CN101585516A - The preparation method of a kind of CdSe and CdSe-ZnSe core-shell quanta dots - Google Patents

Abstract

The present invention discloses the preparation method of a kind of CdSe and CdSe-ZnSe core-shell quanta dots, and one, the Cd source is added in organic coating and the cosolvent, heating makes it dissolving, obtains the Cd precursor solution after the cooling; Two, the Se powder is added in tri octyl phosphine and the cosolvent, at room temperature disperse to make it to dissolve by ultrasonic, obtain the Se precursor solution; Three, Cd precursor solution and Se precursor solution are mixed, mixing solutions is sealed, heating is reacted it at a certain temperature, and cooling promptly obtains CdSe quantum dot original solution then; Four, the Zn source is added in organic coating and the cosolvent, be heated to 100-140 ℃ and make it dissolving, obtain the Zn precursor solution after the cooling; Five, Zn precursor solution, Se precursor solution and CdSe quantum dot original solution are mixed, mixing solutions is sealed, heating is reacted it at a certain temperature, and cooling promptly obtains the CdSe-ZnSe core-shell quanta dots then.

Description

The preparation method of a kind of CdSe and CdSe-ZnSe core-shell quanta dots

Technical field

The present invention relates to the preparation method of a kind of CdSe and CdSe-ZnSe core-shell quanta dots

Background technology

Quantum dot (Quantum Dots, QDs) be often referred to particle diameter less than or near the semiconductor nano crystal grain of exciton Bohr radius, because quantum confinement, dimensional effect and surface effects etc., fluorescence property that quantum dot has many uniquenesses is as the size-dependent of emission wavelength, the excitation wavelength scope is wide, Stokes shift is big etc., compare with organic fluorescent dye that also to have fluorescence intensity strong, highly sensitive and photobleaching speed waits characteristics slowly, thereby fluorescence quantum is at biological fluorescent labelling, biosensor, photodiode fields such as (LED) has broad application prospects.Regulate the size of CdSe quantum dot, its emission wavelength can cover most of visible region (450-650nm), thereby obtains extensive studies.Coat the surface of big shell material (as ZnSe, ZnS, CdS etc.) the passivation quantum dot of energy gap on CdSe quantum dot surface, can improve the optical properties such as stability, fluorescence intensity of quantum dot, help its further application.

Through the literature search of prior art is found, most employing of high quality (quantum yield is greater than the 30%) quanta point material of preparation CdSe and nucleocapsid structure be that the high temperature injection method is synthetic.(J.Phy.Chem.B 1997,101,9463-9475), at first utilize dimethyl cadmium (Me for people such as Bawendi report₂Cd) do the cadmium source, under 350 ℃ of left and right sides high temperature, in trioctyl phosphine oxide (TOPO), can synthesize high-quality CdSe quantum dot, be transferred in TOPO and the TOP solution after then CdSe quantum dot centrifugal classification being separated, utilize zinc ethyl (Et₂Zn) and hexamethyl Thiosilicane ((TMS)₂S) dropwise join reaction system for presoma, obtain the CdSe/ZnS nuclear shell structure quantum point at last.The organometallics that this method is used, toxicity is big, costs an arm and a leg, and character is active, and is inflammable and explosive, need carry out under the condition of anhydrous and oxygen-free; The TOPO that uses as solvent also costs an arm and a leg simultaneously, is unfavorable for extensive synthetic.

People such as Peng Xiaogang report (J.Am.Chem.Soc.2003,125,12567-12575), at first utilize octadecylene hydrocarbon (ODE) to make the reaction medium solvent, Cadmium oxide (CdO) is the cadmium source, reacts under the temperature about 280, obtain the CdSe quantum dot, then monomer extraction not reacted in the quantum dot solution is removed, utilize absorption of continuous ionic layer and reaction (SILAR) alternately to inject Cd presoma and sulphur presoma, thereby prepare the quantum dot of CdSe/CdS nucleocapsid structure.This method has been avoided the use organometallics, adopts metastable metal oxide as raw material, has reduced cost, the danger of reaction and has improved the operability of test.But still need earlier quantum dot to be carried out purifying when coating shell structure, this process is consuming time longer, and the fluorescence property of quantum dot is reduced, and what coat the shell employing simultaneously is multistep injection reaction presoma, and complex operation step is unfavorable for suitability for industrialized production.

Summary of the invention

The invention provides the preparation method of a kind of CdSe and CdSe-ZnSe core-shell quanta dots, not only operating process is simple, economical and reliable for it, is easy to scale operation, and the CdSe and the stable performance of CdSe-ZnSe core-shell quanta dots of preparation.

The present invention has adopted following technical scheme: the preparation method of a kind of CdSe and CdSe-ZnSe core-shell quanta dots, it comprises following concrete steps:step 1, preparation Cd precursor solution: the Cd source is added in organic coating and the cosolvent, and heating makes it dissolving, obtains the Cd precursor solution after the cooling; Step 2, preparation Se precursor solution: the Se powder is added in tri octyl phosphine and the cosolvent, at room temperature disperse to make it to dissolve, obtain the Se precursor solution by ultrasonic; Step 3 is mixed Cd precursor solution and Se precursor solution, and mixing solutions is sealed, and heating is reacted it at a certain temperature, and cooling promptly obtains CdSe quantum dot original solution then; Step 4, preparation Zn precursor solution: the Zn source is added in organic coating and the cosolvent, be heated to 100-140 ℃ and make it dissolving, obtain the Zn precursor solution after the cooling; Step 5 is mixed Zn precursor solution, Se precursor solution and CdSe quantum dot original solution, and mixing solutions is sealed, and heating is reacted it at a certain temperature, and cooling promptly obtains the CdSe-ZnSe core-shell quanta dots then.

The mol ratio of Cd source and organic coating is 1 in thestep 1 of the present invention: 2-1: between 8, the concentration of Cd ion in organic coating and cosolvent mixed solution is 0.01-1.0mol/L, the Cd source is CdO, cadmium acetate, cadmium oxalate, TETRADECONIC ACID cadmium or cadmium stearate, the temperature of heating is for arriving 80-100 ℃, and the refrigerative temperature is a room temperature.The mol ratio of Se powder and tri octyl phosphine (TOP) is 1 in the step 2 of the present invention: 2-1: between 8, Se trioctylphosphine see and the cosolvent mixed solution in concentration be 0.01-1.0mol/L.The mol ratio of Cd precursor solution and Se precursor solution is 1 in the step 3 of the present invention: 10-2: between 1, and logical N in mixing solutions₂Sealed in 10 minutes, the temperature 180-220 of heating ℃, the time of heating is 0.5 hour-2 hours, and the refrigerative temperature is a room temperature.Zn source in the step 4 of the present invention is in ZnO, zinc acetate, zinc oxalate, Zinc Undecylenate, TETRADECONIC ACID zinc or the Zinic stearas, the mol ratio of Zn precursor solution and organic coating is 1: 2-1: between 8, the concentration of Zn ion in organic coating and cosolvent mixed solution is 0.01-1.0mol/L, and the refrigerative temperature is a room temperature.The mol ratio of Zn precursor solution and Se precursor solution is 1 in the step 5 of the present invention: 1-3: between 1, the mol ratio of CdSe quantum dot and Zn precursor solution is 1: 100-1: between 300, mixing solutions is adopted logical N₂Sealed in 10 minutes, the temperature 180-220 of heating ℃, the time of heating is 0.5 hour-2 hours, and the refrigerative temperature is a room temperature.Organic coating of the present invention is one or more the combination in oleic acid, stearic acid, erucic acid, trioctyl phosphine oxide, lauryl amine, hexadecylamine and the octadecylamine.Described cosolvent is in toluene, chloroform, sweet oil, vaccenic acid hydrocarbon, whiteruss or the thermal oil.CdSe and CdSe-ZnSe core-shell quanta dots in the step 5 of the present invention, its fluorescence emission peak scope is between the 500-600nm, the halfwidth of fluorescence emission peak is between the 25-40nm.

The present invention has following beneficial effect: the present invention mixes stable Cd precursor and Se precursor solution, reacting by heating obtains the thick solution of CdSe quantum dot, the thick solution of CdSe quantum dot need not separate, directly in the thick solution of CdSe quantum dot, add stable Zn precursor and Se precursor solution, reacting by heating obtains the CdSe/ZnSe core-shell quanta dots, this method is not only simple, consuming time shorter, the process of preparation is more safe and reliable, be easy to mass preparation, and the CdSe and the stable performance of CdSe-ZnSe core-shell quanta dots of preparation, its fluorescent effect is relatively good.

Description of drawings

Fig. 1 is the CdSe for preparing in the embodiment of the invention one and the normalized fluorescence emission spectrum and the uv-visible absorption spectra of CdSe/ZnSe core-shell quanta dots

Fig. 2 is the CdSe for preparing in the embodiment of the invention one and the fluorescence emission spectrum of CdSe/ZnSe core-shell quanta dots

Embodiment

The present invention is the preparation method of a kind of CdSe and CdSe-ZnSe core-shell quanta dots, it is characterized in that, comprise following concrete steps:step 1, preparation Cd precursor solution: the Cd source is added in organic coating and the cosolvent, the mol ratio of Cd source and organic coating is 1: 2-1: between 8, the concentration of Cd ion in organic coating and cosolvent mixed solution is 0.01-1.0mol/L, the Cd source is CdO, cadmium acetate, cadmium oxalate, TETRADECONIC ACID cadmium or cadmium stearate, be heated to 80-100 ℃ and make it dissolving, obtain the Cd precursor solution behind the cool to room temperature; Step 2, preparation Se precursor solution: the Se powder is added in tri octyl phosphine and the cosolvent, the mol ratio of Se powder and tri octyl phosphine (TOP) is 1: 2-1: between 8, Se trioctylphosphine see and the cosolvent mixed solution in concentration be 0.01-1.0mol/L, at room temperature disperse to make it to dissolve, obtain the Se precursor solution by ultrasonic; Step 3 is mixed Cd precursor solution and Se precursor solution, and the mol ratio of Cd precursor solution and Se precursor solution is 1: 10-2: between 1, to the logical N of mixing solutions₂Sealed in 10 minutes, and be heated to 180-220 ℃ and make its reaction, the time of heating is 0.5 hour-2 hours, and cool to room temperature promptly obtains CdSe quantum dot original solution then; Step 4, preparation Zn precursor solution: the Zn source is added in organic coating and the cosolvent, the Zn source is in ZnO, zinc acetate, zinc oxalate, Zinc Undecylenate, TETRADECONIC ACID zinc or the Zinic stearas, the mol ratio of Zn precursor solution and organic coating is 1: 2-1: between 8, the concentration of Zn ion in organic coating and cosolvent mixed solution is 0.01-1.0mol/L, be heated to 100-140 ℃ and make it dissolving, cool to room temperature obtains the Zn precursor solution; Step 5, Zn precursor solution, Se precursor solution and CdSe quantum dot original solution are mixed, the mol ratio of Zn precursor solution and Se precursor solution is 1: 1-3: between 1, the mol ratio of CdSe quantum dot and Zn precursor solution is 1: 100-1: between 300, to the logical N of mixing solutions₂Sealed in 10 minutes, be heated to 180-220 ℃ and make its reaction, the time of heating is 0.5 hour-2 hours, cool to room temperature then, promptly obtain the CdSe-ZnSe core-shell quanta dots, CdSe and CdSe-ZnSe core-shell quanta dots, its fluorescence emission peak scope is between the 500-600nm, the halfwidth of fluorescence emission peak is between the 25-40nm.The present invention is one or more combination in oleic acid, stearic acid, erucic acid, trioctyl phosphine oxide, lauryl amine, hexadecylamine and the octadecylamine for organic coating.Cosolvent of the present invention is in toluene, chloroform, sweet oil, vaccenic acid hydrocarbon, whiteruss or the thermal oil.

Further specify the present invention below by following examples:

Embodiment one

In Fig. 1 and Fig. 2, with 0.2mmol Cd (MA)₂(TETRADECONIC ACID cadmium), 0.8mmol oleic acid and 10mL toluene add in the reactor, to being colourless transparent solution, are cooled to room temperature at 80 ℃ baking oven internal heating, obtain the Cd precursor solution; 0.2mmol Se powder, 0.36ml tri octyl phosphine (TOP) are joined the 10mL toluene solution, at room temperature obtain the Se precursor solution by the ultrasonic Se powder is dissolved fully; Cd precursor solution and Se precursor solution uniform mixing, logical N₂Behind the 10min, be sealed in the reactor, at 220 ℃ baking oven internal heating 1.7h, the reactor that stops to heat is cooled to room temperature in air, promptly obtains the CdSe quantum dot of different emission.

With 0.0295g Zn (MA)₂, 0.072mL oleic acid and 22.2mL toluene adds in the reactor, to dissolving fully, is cooled to room temperature at 100 ℃ baking oven internal heating again, obtains the Zn precursor solution; In the Zn precursor solution, add the Se precursor solution 7.1mL of preparation as previously mentioned then, CdSe quantum dot original solution 5mL, after mixing, logical N₂Behind the 10min, be sealed in the reactor, at 195 ℃ baking oven internal heating 2.0h, the reactor that stops to heat is cooled to room temperature in air, promptly obtain the CdSe-ZnSe quantum dot.

Embodiment 2

With 0.4mmol Cd (MA)₂(TETRADECONIC ACID cadmium), 0.8mmol oleic acid and 10mL octadecylene hydrocarbon add in the reactor, to being colourless transparent solution, are cooled to room temperature at 100 ℃ baking oven internal heating, obtain the Cd precursor solution; 0.2mmol Se powder, 0.36ml tri octyl phosphine (TOP) are joined 10mL octadecylene hydrocarbon solution, at room temperature obtain the Se precursor solution by the ultrasonic Se powder is dissolved fully; Cd precursor solution and Se precursor solution uniform mixing, logical N₂Behind the 10min, be sealed in the reactor, at 220 ℃ baking oven internal heating 1.7, the reactor that stops to heat is cooled to room temperature in air, promptly obtains the CdSe quantum dot.

With 0.1379g Zn (MA)₂, 0.34mL oleic acid and 22.2mL octadecylene hydrocarbon add in the reactor,, be cooled to room temperature again and obtain the Zn precursor solution to dissolving fully at 140 ℃ baking oven internal heating; In the Zn precursor solution, add the Se precursor solution 13.2mL of preparation as previously mentioned then, CdSe quantum dot original solution 5mL, after mixing, logical N₂Behind the 10min, be sealed in the reactor, at 195 ℃ baking oven internal heating 2.0h, the reactor that stops to heat is cooled to room temperature in air, promptly obtain the CdSe-ZnSe quantum dot.

Embodiment 3

With 0.1mmol Cd (MA)₂(TETRADECONIC ACID cadmium), 0.8mmol oleic acid and 10mL toluene add in the reactor, to being colourless transparent solution, are cooled to room temperature at 90 ℃ baking oven internal heating, obtain the Cd precursor solution; 1.0mmol Se powder, 0.36ml tri octyl phosphine (TOP) are joined the 10mL toluene solution, at room temperature obtain the Se precursor solution by the ultrasonic Se powder is dissolved fully; Cd precursor solution and Se precursor solution uniform mixing, logical N₂Behind the 10min, be sealed in the reactor, at 220 ℃ baking oven internal heating 1.7h, the reactor that stops to heat is cooled to room temperature in air, promptly obtain the CdSe quantum dot.

With 0.0743g Zn (MA)₂, 0.18mL oleic acid and 22.2mL toluene adds in the reactor,, be cooled to room temperature again and obtain the Zn precursor solution to dissolving fully at 120 ℃ baking oven internal heating; In the Zn precursor solution, add the Se precursor solution 2.83mL of preparation as previously mentioned then, CdSe quantum dot original solution 5mL, after mixing, logical N₂Behind the 10min, be sealed in the reactor, at 195 ℃ baking oven internal heating 2.0h, the reactor that stops to heat is cooled to room temperature in air, promptly obtain the CdSe-ZnSe quantum dot.

Claims (9)

1, the preparation method of a kind of CdSe and CdSe-ZnSe core-shell quanta dots, it comprises following concrete steps:

Step 1, preparation Cd precursor solution: the Cd source is added in organic coating and the cosolvent, and heating makes it dissolving, obtains the Cd precursor solution after the cooling;

Step 2, preparation Se precursor solution: the Se powder is added in tri octyl phosphine and the cosolvent, at room temperature disperse to make it to dissolve, obtain the Se precursor solution by ultrasonic;

Step 3 is mixed Cd precursor solution and Se precursor solution, and mixing solutions is sealed, and heating is reacted it at a certain temperature, and cooling promptly obtains CdSe quantum dot original solution then;

Step 4, preparation Zn precursor solution: the Zn source is added in organic coating and the cosolvent, be heated to 100-140 ℃ and make it dissolving, obtain the Zn precursor solution after the cooling;

Step 5 is mixed Zn precursor solution, Se precursor solution and CdSe quantum dot original solution, and mixing solutions is sealed, and heating is reacted it at a certain temperature, and cooling promptly obtains the CdSe-ZnSe core-shell quanta dots then.

2, the preparation method of CdSe according to claim 1 and CdSe-ZnSe core-shell quanta dots, it is characterized in that the mol ratio in Cd source and organic coating is 1 in the step 1: 2-1: between 8, the concentration of Cd ion in organic coating and cosolvent mixed solution is 0.01-1.0mol/L, the Cd source is CdO, cadmium acetate, cadmium oxalate, TETRADECONIC ACID cadmium or cadmium stearate, the temperature of heating is for arriving 80-100 ℃, and the refrigerative temperature is a room temperature.

3, the preparation method of CdSe according to claim 1 and CdSe-ZnSe core-shell quanta dots, it is characterized in that the mol ratio of Se powder and tri octyl phosphine (TOP) is 1 in the step 2: 2-1: between 8, Se trioctylphosphine see and the cosolvent mixed solution in concentration be 0.01-1.0mol/L.

4, the preparation method of CdSe according to claim 1 and CdSe-ZnSe core-shell quanta dots is characterized in that the mol ratio of Cd precursor solution and Se precursor solution is 1 in the step 3: 10-2: between 1, and logical N in mixing solutions₂Sealed in 10 minutes, the temperature 180-220 of heating ℃, the time of heating is 0.5 hour-2 hours, and the refrigerative temperature is a room temperature.

5, the preparation method of CdSe according to claim 1 and CdSe-ZnSe core-shell quanta dots, it is characterized in that the Zn source in the step 4 is in ZnO, zinc acetate, zinc oxalate, Zinc Undecylenate, TETRADECONIC ACID zinc or the Zinic stearas, the mol ratio of Zn precursor solution and organic coating is 1: 2-1: between 8, the concentration of Zn ion in organic coating and cosolvent mixed solution is 0.01-1.0mol/L, and the refrigerative temperature is a room temperature.

6, the preparation method of CdSe according to claim 1 and CdSe-ZnSe core-shell quanta dots, it is characterized in that the mol ratio of Zn precursor solution and Se precursor solution is 1 in the step 5: 1-3: between 1, the mol ratio of CdSe quantum dot and Zn precursor solution is 1: 100-1: between 300, mixing solutions is adopted logical N₂Sealed in 10 minutes, the temperature 180-220 of heating ℃, the time of heating is 0.5 hour-2 hours, and the refrigerative temperature is a room temperature.

7,, it is characterized in that described organic coating is one or more the combination in oleic acid, stearic acid, erucic acid, trioctyl phosphine oxide, lauryl amine, hexadecylamine and the octadecylamine according to the preparation method of claim 1,2 or 5 described CdSe and CdSe-ZnSe core-shell quanta dots.

8,, it is characterized in that described cosolvent is in toluene, chloroform, sweet oil, vaccenic acid hydrocarbon, whiteruss or the thermal oil according to the CdSe described in the claim 1,2,3 or 5 and the preparation method of CdSe-ZnSe core-shell quanta dots.

9, the preparation method of CdSe according to claim 1 and CdSe-ZnSe core-shell quanta dots, it is characterized in that CdSe and CdSe-ZnSe core-shell quanta dots in the step 5, its fluorescence emission peak scope is between the 500-600nm, and the halfwidth of fluorescence emission peak is between the 25-40nm.

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