Copper selenide fluorescent quantum dot and preparation method and application thereof

Abstract

The invention relates to a copper selenide fluorescent quantum dot and a preparation method and application thereof. The copper selenide fluorescent quantum dot is characterized in that the quantum dot is one of Cu2Se, CuSe and Cu(2-x)Se or a combination thereof; the particle size of the quantum dot is 2-10nm, the quantum yield is 10-60%, and the half-peak width of the photoluminescence spectrum is 30-150nm. The preparation method comprises the following steps: with an aqueous solution with copper salt dissolved in as an aqueous phase and an organic solvent with a long-chain ligand dissolved in as an oil phase, stirring in an inertia protective gas, and heating in an oil bath to form a precursor solution; pouring an aqueous solution of sodium hydrogen selenide into the hot precursor solution, and heating for reaction; sampling at different time to obtain organic-phase quantum dot solutions with different emission fluorescence; precipitating the upper-layer organic-phase quantum dot solution; centrifuging and dispersing, and repeating to remove unreacted raw materials to obtain the copper selenide fluorescent quantum dot. The quantum dot does not contain heavy metal elements such as cadmium and the like to realize low toxicity, has the advantages of high quantum yield, uniform particle size, relatively narrow fluorescence emission spectrum and adjustable light color along with excitation wavelength, and can be used for preparing quantum dot solar sensitized cells and LED (light-emitting diode) devices.

Description

technical field [0001] The invention relates to a semiconductor fluorescent nanometer material, a preparation method and an application thereof, in particular to a copper selenide fluorescent quantum dot and a preparation method and application thereof. Background technique [0002] Semiconductor nanocrystals (also known as quantum dots), whose particle size is generally between 1-20nm, are one of the important members of nanomaterials. The average particle size of quantum dots is small, the surface atoms are many, the specific surface area is large, and the surface energy is high, resulting in their properties being different from single atoms, molecules, and ordinary particle materials, and showing unique small size effects and surface effects. And the macroscopic quantum tunneling effect, showing unique advantages in the fields of light, electricity, magnetism, heat and catalysis. There are many preparation methods for quantum dots, the mainstream methods are organometal...

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Problems solved by technology

[0003] Although the research on quantum dots has been developed for decades, the varieties of quantum dots are still relatively limited. At present, the most in-depth research on the theory and application of quantum dots is only II-VI and III-V semiconductor nanocrystals, such as CdTe, CdS, CdSe, CdTe / ZnS, CdTe / CdS, etc. Most of these quantum dots contain heavy metal components, which greatly limits the expansion and improvement of quantum dot theory and its practical application in photovoltaic devices such as solar cells and light-emitting diodes (LEDs). Therefore, the development of a new class of cadmium-free quantum dot materials will be of far-reaching significance.

At present, most of the research on copper selenide semiconductor materials stays at the level of macroscopic bulk materials, and only a few studies involve the nanometer scale of the material, but these reported copper selenide fluorescent quantum dots or quantum yields are very low, particle The diameter distribution is not uniform (Struct.Chem., 2011, 22:103-110), or the raw materials used are very expensive, and a high temperature reaction of 250°C is required (Adv.Mater., 1999, 11, 1441-1444)

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