CN-121108997-B - Synthesis method of large-size high-light-efficiency narrow-band multi-element blue light quantum dot

CN121108997BCN 121108997 BCN121108997 BCN 121108997BCN-121108997-B

Abstract

The invention belongs to the technical field of quantum dot synthesis, and particularly discloses a synthesis method of a large-size high-light-efficiency narrow-band multi-element blue light quantum dot, which comprises the following steps of preparing a quantum dot nuclear solution with a low doping proportion, and washing out a core in the quantum dot nuclear solution; inorganic fluoride ions are introduced to regulate the growth behavior of the quantum dot cores, so that the quantum dot cores uniformly grow, fluorescence spectrum data of the growth process are monitored, when the fluorescence spectrum data reach an expected value, the growth of the quantum dot cores is stopped immediately, and ZnSe and ZnS protective shell coating is carried out on the quantum dot cores with stopped growth. The synthesis method of the large-size high-light-efficiency narrow-band multi-element blue light quantum dot can avoid nonuniform growth caused by oversized dimension, can reduce Te doping proportion in cores, reduces spectrum tailing caused by nonuniform Te doping, and provides a feasible path for preparing high-performance blue light-emitting diodes and realizing commercialization of quantum dots.

Inventors

LIU HONGLI
WANG XIANLONG
WANG SHIRONG
LI XIANGGAO

Assignees

天津大学

Dates

Publication Date: 20260508
Application Date: 20250904

Claims (7)

1. The synthesis method of the large-size high-light-efficiency narrow-band multi-element blue light quantum dot is characterized by comprising the following steps of: S1, preparing a quantum dot nuclear solution with a low doping proportion, and washing out the inner core in the quantum dot nuclear solution; Step S11, preparing selenium nucleation precursor solution and tellurium nucleation precursor solution; step S12, zinc acetate is taken, oleic acid, oleylamine and 1-octadecene are added, and are uniformly mixed, and vacuum pumping is carried out for 40-120 minutes at the temperature of 100-150 ℃ to obtain a solution A; step S13, heating the solution A to 260-320 ℃ in a nitrogen atmosphere, injecting a selenium nucleation precursor solution and a tellurium nucleation precursor solution according to the proportion of 1mL to 0.02mL, wherein the added selenium nucleation precursor solution is 0.5-2mL, the added tellurium nucleation precursor solution is 0.01-0.04mL, and reacting for 40-100 minutes at the temperature of 260-320 ℃ to obtain the ZnSeTe quantum dot core solution; step S14, taking ZnSeTe quantum dot core solution, sequentially adding n-hexane and 99.9% ethanol solution, and dispersing precipitate in n-hexane after centrifuging by using a centrifugal machine, and repeating the step S14 for 2-3 times to obtain washed quantum dot cores; s2, introducing inorganic fluoride ions to enable quantum dot nuclei to grow uniformly, and monitoring fluorescence spectrum data of the growth process; Step S21, preparing tellurium growth precursor solution, selenium growth precursor solution and zinc oleate solution; S22, taking octadecene, adding washed quantum dot kernels, adding inorganic fluoride salt, vacuumizing for 30min at 120 ℃, and heating to 310 ℃, wherein the inorganic fluoride salt is one of ZnF 2 、NH 4 F, liF and KF; Injecting selenium growth precursor solution at a speed of 0.5-2mL/h by using a microinjection pump, injecting tellurium growth precursor solution at a speed of 0.1-0.4mL/h, and simultaneously adding 3-5mL of zinc oleate solution every half hour to uniformly grow ZnSeTe quantum dot cores; S23, monitoring fluorescence spectrum data of the ZnSeTe quantum dot nuclear growth process, stopping adding the precursor solution after reaching the required wavelength, and waiting for further coating of the shell layer; s3, immediately stopping the growth of the quantum dot core when the fluorescence spectrum data reach an expected value; And S4, coating a zinc selenide and zinc sulfide protective shell layer on the quantum dot core which stops growing, and obtaining the quantum dot with the narrow band blue light ZnSeTe/ZnSe/ZnS core-shell structure with high fluorescence quantum yield.
2. The method for synthesizing the large-size high-light-efficiency narrow-band multi-element blue light quantum dot according to claim 1, wherein in the step S11, a selenium nucleation precursor solution is prepared by dissolving selenium powder in diphenylphosphine in a nitrogen atmosphere, and controlling the ratio of the selenium powder to the diphenylphosphine to ensure that the concentration of the selenium nucleation precursor solution is 1-2mmol/mL, thereby obtaining the selenium nucleation precursor solution; The preparation of tellurium nucleation precursor solution is specifically to dissolve tellurium powder in tri-n-octyl phosphine under nitrogen atmosphere, and control the ratio of the tellurium powder and the tri-n-octyl phosphine to ensure that the concentration of the tellurium nucleation precursor solution is 0.05-0.1mmol/mL, thus obtaining the tellurium nucleation precursor solution.
3. The method for synthesizing the large-size high-light-efficiency narrow-band multi-element blue light quantum dot is characterized in that in the step S12, the adding ratio of zinc acetate, oleic acid, oleylamine and 1-octadecene is 2mmol:2mL:1mL:10mL; in step S14, the addition ratio of the ZnSeTe quantum dot core solution, n-hexane and ethanol solution is 2mL:1mL:2mL.
4. The method for synthesizing the large-size high-light-efficiency narrow-band multi-element blue light quantum dot is characterized in that in the step S21, a selenium growth precursor solution is prepared by dissolving selenium powder in tri-n-octyl phosphine in a nitrogen atmosphere, and controlling the ratio of the selenium powder to the tri-n-octyl phosphine to ensure that the concentration of the selenium growth precursor solution is 1-2mmol/mL to obtain the selenium growth precursor solution; the preparation of tellurium growth precursor solution comprises the steps of dissolving tellurium powder in tri-n-octyl phosphine in a nitrogen atmosphere, and controlling the ratio of the tellurium powder to the tri-n-octyl phosphine to ensure that the concentration of the tellurium growth precursor solution is 0.05-0.1mmol/mL, thereby obtaining the tellurium growth precursor solution; The preparation method of the zinc oleate solution comprises the steps of taking zinc acetate, adding tri-n-octylamine and oleic acid into a flask, adding the zinc acetate, the tri-n-octylamine and the oleic acid in a ratio of 2mL to 1mL, uniformly mixing, heating to 100-150 ℃, vacuumizing for 40-120 minutes, and then preserving heat in a nitrogen atmosphere to obtain the zinc oleate solution.
5. The method for synthesizing the large-size high-light-efficiency narrow-band multi-element blue light quantum dot is characterized in that in the step S22, the addition ratio of octadecene, washed quantum dot cores and inorganic fluorine salt is 10-15mL:5-6mL:0.5-2mmol.
6. The method for synthesizing large-size high-light-efficiency narrow-band multi-element blue light quantum dots according to claim 1, wherein step S4 is specifically, Step S41, preparing a selenium cladding precursor solution, a sulfur cladding precursor solution and a zinc oleate solution; step S42, maintaining the ZnSeTe quantum dot nuclear solution at 260-320 ℃, injecting the selenium cladding precursor solution at a speed of 1-3mL/h by using a microinjection pump, and simultaneously adding 3-5mL of zinc oleate solution every half hour to coat the zinc selenide layer; S43, injecting sulfur cladding precursor solution at a speed of 1-3mL/h by using a microinjection pump, and adding 3-5mL of zinc oleate solution every half hour to coat a zinc sulfide layer to obtain a zinc selenide and zinc sulfide double-shell-layer coated quantum dot reaction solution; and S44, cooling the reaction liquid to room temperature, and separating and purifying the reaction liquid for 2-3 times by using normal hexane and ethanol to obtain the narrow band blue light ZnSeTe/ZnSe/ZnS core-shell structure quantum dot with high fluorescence quantum yield.
7. The method for synthesizing the large-size high-light-efficiency narrow-band multi-element blue light quantum dot according to claim 6, wherein in the step S41, a selenium cladding precursor solution is prepared by dissolving selenium powder in tri-n-octyl phosphine in a nitrogen atmosphere, and controlling the ratio of the selenium powder to the tri-n-octyl phosphine to ensure that the concentration of the selenium cladding precursor solution is 1-2mmol/mL to obtain the selenium cladding precursor solution; Preparing a sulfur cladding precursor solution, namely dissolving sulfur powder into tri-n-octyl phosphine in a nitrogen atmosphere, and controlling the ratio of the sulfur powder to the tri-n-octyl phosphine to ensure that the concentration of the sulfur cladding precursor solution is 1-2mmol/mL to obtain the sulfur cladding precursor solution; The preparation method of the zinc oleate solution comprises the steps of taking zinc acetate, adding tri-n-octylamine and oleic acid into a flask, adding the zinc acetate, the tri-n-octylamine and the oleic acid in a ratio of 2mL to 1mL, uniformly mixing, heating to 100-150 ℃, vacuumizing for 40-120 minutes, and then preserving heat in a nitrogen atmosphere to obtain the zinc oleate solution.

Description

Synthesis method of large-size high-light-efficiency narrow-band multi-element blue light quantum dot Technical Field The invention belongs to the technical field of quantum dot synthesis, and particularly relates to a synthesis method of a large-size high-light-efficiency narrow-band multi-element blue light quantum dot. Background The zinc selenide (ZnSeTe) quantum dot can realize Photoluminescence (PL) emission covering the whole blue light spectrum range by changing the doping proportion of tellurium (Te) elements, and is one of the most promising environment-friendly blue light quantum dot materials at present. However, with the increase of the Te doping ratio, spectrum broadening is inevitably caused, and the color purity of the quantum dots is seriously affected. In the existing ZnSeTe quantum dot system, the narrowest emission peak is 14nm, but the emission wavelength is below 450nm, so that the subsequent commercial application is difficult to meet. The quantum dot with the half-peak width of more than 450nm is used at present, the narrowest half-peak width is 22nm, and the color purity is low. This is mainly because zinc selenide (ZnSe) has a bulk band gap of 2.7eV, and after forming quantum dots, the emission peak is located near 420nm, requiring Te doping to adjust the spectrum. However, as the Te proportion increases, te may be unevenly distributed within the quantum dot core, multiple tes aggregate to form Te clusters, introducing shallow energy levels near the valence band top, causing emission peak tailing broadening. Thus ZnSeTe quantum dots have difficulty achieving narrow band emission in the blue emission range (450-465 nm) that is satisfactory for commercial applications. Therefore, a synthesis method of large-size high-light-efficiency narrow-band multi-element blue light quantum dots needs to be developed in the field, and the problems can be effectively solved. Disclosure of Invention The invention aims to provide a synthesis method of a large-size high-light-efficiency narrow-band multi-element blue light quantum dot, which combines a large-size low-doping strategy with a tellurium (Te) doping strategy to jointly promote the spectral red shift of zinc selenide (ZnSe) and synthesize the low-doping blue light-emitting large-size ZnSeTe quantum dot. In order to achieve the above purpose, the invention provides a synthesis method of a large-size high-light-efficiency narrow-band multi-element blue light quantum dot, which comprises the following steps: S1, preparing a quantum dot nuclear solution with a low doping proportion, and washing out the inner core in the quantum dot nuclear solution; s2, introducing inorganic fluoride ions to enable quantum dot nuclei to grow uniformly, and monitoring fluorescence spectrum data of the growth process; s3, immediately stopping the growth of the quantum dot core when the fluorescence spectrum data reach an expected value; And S4, coating a zinc selenide and zinc sulfide protective shell layer on the quantum dot core which stops growing, and obtaining the quantum dot with the narrow band blue light ZnSeTe/ZnSe/ZnS core-shell structure with high fluorescence quantum yield. Preferably, the step S1 is specifically, Step S11, preparing selenium nucleation precursor solution and tellurium nucleation precursor solution; step S12, zinc acetate is taken, oleic acid, oleylamine and 1-octadecene are added, and are uniformly mixed, and vacuum pumping is carried out for 40-120 minutes at the temperature of 100-150 ℃ to obtain a solution A; step S13, heating the solution A to 260-320 ℃ in a nitrogen atmosphere, injecting a selenium nucleation precursor solution and a tellurium nucleation precursor solution according to the proportion of 1mL to 0.02mL, wherein the added selenium nucleation precursor solution is 0.5-2mL, the added tellurium nucleation precursor solution is 0.01-0.04mL, and reacting for 40-100 minutes at the temperature of 260-320 ℃ to obtain the ZnSeTe quantum dot core solution; and S14, taking ZnSeTe quantum dot nuclear solution, sequentially adding n-hexane and ethanol solution, centrifuging by using a centrifugal machine, dispersing precipitate in n-hexane, and repeating the step S142-3 times to obtain the washed quantum dot nuclear. Preferably, in step S11, the selenium nucleation precursor solution is prepared by dissolving selenium powder in diphenyl phosphine under nitrogen atmosphere, controlling the ratio of the selenium powder and the diphenyl phosphine, and making the concentration of the selenium nucleation precursor solution be 1-2mmol/mL to obtain the selenium nucleation precursor solution; The preparation of tellurium nucleation precursor solution is specifically to dissolve tellurium powder in tri-n-octyl phosphine under nitrogen atmosphere, and control the ratio of the tellurium powder and the tri-n-octyl phosphine to ensure that the concentration of the tellurium nucleation precursor solution is 0.05-0.1mmol/mL, thus obtaining t