Ultraviolet narrow emission gallium sulfide quantum dot material and synthesis method thereof
By introducing passivating agents and optimizing reaction conditions during the synthesis of gallium sulfide quantum dots, defect emission was reduced, thus solving the defect emission problem of gallium sulfide quantum dot materials and achieving high-purity ultraviolet narrow emission, thereby enhancing its application potential in multiple fields.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- NANJING UNIV OF SCI & TECH
- Filing Date
- 2024-12-30
- Publication Date
- 2026-06-30
Smart Images
Figure CN122302871A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a lead-free and cadmium-free ultraviolet-emitting quantum dot material and its synthesis method, belonging to the field of semiconductor quantum dot material preparation. Background Technology
[0002] In the field of nanomaterials science, research on colloidal quantum dots has made groundbreaking progress over the past few decades. These nanoscale semiconductor particles, due to their unique photophysical properties and solution-processable characteristics, exhibit enormous application potential in numerous scientific and engineering fields. In particular, colloidal quantum dots show broad application prospects in photocatalysis, biolabeling, lighting, and display technologies. Cadmium-based and lead-based quantum dots have been widely used in optoelectronic devices due to their excellent fluorescence efficiency, spectral tunability, and high color purity. However, the toxic heavy metal components contained in these quantum dots pose a significant obstacle to their transformation from laboratory research to commercial applications. Therefore, lead-free and cadmium-free environmentally friendly semiconductor quantum dots have gradually become a research hotspot. For example, group III-V quantum dots (such as InP), group I-III-VI quantum dots (such as CuInS2, AgInS2, etc.), and group II-VI quantum dots (such as ZnSe) all show excellent potential.
[0003] Ultraviolet-emitting quantum dot materials, due to their wide bandgap and unique emission wavelength range, have wide applications in various fields, such as photopolymerization, anti-counterfeiting, medical treatment, air sterilization, water purification, and ultraviolet-excited LEDs. Gallium sulfide (Ga2S3) quantum dots, as a promising ultraviolet emitting material, have a bandgap width between 2.5 eV and 3.4 eV, demonstrating their great potential in ultraviolet-excited lighting and full-color display technology.
[0004] However, the photoelectric properties of gallium sulfide materials, especially gallium sulfide quantum dots with numerous surface defects, have been limited by their inherent defect emission. Gallium sulfide quantum dots contain many point defects both internally and on their surface, originating from sulfur vacancies (V0.05). S ) and gallium vacancy (V Ga These vacancy defects can alter the band structure of materials, forming defect energy levels that lead to defect luminescence and affect spectral color purity. Therefore, optimizing the synthesis process and reducing or passivating internal and surface defects to obtain gallium sulfide quantum dot materials that can emit light through narrow band edges in the ultraviolet range has become a highly valuable research direction. Summary of the Invention
[0005] Based on the presence of sulfur vacancies (V) in existing gallium sulfide quantum dot materials... S ) and gallium vacancy (V GaTo address the problem of reduced emission purity caused by defects in gallium sulfide quantum dot materials with narrow ultraviolet emission, the present invention aims to provide a method for synthesizing gallium sulfide quantum dot materials with narrow ultraviolet emission.
[0006] To achieve the above objectives, the technical solution of the present invention is as follows:
[0007] In a first aspect, the present invention provides a method for synthesizing ultraviolet narrow-emission gallium sulfide quantum dot materials, comprising the following steps:
[0008] Step 1: Add gallium source, sulfur source and passivator to a mixed solvent of non-coordination solvent and coordination solvent, and heat under vacuum until fully dissolved;
[0009] Step 2: Pour nitrogen gas and raise the temperature to the growth temperature of gallium sulfide quantum dots, then maintain the temperature.
[0010] Step 3: Stop heating, cool down to obtain gallium sulfide quantum dot stock solution, add antisolvent for centrifugal purification, and finally add dispersant to disperse the precipitate.
[0011] Preferably, the gallium source is selected from gallium acetate, gallium acetylacetonate, and gallium iodide, with gallium acetylacetonate being the most preferred.
[0012] Preferably, the sulfur source is any one of 1,3-dimethylthiourea, sulfur powder, or thiourea.
[0013] Preferably, the passivating agent is any one of zinc iodide, silver iodide, or cuprous iodide, with silver iodide being the most preferred.
[0014] Preferably, the noncoordinating solvent is octadecene.
[0015] Preferably, the coordination solvent is selected from any one of oleylamine, oleic acid, tributylphosphine, and trioctylphosphine.
[0016] Preferably, the molar ratio of gallium source to sulfur source is 1:1 to 1:6, more preferably 1:6, the molar ratio of sulfur source to passivating agent is 4:1 to 12:1, and the volume ratio of non-coordinating solvent to coordinating solvent is 8:1 to 6:1.
[0017] Preferably, in step 2, the growth temperature of gallium sulfide quantum dots is 270℃~300℃, and the holding time is 1min~10min.
[0018] Preferably, the antisolvent is selected from methanol, ethanol or acetone, and the volume ratio of gallium sulfide quantum dot stock solution to antisolvent is 1:2 to 1:3.
[0019] Preferably, in step 3, the centrifugation speed is 8000-12000 r / min and the centrifugation time is 10 min.
[0020] Preferably, in step 3, the dispersant is n-octane, n-hexane, or toluene.
[0021] In a second aspect, the present invention provides a narrow-emission gallium sulfide quantum dot material synthesized by the method described in the first aspect.
[0022] Compared with existing technologies, the significant advantage of this invention is that by introducing a specific passivating agent into the reaction system and precisely controlling the reaction conditions and the amount of passivating agent, high-purity gallium sulfide quantum dots with narrow ultraviolet bandgap emission are achieved. This invention improves the spectral purity of gallium sulfide quantum dots, providing them with enormous application potential in high-end application fields such as lighting, full-color displays, anti-counterfeiting, and medical applications. Attached Figure Description
[0023] Figure 1 The photoluminescence spectrum of gallium sulfide quantum dots prepared in Example 1 at a reaction temperature of 300°C.
[0024] Figure 2 The photoluminescence spectrum of gallium sulfide quantum dots prepared in Example 2 at a reaction temperature of 280°C.
[0025] Figure 3 The photoluminescence spectrum of gallium sulfide quantum dots passivated by CuI prepared in Example 3.
[0026] Figure 4 The photoluminescence spectrum of gallium sulfide quantum dots passivated by ZnI2 prepared in Example 4.
[0027] Figure 5 The photoluminescence spectrum of gallium sulfide quantum dots passivated by AgI prepared in Example 5.
[0028] Figure 6 The photoluminescence spectrum of gallium sulfide quantum dots passivated with AgI and with a molar ratio of gallium acetylacetonate to thiourea of 2:3 is shown in Example 6. Detailed Implementation
[0029] The present invention will now be described in detail with reference to specific embodiments and accompanying drawings.
[0030] It should be noted that terms such as "upper", "lower", "left", "right", and "middle" used in this specification are only for clarity of description and are not intended to limit the scope of implementation. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered as within the scope of this application.
[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the term “and / or” as used herein includes any and all combinations of one or more of the associated listed items.
[0032] Unless otherwise specified in the examples, the procedures should be performed under standard conditions or conditions recommended by the manufacturer. Reagents or instruments whose manufacturers are not specified are all commercially available products.
[0033] As used herein, the term “about” is used to provide for the flexibility and imprecision associated with a given term, measure, or value. Those skilled in the art can readily determine the degree of flexibility for a particular variable.
[0034] As used herein, the term “at least one of…” is intended to be synonymous with “one or more of…”. For example, “at least one of A, B, and C” explicitly includes only A, only B, only C, and combinations thereof.
[0035] The concept of this invention is: given that gallium sulfide quantum dots contain sulfur vacancies (V... S ) and gallium vacancy (V Ga To address the problem of reduced emission purity caused by defect emission, this invention introduces a specific passivating agent into the reaction system and controls the reaction conditions to passivate gallium sulfide quantum dots, thereby reducing the presence of defects and suppressing defect emission. Finally, a high-purity narrow emission quantum dot material at 392 nm is obtained.
[0036] Example 1
[0037] Step 1: Mix gallium acetylacetonate and thiourea in a molar ratio of 1:6, add a mixed solution of octadecene and tributylphosphine in a volume ratio of 6:1, place it in the reaction vessel of the heating device, and heat and stir under vacuum until fully dissolved.
[0038] Step 2: Purge with nitrogen and heat to 300°C, then react at 300°C for 5 minutes.
[0039] Step 3: After the reaction is complete, cool the solution in a water bath to room temperature to obtain gallium sulfide quantum dot stock solution. Add ethanol and centrifuge to purify the solution. The volume ratio of gallium sulfide quantum dot stock solution to ethanol is 1:2. The centrifugation speed is 10000 r / min and the centrifugation time is 5 min. Disperse the precipitate with 2 mL of toluene to obtain the purified gallium sulfide quantum dot solution.
[0040] The photoluminescence spectrum of the gallium sulfide quantum dots prepared in this example is as follows: Figure 1 As shown, the quantum dot's band-edge emission peak is located at 392 nm, while a strong defect emission peak exists at 454 nm. The half-width of the band-edge emission peak is 43 nm.
[0041] Example 2
[0042] The reaction temperature in Example 1 was changed to 280°C, while the other conditions remained the same as in Example 1.
[0043] The photoluminescence spectrum of the gallium sulfide quantum dots prepared in this example is as follows: Figure 2 As shown, the emission peak of the quantum dot is located at 392nm, the defect emission at 454nm is suppressed to a certain extent, and the half width of the band-edge emission peak is 38nm.
[0044] Example 3
[0045] Based on Example 2, the passivating agent cuprous iodide was added, wherein the molar ratio of gallium acetylacetonate, thiourea and cuprous iodide was 1:6:1, and the other conditions were the same as in Example 2.
[0046] The photoluminescence spectrum of the gallium sulfide quantum dot in this example is as follows: Figure 3 As shown, the emission peak of the quantum dot is located at 392nm, the defect emission at 454nm is suppressed to a small extent, and the half width of the band-edge emission peak is 43nm.
[0047] Example 4
[0048] Based on Example 2, zinc iodide, a passivating agent, was added, wherein the molar ratio of gallium acetylacetonate, thiourea and zinc iodide was 1:6:1, and the other conditions were the same as in Example 2.
[0049] The photoluminescence spectrum of the gallium sulfide quantum dot in this example is as follows: Figure 4 As shown, the emission peak of the quantum dot is located at 392nm, the defect emission at 454nm is suppressed to a certain extent, and the half width of the band-edge emission peak is 37nm.
[0050] Example 5
[0051] Based on Example 2, silver iodide, a passivating agent, was added, wherein the molar ratio of gallium acetylacetonate, thiourea and silver iodide was 1:6:1, and the other conditions were the same as in Example 2.
[0052] The photoluminescence spectrum of the gallium sulfide quantum dot in this example is as follows: Figure 5 As shown, the emission peak of the quantum dot is located at 392nm, the emission peak at 454nm is completely suppressed, and the half width of the band-edge emission peak is 34nm.
[0053] Example 6
[0054] Based on Example 5, the molar ratio of gallium acetylacetonate, thiourea and silver iodide was changed to 2:3:1, and the other conditions were the same as in Example 5.
[0055] The photoluminescence spectrum of the gallium sulfide quantum dot in this example is as follows: Figure 6As shown, the emission peak of the quantum dot is located at 392nm, the defect emission at 454nm is poorly suppressed, and the half width of the band-edge emission peak is 44nm.
[0056] The above embodiments are merely preferred embodiments of the present invention, but the implementation of the present invention is not limited to the above embodiments. Any changes, modifications, substitutions, or combinations made without departing from the spirit and principle of the present invention, such as various combinations of solutions in the embodiments, should be considered equivalent replacements and are all within the protection scope of the present invention.
Claims
1. A method for synthesizing ultraviolet narrow-emission gallium sulfide quantum dot materials, characterized in that, Includes the following steps: Step 1: Add the gallium source, sulfur source and passivator to a mixed solvent of non-coordination solvent and coordination solvent, and heat under vacuum until fully dissolved; Step 2: Pour nitrogen gas and raise the temperature to the growth temperature of gallium sulfide quantum dots, then maintain the temperature. Step 3: Stop heating, cool down to obtain gallium sulfide quantum dot stock solution, add antisolvent for centrifugal purification, and finally add dispersant to disperse the precipitate.
2. The method as described in claim 1, characterized in that, The gallium source is selected from gallium acetate, gallium acetylacetonate, and gallium iodide, with gallium acetylacetonate being preferred.
3. The method as described in claim 1, characterized in that, The sulfur source is any one of 1,3-dimethylthiourea, sulfur powder, or thiourea.
4. The method as described in claim 1, characterized in that, The passivating agent is any one of zinc iodide, silver iodide, or cuprous iodide, with silver iodide being preferred.
5. The method as described in claim 1, characterized in that, The noncoordination solvent is octadecene.
6. The method as described in claim 1, characterized in that, The coordination solvent is selected from any one of oleylamine, oleic acid, tributylphosphine, and trioctylphosphine.
7. The method as described in claim 1, characterized in that, The molar ratio of gallium source to sulfur source is 1:1 to 1:6, preferably 1:6; the molar ratio of sulfur source to passivating agent is 4:1 to 12:1; and the volume ratio of non-coordinated solvent to coordinated solvent is 8:1 to 6:
1.
8. The method as described in claim 1, characterized in that, In step 2, the growth temperature of gallium sulfide quantum dots is 270℃~300℃, and the holding time is 1min~10min.
9. The method as described in claim 1, characterized in that, The antisolvent is selected from methanol, ethanol or acetone, and the volume ratio of gallium sulfide quantum dot stock solution to antisolvent is 1:2 to 1:
3.
10. A gallium sulfide quantum dot material with narrow ultraviolet emission synthesized by the method as described in any one of claims 1-9.