Preparation Of Silica Modified Bismuth Based Perovskite Quantum Dots And Its Application In Cotton Fabrics

Fluorescent antibacterial cotton fabric can not only be used in areas such as warning and anti-counterfeiting,but also can resist the erosion of bacteria and improve hygiene performance.In this study,a kind of fluorescent antibacterial cotton fabric was prepared.Firstly,the bismuth based perovskite quantum dots nanomaterials were prepared by the ligand-assisted reprecipitation method.Then y-aminopropyltriethoxysilane and ethyl orthosilicate were selected to modify the bismuth based perovskite quantum dots respectively.The modified perovskite quantum dots were applied in the finishing of cotton fabrics,and its performance was investigated.The main research content includes the following aspects:Cs3Bi2Br9 quantum dots were prepared with absolute ethanol and toluene as antisolvents,respectively.They were subjected to fluorescence emission spectroscopy,ultraviolet-visible absorption spectroscopy,time-resolved fluorescence decay,and transmission electron microscopy,high-resolution transmission electron microscopy,Fourier Transform infrared spectroscopy,etc.The experimental results showed that when Cs3Bi2Br9 quantum dots were prepared with anhydrous ethanol as anti solvent,their fluorescence excitation spectrum and fluorescence emission spectrum of Cs3Bi2Br9 nanocrystals are 378 nm and 434 nm,respectively.The average size is about 50-80 nm,and some agglomerations have occurred.When preparing Cs3Bi2Br9 quantum dots with toluene as the anti-solvent,the ligand oleic acid and octylamine was successfully modified on the surface of Cs3Bi2Br9 quantum dots.The excitation peaks of Cs3Bi2Br9 quantum dots were 380 nm and 400 nm,and the emission peaks were 467 nm and 488 nm,respectively.The interplanar spacing of Cs3Bi2Br9 quantum dots were 3.44 A and 3.28 A,and the crystallinity was relatively high.The size was relatively uniform,about 4-5 nm.The band gap was approximately 2.19 eV.The y-aminopropyltriethoxysilane was introduced into the Cs3Bi2Br9 quantum dots colloidal solution to prepare the silica modified bismuth-based perovskite quantum dots(Cs3Bi2Br9 QDs@SiO2)composite material,which was subjected to the characterization of fluorescence emission spectroscopy,time-resolved fluorescence spectrometry,ultraviolet-visible absorption spectroscopy,Fourier Transform infrared spectroscopy,scanning electron microscope,high-resolution transmission electron microscope,and transmission electron microscope.The results showed that the fluorescence excitation peak of Cs3Bi2Br9 QDs@SiO2 was 379 nm,the emission peaks were at 436 nm and 457 nm,respectively.The band gap was about 2.22 eV.Cs3Bi2Br9 QDs@SiO2 had excellent UV resistance and water resistance stability.The application results showed that the cotton fabric finished by Cs3Bi2Br9 QDs@SiO2 composite material had stable fluorescence luminescence performance.Even if it was placed in air for 81 days,it could still maintain obvious fluorescence performance.The cotton fabric finished by Cs3Bi2Br9 QDs@SiO2 composite material also had good antibacterial properties against Escherichia coli(E.coli)and Staphylococcus aureus(S.aureus).Ethyl orthosilicate was introduced into Cs3Bi2Br9 quantum dots to prepare Cs3Bi2Br9 QDs@Si02,and subjected to fluorescence emission spectroscopy,time-resolved fluorescence spectrometry,ultraviolet-visible absorption spectroscopy,Fourier Transform infrared spectroscopy,scanning electron microscopy,high-resolution transmission electron microscopy,and transmission electron microscopy characterization.The results showed that the synthesized Cs3Bi2Br9 QDs@SiO2 fluorescence excitation peak was located at 376 nm,the emission peak was located at 434 nm and 455 nm,respectively.The band gap was about 2.22 eV.The remaining fluorescence results showed that Cs3Bi2Br9 QDs@SiO2 had excellent UV resistance and water resistance stability.The application results showed that the cotton fabric treated with Cs3Bi2Br9 QDs@SiO2 had excellent fluorescence performance.Even if it was placed in air for 81 days,it could still maintain obvious fluorescence performance,and the cotton fabric had a certain effect on E.coli and S.aureus.The properties of the fabrics treated with y-aminopropyltriethoxysilane and tetraethoxysilane modified Cs3Bi2Br9 quantum dots were compared.It was found that there was no significant difference in the fluorescence properties between them,but the antibacterial properties of Cs3Bi2Br9 quantum dots modified byγ-aminopropyltriethoxysilane were better.