Preparation method of silver sulfide quantum dots

Abstract

The invention provides a preparation method of silver sulfide quantum dots, belonging to the technical field of the preparation of semiconductor nanometer materials. The invention mainly provides a novel method for preparing the Ag2S quantum dots with the near infrared fluorescent property, comprising the following steps of: obtaining the quantum dots by a method of thermal injection in non-coordination agent under a relative low temperature due to an organic ligand which is provided with sulfydryl of a short chain, and precipitating in acetone or ethanol and dispersing into chloroform or hexane solvent. The quantum dots prepared by the invention have the fluorescent property at a near infrared region, has certain quantum efficiency and good monodispersity and stability, is uniform in particle size, and the size of the particle does not need selecting, so that the preparation method is simple to operate and low in cost.

Description

technical field [0001] The invention belongs to the technical field of semiconductor nano material preparation. It relates to a new method for preparing semiconductor quantum dots with good monodispersity and near-infrared fluorescence properties. Background technique [0002] After the semiconductor material gradually decreases from the bulk phase to a certain critical size (1-20 nanometers), the volatility of its carriers becomes significant, and the movement will be limited, resulting in an increase in kinetic energy. The corresponding electronic structure is continuous from the bulk phase to The energy level structure becomes a quasi-split discontinuity, a phenomenon known as the quantum size effect. The more common semiconductor nanoparticles, that is, quantum dots, mainly include II-VI, III-V and IV-VI groups. These types of quantum dots are well obeyed by the quantum size effect, and their properties change regularly with the size, for example, the absorption and em...

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Problems solved by technology

With the development of synthesis technology, in 2010, the Wang group reported the preparation of Ag with a size above 5nm by thermal decomposition of unit organic precursors. 2 S quantum dots (J.Am.Chem.Soc.2010,132,1470), and the Ag synthesized by this method 2 S quantum dots have near-infrared optical properties, but this method requires a high temperature above 200 ° C, the particle fluorescence quantum efficiency of the prepared particles is relatively low, and the absorption spectrum is not obvious

Not long ago, the Pang group synthesized Ag with a smaller size (about 1.5~2.8nm) 2 S quantum dots (Chem.Mater.2012, 24, 3) have very obvious near-infrared absorption, and the fluorescence quantum efficiency reaches 0.18%. The TMS-S used in it is very active and prone to redox reactions, so a glove box is required. The tools are strictly stored, so the experimental operation is relatively complicated and requires certain laboratory conditions

In summary, the current Ag 2 There are still many problems in the synthesis of S quantum dots, from the initial synthesis of quantum dots that do not have fluorescent properties, to the gradual synthesis of relatively stable Ag that reaches the detection line of the instrument. 2 S quantum dots, predecessors have made many breakthroughs; however, most of the existing synthesis methods require harsh experimental conditions, such as complex and cumbersome operation processes, expensive, difficult to store and highly toxic experimental raw materials, etc.

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