirred vigorously to obtain a selenium precursor solution.

[0104] Step (7), preparing a sulfur precursor mixture: 1.78 g of selenium powder and 10 ml of tri-n-octylphosphine were mixed and stirred vigorously to obtain a sulfur precursor solution.

[0105] Step (8): 0.1168 g of indium acetate, 0.5 ml of oleic acid, and 6 ml of heptadecane were mixed to obtain a mixed solution. The mixed solution was degassed at 110° C. for 90 minutes, and then nitrogen was introduced and the reaction temperature was set to 295° C. When the temperature reached 290° C., the arsenic source prepared in Example 2 was quickly injected into the reaction system and maintained for 15 minutes. Subsequently, the indium arsenide nanoclusters prepared in Example 1 were continuously dripped into the reaction system through a syringe pump. The entire reaction system was injected at 287°C at a rate of 2.4 ml / h for 60 minutes, and then the temperature of the entire reaction system was set to 288.5°C at a rate of 2.35 ml / h for 60 minutes. The temperature of the entire reaction system was set to 290°C at a rate of 2.30 ml / h for 60 minutes. The temperature of the entire reaction system was further set to 290°C at a rate of 2.20 ml / h for 100 minutes, and then the injection was stopped. The entire reaction system was maintained at 290°C for 10 minutes, and finally the heating source was removed and naturally cooled to room temperature to obtain an indium arsenide core quantum dot (InAs) solution with a fluorescence peak wavelength of 1030 nm.

[0106] Step (9), purifying the indium arsenide core quantum dots with a fluorescence peak wavelength of 1030 nanometers obtained in step (8) in a glove box, specifically as follows: mixing the indium arsenide quantum dot stock solution, hexane and an alcohol mixed solvent in a volume ratio of 1:1:1 to obtain a mixed solution, fully shaking, centrifuging at 7800 rpm for 5 minutes, taking the supernatant and adding 9 ml of the alcohol mixed solvent, fully shaking, centrifuging at 7800 rpm for 5 minutes, and redispersing the precipitate in n-hexane to prepare a 50 mg / ml indium arsenide core quantum dot solution, wherein the alcohol mixed solvent is ethanol and isopropanol mixed at a volume ratio of 2.5:6.

[0107] Step (10): 2 ml of the indium arsenide core quantum dot solution obtained in step (9) is mixed with 4 ml of dehydrated oleylamine and 4 ml of dehydrated ODE to obtain a mixed solution. The mixed solution is degassed at 110° C. for 60 minutes, and then nitrogen is introduced and the reaction temperature is set to 265° C. When it reaches 250° C., the phosphoindium zinc precursor solution prepared in step (2) is continuously injected at 4 ml / h for 90 minutes. Then, about 100 μl of the indium arsenide solution containing the phosphoindium zinc shell is extracted from the reaction system for spectral and absorption spectrum tests, and a phosphoindium zinc shell is formed on the surface of the indium arsenide core quantum dots (the intermediate is InAs@InZnP); then, the gallium phosphide precursor solution prepared in step (3) is immediately injected within 45 minutes to complete the growth of the gallium phosphide shell, and about 100 μl of the indium arsenide solution containing the phosphoindium zinc shell and the gallium phosphide shell is extracted from the reaction system for spectral and absorption spectrum tests to obtain the intermediate InAs@InZnP@GaP. Afterwards, at 265° C., 1 ml of the zinc stearate precursor solution prepared in step (4) and 0.5 ml of the selenium precursor mixture prepared in step (6) were injected completely within 45 minutes through a syringe pump to complete the growth of the zinc selenide shell. Approximately 100 μL of indium arsenide solution containing indium zinc phosphide shell, gallium phosphide shell and zinc selenide shell was extracted from the reaction system for spectral and absorption spectrum testing to obtain the intermediate InAs@InZnP@GaP@ZnSe. Finally, at 260°C, a syringe pump was used to inject 5 ml of the zinc oleate precursor prepared in step (5) and 5 ml of the sulfur precursor mixture prepared in step (7) within 20 minutes to complete the growth of the zinc sulfide shell. About 100 microliters of indium arsenide solution containing zinc indium phosphide shell, gallium phosphide shell, zinc selenide shell and zinc sulfide shell were extracted from the reaction system for spectral and absorption spectrum tests, and finally indium arsenide quantum dots InAs@InZnP@GaP@ZnSe@ZnS with a core-shell structure were obtained. The obtained intermediate extract and the final product were subjected to fluorescence intensity detection and absorption spectrum detection. The results are shown in FIG. Figure 6 and Figure 7 ,Depend on Figure 6 It can be clearly seen that the spectrum is significantly red-shifted when the phosphorus indium zinc shell is coated, indicating that phosphorus indium zinc is successfully grown outside the indium arsenide core. In the process of coating gallium phosphide, zinc selenide, and zinc sulfide, the emission spectrum is slightly red-shifted, and the spectrum curve is smoother, indicating that the gallium phosphide layer, zinc selenide layer, and zinc sulfide layer are successfully grown; Figure 7 It can be seen that the change trends of the first absorption peak and emission peak of the quantum dots are the same.

[0108] Example 4

[0109] This embodiment provides a method for preparing an indium arsenide quantum dot light-emitting device, and the specific steps are as follows:

[0110] Step (1): ultrasonically treat the ITO transparent conductive glass substrate in a commercial cleaning agent, rinse with deionized water, then ultrasonically clean it with deionized water, acetone, and ethanol in sequence, bake it in a clean environment for 30 minutes to completely remove moisture, and then ultraviolet ozone for 30 minutes.

[0111] Step (2): Spin-coat nano zinc oxide on the treated ITO substrate at a rotation speed of 1500 rpm for 1 minute, and then immediately transfer it to a substrate at 140° C. for 10 minutes of annealing to form an electron transport layer.

[0112] Step (3): The ITO substrate coated with nano-zinc oxide was spin-coated with a layer of PEIE (0.4 wt% 2-methoxyethanol) at a rotation speed of 5000 rpm for 1 minute, and then immediately transferred to a substrate at 110°C for 20 minutes of annealing.

[0113] Step (4): Configuring the concentration of the indium arsenide quantum dot solution with a core-shell structure synthesized in Example 3, the specific steps are as follows:

[0114] S1. Mix the indium arsenide quantum dot stock solution, hexane, and an alcohol mixture in a volume ratio of 1:1:2, centrifuge at 7800 rpm for 5 minutes, retain the supernatant, and discard the solid phase. The alcohol mixture is prepared by mixing ethanol and isopropanol in a volume ratio of 2.5:6.

[0115] S2. Add 10 ml of the mixed solution to the supernatant obtained in step S1, centrifuge at 7800 rpm for 5 minutes, dissolve the resulting precipitate with 1 ml of hexane, add 6 ml of the mixed solution, centrifuge at 7800 rpm for 5 minutes, and separate the precipitate.

[0116] S3. The precipitate obtained in step S2 was dissolved with 1 ml of hexane, 6 ml of the mixture was added, and the mixture was centrifuged at 7800 rpm for 5 minutes.

[0117] S4. Repeat step S3 ten times, and finally make the indium arsenide quantum dot solution with a core-shell structure into 20 mg / mL.

[0118] Step (5): When the substrate has cooled to room temperature, 60 μL of 20 mg / mL core-shell indium arsenide quantum dots are added dropwise and spin-coated at 2000 rpm for 1 minute to form a light-emitting layer. The substrate (the base of the LED device itself) obtained in step (3) is then transferred to an inflatable glove box.

[0119] Step (6): In a glove box, spin-coat 8 mg / mL of poly[N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)benzidine] (Poly-TPD) at 3000 rpm for 1 minute to form a hole transport layer.

[0120] Step (7): Place the treated ITO conductive glass in a vacuum chamber and evacuate to 4.0×10 -4 Pa, and a hole transport layer is obtained.

[0121] Step (8): In step (7), a layer of molybdenum oxide (MoO3) is vacuum-deposited on the hole transport layer as a hole injection layer at a deposition rate of The coating thickness is 10 nanometers.

[0122] Step (9): Vacuum evaporate aluminum on the hole injection layer as the device cathode, with the thickness of the aluminum being 120 nanometers, to produce a quantum dot light-emitting diode.

[0123] Step (10): Cool the cavity for 10 minutes, flush with nitrogen to break the vacuum, and package the prepared quantum dot light-emitting device (i.e., diode). Use PR-745 equipped with a near-infrared camera and Keithley 2400 source meter to test the photoelectric performance of the obtained diode, and test the relationship between the current density and voltage, and the luminous brightness and voltage of the obtained diode. The results are shown in Figure 10 ,Depend on Figure 10 It can be seen that the obtained LED device has a larger current density and a lower lighting voltage, which means that it provides a new solution for the near-infrared LED field.

[0124] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. An indium arsenide core-shell quantum dot with short-wave near-infrared emission, characterized in that: The indium arsenide core-shell quantum dots are core-shell structures, with indium arsenide quantum dots as cores and multiple shell layers wrapped around the surface of the indium arsenide quantum dots, wherein the multiple shell layers include two or more of InP shell, InZnP shell, GaP shell, ZnSe shell, ZnS shell, CdSe shell, and CdS shell; The indium arsenide quantum dots are prepared by the following method: S11: dissolving an indium source in an organic solvent, degassing the solution at 90-120°C, filling the solution with an inert gas and raising the temperature to 250-310°C, rapidly injecting an arsenic source, and after the nucleation reaction is complete, continuously injecting indium arsenide nanoclusters at 270-310°C. The nucleation reaction takes 1-30 minutes. S12: Purify the indium arsenide quantum dot cores and mix them with an organic solvent, degas again under heating at 90-120°C, then fill with inert gas and etch with acid, then increase the reaction temperature to 270-310°C, and start continuous injection of indium arsenide nanoclusters to obtain indium arsenide quantum dots; The indium arsenide nanoclusters are prepared by the following method: The indium source is dissolved in an organic solvent, degassed at 90-120°C, filled with inert gas and cooled, and an arsenic source is dripped into the indium source system in a glove box to form indium arsenide nanoclusters. Finally, the indium arsenide nanoclusters are etched with acid. The organic solvent is selected from heptadecane; the arsenic source is selected from one or more of tri(trimethylsilyl)arsenic, tri(trimethylgermanyl)arsenic, and aminoarsenic; the acid is selected from hydrobromic acid and / or hydrofluoric acid; the injection rate of the indium arsenide nanoclusters is: 0.1-5 ml / hour; the fluorescence emission peak wavelength of the indium arsenide core-shell quantum dots exceeds 1500 nanometers, and the peak-to-valley ratio of the absorption spectrum of the indium arsenide core-shell quantum dots is greater than 1.

2.

2. The indium arsenide core-shell quantum dots according to claim 1, characterized in that The particle size of the indium arsenide core-shell quantum dots is 3 to 20 nanometers.

3. A method for preparing indium arsenide core-shell quantum dots having short-wave near-infrared emission according to any one of claims 1 to 2, characterized in that: The following steps are involved: dissolving an indium source in an organic solvent to obtain an indium source solution; An arsenic source is added to an indium source solution for reaction, and an acid is used for etching to obtain indium arsenide quantum dots; A metal precursor of a shell layer wrapped on the surface of the indium arsenide quantum dots is added to a mixed solution containing indium arsenide quantum dots, and the mixture is heated for reaction to obtain the indium arsenide core-shell quantum dots with short-wave near-infrared emission light.

4. The preparation method according to claim 3, characterized in that The organic solvent is selected from heptadecane; the organic solvent is degassed; and the conditions for the heating reaction are: a heating temperature of 100-300° C. and a heating time of 10-200 minutes.

5. The preparation method according to claim 3, characterized in that The indium source is one or more of anhydrous indium acetate, indium chloride, indium bromide, and indium iodide; the arsenic source is one or more of tris(trimethylsilyl)arsenic, tris(trimethylgermanyl)arsenic, and aminoarsenic; and the molar ratio of the indium source to the arsenic source is 1-5:

1.

6. The preparation method according to claim 3, characterized in that The metal precursor of the shell layer includes two or more of a zinc source, a phosphorus source, a selenium source, a sulfur source, a gallium source, and a cadmium source.

7. The preparation method according to claim 6, characterized in that Meet one or more of the following conditions: a), the indium source is selected from one or more of anhydrous indium acetate, indium chloride, indium bromide, and indium iodide; b), the phosphorus source is selected from one or more of TMS-P and tris(trimethylgermanyl)phosphine; c) The zinc source is selected from one or more of anhydrous zinc acetate, zinc stearate, and zinc palmitate; d) The gallium source is selected from gallium chloride and / or gallium oleate.

8. Use of the indium arsenide core-shell quantum dots having short-wave near-infrared emission as claimed in any one of claims 1 to 2 in a light-emitting device, a photodetector or a fluorescence detector.

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