High fluorescent efficiency cadmium telluride quantum point prepared by cathodic tellurium electric pole

Abstract

The invention relates to a method for preparing high fluorescence-efficiency cadmium telluride quantum dots through cathodic tellurium electrodes. The method is characterized in that: (1) stable tellurium rods are taken as tellurium electrodes; under the electric potential between 0.95 V below zero and 1.2 V below zero (relative to Ag|AgCl|KCl(sat.) electrodes), the cathodic tellurium electrodes are used as a tellurium source to prepare a cadmium telluride precursor solution, so as to replace a sodium hydrogen telluride or hydrogen telluride source easy to oxidize by air, or an aluminum telluride source easy to absorb water; therefore, the preparation of the quantum dots can be carried out in an open system without specific protective atmosphere; (2) the cadmium telluride quantum dots with different modified groups on the surfaces can be prepared by taking a mercapto-compound as a stabilizer; (3) preparation process is completed in an aqueous phase at a temperature between 70 and 100 DEG C, and the water-soluble quantum dots used for biological markers and detection can be prepared; and (4) the particle size and maximum emission wavelength of the cadmium telluride quantum dots can be adjusted by controlling heating time. The cadmium telluride quantum dots synthesized in the invention have the particle size between 2.0 and 5.0 nanometers, the maximum emission wavelength between 500 and 650 nanometers, the emission-spectrum half-peak width between 40 and 55 nanometers, as well as the fluorescence quantum yield from 60 to 78 percent. The method has the characteristics of convenience, rapidness, environment protection, good reproducibility, low cost and the like, provides a feasible way for synthesizing high-quality cadmium telluride quantum dots, and can have wide application prospects in the nanometer devices, optoelectronics, biological sensing and other fields.

Description

1. Technical field [0001] The invention belongs to a method for preparing semiconductor quantum dots in the field of nanometer materials. It uses an electrochemical method to prepare a cadmium telluride precursor by cathodicizing a tellurium electrode, using a compound containing a mercapto group or a compound that can coordinate with a cadmium ion as a stabilizer, and preparing a high-fluorescence efficiency cadmium telluride quantum dot in an aqueous phase. Dots can have broad application prospects in the fields of nano-devices, optoelectronics, and biosensing. 2. Background technology [0002] Due to the quantum size effect and dielectric confinement effect, the emission wavelength of cadmium telluride quantum dots can range from green light to red light. Applications in the field of biological imaging and detection [3] are increasingly concerned. Compared with the metal-organic solvent method, the aqueous phase synthesis method has the advantages of low cost, easy oper...

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Problems solved by technology

Because these two sources of tellurium are easily oxidized by oxygen in the air, they need to be prepared on site, and vacuum line technology (Schlenk line) is required, so the preparation process is relatively complicated.

[0003] Due to the low temperature during the aqueous phase synthesis, the nanocrystals in the existing preparation methods have no clear nucleation and growth boundaries, resulting in the obtained quantum dots having a wide half-maximum fluorescence width, uneven particle size distribution, and low quantum efficiency (3 %~10%)[5]

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