A metal chalcogenide alloy compound magic size cluster and a method for preparing the same

Abstract

The application provides a metal chalcogenide alloy compound magic size cluster and a preparation method thereof, and belongs to the technical field of semiconductor materials. The application improves the reaction activity of chalcogenide anions through the activation of an amino phosphine, realizes the synthesis of different types of multi-element alloy magic size clusters (MSCs) by means of a single anion ligand and control of a reaction temperature, and provides a simple and convenient preparation method of metal chalcogenide alloy MSCs, which has important significance for the synthesis of metal chalcogenide alloy semiconductor quantum dots and the subsequent application of quantum dot photoelectric devices based on metal chalcogenide alloy compounds.

Description

Technical Field

[0001] This invention relates to the field of semiconductor materials technology, and in particular to a magic-size cluster of metal chalcogenide compounds and its preparation method. Background Technology

[0002] Colloidal semiconductor quantum dots, due to their excellent light-emitting properties, are the foundation of modern optoelectronic devices. Alloying of semiconductor materials is an effective way to tune their optical properties. Alloying can adjust the lattice constant and band structure, thereby modulating the optical bandgap. Therefore, tuning the optical bandgap over a wide energy range through alloying opens up broad prospects for the application of alloy semiconductors in various optoelectronic devices.

[0003] Currently, the synthesis of metal chalcogenide semiconductors mainly relies on the hot-injection method. However, the varying reactivity of precursors leads to uneven distribution during alloy formation, and even slight changes in reaction conditions can alter the elemental ratios and distributions within the alloy, significantly reducing experimental repeatability and affecting electron and hole behavior, resulting in products that differ greatly from theoretical predictions. For example, zinc chalcogenides, as an important class of wide-bandgap semiconductor materials, are crucial for ultraviolet and blue light emission. Theoretical predictions suggest that by adjusting the proportions of alloying elements in zinc chalcogenide compounds, the minimum optical bandgap of ZnSeTe alloys can reach 2.03 eV (ZnSe... 0.37 Te 0.63 The minimum optical band gap of ZnSTe can reach 1.90 eV (ZnS). 0.32 Te 0.68 This technology holds promise for extending the luminescence range of zinc chalcogenide compounds into the red light region, thereby covering the entire visible light spectrum. However, there are currently very few reports on the synthesis of zinc chalcogenide quantum dots, and the photoluminescence efficiencies are relatively low, indicating that the synthesis is at a bottleneck.

[0004] Magic-size clusters (MSCs) are semiconductor clusters characterized by a defined number of atoms and higher thermal stability compared to slightly larger or smaller clusters. They also exhibit narrow absorption peaks, with the absorption peaks red-shifting in discrete steps as the reaction proceeds. Semiconductor magic-size clusters are considered important intermediates for the synthesis of semiconductor nanostructures. Current research reports that MSCs, through fragmentation, can be used as intermediates to synthesize colloidal semiconductor quantum dots, effectively controlling the composition ratio and size distribution within the quantum dots. The use of MSCs as precursors for the preparation of high-quality quantum dots is currently a hot research topic.

[0005] Synthesizing metal chalcogenide semiconductors from MSCs holds promise as a novel synthetic method, potentially addressing the issue of poor reproducibility in the synthesis of alloy nanomaterials. Currently, there are no reports on the synthesis of metal chalcogenide MSCs. Summary of the Invention

[0006] The purpose of this invention is to provide a magic-size cluster of metal chalcogenide compounds and its preparation method. This invention successfully prepared magic-size clusters of metal chalcogenide compounds, which is of great significance for the synthesis of metal chalcogenide semiconductor quantum dots and the subsequent application of optoelectronic devices based on metal-based chalcogenide compound quantum dots.

[0007] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0008] This invention provides a method for preparing magic-sized clusters of metal chalcogenide alloy compounds, comprising the following steps: dissolving a chalcogenide element in aminophosphine to obtain a chalcogenide precursor solution; wherein the chalcogenide element includes one or more of sulfur powder, selenium powder, and tellurium powder; and wherein the aminophosphine is tris(dimethylamino)phosphine or tris(diethylamino)phosphine.

[0009] The chalcogenide precursor solution, metal precursor, organic amine and 1-octadecene are mixed and subjected to a chemical reaction under a protective atmosphere. The temperature of the chemical reaction is 130-250°C and the holding time is 30-60 min. After cooling to room temperature, an antisolvent is added to the resulting reaction solution to precipitate magic-size clusters of metal chalcogenide compounds.

[0010] Preferably, the metal element in the metal precursor includes one or more of Zn, Cd, Hg, Pb, Sn, In, Ga, Cu, Ag, Au, Mn, Fe, Co, Ni, Pd, and Pt.

[0011] Preferably, the molar ratio of the chalcogenide elements in the chalcogenide precursor solution to the metal elements in the metal precursor is 1:1.

[0012] Preferably, the volume ratio of the organic amine to 1-octadecene is 1:1.

[0013] Preferably, the organic amine is a chain-like primary amine.

[0014] Preferably, the chain primary amine comprises octadecylamine and / or oleylamine.

[0015] Preferably, the antisolvent is a highly polar solvent that is miscible with n-hexane.

[0016] Preferably, the antisolvent includes one or more of acetone, methanol, and ethanol.

[0017] Preferably, mixing the chalcogenide precursor solution, the metal precursor, the organic amine, and 1-octadecene comprises: mixing the organic amine and 1-octadecene, evacuating and purging under nitrogen protection, heating to 100-120°C, evacuating for 30 minutes, and then adding the chalcogenide precursor solution and the metal precursor.

[0018] This invention provides a magic-size cluster of metal chalcogenide compounds prepared by the preparation method described above.

[0019] This invention provides a method for preparing magic-sized clusters of metal chalcogenide compounds, comprising the following steps: dissolving a chalcogenide element in aminophosphine to obtain a chalcogenide precursor solution; wherein the chalcogenide element includes one or more of sulfur powder, selenium powder, and tellurium powder; mixing the chalcogenide precursor solution, a metal precursor, an organic amine, and 1-octadecene, and carrying out a combination reaction under a protective atmosphere at a temperature of 130–250°C for a holding time of 30–60 min; and after cooling, adding an antisolvent to the resulting reaction solution to precipitate magic-sized clusters of metal chalcogenide compounds.

[0020] This invention enhances the reactivity of chalcogenide anions through the activation of aminophosphine, enabling the synthesis of various types of multi-component MSCs by controlling the reaction temperature using a single anionic ligand. This invention provides a systematic, convenient, and simple method for preparing metal chalcogenide MSCs.

[0021] This invention successfully prepared magic-sized clusters of metal chalcogenide compounds, which is of great significance for the synthesis of metal chalcogenide semiconductor quantum dots and the subsequent application of optoelectronic devices based on metal-based chalcogenide compound quantum dots. Attached Figure Description

[0022] Figure 1 Transmission electron microscopy images of ZnSeTe MSCs(a), ZnSTe MSCs(b), ZnSeS MSCs(c), and ZnSeSTe MSCs(d);

[0023] Figure 2 The UV-Vis absorption spectra of n-hexane dispersions of ZnSeTe MSCs, ZnSTe MSCs, ZnSeS MSCs and ZnSeSTe MSCs are shown.

[0024] Figure 3 X-ray powder diffraction patterns of ZnSeTe MSCs, ZnSTe MSCs, ZnSeS MSCs and ZnSeSTe MSCs;

[0025] Figure 4UV-Vis absorption spectra of n-hexane dispersions of ZnSeTe MSCs(a), ZnSeS MSCs(b), and ZnSTe MSCs(c) with different feed ratios;

[0026] Figure 5 The UV-Vis absorption spectra of the products obtained in Comparative Examples 1–5 are shown. Detailed Implementation

[0027] This invention provides a method for preparing magic-sized clusters of metal chalcogenide alloy compounds, comprising the following steps: dissolving a chalcogenide element in aminophosphine to obtain a chalcogenide precursor solution; wherein the chalcogenide element includes one or more of sulfur powder, selenium powder, and tellurium powder;

[0028] The chalcogenide precursor solution, metal precursor, organic amine and 1-octadecene are mixed and subjected to a chemical reaction under a protective atmosphere. The temperature of the chemical reaction is 130-250°C and the holding time is 30-60 min. After cooling, an antisolvent is added to the resulting reaction solution to precipitate magic-size clusters of metal chalcogenide compounds.

[0029] Unless otherwise specified, all raw materials used in this invention are commercially available products well known in the art.

[0030] This invention dissolves chalcogenides in aminophosphine to obtain a chalcogenide precursor solution.

[0031] In this invention, the chalcogenide elements include one or more of sulfur powder, selenium powder, and tellurium powder. When multiple chalcogenide elements are included, the proportion of each chalcogenide element is not particularly important and any proportion is acceptable. In this invention, the aminophosphine is preferably tris(dimethylamino)phosphine or tris(diethylamino)phosphine. In this invention, the dissolution temperature is preferably 80–120°C, more preferably 90–100°C. In this invention, the dissolution is preferably carried out under stirring conditions. The amount of aminophosphine used is not particularly important, as long as it is sufficient to completely dissolve the chalcogenide elements. This invention enhances the reactivity of chalcogenide anions through the activation of aminophosphine.

[0032] After obtaining the chalcogenide precursor solution, the present invention mixes the chalcogenide precursor solution, the metal precursor, the organic amine and 1-octadecene, and carries out a combination reaction under a protective atmosphere.

[0033] In this invention, the metal precursor is preferably an alkyl metal. The metal element in the metal precursor preferably includes one or more of Zn, Cd, Hg, Pb, Sn, In, Ga, Cu, Ag, Au, Mn, Fe, Co, Ni, Pd, and Pt. When the metal element is Zn, the metal precursor is preferably diethylzinc.

[0034] In this invention, the molar ratio of the chalcogenide elements in the chalcogenide precursor solution to the metal elements in the metal precursor is preferably 1:1.

[0035] In this invention, the organic amine is preferably a chain-like primary amine, which preferably includes octadecylamine (ODA) and / or oleylamine (OLA). In this invention, the organic amine and 1-octadecene are used as reaction solvents. In this invention, the volume ratio of the organic amine to 1-octadecene is preferably 1:1; this invention does not have special requirements on the specific amounts of the organic amine and 1-octadecene, as long as the reactants are evenly dispersed.

[0036] In this invention, the mixing preferably includes: mixing the organic amine and 1-octadecene, evacuating and purging under nitrogen protection, heating to 100-120°C, evacuating for 30 minutes, and then adding a chalcogen precursor solution and a metal precursor. Heating the organic amine and 1-octadecene first is to remove small amounts of water from the reaction system.

[0037] In this invention, when the target metal chalcogenide alloy compound magic size cluster contains multiple types of chalcogenide elements, the invention can dissolve different types of chalcogenide elements into aminophosphine to obtain multiple chalcogenide precursor solutions, and mix the multiple chalcogenide precursor solutions with metal precursors, organic amines and 1-octadecene; alternatively, different chalcogenide precursor solutions can be mixed into one aminophosphine solution, so that the same chalcogenide precursor solution contains different types of chalcogenide elements.

[0038] In this invention, the temperature of the chemical reaction is 130–250°C, preferably 140–230°C, and more preferably 160–200°C; the holding time of the chemical reaction is 30–60 min, preferably 40–50 min. During the chemical reaction, chalcogen elements combine with metal ions in the metal precursor to form magic-size clusters of metal chalcogenide alloys.

[0039] After the chemical reaction is completed, the mixture is cooled to room temperature. The present invention adds an antisolvent to the resulting reaction solution to precipitate magic-size clusters of metal chalcogenide compounds.

[0040] In this invention, the antisolvent is preferably a strongly polar solvent miscible with n-hexane; specifically, it can be one or more of acetone, methanol, and ethanol. This invention does not have special requirements on the amount of the antisolvent used, as long as it is sufficient to ensure the precipitation of magic-size clusters of the metal chalcogenide compound.

[0041] After precipitating the magic-size clusters of metal chalcogenide compounds, the present invention preferably centrifuges the precipitated system and collects the precipitate. The resulting solid is the monodisperse magic-size clusters of metal chalcogenide compounds.

[0042] This invention provides a magic-sized cluster of metal chalcogenide compounds prepared by the method described above. The preferred particle size of the magic-sized cluster is 1–2 nm.

[0043] This invention successfully prepared magic-sized clusters of metal chalcogenide compounds, which is of great significance for the synthesis of metal chalcogenide semiconductor quantum dots and the subsequent application of optoelectronic devices based on metal-based chalcogenide compound quantum dots.

[0044] The following detailed description, in conjunction with embodiments, illustrates the magic-size clusters of metal chalcogenide compounds and their preparation methods provided by the present invention. However, these descriptions should not be construed as limiting the scope of protection of the present invention.

[0045] Example 1

[0046] Step 1: Add 0.255g tellurium powder and 1.796g tris(dimethylamino)phosphine to a reaction flask, heat and stir at 90℃ until the solid dissolves and becomes a pale yellow transparent solution, thus obtaining the tellurium source solution with a concentration of 1mol / L;

[0047] Step 2: Add 0.158g of selenium powder and 1.796g of tris(dimethylamino)phosphine to the reaction flask, heat and stir at 90℃ until the solid dissolves and becomes a colorless and transparent solution, thus obtaining the selenium source solution with a concentration of 1mol / L.

[0048] Step 3: Add 5 mL of OLA and 5 mL of 1-octadecene (ODE) to a 100 mL reaction flask. Under nitrogen protection, evacuate the air 3 times, then heat to 120°C and evacuate the air for 30 min.

[0049] Step 4: Inject 0.5 mL of tellurium source solution, 0.5 mL of selenium source solution and 1 mL of diethylzinc into the solution from Step 3, heat to 130°C, stir for 1 hour, and cool to room temperature;

[0050] Step 5: Take 5 mL of reaction solution, add 15 mL of ethanol, centrifuge at 8000 rpm for 3 min, collect the precipitate, and the obtained solid is the monodisperse ZnSeTe magic size clusters powder sample; injection volume Te / Se = 0.5 / 0.5.

[0051] Example 2

[0052] Step 1: Add 0.064g of sulfur powder and 1.796g of tris(dimethylamino)phosphine to a reaction flask, heat and stir at 90℃ until the solid dissolves and becomes a colorless and transparent solution, thus obtaining the sulfur source solution with a concentration of 1mol / L;

[0053] Step 2: Add 0.158g of selenium powder and 1.796g of tris(dimethylamino)phosphine to the reaction flask, heat and stir at 90℃ until the solid dissolves and becomes a colorless and transparent solution, thus obtaining the selenium source solution with a concentration of 1mol / L.

[0054] Step 3: Add 5 mL of OLA and 5 mL of ODE to a 100 mL reaction flask, evacuate the air 3 times under nitrogen protection, then heat to 120°C and evacuate the air for 30 min.

[0055] Step 4: Add 0.5 mL of sulfur source solution, 0.5 mL of selenium source solution, and 1 mL of diethylzinc to the solution from Step 3, heat to 200°C, stir for 1 hour, and then cool to room temperature.

[0056] Step 5: Take 5 mL of reaction solution, add 15 mL of ethanol, centrifuge at 8000 rpm for 3 min, collect the precipitate, and the obtained solid is the monodisperse ZnSeS magic size clusters powder sample; injection volume Se / S = 0.5 / 0.5.

[0057] Example 3

[0058] Step 1: Add 0.064g of sulfur powder and 1.796g of tris(dimethylamino)phosphine to a reaction flask, heat and stir at 90℃ until the solid dissolves and becomes a colorless and transparent solution, thus obtaining the sulfur source solution with a concentration of 1mol / L;

[0059] Step 2: Add 0.255g of tellurium powder and 1.796g of tris(dimethylamino)phosphine to the reaction flask, heat and stir at 90℃ until the solid dissolves and becomes a pale yellow transparent solution, thus obtaining the tellurium source solution with a concentration of 1mol / L.

[0060] Step 3: Add 5 mL of OLA and 5 mL of ODE to a 100 mL reaction flask, evacuate the air 3 times under nitrogen protection, then heat to 120°C and evacuate the air for 30 min.

[0061] Step 4: Add 0.5 mL of sulfur source solution, 0.5 mL of selenium source solution, and 1 mL of diethylzinc to the solution from Step 3, heat to 150°C, stir for 1 hour, and then cool to room temperature.

[0062] Step 5: Take 5 mL of reaction solution, add 15 mL of ethanol, centrifuge at 8000 rpm for 3 min, collect the precipitate, and the obtained solid is the monodisperse ZnSTe Magic size clusters powder sample; injection volume Te / S = 0.5 / 0.5.

[0063] Example 4

[0064] Step 1: Add 0.064g of sulfur powder and 1.796g of tris(dimethylamino)phosphine to a reaction flask, heat and stir at 90℃ until the solid dissolves and becomes a colorless and transparent solution, thus obtaining the sulfur source solution with a concentration of 1mol / L;

[0065] Step 2: Add 0.255g of tellurium powder and 1.796g of tris(dimethylamino)phosphine to the reaction flask, heat and stir at 90℃ until the solid dissolves and becomes a pale yellow transparent solution, thus obtaining the tellurium source solution with a concentration of 1mol / L;

[0066] Step 3: Add 0.158g of selenium powder and 1.796g of tris(dimethylamino)phosphine to the reaction flask, heat and stir at 90℃ until the solid dissolves and becomes a colorless and transparent solution, thus obtaining the selenium source solution with a concentration of 1mol / L.

[0067] Step 4: Add 5 mL of OLA and 5 mL of 1-octadecene (ODE) to a 100 mL reaction flask, evacuate the air 3 times under nitrogen protection, then heat to 120 °C and evacuate the air for 30 min.

[0068] Step 5: Add 0.5 mL of sulfur source solution, 0.25 mL of selenium source solution, 0.25 mL of tellurium source solution, and 1 mL of diethylzinc to the solution from Step 3, heat to 250°C, stir for 1 hour, and then cool to room temperature.

[0069] Step 6: Take 5 mL of reaction solution, add 15 mL of ethanol, centrifuge at 8000 rpm for 3 min, collect the precipitate, and the obtained solid is the monodisperse ZnSSeTe Magic size clusters powder sample; injection volume S / Se / Te = 0.5 / 0.25 / 0.25.

[0070] Examples 5-8

[0071] The only difference from Example 1 is that the amount of tellurium source solution and selenium source solution used in step four is changed, thereby changing the injection amount of Te / Se.

[0072] Examples 9-12

[0073] The only difference from Example 2 is that the amounts of sulfur source solution and selenium source solution used in step four are changed, thereby changing the injection amount of Se / S.

[0074] Examples 13-15

[0075] The only difference from Example 3 is that the amount of sulfur source solution and selenium source solution used in step four is changed, thereby changing the injection amount of Te / S.

[0076] The amount of chalcogens injected into the MSCs prepared in Examples 1 to 15 (except Example 4) is shown in Table 1.

[0077] Table 1. Injection amounts of chalcogens in MSCs prepared in Examples 1-15

[0078] Example 1 Example 5 Example 6 Example 7 Example 8 Te / Se = 0.5 / 0.5 Te / Se = 0.9 / 0.1 Te / Se = 0.7 / 0.3 Te / Se = 0.3 / 0.7 Te / Se = 0.1 / 0.9 Example 2 Example 9 Example 10 Example 11 Example 12 Se / S = 0.5 / 0.5 Se / S = 0.9 / 0.1 Se / S = 0.7 / 0.3 Se / S = 0.3 / 0.7 Se / S = 0.1 / 0.9 Example 3 Example 13 Example 14 Example 15 - Te / S = 0.5 / 0.5 Te / S = 0.9 / 0.1 Te / S = 0.7 / 0.3 Te / S = 0.3 / 0.7 -

[0079] Structural characterization:

[0080] The magic-sized clusters prepared in Examples 1-4 were characterized by transmission electron microscopy, and the results are shown in the figure. Figure 1 . Figure 1 In the images, (a) shows ZnSeTe MSCs, (b) shows ZnSTe MSCs, (c) shows ZnSeS MSCs, and (d) shows ZnSeSTe MSCs. The inset in the upper right corner is a lattice image under high magnification. As can be seen from the images, the MSCs prepared in each embodiment are very uniformly dispersed without agglomeration, and the particle size is about 1 to 2 nm.

[0081] The magic-sized clusters prepared in Examples 1-4 were dispersed in n-hexane, and UV-Vis absorption spectroscopy was performed. The results are shown in [Figure 1]. Figure 2 .Depend on Figure 2 It can be seen that the products obtained in Examples 1 to 4 all have the characteristic absorption peaks of MSCs.

[0082] The magic-sized clusters prepared in Examples 1-4 were characterized by XRD, and the results are shown in the figure. Figure 3 .Depend on Figure 3 It can be seen that the magic-sized clusters prepared in each embodiment are all cubic crystal systems.

[0083] The magic-sized clusters prepared in Examples 1-4 were subjected to inductively coupled plasma atomic emission spectrometry analysis, and the results are shown in Table 2.

[0084] Table 2. MSCs component analysis results from Examples 1-4

[0085]

[0086] According to the ICP element content in Table 2, this invention successfully introduced various anions into metal chalcogenides, indicating that multi-component MSCs were indeed synthesized.

[0087] Figure 4 The UV-Vis absorption spectra of hexane dispersions of ZnSeTe MSCs (a), ZnSeS MSCs (b), and ZnSTe MSCs (c) with different feed ratios are shown. The obtained products have the characteristic absorption peaks of MSCs.

[0088] Comparative Examples 1-5

[0089] The only difference from Example 4 is that tris(dimethylamino)phosphine or tris(diethylamino)phosphine was replaced with tri-n-octylphosphine. The reaction was carried out at 270°C, 230°C, 190°C, 150°C, and 110°C for 30 min, respectively. In all cases, MSCs failed to grow. The UV-Vis absorption spectra of each product are shown below. Figure 5 As shown.

[0090] As can be seen from the above examples and comparative examples, the present invention improves the reactivity of chalcogenide anions by activating aminophosphine (tris(dimethylamino)phosphine or tris(diethylamino)phosphine), thereby achieving the synthesis of different types of multi-component alloy MSCs by controlling the reaction temperature through a single anionic ligand.

[0091] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing magic-sized clusters of metal chalcogenide compounds, comprising the following steps: A chalcogenide element is dissolved in aminophosphine to obtain a chalcogenide precursor solution; the chalcogenide element includes one or more of sulfur powder, selenium powder, and tellurium powder; the aminophosphine is tris(dimethylamino)phosphine or tris(diethylamino)phosphine. The chalcogenide precursor solution, the metal precursor, the organic amine, and 1-octadecene are mixed and subjected to a chemical reaction under a protective atmosphere at a temperature of 130-250°C for 30-60 minutes. After cooling to room temperature, an antisolvent is added to the resulting reaction solution to precipitate magic-size clusters of metal chalcogenide compounds. The metal element in the metal precursor is one or more of Zn, Cd, Hg, Pb, Sn, In, Ga, Cu, Ag, Au, Mn, Fe, Co, Ni, Pd, and Pt, and the metal precursor is an alkyl metal.

2. The preparation method according to claim 1, characterized in that, The molar ratio of the chalcogenide elements in the chalcogenide precursor solution to the metal elements in the metal precursor is 1:

1.

3. The preparation method according to claim 1, characterized in that, The volume ratio of the organic amine to 1-octadecene is 1:

1.

4. The preparation method according to claim 1 or 3, characterized in that, The organic amine is a chain-like primary amine.

5. The preparation method according to claim 4, characterized in that, The chain-like primary amines include octadecylamine and / or oleylamine.

6. The preparation method according to claim 1, characterized in that, The antisolvent is a highly polar solvent that is miscible with n-hexane.

7. The preparation method according to claim 1 or 6, characterized in that, The antisolvent includes one or more of acetone, methanol, and ethanol.

8. The preparation method according to claim 1, 2 or 5, characterized in that, The process of mixing the chalcogenide precursor solution, the metal precursor, the organic amine, and 1-octadecene comprises: mixing the organic amine and 1-octadecene, evacuating and purging under nitrogen protection, heating to 100-120°C, evacuating for 30 minutes, and then adding the chalcogenide precursor solution and the metal precursor.

9. Magic-size clusters of metal chalcogenide compounds prepared by the preparation method according to any one of claims 1 to 8.

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