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    Home > Chem: Professor Xing Mingyang of East China University of science and technology and Professor Yadong Yin of University of California Riverside have made breakthrough in the field of white light inorganic quantum dots synthesis

    Chem: Professor Xing Mingyang of East China University of science and technology and Professor Yadong Yin of University of California Riverside have made breakthrough in the field of white light inorganic quantum dots synthesis

    • Last Update: 2019-09-06
    • Source: Internet
    • Author: User
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    The traditional preparation method of white emitting inorganic quantum dots (QDs) mainly depends on the encapsulation of the three primary colors (red, yellow, blue) in the solid matrix This method is faced with the major challenges, such as the aggregation of QDs, fluorescence quenching, complex synthesis control and mass production Recently, Professor Xing Mingyang, School of chemistry and molecular engineering, East China University of science and technology, in cooperation with Professor Yadong Yin, University of California Riverside, has made significant research progress in the field of pure water phase synthesis of white light quantum dots The relevant results "confirmed growth of quantum dots in silica spheres by ion exchange of" trapped NH 4 + "for white light emission" were published online at Chem (if: 18.205, DOI: 10.1016/j.checker 2019.06.010) The research team developed a new method of liquid-phase synthesis of quantum dots directly growing in the small spherical phase of SiO 2 - "trapped NH 4 +" ion exchange method (figure a) Using the characteristics of "trapped NH 4 +" which is easy to react with metal cations such as Zn 2 +, Cd 2 +, they successfully introduced metal cations into the small spherical phase of SiO 2 (Fig a, b) The metal sulfur compounds were produced by room temperature vulcanization Finally, through the ingenious pickling and alcohol washing process (the acid concentration needs to be regulated), the "bulk" sulfide covered on the surface of the SiO2 spheres can be selectively washed out, and then the crystallization of the SiO2 spheres phase quantum dots can be realized by high-temperature calcination In the process of calcination, the "confinement effect" of the small spherical phase channel of SiO2 is used to effectively inhibit the agglomeration phenomenon in the crystallization process of quantum dots At the same time, the "confinement effect" of different size channels can well control the size distribution of the QDs, so that the QDs can emit white light directly under the ultraviolet irradiation The traditional method of constructing white LEDs by the combination of three primary color quantum dots has poor reproducibility, and the half peak width of the emission wavelength of quantum dots is difficult to control The strategy of "trapped NH 4 +" ion exchange synthesis of quantum dots can adjust the calcination temperature, control the pore size distribution of SiO2 spheres, so as to adjust the half peak width of ZnS @ SiO2 quantum dots fluorescence emission spectrum (the half peak width can be adjusted from 109.6 to 203.8 nm, figure C) It is worth noting that the whole synthesis process of QDs is completed in pure water system without any oil phase reagent or any organic "capping agent" (source: Chem) another advantage of this synthesis strategy is that the preparation of quantum dots can achieve mass production Taking the synthesis of ZnS @ SiO2 quantum dots as an example, the mass-produced SiO2 spheres and zinc salt are ion exchanged in pure water solution, and then a proper amount of sodium sulfide is added under normal temperature and pressure for sulfurization, and then the SiO2 spheres after pickling and alcohol washing are calcined at 600 ℃ for 2-10 hours, then the mass-produced ZnS @ SiO2 spheres directly emitting white light can be obtained (Figure d) The fluorescent quantum yield of the white light quantum dots can reach 31.1% The white light quantum dots after mass production can be used to construct white light LEDs The CIE coordinates of the white light quantum dots are: (0.312,0.318) and the CRI value is 92.5 (Figure E) The white light quantum dot synthesis strategy effectively avoids the complex encapsulation process required by traditional synthesis methods, and provides a new universal platform for the synthesis of new functional nanocomposites It can easily combine all kinds of nanoparticles into sol gel derived colloidal matrix In recent years, Professor Xing Mingyang has made a series of important research results in the synthesis of multifunctional nanomaterials and their application in the field of environment and energy The first or corresponding author is NAT Commun., chem, J am Chem SOC., angel Chem., chem SOC Rev., nano lett., adv funct Mater., appl Catalyst B, mater Horiz, There are 60 SCI papers published in environ SCI Technology, water res and other journals, among which 20 papers with impact factor > 10.0, 13 papers selected as "highly cited papers of ESI", and 4 papers selected as "0.1% hot articles" In this work, East China University of science and technology is the first communication unit, and has received the guidance of Professor Zhang Jinlong, academician of the European Academy of Sciences Thanks to Professor Zhong Haizheng and Dr Chen Bingkun of Beijing University of technology for their help in WLED test The research was supported by the National Natural Science Foundation of China (excellent youth fund and general program), and the national key research and development program youth program.
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