Green synthetic method of controllable dimension semi-conductor nano cluster and nanocrystalline

Abstract

The invention provides a green synthesis method of a cadmium selenide nano-cluster and a cadmium selenide nanocrystal with controllable size. In the method, a series of low toxic / economical ligands are adopted, a selenium elementary substance and cadmium oxide dispersed in a non-ligand solvent are taken as precursors, and the cadmium selenide nano-cluster and the cadmium selenide nanocrystal are synthesized in the non-ligand solvent. The size can be adjusted within 0.7nm-13nm by adjusting the proportion of the ligands and the precursors. The obtained nanocrystal has high crystallinity and narrow size distribution fwhm which equals 25 plus or minus 2nm, relatively high fluorescence quantum efficiency which is 5%-38%, and a fluorescence emission spectrum can be adjusted within 450nm-690nm.

Description

technical field [0001] The invention relates to a green synthesis method of size-controllable cadmium selenide nano-clusters and nano-crystals. Background technique [0002] Colloidal semiconductor nanocrystals (SNCs), which have a strong "quantum confinement effect" because they are smaller than the exciton Bohr diameter, exhibit unique size-dependent optoelectronic properties. They are widely used in basic theory and technical applications (optoelectronic devices, light-emitting diodes) , solar cells, lasers, photoelectric probes, biomarkers, optical imaging in the field of biology, biomolecular interactions, biomolecular conformation studies, catalysis, etc.) have aroused a wide range of research interests. Among the numerous semiconductor materials (II-VI, III-V and IV-VI groups...), II-VI group semiconductor nanocrystals, especially CdSe nanocrystals as an important model system have been studied most deeply. CdSe (direct bandgap semiconductor, the macroscopic material...

AI Technical Summary

Problems solved by technology

But so far, the improved methods based on non-coordinating solvent systems have some disadvantages: (i) re-involved expensive and environmentally unfriendly organophosphine-related ligands; (ii) involved expensive and uncommon ligands body, dialkyl ester and diaryl ketone (hexadecyl hexadecanoate and benzophenone) [Wu, D.G. et al. Chem. Mater (2005), 17, 6436-6441.]; (iii) it is difficult to precisely and economically control nano Crystal size, (iv) At present, there is still a lack of a single and simple chemical route to prepare high-quality CdSe nanocrystals with a full-size range, which means that the fluorescence emission spectrum can span the entire visible range

At present, the synthesis methods of magic-sized nanoclusters are relatively cumbersome, and a large amount of phosphorus-containing compounds are used.

Moreover, the optical properties are not very good, and the fluorescence quantum efficiency is low

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