WO2017016438A1 - 魔尺寸纳米晶类物质的制备方法 - Google Patents

魔尺寸纳米晶类物质的制备方法 Download PDF

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WO2017016438A1
WO2017016438A1 PCT/CN2016/090940 CN2016090940W WO2017016438A1 WO 2017016438 A1 WO2017016438 A1 WO 2017016438A1 CN 2016090940 W CN2016090940 W CN 2016090940W WO 2017016438 A1 WO2017016438 A1 WO 2017016438A1
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reaction
temperature
component
msncs
metal element
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刘明洋
余睽
余启钰
张静
朱婷婷
付敏
张莉
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Sichuan University
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Definitions

  • the invention relates to a method for preparing a magic size nanocrystalline substance in the field of nano materials.
  • Quantum dots are a kind of semiconductor nanocrystals, which have attracted increasing attention in the field of materials science.
  • the meaning of nanocrystals and quantum dots is the same in this paper.
  • Existing studies have shown that the number of atoms in nanocrystals is between a dozen and a few thousand, and the nearly spherical particles, which are 1-20 nm in size, are smaller or closer to the exciton Bohr radius of their own materials, so the exciton motion is directly affected. Limited to the size of the sphere, the limiting effect is obvious.
  • Most of the properties of nanocrystals such as light, electricity, magnetism and catalysis depend directly on the size of one parameter. This unique correlation brings great convenience to the properties of nanocrystals.
  • the nanocrystals have a large specific surface area, and the number of atoms on the surface is similar to or even larger than the number of atoms in the interior. Therefore, the surface structure is closely related to the properties of the material itself, and the nanometer surface can be modified to improve the nanometer.
  • Crystal related properties thus having special photoelectric properties and easy to adjust characteristics, can be used as a new type of material that can easily adjust properties, including medical, energy, and physical devices such as solar cells, bio-imaging, and light-emitting diodes.
  • NCs nanocrystals
  • soft stencils such as reverse micelles and microemulsions.
  • Water/non-polar solvent mixed system synthesis etc.
  • the synthesis method of nanocrystals is becoming more and more mature, and the synthesis process currently used is far superior to the early development stage of nanocrystals, and has been developed to use high-boiling organic solvent synthesis.
  • the raw materials used are metal element components containing Group IIB, Group IIIA and Group IA of the periodic table of elements such as Cd, Pb, Zn, In, Ga, etc., and Group VIA and VA of S, Se, Te, P, As, etc.
  • Non-metallic elements are included in the typical nanocrystalline materials that have been studied and reported.
  • CdSe, PbSe, ZnTe, CdS, CdTe and the like At present, it is mainly synthesized by colloidal chemical method and can be divided into two categories.
  • the nanocrystalline products such as CdS, CdSe and CdTe have been successfully synthesized.
  • Peng et al. introduced CdO and other air-stable cadmium compounds to replace dimethyl cadmium as a cadmium precursor, avoiding the use of dimethyl cadmium, a toxic, hazardous and expensive reagent. It also makes the reaction conditions simple (no need to be carried out under strictly anhydrous anaerobic conditions, and the reaction temperature is effectively lowered).
  • Peng Group used oleic acid (OA) and octadecene (ODE) as ligands and non-coordinating solvents, which effectively expanded the range of raw materials and solvents of nanocrystals (W.
  • OA oleic acid
  • ODE octadecene
  • Another method of synthesis is the "non-hot-injection one-pot" reported by the Cao team in 2004.
  • sulfur powder is used as a sulfur source
  • cadmium tetradecanoate is used as a cadmium source
  • octadecene having no coordination ability is added, and the nanocrystals are grown in a reaction bottle at 240 ° C.
  • the high synthesis temperature and fast reaction speed of the method make the nucleation and growth process of CdS nanocrystals together, and the growth of nanocrystals cannot be studied in detail.
  • the hot injection method is a reaction at a high temperature
  • the nucleation and growth processes of the nanocrystals in the "non-thermal injection one-pot method” are linked together, so most of the methods synthesized by these methods are large-sized NCs products, which are rarely observed. To the magic size nanocrystalline substances.
  • Magic-sized nanocrystalline materials are a special class of nanocrystals that are found in CdSe, CdTe, and ZnSe preparation systems. It has a very small particle size, consisting of only a few tens of atoms between 1-3 nm, and has sharper UV absorption than conventional nanocrystalline materials (RNCs), showing both UV absorption and fluorescence emission patterns.
  • RNCs conventional nanocrystalline materials
  • MSNCs are not easy to passivate and are easy to aggregate, they are difficult to characterize (Emily A. Weiss, et al, The Use of Size-Selective Excitation To Study Photocurrent through Junctions Containing Single-Size and Multi-Size Arrays of Colloidal CdSe Quantum Dots.J .Am. Chem. Soc. 2008, 130, 83-92).
  • MSNCs were originally synthesized by the A. Henglein in 1984 in the water phase of the magic size CdS nanocrystals.
  • Manna et al. dissolved CdO with dodecylamine and citric acid and added SeTOP.
  • F330 UV absorption peak at 330 nm
  • F360, F384, F406, F431, F447 CdSe MSCs were successfully synthesized.
  • MSNCs magic size nanocrystalline substances
  • the MSNCs of the present invention can be prepared in the same reaction system as the RNCs.
  • a component having at least one metal element of Groups IIB, IIIA and IVA of the periodic table, and a component of at least one non-metal element of Group VIA and Group VA as raw materials in the same reaction system and inert gas atmosphere for preparing RNCs
  • the heating process is carried out, and the basic process is as follows:
  • reaction time after setting the reaction temperature is preferably 5-30 minutes;
  • the reaction product after the reaction is cooled to a temperature lower than 50% of the actual heating temperature of the reaction, and then allowed to stand to obtain the target product of the corresponding magic size nanocrystals (MSNCs).
  • the half-value width of the ultraviolet absorption spectrum peak of the target product of the MSNCs is usually 10-20 nm.
  • the preferred reaction heating temperature is 40% to 80% of the reaction temperature of the corresponding conventional nanocrystalline material preparation.
  • the preferred molar ratio of the metal element to the non-metal element starting material is (4-8):1.
  • the reaction temperatures of the different forms of RNCs required for heating are different.
  • the current reaction heating temperatures for preparing CdS RNCs and CdSe RNCs are usually 300 ° C - 330 ° C and 240 ° C - 300, respectively. °C, therefore, the above preparation method of the present application is 40% to 80% of the reaction heating temperature of the corresponding RNCs, and the reaction heating temperature for preparing CdTe MSNCs or CdSe MSNCs is generally ⁇ 140 ° C (for example, 80 ° C - 120 ° C).
  • the reaction heating temperature for the CdS MSNCs of the present invention is generally ⁇ 190 ° C (e.g., 90 ° C - 180 ° C).
  • the cooling and standing temperature is preferably lower than 30 ° C or room temperature, and the preferred cooling and standing modes are first cooled to -18 to liquid nitrogen temperature (abbreviated as "liquid nitrogen” in the present invention, All refer to the temperature condition of liquid nitrogen), and then the temperature is raised to ⁇ 30 °C.
  • liquid nitrogen abbreviated as "liquid nitrogen” in the present invention, All refer to the temperature condition of liquid nitrogen
  • the component containing at least one metal element of Groups IIB, IIIA and IVA of the periodic table, and the component of at least one non-metal element of Group VIA and VA are selected and used as raw materials.
  • a combination of a component containing one of the Group IIB metal elements and a component containing a Group VIA non-metal element eg, CdSe, PbSe) , ZnTe, CdS, etc.
  • a combination of a component containing a Group IIIA metal element and a component comprising a VA group of non-metal elements such as InP, GaAs, etc.
  • Containing a Group IVA metal element component and containing one of said Group VIA non-metal element components or a combination of three or four components referred to as alloy nanocrystals, comprising said Group IIB and Or one or both of the Group IIIA metal element
  • the metal element component may preferably be selected and used as a metal organic acid salt or a mineral acid salt such as Cd, Pb, Zn, In, Ga;
  • Non-metallic elemental components which are preferably selected and used include elemental ingredients or compounds such as S, Se, Te, P, As.
  • the present invention is preferably recommended on the premise that a plurality of solvent systems which can also successfully prepare RNCs can be used.
  • It is a high-boiling organic solvent used in high-temperature oil phase reaction, including organic solvents such as octadecene, oleic acid or oleylamine, trioctylphosphine, etc., among which the more preferred reaction system solvents contain volume ratios respectively. ⁇ 30% octadecene oleic acid-octadecene mixed solvent or oleylamine-octadecene mixed solvent.
  • the above preparation method of the present invention includes the corresponding metal/nonmetal component charge ratio in the raw material, the reaction temperature, the solvent composition of the reaction system, the use of the additive, and the conditions/environment for cooling after the reaction. Adjustments or changes can result in different MSNCs with different degrees of stability, rate of formation and/or yield, as well as conversions between different MSNCs, and the like.
  • the main preferred conditions for preparing the target products of the corresponding compositions of the MSNCs by the above method of the present invention include:
  • the molar ratio of Cd:Te in the raw material component is ⁇ 4:1
  • the heating temperature of the reaction is 120° C. to 160° C.
  • the cooling standing temperature after the reaction is room temperature to liquid nitrogen temperature
  • the Cd:S molar ratio of the raw material component is ⁇ 4:1
  • the oleic acid: cadmium 2.2:1
  • the heating temperature of the reaction is 120° C.-240° C.
  • the preferred heating temperature of the reaction is 190° C.
  • the subsequent cooling and standing temperature is -20 ° C ⁇ 80 ° C;
  • the molar ratio of Cd:Se in the raw material component is ⁇ 4:1
  • the heating temperature of the reaction is 120 °C to 160 °C
  • the cooling standing temperature after the reaction is the liquid nitrogen temperature (-196 ° C).
  • the reactant after the reaction at the heating temperature, the reactant may be directly cooled to the temperature and then allowed to stand, and an appropriate additive may be added to the reactant as needed. Further, the reactant after the reaction may be diluted in an organic solvent including toluene or cyclohexane in a volume ratio of 1: (100 to 150), followed by cooling and standing.
  • the additive is one of acetone, ethyl acetate (EA), acetic acid, methanol, ethanol, chloroform, tetrahydrofuran (THF), water, and ethylamine; experiments have shown that preferred additives may be methanol, ethanol, THF, and EA.
  • the amount of the additive added is generally not more than 1/2 of the volume of the reactant, as the case may be.
  • a suitable additive component in a solvent for diluting the reactant as needed.
  • the additive is an amine component including butylamine, octylamine, dodecylamine, oleylamine, and/or an alcohol component including methanol, ethanol, isopropanol, hexanol, decyl alcohol, Or tetrahydrofuran, and / or carboxylic acids.
  • dilution solvent 1: (60 to 150).
  • the reactants separated or not separated from the RNCs formed in the reaction system are diluted in toluene or cyclohexane, and in addition to using a single toluene or cyclohexane, depending on the case and It is necessary to further use a mixed solution of toluene or cyclohexane with an appropriate additive component.
  • the additive may be an amine component including butylamine, octylamine, dodecylamine, oleylamine, and/or an alcohol component including methanol, ethanol, isopropanol, hexanol, decyl alcohol. , or tetrahydrofuran.
  • the corresponding pure MSNCs products can be directly prepared, which not only facilitates in-depth study of MSNCs, but also has more sharp ultraviolet absorption compared with RNCs, although the current photoluminescence efficiency (PLQY) ), stability and equidistance can be directly applied to the distance, but since strong absorption occurs, it is possible to achieve good PLQY and stability by adjusting surface factors such as defects and ligands.
  • PLQY current photoluminescence efficiency
  • MSNCs have been shown to be able to convert to more stable RNCs at room temperature under certain conditions, thus opening up a new way to prepare RNCs, while low-temperature synthesis can be highly controlled and simple to operate, which is more conducive to industrial applications. And further research on the reaction mechanism.
  • Figure 14 is a detection map of Example 4.
  • Figure 15 is a detection map of Example 5.
  • Figure 16 is a graph showing the detection of the product of the magic size CdTeSe alloy nanocrystals of Example 6.
  • Figure 17 is a detection map of the magic size CdTeSe alloy nanocrystals prepared by the method of Example 7.
  • Figure 18 is a graph showing the preparation of a nano-sized material of the magic size CdSeS alloy of Example 8.
  • Figure 19 is a graph showing the effect of solvent on the preparation of the magic size ZnSe nanocrystals of Example 9.
  • TECHCOMP UV 2310II UV spectrophotometer is Shanghai Tianmei Technology Instrument.
  • the reaction was carried out under the conditions of a concentration of Te of 10 mmol/kg, 30 mmol/kg and 44 mmol/kg in the reaction system, and the sample No. 1 was taken at 120 ° C for 15 min, respectively, and then the temperature was raised and then sequentially at 140 ° C for 0 min. , 15 min; 160 ° C 0 min, 15 min; 180 ° C 0 min, 15 min, respectively, take samples No. 2-7.
  • the results of the absorption spectra measured for each sample are shown in Fig. 1 (the curves from bottom to top correspond to the ultraviolet absorption spectra of samples No. 1-7, respectively).
  • TOPTe was added at room temperature and allowed to stand at room temperature until no RNCs appeared at 7 h.
  • Te TOP was added at 140 ° C, the reaction was taken for 10 min and then sampled. RNCs did not appear after removal; F365 appeared after storage for 3 h at 30 ° C; F365 was red shifted to F370 after storage at 30 ° C for 7 h.
  • Figure 2 shows that it is advantageous to grow smaller MSNCs at room temperature storage.
  • a sample of the sample sampled after reacting at a temperature of 130 ° C for 5 to 30 minutes was examined for ultraviolet absorption, as shown in Fig. 4, and showed no characteristic absorption.
  • the sample was stored in liquid nitrogen.
  • the sample was selected from the sample at 140 ° C for 5 min during the above reaction.
  • F372 appeared immediately after the sample was added, but the amount was less than that of the butylamine solution; after 20 minutes, the amount of F372 was close to that of butylamine, and F416 appeared; the amount of F372 after 1 hour The highest value was reached and the amount of butylamine was exceeded. At the same time, F416 also grew obviously. At this time, F372 still dominated; after 3h, F372 decreased and F416 increased; after 6h, the number of F416 exceeded F372.
  • F372 appeared immediately after the sample was added, and the amount of F372 was more than 0 min in the octylamine solution; F416 appeared after 5 min, but the number of F372 reached the maximum; after F372 The number is slowly decreasing, and F416 is growing; after 3h, the amount of F372 and F416 is almost the same.
  • F372 appeared immediately after the sample was added for 0 min, but the amount was small; the amount of F372 reached the maximum at 5 min, and F416 appeared; in the subsequent process, the F372 in the system decreased continuously. F416 is increasing, and the number of F416 exceeds F372 after 3h.
  • Cadmium acetate dihydrate (Cd(OAc) 2 ⁇ 2H 2 O): from Alfa Aesar, purity 99.999%;
  • TOP Trioctylphosphine
  • Oleylamine from Aldrich Chemistry, with a purity of 70%.
  • the cadmium acetate dihydrate gradually dissolves completely to obtain a clear solution.
  • the temperature was raised to 120 ° C, and a vacuum was applied at this temperature for one hour. At this point the solution is in a pale pink transparent state.
  • the atmosphere was then maintained with nitrogen to obtain the corresponding cadmium precursor (Cd precursor).
  • the weighed selenium powder, 90% trioctylphosphine and oleylamine were added to 25 mL with a straight line according to the total reaction system of 5 g and the desired ratio of cadmium/selenium/trioctylphosphine (90%).
  • stirring was started at room temperature, and a nitrogen/vacuum operation similar to that in the preparation of a cadmium source was performed three times with a vacuum pump. At this time, the solution was in a colorless and transparent state, and then nitrogen gas was introduced to maintain the atmosphere to obtain a corresponding selenium precursor.
  • the selenium precursor was quickly transferred to the cadmium precursor in one go, and the addition time was recorded as the starting point of the reaction.
  • the reaction system was purged with nitrogen to maintain the atmosphere. According to the fixed temperature at a certain reaction temperature, the sampling operation is performed at a certain time, and the constant temperature experiment of the corresponding spectrum detection is performed; and in the temperature range of 120 ° C to 240 ° C, the reaction is sampled at 120 ° C for a certain time, and then the temperature is programmed. A sample was taken after sampling at 140 ° C, and the temperature was raised to 240 ° C to measure the temperature.
  • Each sample taken out was diluted with a toluene solution, and then subjected to corresponding detection and characterization by an ultraviolet spectrophotometer.
  • the sample of 0 min at 160 ° C in the above reaction was statically placed at 15 ° C in a mixed solution of octylamine-toluene in two different ratios of 1 ml OTA + 2 ml Tol and 1.5 ml OTA + 2.5 ml Tol, ultraviolet absorption spectrum.
  • the test results are shown in Figure 8.
  • a and b are respectively a mixed solution of octamine-toluene in two different ratios of 1 ml OTA + 2 ml Tol and 1.5 ml OTA + 1.5 ml Tol.
  • the curves from bottom to top in the figure are divided into UV absorption spectra which are statically stored for 0 min, 6 h and 20 h. It can be seen that increasing the concentration of octylamine in the octylamine-toluene mixed solution can be beneficial to increase the amount of MSNCs produced.
  • the samples sampled at 200 ° C for 15 min were directly stored in liquid nitrogen, -20 ° C, 4 ° C, 30 ° C and 60 ° C for 7 days, and the UV absorption spectrum detected is shown in FIG. 9 .
  • the curves from bottom to top in Figure a are samples stored under liquid nitrogen, -20 ° C and 4 ° C respectively.
  • the curves from bottom to top in Figure b are the synthesis temperatures and are stored at 60 ° C and 30 ° C respectively. sample.
  • Cadmium oxide ( ⁇ 99.99%), oleic acid ( ⁇ 90%), octadecene ( ⁇ 90%), from Aldrich; sulfur powder ( ⁇ 99.5%), cyclohexane ( ⁇ 99.5%), toluene, isopropanol ( ⁇ 99.7%), methanol ( ⁇ 99.5%), from Chengdu Kelon Chemical Reagent Factory.
  • TECHCOMP UV 2310II ultraviolet spectrometer (Shanghai Tianmei Technology Instrument); Fluoromax-380 fluorescence spectrometer; X'Pert Pro MPD X-ray diffractometer (XRD); Tecnai G2F20S-TWIN field emission transmission electron microscope (TEM); Zetasizer Nano instrument.
  • OA octadecene
  • a sample of F311 or F322 to be purified is added dropwise to isopropanol under conditions of excess isopropyl alcohol (e.g., a v/v ratio of about 100:1).
  • excess isopropyl alcohol e.g., a v/v ratio of about 100:1.
  • the redispersed sample was redispersed in toluene or cyclohexane to obtain CdS MSNCs with unchanged UV absorption peak positions, as shown in FIG.
  • a is the absorption peak of the sample dispersed in CdS MSNCs F322 in toluene
  • b is the ultraviolet absorption spectrum of the absorption peak of the sample dispersed in CdS MSNCs F311 in cyclohexane.
  • the bottom-up curves in the figure are the absorption peaks of the samples after purification and before purification, respectively. It indicates that the material near 290 nm and the larger RNCs near 330 nm have been substantially removed by the purification treatment.
  • Figure 11 shows the results of high resolution electron microscopy (TEM) and XRD of the single nanoclustered F11 and F322 products obtained after purification.
  • a1 and a2 are the TEM images of the F322 product (resolutions are 100nm and 2nm, respectively), a3 is the XRD pattern; b1 and b2 are the TEM images of the F311 product (resolutions 50nm and 20nm, respectively), b3 is XRD map.
  • the small plots in the a1 and b1 plots are the UV absorbance spectra of the corresponding products, respectively.
  • the sample is dispersed with toluene and tested Ultraviolet absorption spectrum. The sampling temperature range is 120-240 °C. Each of the taken samples was immediately tested and then allowed to stand at 15 ° C for 1 day, 7 days, and 10 days, respectively.
  • the additives with significant effects of methanol, THF and EA were selected, and the samples were respectively stored in the additive-containing mixture at 4 ° C and 60 ° C for 1 h to 3 days.
  • the results showed that in the samples stored at 4 ° C, the additive-free control group produced stable F323, while the methanol and THF additives only obtained pure F311 product.
  • F309MSNCs showed conversion to RNCs over 5 days
  • F307MSNCs showed conversion to RNCs in 1 ml of HAc + 1.975 ml Tol mixed solution
  • F310MSNCs In 1 ml of dioxane + 1.975 ml Tol mixed solution, conversion to RNCs was shown in 2 days
  • F308/F311 MSNCs in 0.05 ml methanol + 3 ml Tol mixed solution showed conversion to RNCs in 2 days.
  • Example 2 200 ⁇ L of the obtained pure sample of F369CdTe MSNCs was dispersed in 1 mL of hexane, centrifuged, and the lower layer solid was left, and then dispersed with 3 mL of toluene, and allowed to stand. During the rest period from 0 to 60 minutes, the color of the solution began to slowly turn yellow, F369 began to slowly decrease, and RNCs gradually grew.
  • the UV absorption detection spectrum of the process is shown in Figure 14.
  • Example 3 In the manner of Example 3, in the CdS system, the sample was heated to 190 ° C for 5 minutes, and the reactants of the sample were stored in an environment of -20 ° C for 1 day, and then the obtained pure F323CdS MSNCs sample - 0.02 g was dispersed in 3 mL of toluene solution. Approximately 50 ⁇ L of methanol was stored in the solution at room temperature. Over time, CdS MSNCs gradually decreased and CdS RNCs gradually grew. The UV absorption detection spectrum of the process is shown in Figure 15.
  • Toluene, methanol, ethanol and isopropanol are all from Chengdu Kelon Chemical Reagent Factory.
  • Te powder and 0.247 g of TOP trioctylphosphine were weighed into a separate round bottom flask, vacuumed at room temperature, and nitrogen-protected three times to remove water and oxygen from the system. Then, the temperature was raised to 300 ° C under the protection of nitrogen until the solution in the bottle became a yellow-green transparent liquid TOPTe. After the liquid was cooled, TeTOP was added to a set of 130 ° C Cd(Ac) 2 solution. And keep it for 30 minutes. A Te precursor was prepared.
  • Se powder 0.012 g of Se powder and 0.247 g of TOP (trioctylphosphine) were weighed into an additional round bottom flask, vacuumed at room temperature, and nitrogen gas was switched three times to remove water and oxygen from the system. The hair dryer is slightly hot to dissolve the Se powder. SeTOP was added to one of a set of Cd(Ac) 2 solutions at 140 °C. And keep it for 30 minutes. A Se precursor was prepared.
  • Te and Se precursors were cooled, they were mixed directly and kept at 25 ° C for 24 h. 30 ⁇ L of the sample was dispersed in 3 mL of toluene, and F398 of the ultraviolet absorption peak of CdTeSe MSNCs at 398 nm was observed by measurement with an ultraviolet spectrophotometer, as shown in FIG.
  • Te and Se precursors were prepared in the same manner as in Example 6. After the Te and Se precursors were cooled, they were mixed directly and kept at 25 ° C for 24 h. A further 30 ⁇ L of the sample was dispersed in 2.3 mL of toluene for 20 h. No UV absorption peak appeared, indicating no crystal-generated intermediates, as shown in Figure 17a. 0.7 mL of octylamine (OTA) was added to this solution and immediately monitored for in situ UV absorption. It was observed that CdTe MSNCs F370 was immediately formed, then CdTe MSNCs F370 slowly disappeared, CdTeSe MSNCs F398 was slowly generated, and pure CdTeSe MSNCs F398 was obtained after 80 minutes. As shown in Figure 17b.
  • OTA octylamine
  • Toluene, methanol, ethanol and isopropanol are all from Chengdu Kelon Chemical Reagent Factory.
  • CdSe precursor 0.154 g (1.20 mmol) of CdO, 0.746 g (2.64 mmol) of OA and 3.832 g of ODE were placed in a 50 mL three-neck reaction flask, and gas was exchanged at room temperature for 30 min until no bubbles were generated. Deg.] C under vacuum was heated to 120 revolutions N 2 continue to heat up to 230 °C, 1h until a clear solution maintained at 230 °C. The clear solution was cooled to 120 ° C for 30 min and cooled to 60 ° C.
  • CdS precursor 0.077 g (0.60 mmol) of CdO, 0.373 g (1.32 mmol) of OA and 4.423 g of ODE were placed in a 50 mL three-neck reaction flask, and gas was exchanged at room temperature for 30 min until no bubbles were formed.
  • Deg.] C under vacuum was heated to 120 revolutions N 2 continue to heat up to 230 °C, 1h until a clear solution maintained at 230 °C. The clear solution was cooled to 120 ° C for 30 min and cooled to 90 ° C.
  • CdSeS MSCs The prepared CdSe precursor and CdS precursor were mixed at room temperature at a volume ratio of 600 ⁇ L: 200 ⁇ L, 200 ⁇ L: 200 ⁇ L, 200 ⁇ L: 600 ⁇ L. Samples were taken at rest time, and 25 ⁇ L of the sample was dispersed in a mixed solvent of 3 mL of OTA/toluene, and its growth was examined by in situ ultraviolet absorption spectroscopy.
  • the sample was dispersed into a mixed solvent of 1 mL OTA/2mL TOL, and the in-situ ultraviolet absorption test was immediately performed.
  • the test time was (1) 0 min, (2) 15 min, (3) 45 min, (4) 2 h, (5) 5h, (6) 10h, (7) 23h, (8) 50h and (9) 72h.
  • CdSe volume ratio: 600 ⁇ L: 200 ⁇ L
  • an absorption peak appears at 388 nm, and the absorption peak becomes sharp and the peak position is fixed with the dispersion time (as shown in Fig.
  • Zinc oxide (ZnO), selenium powder (Se), trioctylphosphine (TOP), diphenylphosphine (DPP) oleic acid (OLA), octylamine (OTA), octadecene (ODE) are all from Aldrich;
  • Toluene, cyclohexane, methanol, ethanol, and isopropanol were all from Chengdu Kelon Chemical Reagent Factory.

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Abstract

魔尺寸纳米晶类物质的制备方法，以含有元素周期表ⅡB族、ⅢA和IVA族中至少一种金属元素的成分，以及ⅥA族和ⅤA族中至少一种非金属元素的成分为原料，在制备常规纳米晶类物质的反应体系中和惰性气体氛围中，加热反应后，冷却至低于其反应实际加热温度50％的温度后静置，得到所述的魔尺寸纳米晶类物质目标产物。该制备方法可以得到纯净的所需目标产物。

Description

魔尺寸纳米晶类物质的制备方法 技术领域
本发明涉及纳米材料领域中对魔尺寸纳米晶类物质的制备方法。
背景技术
量子点是一种半导体纳米晶，已日益引起了材料科学领域的广泛关注。本文中所称的纳米晶与量子点的含义是相同的。现有研究显示，纳米晶的原子个数在十几个到几千个之间，近球形微粒，尺寸为1-20nm，小于或接近自身材料的激子波尔半径，因此激子运动直接受限于球体尺寸，限域效应明显。纳米晶的光、电、磁、催化等性能绝大部分直接取决于尺寸一个参数，这种唯一相关性给调节纳米晶的性质带来巨大的方便。此外，纳米晶具有大的比表面积，其表面的原子数目相近于或甚至大于内部的原子数目，因此表面结构与材料自身的性能密切相关，通过对半导体纳米晶的表面进行修饰，也可以改善纳米晶的相关性能，因而具备特殊的光电性质及易于调节性等特点，可作为一类容易调节性质的新型材料，在包括如太阳能电池、生物成像，发光二极管等在内的医疗、能源、物理器件许多领域中都有广泛的应用前景。如1994年，Bawendi及Paul Alivisatos等首次将硒化镉纳米晶用于LED领域；1998年Alivisatos与聂书明分别报道实现了纳米晶的生物标记和生物传感器的应用；2002年J.Nozik报道实现了纳米晶在太阳能电池上的应用。
纳米晶(NCs，或常规纳米晶RNCs)的合成，在20世纪80年代就已经开始发展，如水溶液体系合成，有机介质体系合成，以及利用软模版(如反相胶束和微乳剂等)在水/非极性溶剂混合体系合成等。目前对纳米晶合成方法日趋成熟，现在所采用的合成工艺远比纳米晶早期发展阶段时优异不少，已发展到使用的高沸点有机溶剂合成。其所用原料，分别为含有Cd、Pb、Zn、In、Ga等元素周期表中ⅡB族、ⅢA族和IVA族的金属元素成分，以及S、Se、Te、P、As等ⅥA族和ⅤA族的非金属元素。其中已有较多研究和报道的典型纳米晶物质有CdSe、PbSe、ZnTe、CdS、CdTe等。目前主要由胶体化学法合成制备，可分为两大类。其一最成功的油相合成纳米晶方法，是1993年由Bawendi小组提出的高效制备高质量纳米晶合成的热注射法(Hot-injection)，以有机镉为镉源，以三辛基膦(TOP)有机膦配体活化Se源，用注射器将硒化三丁基膦快速注入到300-330℃高温的含二甲基镉的三辛基氧化膦(TOPO)溶液(作为表面活性剂、配体和溶剂)，然后降温至250-300℃左右，反应不同的时间等待CdSe纳米晶成核并形成纳米晶，制备了高均一度的硒化镉纳米晶，有效提升了合成中对粒子尺寸分布的控制，已成功合成了如CdS、CdSe和CdTe等纳米晶产物。2001年Peng等人引入CdO和其他空气中稳定的镉化合物来替代二甲基镉作为镉前驱体(Cadmium precursor)，避免了使用二甲基镉这种既有毒性、使用危险以及价格高昂的试剂，还使得反应条件变得简化(无需在严格的无水无氧条件下进行，并且有效降低了反应温度)。2002年Peng小组分别使用油酸(Oleic acid，OA)和十八烯(ODE)来作为配体和非配位溶剂，从而有效地扩展了纳米晶的原料和溶剂范围(W.William Yu,X.Peng,et al.Formation of high-quality CdS and other II-VI semiconductor nanocrystals in non-coordinating  solvents:tunable reactivity of monomers,Angew.Chem.Int.Ed.,2002,41,2368-2371)。
另一种合成方法是2004年由Cao课题组报道的“非热注射一锅法”(non-hot-injection one-pot)。这种方法是以硫粉为硫源，十四酸镉为镉源，加入没有配位能力的十八烯，纳米晶在240℃的反应瓶中生长。但该方法的合成温度高、反应速度快使得CdS纳米晶的成核和生长过程连在一起，无法细致的研究纳米晶生长情况。由于热注射法是在高温下反应，“非热注射一锅法”中纳米晶的成核和生长过程连在一起，因此这些方法合成得到的大多都是大尺寸的NCs产物，很少能观察到魔尺寸纳米晶类物质。
魔尺寸(Magic-sized)纳米晶类物质(也称魔尺寸纳米簇，MSNCs)，是一类特殊的纳米晶体，是在CdSe、CdTe和ZnSe等制备体系中发现的一系列物质。其粒径极小，在1-3nm之间，仅有几十个原子构成，与常规纳米晶类物质(RNCs)相比，有更尖锐紫外吸收，在紫外吸收图谱和荧光发射图谱上都表现出半峰宽较窄的峰型，半峰宽＜30nm(通常为10～15nm)，且在生长过程中吸收图谱中的峰位不会发生移动，只会因存在数量的变化引起峰高的改变。因MSNCs不易钝化，易于聚集，故很难表征(Emily A.Weiss,et al,The Use of Size-Selective Excitation To Study Photocurrent through Junctions Containing Single-Size and Multi-Size Arrays of Colloidal CdSe Quantum Dots.J.Am.Chem.Soc.2008,130,83-92)。
MSNCs最早是由1984年A.Henglein在水相中合成出了魔尺寸的CdS纳米晶。2007年，Manna等人用十二胺和壬酸溶解CdO后加入SeTOP，在80℃下成功合成了F330(紫外吸收峰位在330nm处)，F360，F384，F406，F431，F447的CdSe MSCs。
2008年，Pan等人报道了由两相合成法合成了紫外吸收峰位在311nm(F311)处的MSCs，并认为这种尺寸单一的物质是常规纳米晶(RNCs)的核，但并没有获得只有F311存在的样品。2009年，Yu在其文章中报道了吸收峰在323nm处(F323)的MSCs，并描述了加入乙醇后，F323会逐渐减少，在309nm和347nm(F309和F347)被认为是RNCs处有吸收增强的趋势，但并未给出其间的关系，且合成的F323量相对较少[Yu,Q.；Liu,C.Study of Magic-Size-Cluster Mediated Formation of CdS Nanocrystals:Properties of the Magic-Size Clusters and Mechanism Implication.J.Phys.Chem.C 2009,113,12766–12771]。2010年，Parak等人在保持80℃的恒温条件下合成得到了由具有若干不同吸收峰的CdS MSCs混合物，并观测到了其可以离散形式从303nm一直生长到387nm。之后Weiss、Robinson、Yang、Yu等人也先后对F303和F387、F311和F322，以及F324等相关发现和研究有过报道。关于对CdTe的MSNCs有关研究，也分别仅有2007年Quanqin Daisy在Nanotechnology报道的F433、2009年Kui Yu等人在Chem.Common.中报道的F427、F500、F550、F600，以及2010年Sandra J.等人在Chem.Mater中报道的F445和F483。总之，关于纯的魔尺寸纳米晶类物质的有效合成方法的报道非常有限。
发明内容
针对上述情况，为充分研究、开发和利用魔尺寸纳米晶类物质(MSNCs)，本发明的目的是提供一种对MSNCs的制备方法。
由于魔尺寸纳米晶类物质(MSNCs)是在研究和制备常规纳米晶类物质(RNCs)的过程中被发现的，因此，本发明的MSNCs制备方法，可采用在与制备RNCs同样的反应体系中进行，即，以含 有元素周期表ⅡB族、ⅢA族和IVA族中至少一种金属元素的成分，以及ⅥA族和ⅤA族中至少一种非金属元素的成分为原料，在制备RNCs同样的反应体系和惰性气体氛围中进行加热反应，其基本过程如下：
1'：加热进行反应；至设定反应温度后的反应时间优选为5-30分钟；
2'：反应后的反应物冷却至低于其反应实际加热温度50％的温度后静置，即可得到所述的相应魔尺寸纳米晶(MSNCs)类物质目标产物。所述MSNCs目标产物的紫外吸收光谱峰的半峰宽通常为10-20nm。
其中，优选的反应加热温度为相应常规纳米晶物质制备反应温度的40％～80％。所述金属元素与非金属元素原料的优选摩尔比是(4～8):1。
根据现有研究的报道，不同组成形式的RNCs制备时所需加热的反应温度不同，例如，目前制备CdS RNCs和CdSe RNCs时的反应加热温度通常可分别为300℃-330℃和240℃-300℃，因此本申请上述制备方法中所述为相应RNCs物质时反应加热温度的40％～80％，对于制备CdTe MSNCs或CdSe MSNCs的反应加热温度一般可＜140℃(例如80℃-120℃)；对于本发明CdS MSNCs时的反应加热温度则一般可＜190℃(如90℃-180℃)。
在上述制备方法中，在所述的反应温度加热反应后，所述冷却至低于其反应实际加热温度50％的温度后静置。一般情况下，所述的冷却和静置温度宜低于30℃或室温，优选的冷却和静置方式，是先冷却至-18～液氮温度后(本发明中简称的“液氮”，均指的是液氮的温度条件)，再升温至≤30℃。试验结果表明，这些优选冷却静置方式条件/方式，都更有利于得到相应的MSNCs产物，和/或更为单一的MSNCs产物。
上述制备方法中，所述的含有元素周期表ⅡB族、ⅢA族和IVA族中至少一种金属元素的成分，以及ⅥA族和ⅤA族中至少一种非金属元素的成分为原料的选择和使用方式，至少可以同样按照目前已有研究和/或报道的RNCs的方式，采用含有一种所述的ⅡB族金属元素的成分和含有一种ⅥA族非金属元素的成分的组合(如CdSe、PbSe、ZnTe、CdS等)；或者是由所述的含有一种ⅢA族金属元素的成分和含有一种所述的ⅤA族非金属元素成分的组合(如InP、GaAs等)；或者是由所述的含有一种ⅣA族金属元素成分和含有一种所述的ⅥA族非金属元素成分；或者是被称为合金纳米晶的为三种或四种成分的组合，其中含有所述的IIB族和/或IIIA族金属元素成分中的一种或两种，以及含有所述的VIA族和/或VA族非金属元素中的一种或两种(如CdTeSe、CdZnSe、CdZnSSe等)。这里有一些我们自己没有做过的，我用蓝色标记出来。
据此，就上述所涉及的原料而言，所述的金属元素成分，可优先选择和采用包括如Cd、Pb、Zn、In、Ga在内的金属有机酸盐或无机酸盐；所述的非金属元素成分，可优先选择和采用的包括如S、Se、Te、P、As在内的单质成分或化合物。
就反应体系的溶剂而言，在采用目前为制备RNCs所允许的各种溶剂基础上，在不排除可采用目前同样已能成功制备出RNCs的多种溶剂体系的前提下，本发明优先推荐采用的是高温油相反应所使用的高沸点有机溶剂，包括如十八烯、油酸或油胺、三辛基膦等在内的有机溶剂，其中更为推荐的反应体系溶剂是分别含有体积比例≤30％十八烯的油酸-十八烯混合溶剂或油胺-十八烯混合溶剂。
进一步的研究显示，在本发明上述制备方法中，包括原料中相应的金属/非金属成分投料比、反应温度、反应体系的溶剂组成、添加剂的使用、以及反应后冷却静置的条件/环境等的调整或改变，可以得到不同稳定程度、形成速度和/或收率的目标MSNCs，以及不同MSNCs间的转化等。
例如，与目前已有较多研究和报道的RNCs相对应，以本发明上述方法制备相应组成的MSNCs目标产物的主要优选条件包括：
制备目标产物CdTe MSNCs时，原料成分中的Cd:Te的摩尔比≥4:1，反应的加热温度为120℃～160℃，反应后的冷却静置温度为室温～液氮温度；
制备目标产物CdS MSNCs时，原料成分的Cd:S摩尔比≥4:1，油酸:镉＝2.2:1，反应的加热温度为120℃-240℃，反应的优选加热温度为190℃，反应后的冷却静置温度为-20℃～80℃；
制备目标产物CdSe MSNCs时，原料成分中的Cd:Se的摩尔比≥4:1，反应的加热温度为120℃～160℃，反应后的冷却静置温度为液氮温度(-196℃)。
上述制备方法中，所述的加热温度反应后，可以将反应物直接冷却至所述温度后静置，根据需要还可在反应物中加入适当的添加剂。此外，也可以将反应后的反应物以体积比1:(100～150)稀释于包括甲苯或环己烷在内的有机溶剂中后冷却和静置。所述的添加剂为丙酮、乙酸乙酯(EA)、醋酸、甲醇、乙醇、氯仿、四氢呋喃(THF)、水、乙胺中的一种；实验显示，优选的添加剂可以为甲醇、乙醇、THF和EA。所述添加剂的加入量一般不超过反应物体积量的1/2，可视具体情况而定。
在采用将反应物稀释于包括甲苯或环己烷在内的有机溶剂中进行冷却和静置时，还可以根据需要使用于稀释反应物的溶剂中含有适当的添加剂成分。所述的添加剂为包括丁胺、辛胺、十二胺、油胺在内的胺类成分，和/或含有包括甲醇、乙醇、异丙醇、己醇、癸醇在内的醇类成分，或四氢呋喃，和/或羧酸类。使用添加剂时，添加剂与稀释溶剂的优选体积比例为添加剂:稀释溶剂＝1:(60～150)。
在所述反应后与反应体系中已形成的RNCs产物分离或不分离后的反应物稀释于甲苯或环己烷中冷却时，除使用单一的甲苯或环己烷外，还可以根据不同情况和需要，进一步使用甲苯或环己烷与适当添加剂成分的混合溶液。所述的添加剂可以为包括丁胺、辛胺、十二胺、油胺在内的胺类成分，和/或含有包括甲醇、乙醇、异丙醇、己醇、癸醇在内的醇类成分，或四氢呋喃。
采用本发明上述的制备方法可以直接制备得到相应较为纯净的MSNCs产物，不仅方便了对MSNCs的深入研究，而且MSNCs与RNCs相比，有更尖锐的紫外吸收，虽目前其光致发光效率(PLQY)、稳定性等距离能直接应用尚有距离，但既然发生了强烈的吸收，通过调节缺陷、配体等表面因素，就有可能实现好的PLQY和稳定性。同时，已表明的MSNCs在一定条件下可以向在室温下更稳定的RNCs转化，从而开辟了制备RNCs的新途径，而低温合成能具有高效的控制性，且操作简单，因而更有利于工业应用，以及对反应机理的进一步深入研究。
以下结合附图所的实施例，以与目前已有较多研究和报道的典型RNCs相对应的MSNCs目标产物为例，对本发明的上述内容再作进一步的详细说明。但不应将此理解为本发明上述主题的范围仅限于以下的实例。在不脱离本发明上述技术思想情况下，根据本领域普通技术知识和惯用手段做出的各种替换或变更，均应包括在本发明的范围内。
附图说明
图1～图6是实施例1对产物检测的图谱。
图7～图9是实施例2对产物检测的图谱。
图10～图13是实施例3对产物检测的图谱。
图14是实施例4的检测图谱。
图15是实施例5的检测图谱。
图16是实施例6对魔尺寸CdTeSe合金纳米晶类物质产物的检测图谱。
图17是对实施例7方法制备的魔尺寸CdTeSe合金纳米晶类物质的检测图谱。
图18是实施例8对魔尺寸CdSeS合金纳米晶类物质制备的检测图谱。
图19是对实施例9魔尺寸ZnSe纳米晶类物质制备中溶剂影响的检测图谱。
具体实施方式
实施例1 魔尺寸CdTe纳米晶类物质(CdTe MSNCs)的制备
实验药品：醋酸镉二水化合物(Cd(Ac)2)、碲粉(Te)、三辛基磷(TOP)、油胺(OLA)均来自Aldrich；甲苯、甲醇、乙醇、异丙醇均来自成都科龙化工试剂厂；己醇、癸醇、十八烯(ODE)、丁胺、辛胺、十二胺来自Aldrich。
检测仪器：
TECHCOMP UV 2310Ⅱ紫外分光光度计为上海天美科技仪器。
Fluoromax-380荧光光谱仪
一、制备：
按照制备常规CdTe量子点(CdTe RNCs)的方式和要求称取0.2345g Cd(Ac)2以及3g的OLA(油胺)加入到三颈圆底烧瓶中，加热到80℃的过程中真空-氮气转换三次以上，然后升温至120℃，并保持在120℃抽真空2h。再称取0.0281g Te以及0.3264g TOP(三辛基膦)加入到另外一个圆底烧瓶中，在室温时抽真空、氮气保护转换三次，抽去体系内的水以及氧气。然后在氮气的保护下升温到300℃，至瓶内溶液变成黄绿色透明液体。待液体降温到室温后向其中加入1.4114g OLA。混合均匀后，将TeTOP加入到120℃的Cd(Ac)2溶液中。在120℃的温度下开始升温反应，并在不同的温度时间取出样品进行检测。
二、反应温度的影响
1.分别在反应体系中Te的浓度为10mmol/kg、30mmol/kg、44mmol/kg条件下进行反应，并分别在120℃保持15min取出1号样品，然后升温反应，并依次在140℃的0min、15min；160℃的0min、15min；180℃的0min、15min分别取出2-7号样品。对各样品测得的吸收光谱结果如图1所示(图中由下至上的各曲线分别对应为1-7号样品的紫外吸收光谱)。
由图1可以看出，Te的浓度为10mmol/kg时，各样品均没有任何现象出现；
Te浓度为30mmol/kg时，1-4号都没有任何现象出现。5号样品出现了443nm(F443)与493nm(F493)吸收峰的MSNCs RNCs。而加热至180℃的6、7号样品中则仅出现了RNCs；
Te浓度为44mmol/kg时，4号样品有F443、F493以及RNCs出现，5号也有F443与F493以及RNCs，数量也较30mmol/kg多。6、7号样品则只有RNCs出现。
2.在上述的反应过程中，分别于不同温度下取样后分散保存于甲苯中，检测其紫外吸收光谱情况是：
140℃时15min的样品在甲苯中保存的现象，在甲苯中静置0h和3h时都没有RNCs出现；6h时有F421出现；在9h和21h的现象中，MSNCs有连续红移生长的过程，最后峰位稳定于F451nm。
在150℃时0min的样品，开始在甲苯中无RNCs出现；3h后出现较多的F421，随后体系中的MSNCs有一个连续生长红移的过程，在21h后停留在F455。
在160℃时15min的样品，开始出现MSNCs以及RNCs。
在180℃的0min时只有RNCs出现。
3.将TOP e分别于i)140℃下加入到Cd-OLA反应物中并在140℃下反应3min；ii)在140℃下反应10min和iii)在室温下加入。然后都储存在30℃恒温环境下。
结果：在室温中加入将TOPTe并在室温下静置，直到7h都没有RNCs出现。在140℃下加入TOPTe，混合后即取样并静置保存在30℃条件下，直到7h后依然没有RNCs出现。在140℃下加入Te TOP后反应10min再取样，取出后未出现RNCs；在30℃的条件下储存3h后出现了F365；在30℃下储存7h后F365红移至F370。
上述实验显示，MSNCs更倾向于在低温下生成，温度升高(例如≥180℃)后则更有利于RNCs的存在。
三、静置保存环境对于室温样品的影响
1.储存方式的影响
上述实验显示，Te浓度为44mmol/kg时MSNCs出现较早，故以Te浓度为44mmol/kg进行实验：
分别取120℃反应的15min；140℃反应的0min、5min、15min；150℃反应的0min；160℃反应的0min、10min、20min为1-8号样品，分别于室温下静置和于甲苯中稀释后静置不同时间，考察静置的环境对MSNCs的影响。结果如图2所示。图中的a是样品直接静置2h后再置于甲苯中保存2h的紫外吸收图谱；b是在直接静置8h后的紫外吸收图谱，c是样品取出后稀释于甲苯中8h的紫外吸收图谱。图中2中的各曲线，由下向上依次分别为对应1-8号样品的紫外吸收图谱。
图2显示，在室温储存中有利于生长体积较小的MSNCs。
2.在甲苯中储存
由于在反应过程中升温至≥160℃后基本只有RNCs存在，故在加热反应过程中，分别取120℃的15min，以及140℃的0min、5min、15min、30min、60min为1-6号的样品，取样后的样品分别于甲苯中稀释，检测其紫外吸收。结果如图3所示。图中的各曲线，由下向上依次分别为1-6号样品的紫外吸收图谱。图中的a是各样品在甲苯中的吸收图谱(1-4号样品的曲线重叠)，b是各样品在甲苯中储存17h后的吸收图谱(1-3号样品的曲线重叠)。
由图3可见，a图中1-4号样品都没有RNCs出现，5、6号样品出现了F437、F487以及RNCs，6号样品中NCs的量都要多于5号；b图中，经过在甲苯中保存17h，1-3号样品仍然没有RNCs的出现，4号样品则出现了RNCs，5、6号样品的F437以及F483的量较a图有减少，RNCs没有明显变化。
3.OTA添加剂量的影响
另将130℃温度下反应5-30min后取样的反应物样品检测紫外吸收，如图4所示，未表现出任何特征吸收。将样品置于液氮中保存。
取出液氮冷冻下的30μL中间体，加入1.5mL octylamine/1.5mL toluene混合溶剂，结果如图5所示：10分钟后得到上图所示的纯的F370(吸收峰位在370nm)MSNCs产物，为半峰宽非常窄的尖锐峰形。如果加入0.5mL octylamine/2.5mL toluene混合溶剂，2h后得到中图所示的纯F417MSNCs产物；如果加入0.1mL octylamine/2.9mL toluene，10分钟后得到下图所示的纯的F448MSNCs产物。各MSNCs吸收主峰左边都有明显的二级吸收峰。
若直接取出液氮下静置的样品，直接将其置于室温中4小时后测试，得到一种特别的F369MSNCs产物。如图6所示。
上述结果表明，通过将冷却后的反应物直接结晶或稀释于有机溶剂中结晶，以及改变稀释溶剂体系的成分和/或组成比例，特别是先于液氮下冷却后，再升温(至≤30℃)，可以由冷却静置后的反应物中分别得到不同结构的单一魔尺寸纳米晶产物。
4.添加剂的影响
(1)胺种类的影响
分别将丁胺、辛胺、十二胺、油胺，以0.5ml胺与2.5ml甲苯的混合溶液用于对样品的静置保存。样品选取的是上述反应过程中于140℃时5min的样品。
在丁胺-甲苯混合液中，样品刚加入分散剂中就有大量的F372出现，达到最大值，并且半峰宽很窄，说明MSNCs的大小均一；5min时F372的量有一些降低但是不明显；20min后F372的量几乎不变，并有F415出现。
在辛胺-甲苯混合液中，样品加入后同样立刻有F372出现，但数量比丁胺溶液的少；20min后F372的数量已经接近丁胺中的数量，同时有F416出现；1h后F372的量达到最高值并超过了丁胺中数量，同时F416也明显的生长出来，此时仍旧是F372占据优势；3h后F372有降低，F416在增长；6h后F416的数量超过F372。
在十二胺-甲苯混合溶液中，加入样品后也立刻有F372出现，数量比辛胺溶液中0min时F372的数量要多；5min后有F416出现，但F372的数量达到最大值；之后F372的数量缓慢减少，F416则在增长；3h后F372与F416的量已相差不大。
在油胺-甲苯混合溶液中，样品加入0min时也立刻出现F372，但数量较少；5min时F372数量达到最大值，并有F416出现；在随后的过程中，体系中的F372在不断减少，F416在增加，3h后F416的数量超过了F372。
上述结果表明，胺类成分的加入可以加速MSNCs的产生。丁胺和辛胺对于F372的出现起到很重要的作用，而丁胺对F372有很好的稳定作用。在有胺存在的环境中，MSNCs中的F416是一个稳定的产物，且碳链越长的胺可使F416越早出现。因此，通过选择不同的胺成分作为添加剂，可选择得到不同形式的MSNCs产物。
(2)醇种类的影响
将上述反应过程中140℃时10min的样品，分别静置保存于同样以体积比为1:149的甲醇、乙醇、 异丙醇、己醇、癸醇与甲苯混合的醇-甲苯溶液中。结果显示，与含胺混合溶液对比，使用胺类成分的添加剂可更倾向于生成尺寸较小的MSNCs，在含醇类添加剂的溶液中则更倾向于生成尺寸较大的MSNCs。
进一步的实验显示，在醇类存在、特别是甲醇、乙醇存在的环境中，无论醇的加入量多少，结果都会是F447首先出现，之后则会缓慢生成稳定的尺寸较大的RQDs
实施例2 魔尺寸CdSe纳米晶类物质(CdSe MSNCs)的制备
实验药品：
1)二水合乙酸镉(Cd(OAc)2·2H2O)：来自Alfa Aesar，纯度为99.999％；
2)硒粉(Se)：来自Alfa Aesar，纯度为99.5％；
3)三辛基膦(TOP)：来自Aldrich Chemistry，纯度为90％；
4)油胺(Oleylamine)：来自Aldrich Chemistry，纯度为70％。
实验仪器：
1)U-4100分光光度计；
2)F-7000FL荧光光谱仪。
一、制备：
按照制备常规CdSe量子点(CdSe RNCs)的方式和要求,将0.1599g(0.6mmol)的二水合醋酸镉和3.000g的油胺加入到25mL的配有直形冷凝管的圆底烧瓶中，在室温下启动搅拌，并用真空泵进行脱气操作，待气泡消失后通入氮气，然后重复脱气操作。如此进行氮气/真空操转换操作三次，最后保持在真空状态。升温到80℃，并在此温度下抽真空一小时。升温过程中二水合醋酸镉逐渐完全溶解得到澄清溶液。此操作完成后再升温到120℃，并在此温度下抽真空一小时。此时溶液呈淡粉红色透明状态。然后通入氮气保持氛围，得到相应的镉前驱体(Cd precursor)。
按照总反应体系为5g和所需的镉/硒/三辛基膦(90％)的比例，将称量后的硒粉、90％三辛基膦和油胺加入到25mL的配有直形冷凝管的圆底烧瓶中，在室温下启动搅拌，并用真空泵进行类似镉源制备中的氮气/真空操转换操作三次。此时溶液呈无色透明状态，然后通入氮气保持氛围，得到相应的硒前驱体。
将硒前驱体快速地一次性转移至镉前驱体中，并记录下加入时间，作为反应起点。反应体系通入氮气保持氛围。分别按照固定于某个反应温度，在一定时间进行取样操作，并进行相应光谱检测的恒温实验；以及在120℃～240℃温度区间内，分别于120℃反应一定时间后取样，再进行程序升温至140℃后取样，并依次升温至240℃反应后取样的升温实验。
将取出的各样品用甲苯溶液稀释后，用紫外分光光度计进行相应检测表征。
二、反应物中不同Cd/Se摩尔投料比例在不同反应温度条件下对结果的影响
1.上述反应中，在保持硒前驱体浓度一定，改变Cd/Se投料摩尔比例后发现，低Cd/Se比的条件可以在更短时间内生成更多种类的CdSe MSNCs。结果如图7所示。图中的a和b分别是Cd/Se摩尔比为1/1和4/1投料的各样品的紫外吸收图谱。图中的各曲线，由下向上依次分别为在温度120℃的15min、140℃的15min和0min、160℃的15min和0min、180℃的15min和0min、200℃的 15min不同取样的1-8号样品的紫外吸收图谱(图a中1、2号样品的曲线重叠，3、4号曲线部分重叠；图b中的1-4号样品的曲线重叠)。
由图7可以看出，当反应温度逐渐升高到一定程度(＞180℃)，产物中不再出现CdSe MSNCs，而以CdSe RNCs为主要产物。而120℃～160℃的较低反应温度则可使MSCs的生成更早，量也更多。
2.将上述15min/160℃的5号样品和0min/180℃的6号样品，经室温下15小时置后，再分散到甲苯溶液中进行检测，结果显示，在其中RNCs的含量基本保持不变的时候，F415MSNCs则有了较明显的生长，说明MSNCs的生长和形成与CdSe RNCs的生长无关，二者在晶体生长阶段是相互独立的。
三、静置保存环境的影响
1.添加剂的影响
将上述反应中160℃的0min的样品，在15℃分别静置于由1ml OTA+2ml Tol，以及1.5ml OTA+2.5ml Tol两种不同比例的辛胺-甲苯混合溶液中，紫外吸收光谱的检测结果如图8所示。图中的a、b分别为1ml OTA+2ml Tol和1.5ml OTA+1.5ml Tol两种不同比例的辛胺-甲苯混合溶液。图中由下向上的各曲线分为静置保存0min、6h和20h的紫外吸收图谱。可以看出，提高辛胺-甲苯混合溶液中辛胺的浓度，可有利于提高MSNCs的生成量。
六、冷却静置温度的影响
将取样于200℃-15min的反应物样品分别在液氮、-20℃、4℃、30℃和60℃中直接静置保存7天，检测的紫外吸收图谱如图9所示。图a中由下向上的各曲线分别为保存于液氮、-20℃和4℃条件下的样品，图b中由下向上的各曲线分别为合成温度及保存于60℃和30℃条件下的样品。
图9结果显示，取样于200℃的15min样品冷却静置后，可以得到MSNCs和RNCs，但在较低温度下(＜4℃)下静置保存，可更利于F311，F348MSNCs的生长，而温度较高时(＞30℃)，则更利于具有更大尺寸的RNCs生长。
实施例3 魔尺寸CdS纳米晶类物质(CdS MSNCs)的制备
实验药品：
氧化镉(≥99.99％)，油酸(≥90％)，十八烯(≥90％)，来自Aldrich；硫粉(≥99.5％)，环己烷(≥99.5％)，甲苯，异丙醇(≥99.7％)，甲醇(≥99.5％)，来自成都科龙化工试剂厂。
实验仪器：
TECHCOMP UV 2310Ⅱ紫外分光广度计(上海天美科技仪器)；Fluoromax-380荧光光谱仪；X'Pert Pro MPD X射线衍射仪(XRD)；Tecnai G2F20S-TWIN场发射透射电子显微镜(TEM)；Zetasizer Nano仪器。
一、制备：
按照制备常规CdS量子点(CdS RNCs)的方式和要求,以摩尔配比为Cd:OA:S＝4:8.8:1的方式准备原料。
首先制备Cd:OA＝4:8.8的油酸镉储备液。将13.2mmol油酸(OA)和6mmol氧化镉(CdO)加入到 5g十八烯(ODE)中，在40℃脱气脱氧，等到气泡消失后升温至120℃，保持真空加热1h，换N2气氛升温至230℃，在230℃保持10分钟，再升温至250℃，保持10分钟(溶液澄清透明)，降温至120℃，保持真空30分钟，再降温至80℃，换N2降至室温保存待用。
纳米晶的制备：将6mmol的上述油酸镉和1.5mmol硫粉加入到适量的十八烯中(使体系总量为5g)，在40℃保持真空30分钟，升温至120℃，保持真空30分钟，换N2气氛计时取样，加热升温的温度范围为120℃～240℃，保持一定的时间，将样品在室温静置一段时间，即得到F311和F322的CdS MSNCs。
样品的纯化：在样品与过量的异丙醇(例如v/v比例约为100:1)的条件下，向异丙醇中逐滴加入待纯化的F311或F322样品。加入时用玻璃棒充分搅拌，可以观测到有固体沉出(固体太大时可超声粉碎约半分钟)，离心，弃去上清液，得到固体(如需要可以同样方式再洗涤一遍)，迅速抽真空除去残余溶剂(异丙醇)。将纯化后的样品再分散到甲苯或环己烷中，可以得到紫外吸收峰位不变的CdS MSNCs，如图10所示。图中：a为样品分散于甲苯中CdS MSNCs F322的吸收峰；b为样品分散于环己烷中CdS MSNCs F311的吸收峰的紫外吸收图谱。图中由下向上曲线分别为纯化后和纯化前的样品吸收峰。表明经纯化处理，290nm附近的物质及330nm附近更大的RNCs都已基本除去。
图11显示了纯化后得到的单一纳米簇F11和F322产物的高分辨电镜(TEM)和XRD的测试结果。图中：a1和a2分别为F322产物的TEM图(分辨率分别为100nm和2nm)，a3为XRD图；b1和b2分别为F311产物的TEM图(分辨率分别为50nm和20nm)，b3为XRD图。a1和b1图中的小图分别为对应产物的紫外吸收图谱。
二、反应温度的影响
1.取0.9393g(约6mmol)油酸镉和0.0048g(约1.5mmol)硫粉加入到约4g十八烯中(保持体系总量为5g，浓度[S]＝30mmol/kg)，将混好反应物的三口瓶放在油浴锅中加热、搅拌，连接双排管，先在40℃抽真空，真空下升温至120℃，再保持真空30分钟，换N2后，依120℃的15min、140℃的5min、160℃的15min、180℃的15min、200℃的15min、220℃的15min和240℃的15min梯度升温并计时取样(1～7号样品)，各样品分别与取样后和室温静置1天后检测其紫外吸收图谱，结果如图12所示。图中：a为取样后立即检测的结果，b为室温静置1天后检测的结果；图中各曲线由下至上分别为1～7号样品的紫外吸收图谱。
由图12可以看出，在高温反应过程中，体系在200℃以后，即开始长出吸收350～450nm之间的RNCs产物(250～300nm之间的吸收代表未反应的前驱物)，并没有出现CdS纳米簇。在室温静置一天后发现180℃反应15min取样的样品中有大量MSNCs生成，而且无论体系中是否有RNCs的存在，原本没有明显紫外吸收峰的样品在低温下静置一定时间后，体系中都会有较小的单一尺寸的MSNCs出现，而此时的RNCs的位置与数量则保持不变。表明了MSNCs与RNCs的生成是平行独立进行的。而MSNCs出现在更低的温度，并且可以在室温下生长，表明MSNCs的活化能比RNCs的低。
2.以镉与硫成分摩尔比例为12:1的原料和STOP(三辛基膦硫)用作硫前驱物，以及镉与硫摩尔比为1:1的原料和SODE(十八烯硫)用作硫前驱物，以上述同样方法进行制备。样品用甲苯分散，检测 紫外吸收光谱。取样温度范围为120-240℃。将每个取出的样品立刻测试，然后于15℃分别静置1天、7天、10天。结果清楚显示，反应温度达到180℃以后的样品，低温静置后会由一个完全没有吸收的样品生长出MSNCs F322。而且，在STOP和SODE作硫前驱物的高温反应后再低温静置不同时间下生长，由于STOP的活性比SODE高，更易生成RNCs，而MSNCs则以在相对低的温度为好。故后续实验以活性更低的SODE作为硫的前驱体，并选择范围为180℃～200℃的恒温下反应。
三、冷却静置温度的影响
以摩尔比为Cd:S＝4:1投料比加热反应，取一个高温反应后无吸收峰的样品，分别观察其在表1所示的5种温度下检测的紫外吸收图谱，结果如图13所示。图中：a的取样温度分别为200℃、220℃和240℃，b-e的取样温度均为190℃；a-c的样品均为被稀释在环己烷中，d-e的样品均为被稀释在甲苯中。
表1不同温度下静置后的产物
Figure PCTCN2016090940-appb-000001
结果显示，在较低的温度下(≤4℃)，反应物中将生成MSNCs F311；在较高的温度下(30℃、80℃)可生成MSNCs F323，但在80℃下，F323并不能稳定存在，最终会分解消失；在高温(≥180℃)下长时间反应，将主要生成RNCs产物。从而表明，样品的保存温度越低，越倾向于生成F311的产物；当储存温度升高到30℃或以上时，则样品中更易生成F322产物，因此可以通过调节和控制冷却静置的温度，分别得到不同形式的MSNCs产物。
四、添加剂的影响
1.以丙酮、乙酸乙酯(EA)、醋酸、甲醇、乙醇、氯仿、四氢呋喃(THF)、水、乙胺等作为添加剂，将从反应中直接取出(尚含有未反应的油酸镉、ODE溶剂等)的200μl样品+100μl添加剂的比例，分别在4℃、60℃下放在样品瓶中储存后检测紫外吸收光谱。经初试后，选择有明显作用的添加剂甲醇、THF和EA，分别将样品在含有添加剂的混合物中于4℃和60℃下保存1h～3天。结果显示，在4℃下储存的样品中，无添加剂的对照组均生成了稳定的F323，而甲醇、THF添加剂则只得到纯的F311产物。
2.以甲醇、THF为添加剂，将高温条件下制备的无紫外吸收峰的样品分别分散到3ml甲苯+20μl甲醇、3ml甲苯+50μl THF的混合溶剂中，连续检测紫外吸收光谱。结果显示，无添加剂溶液的对照组与含添加剂溶液组的最终结果一致，均生成F311的MSNCs产物(F311、F306、F308)，但生长速率却有显著区别：无添加剂的对照组在519-1130min才开始长出部分MSNCs，而含添加剂的组在0min(刚添加时)就有生长现象，速率提高了1000倍左右。表明了甲醇、THF添加剂虽未改变均生成F311产物的生长路径，但极大地提高了生长速率。
将甲醇添加剂的含量由5μl提高至100μl后，实验显示可以进一步增加反应速率(生长图的斜率越来越大)，而对于MSNCs的生成量则含50μl的甲醇是最宜添加量。THF添加后，开始时可有明显的促生长作用，但随时间进行又会使MSNCs分解消失，例如将50μl THF添加组产物的光谱分为0-8min 和8-1872min两个部分，可以清晰看出，MSNCs产物在8min内可迅速生长，但在8-1872min内则会逐渐消失至无，显示出其可具有双向作用。由此表明，根据情况和需要，通过选择适当的添加剂，可以有效快速获得MSNCs，和/或选择得到不同的MSNCs产物。
3.添加剂对不同MSNCs间，以及MSNCs向RNCs转化的影响
在上述实验的基础上，进一步将190℃的0min和190℃的5min取样的样品分别置于甲苯与甲醇、异丙醇添加剂的混合溶液中，分别实现了F323-F311间，F323-F308间，F323-F343间和F311-F308间的转换。
此外，由于室温下RNCs产物比MSNCs更加稳定，因此RNCs间MSNCs的转换应是必然的。虽然将CdS MSNCs直接在室温静置较长时间后(如2个月后)才出现有RNCs，但一些含添加剂的混合溶液可以帮助MSNCs加速向RNCs转换。例如，实验已显示，在0.2ml OLA-2.775ml Tol混合溶液中，F309MSNCs经5天即显示出向RNCs转化；F307MSNCs在1ml HAc+1.975ml Tol混合溶液中，4天即显示出向RNCs的转化；F310MSNCs在1ml二氧六环+1.975ml Tol混合溶液中，2天即显示出向RNCs转化；F308/F311MSNCs在0.05ml甲醇+3ml Tol混合溶液中，2天即显示出向RNCs转化。
实施例4 以CdTe F369MSNCs为原料制备CdTe RNCs
采用实施例1的方式，将得到的F369CdTe MSNCs的纯样品200μL分散到1mL hexane中，离心，留下下层固体，再用3mL toluene分散，静置。从0到60分钟的静置过程中，溶液的颜色开始慢慢变黄，F369开始慢慢减少，同时RNCs也逐渐生长出来。其过程的紫外吸收检测图谱如图14所示。
实施例5 以CdS MSNCs为原料制备CdS RNCs
采用实施例3的方式，在CdS体系中加热至190℃-5分钟取样品的反应物保存于-20℃环境中1天后，将得到的纯净F323CdS MSNCs样品～0.02g分散于3mL甲苯溶液中添加约50μL甲醇于溶液，置室温的环境中保存。随时间推移，CdS MSNCs逐渐减少，CdS RNCs逐渐生长出来。其过程的紫外吸收检测图谱如图15所示。
实施例6 魔尺寸CdTeSe纳米晶类物质(CdTeSe MSNCs)的制备
实验药品：
醋酸镉二水化合物(Cd(Ac)2)、碲粉(Te)、硒粉(Se)三辛基磷(TOP)、油胺(OLA)、辛胺(OTA)，均来自Aldrich；
甲苯、甲醇、乙醇、异丙醇均来自成都科龙化工试剂厂。
检测仪器：
日立U-2910紫外分光光度计
一、制备：
1.中间体的制备：
称取0.160g Cd(Ac)2以及4.58g的OLA(油胺)加入到三颈圆底烧瓶中，加热到80℃的过程中 真空-氮气转换三次以上，然后升温至120℃，并保持在120℃抽真空2h。同样的条件下制备出两份Cd前驱体分别升温至130℃和140℃。
称取0.019g Te粉以及0.247g TOP(三辛基膦)加入到另外的圆底烧瓶中，在室温时抽真空、氮气保护转换三次，抽去体系内的水以及氧气。然后在氮气的保护下升温到300℃，至瓶内溶液变成黄绿色透明液体TOPTe。待液体降温后，将TeTOP加入到其中一组130℃的Cd(Ac)2溶液中。并保持30分钟。制备出Te前驱体。
称取0.012g Se粉以及0.247g TOP(三辛基膦)加入到另外的圆底烧瓶中，在室温时抽真空、氮气保护转换三次，抽去体系内的水以及氧气。吹风机微热，使Se粉溶解。将SeTOP加入到其中一组140℃的Cd(Ac)2溶液中。并保持30分钟。制备出Se前驱体。
2.CdTeSe MSNCs的制备：
将Te和Se前驱体降温后，直接混合并保持在25℃下24h。取30μL样品分散在3mL甲苯中，用紫外分光光度计进行测量即可观察到CdTeSe MSNCs紫外吸收峰在398nm处的F398，如图16所示。
实施例7
以实施例6的同样方式制备得到Te和Se前驱体。将Te和Se前驱体降温后，直接混合并保持在25℃下24h。再取30μL样品分散在2.3mL甲苯中保持20h。未出现紫外吸收峰，表明没有晶体生成的中间体，如图17a所示。再将0.7mL辛胺(OTA)加入此溶液中，并立即进行原位紫外吸收的监测。可以观察到立即有CdTe MSNCs F370的生成，随后CdTe MSNCs F370慢慢消失，CdTeSe MSNCs F398慢慢生成，80分钟后得到纯净的CdTeSe MSNCs F398。如图17b所示。
实施例8 魔尺寸CdSeS纳米晶类物质(CdSeS MSNCs)的制备
实验药品：
氧化镉(CdO)、硫粉(S)、硒粉(Se)三辛基磷(TOP)、十八烯(ODE)、油酸(OA)辛胺(OTA)，均来自Aldrich；
甲苯、甲醇、乙醇、异丙醇均来自成都科龙化工试剂厂。
检测仪器：
日立U-2910紫外分光光度计
一、制备：
1.CdSe前驱物的制备：0.154g(1.20mmol)CdO，0.746g(2.64mmol)OA和3.832g ODE置于50mL三口反应瓶中，在室温下抽换气30min直到没有气泡产生。真空下升温到120℃转N2继续升温至230℃，在230℃下保持1h直至溶液澄清。将澄清溶液降温至120℃抽气30min，降温至60℃。0.024g(0.30mmol)Se粉和0.245g(1.32mmol)TOP在室温下混合搅拌至溶液澄清，在60℃注入Cd(OA)2溶液保持30min，取样。
CdS前驱物的制备：0.077g(0.60mmol)CdO，0.373g(1.32mmol)OA和4.423g ODE置于50mL三口 反应瓶中，在室温下抽换气30min直到没有气泡产生。真空下升温到120℃转N2继续升温至230℃，在230℃下保持1h直至溶液澄清。将澄清溶液降温至120℃抽气30min，降温至90℃。0.005g(0.15mmol)S粉和0.122g(0.33mmol)TOP在室温下混合搅拌至溶液澄清，在90℃注入Cd(OA)2溶液升温至160℃保持15min，取样。
2.CdSeS MSCs的制备：将制备好的CdSe前驱物和CdS前驱物按体积比600μL:200μL、200μL:200μL、200μL:600μL进行室温混合。随静置时间取样，将25μL样品分散扫3mL OTA/甲苯的混合溶剂中，并利用原位紫外吸收光谱来检测其生长。
将样品分散到1mL OTA/2mL TOL的混合溶剂中，立即进行原位紫外吸收的测试，测试时间分别是(1)0min，(2)15min，(3)45min，(4)2h，(5)5h，(6)10h，(7)23h，(8)50h和(9)72h。混合样品中当CdSe过量时(体积比600μL:200μL)，在388nm出现了一个吸收峰，随分散时间该吸收峰逐渐变尖锐且峰位固定(如图19a所示)；等量混合时(200μL:200μL)，吸收峰蓝移到379nm(如图19b所示)；CdS过量时(200μL:600μL)，吸收峰继续蓝移到在369nm(如图19c所示)。由此表明，少量OTA的加入能够诱导三元CdSeS MSCs的生成，同时通过增加CdSe的混合量能实现其吸收峰位的红移，证实了其为合金型的物质。
实施例9 魔尺寸ZnSe纳米晶类物质(ZnSe MSNCs)的制备
实验药品：
氧化锌(ZnO)、硒粉(Se)、三辛基磷(TOP)、二苯基膦(DPP)油酸(OLA)、辛胺(OTA)，十八烯(ODE)均来自Aldrich；
甲苯、环己烷、甲醇、乙醇、异丙醇均来自成都科龙化工试剂厂。
检测仪器：
日立U-2910紫外分光光度计
一、制备：
1.前驱体的制备：
将0.492g ZnO，3.739g OA，5g ODE置于三口瓶中，在室温进行真空-氮气转换三次以上，升温至100℃抽气至没有气泡产生，转换氮气气氛，升温至300℃至氧化锌固体完全溶解。生成浅黄色透明溶液，降温至110℃抽气1h后冷却至室温。转入手套箱中保存。
将0.428g Se粉，2.079g TOP，0.827g ODE置于三口瓶中，在室温进行真空-氮气转换三次以上。室温抽气下搅拌1h，硒粉充分溶解(仍有少量残留)。
2.ZnSe纳米晶类物质的制备：
取Zn前驱体2.2mL溶于3.726mL ODE中，在室温进行真空-氮气转换三次以上，升温至100℃抽气1h，降温到80℃。在0.215mL TOPSe中加入0.052mL DPP，然后加入到Zn前驱体中，采取80℃/15min，100℃/15min，120℃/15min，140℃/15min，160℃/15min，180℃/15min的升温程序。最后取180℃/15min的样品作为最佳实验样品。
取出15μL中间体样品于3mL环己烷中进行紫外吸收测试，表现出无晶体特征吸收峰，如图19a 所示。但是将15μL中间体分散到2mL OTA和1mL环己烷的混合溶剂中，则立即有ZnSe MSNCs F299生成，如图19b所示。表明了OTA和环己烷的混合溶剂可诱导中间体反应生成ZnSe MSNCs F299。

Claims (9)

  1. 魔尺寸纳米晶类物质的制备方法，以含有元素周期表ⅡB族、ⅢA族和IVA族中至少一种金属元素的成分，以及ⅥA族和ⅤA族中至少一种非金属元素的成分为原料，在制备常规纳米晶类物质的反应体系和惰性气体氛围中加热反应，其特征是按下述方式进行：
    1'：加热进行反应；优选的反应加热温度为相应常规纳米晶物质制备反应温度的40％～80％；优选的反应时间为5-30分钟；所述金属元素与非金属元素的优选摩尔比为(4～8):1；
    2'：反应后的反应物冷却至低于其反应实际加热温度50％的温度后静置，得到所述的魔尺寸纳米晶类物质目标产物。
  2. 如权利要求1所述的制备方法，其特征是所述的原料为含有一种所述的ⅡB族金属元素成分和含有一种ⅥA族非金属元素成分；或者是由所述的含有一种ⅢA族金属元素成分和含有一种所述的ⅤA族非金属元素成分；或者是由所述的含有一种ⅣA族金属元素成分和含有一种所述的ⅥA族非金属元素成分；或者是为三种或四种成分，其中含有所述的ⅡB族和/或ⅢA族金属元素成分中的一种或两种，以及含有所述的ⅥA族和ⅤA族非金属元素中的一种和/或两种。
  3. 如权利要求1所述的制备方法，其特征是所述原料中的金属元素成分为包括Cd、Pb、Zn、In、Ga在内的金属元素的有机酸盐或无机酸盐；所述原料中的非金属元素成分为包括S、Se、Te、P、As在内的单质成分或化合物成分。
  4. 如权利要求1所述的制备方法，其特征是反应体系的溶剂为包括十八烯、三辛基膦、油酸或油胺在内的有机溶剂，优选的反应体系溶剂为含有十八烯的体积比例≤30％的油酸-十八烯混合溶剂，或者含有十八烯的体积比例≤30％的油胺-十八烯混合溶剂。
  5. 如权利要求1所述的制备方法，其特征是所得到的魔尺寸纳米晶类物质目标产物的紫外吸收光谱峰的半峰宽为10-20 nm，且该吸收峰的波长几乎不随反应进行而发生改变。
  6. 如权利要求1所述的制备方法，其特征是制备目标产物CdTe时，原料成分中的Cd:Te的摩尔比≥4:1，反应的加热温度为120℃～160℃，反应后的冷却静置温度为室温～液氮温度；
    制备目标产物CdS时，原料成分的镉:硫摩尔比≥4:1，油酸:镉＝2.2:1，反应的加热温度为120℃-240℃，反应的优选加热温度为190℃，反应后的冷却静置温度为-20℃～80℃；
    制备目标产物CdSe时，原料成分中的Cd:Se的摩尔比≥4:1，反应的加热温度为120℃～160℃，反应后的冷却静置温度为液氮温度～60℃。
  7. 如权利要求1至6之一所述的制备方法，其特征是加热至所述的反应温度反应后，将反应物冷却至30℃至液氮温度后静置；优选的冷却和静置方式是先冷却至-18℃～液氮温度，然后再升温至≤30℃的温度下静置。
  8. 如权利要求1至7之一所述的制备方法，其特征是在所述的加热温度反应后，将反应物直接冷却静置，需要时可在反应物中加入添加剂；或者是将反应物以体积比1:(100～150)稀释于包括甲苯或环己烷在内的有机溶剂中后冷却和静置；所述的添加剂为丙酮、乙酸乙酯、醋酸、甲醇、乙醇、氯仿、四氢呋喃、水、乙胺中的一种，优选的添加剂为甲醇、乙醇、THF和EA；所述添加剂的加入量不超 过反应物体积量的1/2。
  9. 如权利要求1至7之一所述的制备方法，其特征是加热至所述的反应温度反应后，将反应物稀释于包括甲苯或环己烷在内的有机溶剂中进行冷却和静置，且稀释溶剂中还含有添加剂成分，所述的添加剂为包括丁胺、辛胺、十二胺、油胺在内的胺类成分，和/或含有包括甲醇、乙醇、异丙醇、己醇、癸醇在内的醇类成分，或四氢呋喃，和/或羧酸类；添加剂与稀释溶剂的优选体积比例为添加剂:稀释溶剂＝1:(60～150)。
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