Preparation And Luminescent Properties Of Sulfides Quaternary Quantum Dots

Colloidal semiconductor quantum dots are more and more get the attention of many scholars because the light spectra can be changed as the size of quantum dots and the content of elements. In addition, it has some of the classic features like high thermal and chemical stability, high fluorescence quantum efficiency properties. Its preparation process is more and more simple, synthesis tend to be low cost. At present it has very important application in many fields, such as solar cells, light-emitting device, display field, biological fluorescence labeling, memory devices, etc. The semiconductor quantum dots based on heavy metals such as Cd II-VI(such as Cd Se nanocrystals) have good monochromaticity, but the toxicity of Cd and Pb itself restricted their development in many application fields. Therefore, we synthesized a series of Zn-Cu-In-S and Zn-Ag-In-S quaternary quantum dots which didn’t contain toxic heavy metals elements using high temperature pyrolysis method in this article.The luminescence properties and thermal stability were analysis and research, and ultimately the white light emission under the blue excitation is realized.Zn-Cu-In-S quantum dots with different reaction time are synthesized by using thermal decomposition method. We studied the luminescence properties of the Zn-Cu-In-S quantum dots which were prepared under the same reaction temperature(220 o C) and different reaction.With the extension of reaction time, the Zn-Cu-In-S quantum dots grain size increases gradually, and the emission spectra obviously redshift. We found the light-emitting spectral range can be regulated from the yellow green to red. We tested the variable temperature spectra of the sample under the reaction time of 60 min and studied the luminescence mechanism. The samples synthesized for 10 min produced white light which were excited by450 nm blue light; The influences of the particle size of Zn-Cu-In-S quantum dot on the luminescence properties and the variable temperature spectra are studied. The content included the movement of the temperature dependence of spectra itself, the comparison of the changing trend of light intensity, the comparison of the tendency band gap of Zn-Cu-In-S quantum dots under different test temperature and the comparison of the changing trend of full width at half maximum, etc.Thermal decomposition method is used to synthesize a series of different reaction time of Zn-Ag-In-S quantum dots. The luminescence properties of the Zn-Ag-In-S quantum dots which were prepared under the same reaction temperature and different reaction time are studied. Zn-Ag-In-S quantum dots grain size increases gradually with the extension of reaction time and the emission spectra red shift obviously. We test the infrared Fourier spectra,and find there are ligands in the surface of the Zn-Ag-In-S quantum dots; Furthermore, we study on the lifetime and thermal stability. The content included the movement of the temperature dependence of spectra itself, the comparison of the changing trend of light intensity,the comparison of the tendency band gap of Zn-Ag-In-S quantum dots under different test temperature and the comparison of the changing trend of full width at half maximum, etc.