TWI763281B - Method for preparing zninp/zns quantum dots with narrow full width at half maximum - Google Patents

Abstract

The present invention provides a method for preparing quantum dots. The method comprises: mixing a first precursor, a complexing agent and a capping agent to a mixture, and heating the mixture to form a complex reaction product; rapidly heating the complex reaction product to a nucleation reaction temperature, and adding a second precursor to the complex reaction product in order to conduct a nucleation reaction to form a nucleation reaction product; adding a third precursor to the nucleation reaction product and conducting a shell-forming reaction at a shell-forming temperature so as to obtain ZnInP/ZnS quantum dots; wherein the shell-forming temperature is lower or equal to the nucleation reaction temperature; the first precursor comprises an indium precursor and a zinc precursor; the second precursor comprises a phosphorus precursor, and the third precursor comprises a sulfur precursor.

Description

Preparation method of narrow half-width ZnInP/ZnS quantum dots

The present invention relates to a preparation method of quantum dots, and particularly to a preparation method of narrow half-width ZnInP/ZnS quantum dots.

The development and application of early quantum dot materials are mostly based on cadmium-based core-shell materials, but because cadmium and cadmium compounds are poisons, with the rising awareness of environmental protection, the research direction of quantum dots has gradually developed towards cadmium-free quantum dots. Indium phosphide (InP) is one of the candidate materials, but indium phosphide quantum dots are easily oxidized, resulting in low quantum efficiency and high full width at half maximum (FWHM). Layer (ZnS) coating regulates emission wavelength and improves quantum efficiency, and improves the problem of over-width at half maximum, so as to facilitate the subsequent application of white light backlight in displays.

Optoelectronic materials have different properties; in addition, quantum dot processing of optoelectronic materials and other functional treatment agents is more conducive to adjusting and optimizing the properties of optoelectronic materials, so that light-emitting elements made of optoelectronic materials can be applied to solid-state lighting (solid-state lighting). lighting, SSL), light-emitting diode (light-emitting diode, LED) products, liquid crystal display (liquid crystal display, LCD) products and other fields. For displays, the original displays were cathode ray tubes (CRTs), which were later replaced by liquid crystal displays (LCDs). With the development of technology, white light-emitting diodes (WLEDs) have gradually replaced incandescent displays. lamps and fluorescent lamps, and are widely used in backlight displays. Commercially available WLEDs are fabricated by using blue and violet chips to excite one or more phosphors of different colors. Due to the wide half-height width of phosphors, the color gamut area cannot exceed 100% of the standard area set by the National Television System Committee (NTSC); however, quantum dots have the advantages of narrow half-height width and wavelength tunability. , can be used as a substitute for fluorescent powder to become the material of display backlight.

According to, the preparation method of conventional quantum dots, such as "Methods of producing metal sulfides, metal selenides, and metal sulfides/selenides having controlled architectures using kinetic control" disclosed in US Patent Application No. US10767112B2, is characterized by oxidation Cadmium is used as the material. Under the action of the complexing agent oleic acid, the complexing reaction is carried out with the coating agent octadecene (ODE) at a high temperature of 240 °C. Alkylamine, after the mixture is stabilized, the temperature is raised to 270°C, the tributylphosphine selenide is added by hot injection method, and the temperature is rapidly lowered to 250°C again to generate CdSe crystal nuclei, and finally the temperature is lowered to below 80°C and the CdSe is eluted with n-hexane. The crystal nucleus is stored in the dark; the CdSe crystal nucleus generated above is then added with octadecylamine and 1-octadecene, degassed and heated to 240 ° C for reaction, and then alternately added cadmium oleate and N-n-hexyl-N' -Di-n-octyl-iodourea to form the shell of CdS to obtain CdSe/CdS; finally, the aforementioned CdSe/CdS was alternately added with zinc oleate and N-n-hexyl-N', N'-di-n-octylthiourea to Form the shell of ZnS to obtain CdSe/CdS/ZnS quantum dots; however, its quantum yield is not more than 77% and the nucleation/shell reactions are interleaved, the operation method is complicated, and more sophisticated facilities are required to control the process conditions , thereby increasing production costs.

According to the conventional method for preparing quantum dots, such as "Method of manufacturing quantum dot having tunable and narrow light emission wavelength for achieving high color purity and a method of manufacturing film" disclosed in US Patent Application No. US10581008B2, its features are: It is to use indium acetate and zinc acetate as materials, under the action of complexing agent palmitic acid, carry out a complexing reaction to generate a complexing reaction product, and its complexing reaction time is up to 12 hours; The aforementioned complexing reaction product is cooled to room temperature and injected with three ( Trimethylsilyl)phosphine (C ₉ H ₂₇ PSi ₃ , 3(TMS)P) and trioctylphosphine (C ₂₄ H ₅₁ P, TOP), and then heated to 305°C for nucleation reaction to generate nucleation reaction products ; Then inject TOP-Se into the aforementioned nucleation reaction product, and react with the coating agent ODE and zinc stearate at 300 ° C to produce quantum dots In(Zn)P/ZnSe; The aforementioned quantum dots In(Zn)P/ZnSe It was further mixed with zinc oleate and heated to 210°C. Finally, 1-DDT was added to form a shell at 260°C to form quantum dots In(Zn)P/ZnSe/ZnS; however, the quantum efficiency did not exceed 75%. , the complexation reaction time is too long, and the nucleation reaction temperature and the shell formation reaction temperature both exceed 260 ° C, thereby increasing the time and the cost of production equipment.

According to, the preparation method of conventional quantum dots, such as "quantum dots, their manufacturing methods, and compositions, composites and electronic devices including the same" disclosed in Chinese Patent Application No. CN110746958A, is characterized in that indium acetate is used. And zinc acetate as material, under the action of complexing agent palmitic acid and coating agent 1-octadecene heated to complexing reaction temperature, reacted for 1 hour to generate complexing reaction product; then, the aforementioned complexing reaction product was heated to 280 After ℃, the mixed solution of tris(trimethylsilyl)phosphine and trioctylphosphine was rapidly injected and the nucleation reaction was carried out for 20 minutes to generate the nucleation reaction product; the aforementioned nucleation reaction product was rapidly cooled to room temperature and acetone was added , the mixture is centrifuged to obtain a precipitate, and the aforementioned precipitate is dispersed with toluene to obtain the quantum dot InZnP; although the technology disclosed here is greatly simplified in the process, its quantum efficiency is only about 80%, which is not excellent Quantum dot production technology.

Quantum dot (quantum dot) is a zero-dimensional semiconductor nano-photoelectric material. By applying a certain electric field or voltage to the nano-photoelectric material, the electrons are excited by the energy and then recombine with the holes, which will emit light of a specific frequency. High efficiency, small size, adjustable wavelength and other characteristics, so white light components made of quantum dots have been widely used in solid-state lighting and display backlights and other fields, and replaced display backlight components made of phosphors.

However, the quantum efficiency of existing developed technologies such as InP core quantum dots is only about 1%, which is due to the fact that the core quantum dots are susceptible to photodegradation or surface oxidation during preparation. A large semiconductor (eg, ZnS) coats the surface of the quantum dots to passivate their surface defects. This method can not only effectively improve the quantum efficiency, but also improve the optical and chemical stability. Although the above-mentioned manufacturing method of quantum dots can effectively improve the quantum efficiency, the obtained half-height width is about 70 nm, and the NTSC color gamut still cannot exceed 100% after being prepared into a white light element, so it is necessary to develop other The manufacturing method of InP/ZnS quantum dots can improve the problem of too small color gamut area caused by too wide half-height width.

In view of the above-mentioned technical shortcomings, the purpose of the present invention is to develop a method that can effectively reduce the full width at half maximum of ZnInP/ZnS quantum dots, which can replace the problem that the NTSC color gamut area is too small due to the wide half width of the prior art. Improve the application field and market value of white light components made by ZnInP/ZnS quantum dots.

Therefore, the present invention provides a method for preparing quantum dots, comprising: mixing a first precursor, a complexing agent and a coating agent into a mixed solution, and heating the mixed solution to a complexing reaction temperature to perform complexing reaction , to obtain a complex reaction product, wherein the first precursor includes an indium precursor and a zinc precursor; rapidly heat the complex reaction product to a nucleation reaction temperature, then add a second precursor and react for 10 seconds to 30 minutes To obtain a nucleation reaction product, wherein the second precursor comprises a phosphorus precursor; and add a third precursor to the nucleation reaction product and react at a shell-forming reaction temperature for 1-8 hours to obtain ZnInP/ ZnS quantum dots, wherein the third precursor comprises a sulfur precursor, and the shelling reaction temperature is less than or equal to the nucleation reaction temperature.

Preferably, the complexation reaction temperature is 100-120°C; the nucleation reaction temperature is 200-260°C; the shell-forming reaction temperature is 200-260°C.

Preferably, the molar ratio of indium element and zinc element of the first precursor is 1:1-1:4.

Preferably, the indium precursor comprises indium halide, organic acid indium compound or IIIA~VA inorganic indium compound; preferably, the indium precursor is indium chloride (InCl ₃ ); the zinc precursor comprises zinc halide, Organic acid zinc compounds or IIA-VIA inorganic zinc compounds; preferably, the zinc precursors are zinc bromide (ZnBr ₂ ) and zinc iodide (ZnI ₂ ).

Preferably, the capping agent comprises an organic compound with a C ₈ -C ₂₂ long carbon chain, and its functional group comprises a hydrocarbon group (CH ₃ ), an amine group (NH ₂ ) or an aromatic hydrocarbon group; the complexing agent comprises a saturated fatty acid; the The phosphorus precursor includes an organic phosphorus compound; the sulfur precursor includes a sulfur powder or a thiol compound.

Preferably, the preparation method further comprises a purification treatment, the steps of which include: rapidly freezing the ZnInP/ZnS quantum dots and adding absolute ethanol to remove excess coating agent to obtain a stopped reaction product; the stopped reaction product Perform ultrasonic vibration treatment and centrifugation to obtain a precipitate; drain the precipitate; disperse the precipitate with n-hexane to obtain a purified ZnInP/ZnS quantum dot.

According to the preparation method of quantum dots provided by the present invention, by regulating the reaction time of the nucleation reaction temperature and the shelling reaction temperature, the full width at half maximum of the quantum dots can be effectively reduced, and the quantum efficiency of the prepared quantum dots can exceed 100%, so The color gamut area of the component NTSC can be substantially increased, thereby overcoming the problems of the above-mentioned prior art that the width at half maximum is too wide and the color gamut area is too small. Accordingly, compared with the wide half-height width caused by the above-mentioned manufacturing method of the prior art, the manufacturing method of the quantum dots of the present invention has the advantage of being able to shorten the half-height width.

Please refer to FIG. 1 , which is a schematic flowchart illustrating a method 100 for preparing quantum dots provided by the present invention, but not limited thereto.

As shown in step 101, a first precursor, a complexing agent and a coating agent are mixed into a mixed solution, and the mixed solution is heated to a complexing reaction temperature to perform a complexing reaction to obtain a complexing reaction product, wherein The first precursor includes an indium precursor and a zinc precursor; the complexing agent is a saturated fatty acid, which includes lauric acid, palmitic acid, oleic acid, and stearic acid ), myristic acid, eladic acid, eicosanoic acid, heneicosanoic acid, tricosanoic acid, behenic acid ( docosanoic acid), tetracosanoic acid, hexacosanoic acid, heptacosanoic acid, octacosanoic acid, or cis-13-docosenoic acid (cis-13-docosenoic acid), preferably, the complexing agent is myristic acid; the encapsulating agent is an organic compound with a C ₈ -C ₂₂ long carbon chain, and its functional group contains a hydrocarbon group (CH ₃ ), amine group ( _NH2 ) or aromatic hydrocarbon group, which comprises octylamine (octylamine), decylamine (decylamine), didecylamine (didecylamine), tridecylamine (tridecylamine), tetradecylamine (tetradecylamine), ten Pentadecylamine, hexadecylamine, octadecene, octadecylamine, dodecylamine or oleylamine, preferably, the coating agent For octadecene (octadecene) and oleylamine (oleylamine); The complex reaction temperature is 100 ~ 120 ℃, preferably, the complex reaction temperature is 105 ~ 115 ℃, more preferably, the complex reaction temperature is 110° C.; the indium precursor is indium halide, organic acid indium compound or IIIA~VA group inorganic indium compound, which includes indium fluoride (InF ₃ ), indium chloride (InCl ₃ ), indium bromide (InBr ₃ ), Indium iodide (InI ₃ ), indium acetate (In(CH ₃ COO) ₃ ), indium phosphide (InP), indium arsenide (InAs), indium antimonide (InSb), indium nitride (InN), arsenic phosphorus Indium Phosphide (InPAs), Indium Phosphorus Antimonide (InPSb), Indium Phosphorus Nitride (I nPN), Indium Arsenide Nitride (InAsN), Indium Antimony Nitride (InSbN), Indium Gallium Phosphide (InGaP), Indium Gallium Arsenide (InGaAs), Indium Gallium Antimonide (InGaSb), Indium Gallium Nitride (InGaN) , Indium Arsenide Nitride (InAsN), Indium Antimony Nitride (InSbN), Aluminum Indium Phosphide (AlInP), Aluminum Indium Arsenide (AlInAs), Aluminum Indium Antimonide (AlInSb), Aluminum Indium Nitride (AlInN), Phosphorus Gallium Indium Arsenide (GaInPAs), Gallium Indium Aluminum Arsenide (GaInAlAs), Gallium Indium Phosphate Nitride (GaInPN), Gallium Indium Arsenide Nitride (GaInAsN), Gallium Indium Aluminum Nitride (GaInAlN), Gallium Indium Phosphorus Antimonide (GaInAlN) GaInPSb), Gallium Indium Phosphate Nitride (GaInPN), Gallium Indium Antimony Nitride (GaInSbN), Indium Aluminum Arsenide Phosphide (InAlPAs), Indium Aluminum Phosphorus Nitride (InAlPN), Indium Phosphorus Arsenide Nitride (InPAsN), Antimony Nitrogen Indium Aluminum Antimonide (InAlSbN), Indium Phosphorus Antimony Nitride (InPSbN), Indium Arsenic Antimony Nitride (InAsSbN) or Indium Aluminum Antimonide Phosphide (InAlPSb), preferably, the indium precursor is indium chloride (InCl ₃ ) ; The zinc precursor is zinc halide, organic acid zinc compound or IIA~VIA group inorganic zinc compound, which comprises zinc fluoride (ZnF ₂ ), zinc chloride (ZnCl ₂ ), zinc bromide (ZnBr ₂ ), iodide Zinc (ZnI ₂ ), zinc diethyldithiocarbamate ([(C ₂ H ₅ ) ₂ NCS ₂ ] ₂ Zn), zinc acetate (Zn(CH ₃ COO) ₂ ), zinc stearate (Zn( C ₁₇ H ₃₅ COO) ₂ , zinc carbonate (ZnCO ₃ ), zinc oxide (ZnO), cadmium zinc sulfide (CdZnS), cadmium zinc selenide (CdZnSe), cadmium zinc telluride (CdZnTe), zinc selenium sulfide (ZnSeS) , zinc selenide telluride (ZnSeTe), zinc sulfide telluride (ZnSTe), mercury zinc sulfide (HgZnS), mercury zinc selenide (HgZnSe), cadmium zinc oxide (CdZnO), zinc selenate (ZnSeO), zinc tellurate ( ZnTeO), zinc sulfate (ZnSO), cadmium zinc selenium sulfide (CdZnSeS), cadmium zinc selenium telluride (CdZnSeTe), cadmium zinc sulfide telluride (CdZnSTe), mercury zinc selenium sulfide (HgZnSeS), mercury zinc selenide telluride (HgZnSeTe) ), mercury zinc sulfide telluride (HgZnSTe), cadmium zinc selenate (CdZnSeO), cadmium zinc tellurate (CdZnTeO) or cadmium zinc sulfate (CdZnSO), preferably, the zinc precursor is zinc bromide (ZnBr ₂ ) and zinc iodide (ZnI ₂ ); the molar ratio of indium element and zinc element of the first precursor is 1:1~1:4, preferably, the molar ratio of indium element and zinc element of the first precursor is The molar ratio is 1:1.5~1:3.5, more preferably, the molar ratio of the indium element and the zinc element of the first precursor is 1:3.

As shown in step 102, the complex reaction product is rapidly heated to a nucleation reaction temperature, and a second precursor is added and reacted for 10 seconds to 30 minutes to obtain a nucleation reaction product, wherein the second precursor comprises a phosphorus precursor The nucleation reaction temperature is 200~260°C, preferably, the nucleation reaction temperature is 220~250°C, and more preferably, the nucleation reaction temperature is 240°C; the phosphorus precursor is an organophosphorus compound, which contains six Hexamethylphosphoramide (HMPA), Tris(dimethylamino)phosphine (HMPT), tri-n-octylphosphine oxide (tri-n-octylphosphine oxide), tri-n-octylphosphine (tri-n-octylphosphine), tris(trimethylsilyl)phosphine (TMSP) or tris(dimethyl tert-butyl)silyl phosphine , preferably, the phosphorus precursor is hexamethylphosphoramide (Hexamethylphosphoramide, HMPA).

As shown in step 103, a third precursor is added to the nucleation reaction product and reacted at a shell-forming reaction temperature for 1-8 hours to obtain ZnInP/ZnS quantum dots, wherein the third precursor includes a sulfur precursor material, the shelling reaction temperature is less than or equal to the nucleation reaction temperature; the shelling reaction temperature is 200~260 ℃, preferably, the shelling reaction temperature is 220~250 ℃, more preferably, the shelling reaction temperature is 240°C; the sulfur precursor is sulfur powder or thiol compound, which includes sulfur powder, octanethiol, decanethiol, 1-dodecanethiol, dithiothre Sugar alcohol (dithiothreitol, DTT) or n-octadecanethiol (1-octadecanethiol, ODT), preferably, the sulfur precursor is dithiothreitol (dithiothreitol, DTT).

As shown in step 104, the ZnInP/ZnS quantum dots are rapidly frozen and anhydrous ethanol is added to remove excess coating agent to obtain a terminated reaction product.

As shown in step 105, the stopped reaction product is subjected to ultrasonic shock treatment and centrifugation to obtain a precipitate.

As shown in step 106, the precipitate is drained.

As shown in step 107, the precipitate is dispersed with n-hexane to obtain a purified ZnInP/ZnS quantum dot.

According to an embodiment of the present invention, ZnInP/ZnS quantum dots are obtained by adjusting the nucleation reaction temperature, shell formation reaction temperature and reaction time by means of thermal injection. Breaking through 100%, it can be expected that the NTSC color gamut area of the component will be substantially increased after subsequent fabrication as a white light component, thereby overcoming the problems of excessive half-height width and too small color gamut area in the prior art.

Several preferred embodiments of the present invention are listed below to further illustrate the technical characteristics of the present invention, the application of technical means and the expected effect:

Example 1

Indium precursor 0.72 mmol indium chloride (InCl ₃ ) and zinc precursor 1.08 mmol zinc bromide (ZnBr ₂ ), 1.08 mmol zinc iodide (ZnI ₂ ) and complexing agent 0.72 mmol myristic acid (myristic acid) were mixed, The molar ratio of indium element and zinc element is 1:3, and after mixing, poured into a three-necked bottle to remove water vapor for 30 minutes. Next, 4 ml of octadecene (ODE) and 6 ml of oleylamine (OLA) as capping agents were added, and the temperature was raised to a complexation reaction temperature of 110 ^oC for a complexation reaction, and then rapidly heated to a nucleation reaction temperature of 220 ^oC . The hot injection method was implemented here, maintaining the temperature at 220 ^oC and injecting 0.2 ml of hexamethylphosphoric triamine as a phosphorus precursor, and making it undergo a nucleation reaction for 15 minutes to generate the core ZnInP. After the growth of the core ZnInP, the temperature was lowered to the shell-forming reaction temperature of 200 ^o C, and 3 ml of DDT was slowly injected into the sulfur precursor. The solution containing ZnInP/ZnS quantum dots was snap-frozen to stop the shelling reaction, followed by addition of absolute ethanol to remove excess surface coating agent. Next, ultrasonic vibration and centrifugation were performed to obtain ZnInP/ZnS quantum dot precipitates. The precipitate was drained by suction, and the precipitate was dispersed with n-hexane to obtain purified ZnInP/ZnS quantum dots.

Please refer to Table 1. Purified ZnInP/ZnS quantum dots prepared according to the aforementioned experimental conditions, under the same nucleation reaction time, the sample with shelling reaction for 3 hours has an emission wavelength of 487 nm, a full width at half maximum of 72 nm and a quantum efficiency of 35 %; The sample with shell-forming reaction for 5 hours has an emission wavelength of 493 nm, a full width at half maximum of 72 nm and a quantum efficiency of 40%.

Example 2

Indium precursor 0.72 mmol indium chloride (InCl ₃ ) and zinc precursor 1.08 mmol zinc bromide (ZnBr ₂ ), 1.08 mmol zinc iodide (ZnI ₂ ) and complex agent 0.72 mmol myristic acid (myristic acid) were mixed, The molar ratio of indium element and zinc element is 1:3, and after mixing, poured into a three-necked bottle to remove water vapor for 30 minutes. Next, 4 ml of octadecene (ODE) and 6 ml of oleylamine (OLA) as capping agents were added, and the temperature was raised to a complexation reaction temperature of 110 ^oC for a complexation reaction, and then rapidly heated to a nucleation reaction temperature of 220 ^oC . The hot injection method was implemented here, maintaining the temperature at 220 ^oC and injecting 0.2 ml of hexamethylphosphoric triamine as a phosphorus precursor, and making it undergo a nucleation reaction for 1 minute to generate the core ZnInP. After the growth of the core ZnInP, the temperature was lowered to the shell-forming reaction temperature of 200 ^o C, and 3 ml of DDT was slowly injected into the sulfur precursor. The solution containing ZnInP/ZnS quantum dots was snap-frozen to stop the shelling reaction, followed by addition of absolute ethanol to remove excess surface coating agent. Next, ultrasonic vibration and centrifugation were performed to obtain ZnInP/ZnS quantum dot precipitates. The precipitate was drained by suction, and the precipitate was dispersed with n-hexane to obtain purified ZnInP/ZnS quantum dots.

Please refer to Table 1. Purified ZnInP/ZnS quantum dots prepared according to the above experimental conditions, under the same nucleation reaction time, the sample after shelling reaction for 3 hours has an emission wavelength of 499 nm and a full width at half maximum of 37 nm, but no measured Its quantum efficiency; the emission wavelength of the sample after shelling reaction for 5 hours is 500 nm and the half width at half maximum is 37 nm, but its quantum efficiency has not been measured.

Example 3

Indium precursor 0.72 mmol indium chloride (InCl ₃ ) and zinc precursor 1.08 mmol zinc bromide (ZnBr ₂ ), 1.08 mmol zinc iodide (ZnI ₂ ) and complex agent 0.72 mmol myristic acid (myristic acid) were mixed, The molar ratio of indium element and zinc element is 1:3, and after mixing, poured into a three-necked bottle to remove water vapor for 30 minutes. Then, 4 ml of octadecene (ODE) and 6 ml of oleylamine (OLA) were added as capping agents, and the temperature was raised to a complexation reaction temperature of 110 ^oC for a complexation reaction, and then rapidly heated to a nucleation reaction temperature of 200 ^oC . The hot injection method is implemented here, maintaining the temperature at 200 ^oC and injecting 0.2 ml of hexamethylphosphoric triamine as a phosphorus precursor, and making it undergo a nucleation reaction for 1 minute to generate the core ZnInP. After the growth of the core ZnInP, keep the temperature at 200 ^oC and slowly inject 3 ml DDT of the sulfur precursor, and keep the temperature for 2 to 5 hours to generate the shell layer, that is, the ZnInP/ZnS quantum dots are obtained. The solution containing ZnInP/ZnS quantum dots was snap-frozen to stop the shelling reaction, followed by addition of absolute ethanol to remove excess surface coating agent. Next, ultrasonic vibration and centrifugation were performed to obtain ZnInP/ZnS quantum dot precipitates. The precipitate was drained by suction, and the precipitate was dispersed with n-hexane to obtain purified ZnInP/ZnS quantum dots.

Please refer to Table 1. Purified ZnInP/ZnS quantum dots prepared according to the aforementioned experimental conditions, under the same nucleation reaction time, the sample with shelling reaction for 3 hours has an emission wavelength of 483 nm, a full width at half maximum of 34 nm and a quantum efficiency of 14 %; The sample with shell-forming reaction for 5 hours has an emission wavelength of 482 nm, a full width at half maximum of 29 nm and a quantum efficiency of 3%.

Example 4

Indium precursor 0.72 mmol indium chloride (InCl ₃ ) and zinc precursor 1.08 mmol zinc bromide (ZnBr ₂ ), 1.08 mmol zinc iodide (ZnI ₂ ) and complex agent 0.72 mmol myristic acid (myristic acid) were mixed, The molar ratio of indium element and zinc element is 1:3, and after mixing, poured into a three-necked bottle to remove water vapor for 30 minutes. Then, 4 ml of octadecene (ODE) and 6 ml of oleylamine (OLA) were added as capping agents, and the temperature was raised to a complexation reaction temperature of 110 ^oC for a complexation reaction, and then rapidly heated to a nucleation reaction temperature of 200 ^oC . The hot injection method was implemented here, maintaining the temperature at 200 ^oC and injecting 0.2 ml of hexamethylphosphoric triamine as a phosphorus precursor, and making it undergo a nucleation reaction for 15 minutes to generate core ZnInP. After the growth of the core ZnInP, keep the temperature at 200 ^oC and slowly inject 3 ml DDT of the sulfur precursor, and keep the temperature for 2 to 5 hours to generate the shell layer, that is, the ZnInP/ZnS quantum dots are obtained. The solution containing ZnInP/ZnS quantum dots was snap-frozen to stop the shelling reaction, followed by addition of absolute ethanol to remove excess surface coating agent. Next, ultrasonic vibration and centrifugation were performed to obtain ZnInP/ZnS quantum dot precipitates. The precipitate was drained by suction, and the precipitate was dispersed with n-hexane to obtain purified ZnInP/ZnS quantum dots.

Please refer to Table 1. Purified ZnInP/ZnS quantum dots prepared according to the above experimental conditions, under the same nucleation reaction time, the sample with shelling reaction for 3 hours has an emission wavelength of 483 nm, a full width at half maximum of 33 nm and a quantum efficiency of 20 %; The sample with shell-forming reaction for 5 hours has an emission wavelength of 490 nm, a full width at half maximum of 39 nm and a quantum efficiency of 27%.

Example 5

Indium precursor 0.72 mmol indium chloride (InCl ₃ ) and zinc precursor 1.08 mmol zinc bromide (ZnBr ₂ ), 1.08 mmol zinc iodide (ZnI ₂ ) and complex agent 0.72 mmol myristic acid (myristic acid) were mixed, The molar ratio of indium element and zinc element is 1:3, and after mixing, poured into a three-necked bottle to remove water vapor for 30 minutes. Next, 4 ml of octadecene (ODE) and 6 ml of oleylamine (OLA) as capping agents were added, and the temperature was raised to a complexation reaction temperature of 110 ^oC for a complexation reaction, and then rapidly heated to a nucleation reaction temperature of 220 ^oC . The hot injection method was implemented here, maintaining the temperature at 220 ^oC and injecting 0.2 ml of hexamethylphosphoric triamine as a phosphorus precursor, and making it undergo a nucleation reaction for 1 minute to generate the core ZnInP. After the growth of the core ZnInP, keep the temperature at 220 ^oC and slowly inject 3 ml DDT of the sulfur precursor, and keep the temperature to react for 2-5 hours to generate the shell layer, that is, ZnInP/ZnS quantum dots are obtained. The solution containing ZnInP/ZnS quantum dots was snap-frozen to stop the shelling reaction, followed by addition of absolute ethanol to remove excess surface coating agent. Next, ultrasonic vibration and centrifugation were performed to obtain ZnInP/ZnS quantum dot precipitates. The precipitate was drained by suction, and the precipitate was dispersed with n-hexane to obtain purified ZnInP/ZnS quantum dots.

Please refer to Table 1. Purified ZnInP/ZnS quantum dots prepared according to the above experimental conditions, under the same nucleation reaction time, the sample with shelling reaction for 3 hours has an emission wavelength of 483 nm, a full width at half maximum of 34 nm and a quantum efficiency of 59 %; The sample with shell-forming reaction for 5 hours has an emission wavelength of 482 nm, a full width at half maximum of 32 nm and a quantum efficiency of 68%.

Example 6

Indium precursor 0.72 mmol indium chloride (InCl ₃ ) and zinc precursor 1.08 mmol zinc bromide (ZnBr ₂ ), 1.08 mmol zinc iodide (ZnI ₂ ) and complex agent 0.72 mmol myristic acid (myristic acid) were mixed, The molar ratio of indium element and zinc element is 1:3, and after mixing, poured into a three-necked bottle to remove water vapor for 30 minutes. Next, 4 ml of octadecene (ODE) and 6 ml of oleylamine (OLA) as capping agents were added, and the temperature was raised to a complexation reaction temperature of 110 ^oC for a complexation reaction, and then rapidly heated to a nucleation reaction temperature of 220 ^oC . The hot injection method was implemented here, maintaining the temperature at 220 ^oC and injecting 0.2 ml of hexamethylphosphoric triamine as a phosphorus precursor, and making it undergo a nucleation reaction for 15 minutes to generate the core ZnInP. After the growth of the core ZnInP, keep the temperature at 220 ^oC and slowly inject 3 ml DDT of the sulfur precursor, and keep the temperature to react for 2-5 hours to generate the shell layer, that is, ZnInP/ZnS quantum dots are obtained. The solution containing ZnInP/ZnS quantum dots was snap-frozen to stop the shelling reaction, followed by addition of absolute ethanol to remove excess surface coating agent. Next, ultrasonic vibration and centrifugation were performed to obtain ZnInP/ZnS quantum dot precipitates. The precipitate was drained by suction, and the precipitate was dispersed with n-hexane to obtain purified ZnInP/ZnS quantum dots.

Please refer to Table 1. The purified ZnInP/ZnS quantum dots prepared according to the aforementioned experimental conditions, under the same nucleation reaction time, the sample with shelling reaction for 3 hours has an emission wavelength of 489 nm, a half-width of 42 nm and a quantum efficiency of 72 %; The sample with shell-forming reaction for 5 hours has an emission wavelength of 490 nm, a full width at half maximum of 44 nm and a quantum efficiency of 91%.

Example 7

Indium precursor 0.72 mmol indium chloride (InCl ₃ ) and zinc precursor 1.08 mmol zinc bromide (ZnBr ₂ ), 1.08 mmol zinc iodide (ZnI ₂ ) and complex agent 0.72 mmol myristic acid (myristic acid) were mixed, The molar ratio of indium element and zinc element is 1:3, and after mixing, poured into a three-necked bottle to remove water vapor for 30 minutes. Next, 4 ml of octadecene (ODE) and 6 ml of oleylamine (OLA) as capping agents were added, and the temperature was raised to a complexation reaction temperature of 110 ^oC for a complexation reaction, and then rapidly heated to a nucleation reaction temperature of 240 ^oC . The hot injection method was implemented here, maintaining the temperature at 240 ^oC and injecting 0.2 ml of hexamethylphosphoric triamine as a phosphorus precursor, and making it undergo a nucleation reaction for 1 minute to generate the core ZnInP. After the growth of the core ZnInP, keep the temperature at 240 ^oC and slowly inject 3 ml DDT of the sulfur precursor, and react at the temperature for 2 to 5 hours to generate the shell layer, that is, ZnInP/ZnS quantum dots are obtained. The solution containing ZnInP/ZnS quantum dots was snap-frozen to stop the shelling reaction, followed by addition of absolute ethanol to remove excess surface coating agent. Next, ultrasonic vibration and centrifugation were performed to obtain ZnInP/ZnS quantum dot precipitates. The precipitate was drained by suction, and the precipitate was dispersed with n-hexane to obtain purified ZnInP/ZnS quantum dots.

Please refer to Table 1. Purified ZnInP/ZnS quantum dots prepared according to the aforementioned experimental conditions, under the same nucleation reaction time, the sample with shelling reaction for 3 hours has an emission wavelength of 489 nm, a full width at half maximum of 39 nm and a quantum efficiency of 104 %; The sample with shell-forming reaction for 5 hours has an emission wavelength of 488 nm, a full width at half maximum of 38 nm and a quantum efficiency of 79%.

Example 8

Indium precursor 0.72 mmol indium chloride (InCl ₃ ) and zinc precursor 1.08 mmol zinc bromide (ZnBr ₂ ), 1.08 mmol zinc iodide (ZnI ₂ ) and complex agent 0.72 mmol myristic acid (myristic acid) were mixed, The molar ratio of indium element and zinc element is 1:3, and after mixing, poured into a three-necked bottle to remove water vapor for 30 minutes. Next, 4 ml of octadecene (ODE) and 6 ml of oleylamine (OLA) as capping agents were added, and the temperature was raised to a complexation reaction temperature of 110 ^oC for a complexation reaction, and then rapidly heated to a nucleation reaction temperature of 240 ^oC . The hot injection method is implemented here, maintaining the temperature at 240 ^oC and injecting 0.2 ml of hexamethylphosphoric triamine as a phosphorus precursor, and making it undergo a nucleation reaction for 15 minutes to generate core ZnInP. After the growth of the core ZnInP, keep the temperature at 240 ^oC and slowly inject 3 ml DDT of the sulfur precursor, and react at the temperature for 2 to 5 hours to generate the shell layer, that is, ZnInP/ZnS quantum dots are obtained. The solution containing ZnInP/ZnS quantum dots was snap-frozen to stop the shelling reaction, followed by addition of absolute ethanol to remove excess surface coating agent. Next, ultrasonic vibration and centrifugation were performed to obtain ZnInP/ZnS quantum dot precipitates. The precipitate was drained by suction, and the precipitate was dispersed with n-hexane to obtain purified ZnInP/ZnS quantum dots.

Please refer to Table 1. Purified ZnInP/ZnS quantum dots prepared according to the aforementioned experimental conditions, under the same nucleation reaction time, the sample with shelling reaction for 3 hours has an emission wavelength of 488 nm, a full width at half maximum of 43 nm and a quantum efficiency of 50 %; The sample with shell-forming reaction for 5 hours has an emission wavelength of 486 nm, a full width at half maximum of 42 nm and a quantum efficiency of 76%.

Example 9

Indium precursor 0.72 mmol indium chloride (InCl ₃ ) and zinc precursor 1.08 mmol zinc bromide (ZnBr ₂ ), 1.08 mmol zinc iodide (ZnI ₂ ) and complex agent 0.72 mmol myristic acid (myristic acid) were mixed, The molar ratio of indium element and zinc element is 1:3, and after mixing, poured into a three-necked bottle to remove water vapor for 30 minutes. Next, 4 ml of octadecene (ODE) and 6 ml of oleylamine (OLA) as capping agents were added, and the temperature was raised to a complexation reaction temperature of 110 ^oC for a complexation reaction, and then rapidly heated to a nucleation reaction temperature of 240 ^oC . The hot injection method was implemented here, maintaining the temperature at 240 ^oC and injecting 0.2 ml of hexamethylphosphoric triamine, a phosphorus precursor, to perform a nucleation reaction for 30 seconds to generate core ZnInP. After the growth of the core ZnInP, keep the temperature at 240 ^oC and slowly inject 3 ml DDT of the sulfur precursor, and keep the temperature to react for 2 to 7 hours to generate the shell layer, that is, ZnInP/ZnS quantum dots are obtained. The solution containing ZnInP/ZnS quantum dots was snap-frozen to stop the shelling reaction, followed by addition of absolute ethanol to remove excess surface coating agent. Next, ultrasonic vibration and centrifugation were performed to obtain ZnInP/ZnS quantum dot precipitates. The precipitate was drained by suction, and the precipitate was dispersed with n-hexane to obtain purified ZnInP/ZnS quantum dots.

Please refer to Table 1. Purified ZnInP/ZnS quantum dots prepared according to the aforementioned experimental conditions, under the same nucleation reaction time, the sample with shelling reaction for 3 hours has an emission wavelength of 484 nm, a half-width of 36 nm and a quantum efficiency of 97 %; the sample with shelling reaction for 5 hours has an emission wavelength of 483 nm, a full width at half maximum of 35 nm and a quantum efficiency of 91%, and the sample with shelling reaction for 7 hours has an emission wavelength of 484 nm, a full width at half maximum of 36 nm and a quantum efficiency of 93%.

Example 10

Indium precursor 0.72 mmol indium chloride (InCl ₃ ), zinc precursor 1.47 mmol zinc bromide (ZnBr ₂ ), 1.08 mmol zinc iodide (ZnI ₂ ) and complex agent 0.72 mmol myristic acid (myristic acid) were mixed, The molar ratio of indium element and zinc element is 1:3.5, and after mixing, poured into a three-necked bottle to remove water vapor for 30 minutes. Next, 4 ml of octadecene (ODE) and 6 ml of oleylamine (OLA) as capping agents were added, and the temperature was raised to a complexation reaction temperature of 110 ^oC for a complexation reaction, and then rapidly heated to a nucleation reaction temperature of 220 ^oC . The hot injection method was implemented here, maintaining the temperature at 220 ^oC and injecting 0.2 ml of hexamethylphosphoric triamine as a phosphorus precursor, and making it undergo a nucleation reaction for 15 minutes to generate the core ZnInP. After the growth of the core ZnInP, the temperature was lowered to the shell-forming reaction temperature of 200 ^o C, and 3 ml of DDT was slowly injected into the sulfur precursor. The solution containing ZnInP/ZnS quantum dots was snap-frozen to stop the shelling reaction, followed by addition of absolute ethanol to remove excess surface coating agent. Next, ultrasonic vibration and centrifugation were performed to obtain ZnInP/ZnS quantum dot precipitates. The precipitate was drained by suction, and the precipitate was dispersed with n-hexane to obtain purified ZnInP/ZnS quantum dots.

Please refer to Table 1. Purified ZnInP/ZnS quantum dots were prepared according to the above experimental conditions. Under the same nucleation reaction time, ZnInP/ZnS quantum dots were not prepared for the samples with shelling reaction for 3 hours; The emission wavelength is 491nm, the full width at half maximum is 57nm and the quantum efficiency is 80%.

Example 11

Indium precursor 0.72 mmol indium chloride (InCl ₃ ), zinc precursor 1.47 mmol zinc bromide (ZnBr ₂ ), 1.08 mmol zinc iodide (ZnI ₂ ) and complex agent 0.72 mmol myristic acid (myristic acid) were mixed, The molar ratio of indium element and zinc element is 1:3.5, and after mixing, poured into a three-necked bottle to remove water vapor for 30 minutes. Next, 4 ml of octadecene (ODE) and 6 ml of oleylamine (OLA) as capping agents were added, and the temperature was raised to a complexation reaction temperature of 110 ^oC for a complexation reaction, and then rapidly heated to a nucleation reaction temperature of 230 ^oC . The hot injection method was implemented here, maintaining the temperature at 230 ^oC and injecting 0.2 ml of hexamethylphosphoric triamine as a phosphorus precursor, and making it undergo a nucleation reaction for 15 minutes to generate core ZnInP. After the growth of the core ZnInP, the temperature was lowered to the shell-forming reaction temperature of 200 ^o C, and 3 ml of DDT was slowly injected into the sulfur precursor. The solution containing ZnInP/ZnS quantum dots was snap-frozen to stop the shelling reaction, followed by addition of absolute ethanol to remove excess surface coating agent. Next, ultrasonic vibration and centrifugation were performed to obtain ZnInP/ZnS quantum dot precipitates. The precipitate was drained by suction, and the precipitate was dispersed with n-hexane to obtain purified ZnInP/ZnS quantum dots.

Please refer to Table 1. Purified ZnInP/ZnS quantum dots were prepared according to the above experimental conditions. Under the same nucleation reaction time, ZnInP/ZnS quantum dots were not prepared for the samples with shelling reaction for 3 hours; Its emission wavelength is 493nm, its full width at half maximum is 54nm and its quantum efficiency is 49%.

The characteristics of the ZnInP/ZnS quantum dots prepared according to the preparation method of quantum dots provided by the present invention are further described below in conjunction with the diagrams:

As shown in Figure 2, the gray bars represent the measured width at half maximum of the ZnInP/ZnS quantum dots prepared by the nucleation reaction for 30 seconds, and the blue bars represent the ZnInP/ZnS quantum dots prepared by the nucleation reaction time of 1 minute. The measured width at half maximum of the quantum dots, and the orange bars represent the measured width at half maximum of the ZnInP/ZnS quantum dots prepared by the nucleation reaction time of 15 minutes.

As shown in FIG. 3 , the light color diagram of the ZnInP/ZnS quantum dots prepared according to the preparation conditions of Example 4 of the present invention and the shell-forming reaction time of 3 hours.

As shown in FIG. 4 , the light color diagram of the ZnInP/ZnS quantum dots prepared under the preparation conditions of Example 7 of the present invention and the shell-forming reaction time of 3 hours is shown. Table 1 Sample serial number Shelling reaction time (hours) Emission wavelength (nm) Half width (nm) Quantum efficiency (%) Example 1 3 487 72 35 5 493 72 40 Example 2 3 499 37 - 5 500 37 - Example 3 3 483 34 14 5 482 29 3 Example 4 3 483 33 20 5 490 39 27 Example 5 3 483 34 59 5 482 32 68 Example 6 3 489 42 72 5 490 44 91 Example 7 3 489 39 104 5 488 38 79 Example 8 3 488 43 50 5 486 42 76 Example 9 3 484 36 97 5 483 35 91 7 484 36 93 Example 10 3 - - - 5 491 57 80 Example 11 3 - - - 5 493 54 49

As shown in Figure 5, the fluorescence spectra of ZnInP/ZnS quantum dots prepared according to Example 1 and Example 4: the black curve is the ZnInP prepared by shell-forming reaction for 3 hours under the preparation conditions of Example 1 / The fluorescence spectrum of ZnS quantum dots, which is marked as "Example 1 (3 hours of shelling reaction)"; the red curve is the ZnInP/ZnS prepared by shelling reaction for 3 hours under the preparation conditions of Example 4 The fluorescence spectrum of quantum dots is marked here as "Example 4 (shell-forming reaction for 3 hours)"; it can be clearly observed that the fluorescence emission peaks of the aforementioned Example 1 (shell-forming reaction for 3 hours) are compared with the previous implementation. The fluorescence emission peak of Example 4 (shelling reaction for 3 hours) has a significant blue-shift phenomenon, and its half-height width is significantly narrowed, which makes it more suitable for mixing with red phosphors to make white light components.

As shown in Figure 6, the spectrum of ZnInP/ZnS quantum dots prepared according to Example 2 of the present invention: the black curve is the emission spectrum; the blue dotted line is the excitation spectrum; the red curve is the absorption spectrum; it can be observed that at different times The emission spectrum peaks of the ZnInP/ZnS quantum dots prepared by points a, b, c and d are stably concentrated at 500 nm, and the half width and height are all maintained at about 37 nm. It is obvious that the preparation method of the quantum dots provided by the present invention has stable production quality. The advantages of ZnInP/ZnS quantum dots.

To sum up, the ZnInP/ZnS quantum dots prepared by the quantum dot preparation method provided by the present invention use InCl ₃ and ZnI ₂ /ZnBr ₂ In ³⁺ and Zn ²⁺ as cations, hexamethylphosphoric acid P ^3- in triamine (HMPA) acts as an anion for the nucleation and growth of InP and ZnInP cores. By adjusting the reaction time between the ZnInP core and the coated ZnS shell, the purpose of adjusting the full width at half maximum of the ZnInP/ZnS quantum dots and improving the quantum efficiency is achieved. From the results, it can be seen that the preparation method of quantum dots provided by the present invention can effectively narrow the half-height width below 40 nm, and improve the quantum efficiency by more than 100%. Therefore, it can be expected to substantially increase after subsequent investment in the fabrication of white light components. The NTSC color gamut area of the device solves the problems of too wide half-height width and too small color gamut area of the quantum dots produced in the prior art, and has the advantage of producing ZnInP/ZnS quantum dots with stable quality. Accordingly, compared with the disadvantages of wide half-height width and low quantum efficiency, the quantum dots prepared by the manufacturing method of the present invention have the advantages of shortening the half-height width and improving the quantum efficiency. .

(101 to 107): Steps

FIG. 1 is a flow chart illustrating the preparation method of the quantum dots disclosed in the present invention. FIG. 2 is a bar graph illustrating the full width at half maximum of the ZnInP/ZnS quantum dots prepared by the quantum dot preparation method disclosed in the present invention. 3 is a light color diagram showing the light color of the ZnInP/ZnS quantum dots prepared in Example 4 of the present invention. 4 is a light color diagram showing the light color of the ZnInP/ZnS quantum dots prepared in Example 7 of the present invention. 5 is a fluorescence spectrum diagram showing the fluorescence spectrum diagrams of the ZnInP/ZnS quantum dots prepared in Example 1 and Example 4 of the present invention. FIG. 6 is a spectrogram showing the spectrogram of the ZnInP/ZnS quantum dots prepared in Example 2 of the present invention.

(101 to 107): Steps

Claims (10)

A preparation method of quantum dots, comprising: A first precursor, a complexing agent and a coating agent are mixed into a mixed solution, and the mixed solution is heated to a complexing reaction temperature to carry out a complexing reaction to obtain a complexing reaction product, wherein the first precursor comprises Indium precursor, zinc precursor; heating the complex reaction product to a nucleation reaction temperature, then adding a second precursor and reacting for 10 seconds to 30 minutes to obtain a nucleation reaction product, wherein the second precursor comprises a phosphorus precursor; and Adding a third precursor to the nucleation reaction product and reacting at a shell-forming reaction temperature for 1-8 hours to obtain ZnInP/ZnS quantum dots, wherein the third precursor comprises a sulfur precursor, the shell-forming reaction The temperature is less than or equal to the nucleation reaction temperature. The preparation method according to claim 1, wherein the complexation reaction temperature is 100-120°C; the nucleation reaction temperature is 200-260°C; and the shell-forming reaction temperature is 200-260°C. The preparation method as claimed in claim 1, wherein the molar ratio of the indium element and the zinc element of the first precursor is 1:1 to 1:4. The preparation method according to claim 1, wherein the indium precursor comprises indium halide, an organic acid indium compound or an inorganic indium compound of Group IIIA to VA; and the preparation method according to claim 1, wherein the zinc precursor comprises zinc halide , organic acid zinc compounds or IIA~VIA inorganic zinc compounds. The preparation method according to claim 1, wherein the coating agent comprises an organic compound with a C ₈ -C ₂₂ long carbon chain, and its functional group comprises a hydrocarbon group (CH ₃ ), an amine group (NH ₂ ) or an aromatic hydrocarbon group. The preparation method of claim 1, wherein the complexing agent comprises saturated fatty acid. The preparation method according to claim 1, wherein the phosphorus precursor comprises an organic phosphorus compound. The preparation method of claim 1, wherein the sulfur precursor comprises sulfur powder or a thiol compound. The preparation method according to claim 1, wherein the indium precursor is indium chloride (InCl ₃ ); the zinc precursor is zinc bromide (ZnBr ₂ ) and zinc iodide (ZnI ₂ ). The preparation method according to any one of claims 1-9, the preparation method further comprises a purification treatment, the steps of which include: The ZnInP/ZnS quantum dots were snap-frozen and anhydrous ethanol was added to remove excess capping agent to obtain a quenched reaction product. The quenched reaction product is subjected to ultrasonic shock treatment and centrifugation to obtain a precipitate; drain the sediment; Disperse the precipitate with n-hexane to obtain a purified ZnInP/ZnS quantum dot.

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