CdX quantum dot and preparation method thereof

Abstract

The present invention relates to a method for preparing a CdX (X= Se or Te) quantum dot nano material with high quantum yield in an aqueous phase by using simple operation conditions, and belongs to the field of nano material preparation. The preparation method does not require nitrogen as a protective gas, or a buffer solution, or a particular ligand, or a large amount of hydrazine hydrate as a reducing agent, or a special post-treatment. In the aqueous phase, a thiol compound is used as a ligand; cadmium salt and potassium tellurite (selenite) are selected respectively as a cadmium source and a tellurium (selenium) source; and sodium borohydride is used as a reducing agent. The water-soluble CdTe (CdSe) quantum dot with quantum yield up to 83% can be prepared from a one-pot reaction.

Description

technical field

[0001] The invention relates to a method for preparing a CdX quantum dot nano material with high quantum yield in an aqueous phase using simple operating conditions, and belongs to the field of nano material preparation. Background technique

[0002] Quantum dots (quantum dots, QDs), also known as semiconductor nanocrystals (NCs), are three-dimensional restricted molecular clusters, which are composed of a limited number of atoms, and the three dimensions are all on the order of nanometers. Due to the quantum confinement effect, QDs make their energy bands into discrete energy levels with molecular characteristics, and exhibit many unique optical and electrical properties, which have become a hot research topic.

[0003] The evaluation of the performance of QDs mainly depends on their fluorescence characteristics, that is, the fluorescence emission wavelength and fluorescence quantum yield. The general fluorescence characteristics of QDs are: ① strong fluore...

Examples

Embodiment 1

[0032] First, 0.0272 g (0.1 mmol) of cadmium acetate was dissolved in deionized water to prepare 50 ml of cadmium acetate solution, and then 10 microliters (0.1 mmol) of thioglycolic acid was added dropwise. Sodium oxide solution adjusted the pH of the solution to 10, stirred for 5 minutes to obtain a cadmium source solution; dissolved 0.0052 g (0.02 mmol) of potassium tellurite in ionized water to prepare 50 ml of potassium tellurite solution, and added the cadmium source The solution was stirred for 5 minutes; then, 0.04 g (1 mmol) of sodium borohydride was added to the above solution, and stirred for 5 minutes; finally, the temperature was raised to 100 degrees Celsius and refluxed for 15 minutes. Add an equal volume of acetone to the reaction solution, centrifuge at a speed of 5000 rpm, and wash with acetone three times to obtain pure solid quantum dots with a quantum yield of 79%.

Embodiment 2

[0034] First, 0.0272 g (0.1 mmol) of cadmium acetate was dissolved in deionized water to prepare 50 ml of cadmium acetate solution, and then 10 microliters (0.1 mmol) of thioglycolic acid was added dropwise. Sodium oxide solution adjusted the pH of the solution to 10.5, stirred for 5 minutes to obtain a cadmium source solution; dissolved 0.0052 g (0.02 mmol) of potassium tellurite in ionized water to prepare 50 ml of potassium tellurite solution, and added the cadmium source The solution was stirred for 5 minutes; then, 0.08 g (2 mmol) of sodium borohydride was added to the above solution, and stirred for 5 minutes; finally, the temperature was raised to 100 degrees Celsius and refluxed for 1 hour. Add an equal volume of acetone to the reaction solution, centrifuge at a speed of 5000 rpm, and wash with acetone for 3 times to obtain pure solid quantum dots with a quantum yield of 83%.

Embodiment 3

[0036] First, 0.0272 g (0.1 mmol) of cadmium acetate was dissolved in deionized water to prepare 50 ml of cadmium acetate solution, and then 10 microliters (0.1 mmol) of thioglycolic acid was added dropwise. Sodium oxide solution adjusted the pH of the solution to 11, stirred for 5 minutes to obtain a cadmium source solution; dissolved 0.0052 g (0.02 mmol) of potassium tellurite in ionized water to prepare 50 ml of potassium tellurite solution, and added cadmium The source solution was stirred for 5 minutes; then, 0.02 g (0.5 mmol) of sodium borohydride was added to the above solution, and stirred for 5 minutes; finally, the temperature was raised to 100 degrees Celsius and refluxed for 13 hours. Add an equal volume of acetone to the reaction solution, centrifuge at a speed of 5000 rpm, and wash with acetone for 3 times to obtain pure solid quantum dots with a quantum yield of 60%.

technical field

[0001] The invention relates to a method for preparing a CdX quantum dot nano material with high quantum yield in an aqueous phase using simple operating conditions, and belongs to the field of nano material preparation. Background technique

[0002] Quantum dots (quantum dots, QDs), also known as semiconductor nanocrystals (NCs), are three-dimensional restricted molecular clusters, which are composed of a limited number of atoms, and the three dimensions are all on the order of nanometers. Due to the quantum confinement effect, QDs make their energy bands into discrete energy levels with molecular characteristics, and exhibit many unique optical and electrical properties, which have become a hot research topic.

[0003] The evaluation of the performance of QDs mainly depends on their fluorescence characteristics, that is, the fluorescence emission wavelength and fluorescence quantum yield. The general fluorescence characteristics of QDs are: ① strong fluore...

Examples

Embodiment 1

[0032] First, 0.0272 g (0.1 mmol) of cadmium acetate was dissolved in deionized water to prepare 50 ml of cadmium acetate solution, and then 10 microliters (0.1 mmol) of thioglycolic acid was added dropwise. Sodium oxide solution adjusted the pH of the solution to 10, stirred for 5 minutes to obtain a cadmium source solution; dissolved 0.0052 g (0.02 mmol) of potassium tellurite in ionized water to prepare 50 ml of potassium tellurite solution, and added the cadmium source The solution was stirred for 5 minutes; then, 0.04 g (1 mmol) of sodium borohydride was added to the above solution, and stirred for 5 minutes; finally, the temperature was raised to 100 degrees Celsius and refluxed for 15 minutes. Add an equal volume of acetone to the reaction solution, centrifuge at a speed of 5000 rpm, and wash with acetone three times to obtain pure solid quantum dots with a quantum yield of 79%.

Embodiment 2

[0034] First, 0.0272 g (0.1 mmol) of cadmium acetate was dissolved in deionized water to prepare 50 ml of cadmium acetate solution, and then 10 microliters (0.1 mmol) of thioglycolic acid was added dropwise. Sodium oxide solution adjusted the pH of the solution to 10.5, stirred for 5 minutes to obtain a cadmium source solution; dissolved 0.0052 g (0.02 mmol) of potassium tellurite in ionized water to prepare 50 ml of potassium tellurite solution, and added the cadmium source The solution was stirred for 5 minutes; then, 0.08 g (2 mmol) of sodium borohydride was added to the above solution, and stirred for 5 minutes; finally, the temperature was raised to 100 degrees Celsius and refluxed for 1 hour. Add an equal volume of acetone to the reaction solution, centrifuge at a speed of 5000 rpm, and wash with acetone for 3 times to obtain pure solid quantum dots with a quantum yield of 83%.

Embodiment 3

[0036] First, 0.0272 g (0.1 mmol) of cadmium acetate was dissolved in deionized water to prepare 50 ml of cadmium acetate solution, and then 10 microliters (0.1 mmol) of thioglycolic acid was added dropwise. Sodium oxide solution adjusted the pH of the solution to 11, stirred for 5 minutes to obtain a cadmium source solution; dissolved 0.0052 g (0.02 mmol) of potassium tellurite in ionized water to prepare 50 ml of potassium tellurite solution, and added cadmium The source solution was stirred for 5 minutes; then, 0.02 g (0.5 mmol) of sodium borohydride was added to the above solution, and stirred for 5 minutes; finally, the temperature was raised to 100 degrees Celsius and refluxed for 13 hours. Add an equal volume of acetone to the reaction solution, centrifuge at a speed of 5000 rpm, and wash with acetone for 3 times to obtain pure solid quantum dots with a quantum yield of 60%.

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