Preparation And Properties Research Of CsPbBrI₂ Perovskite Quantum Dots And Inks

Lead halide perovskite quantum dot CsPbX₃（X=Cl,Br,I）is new photoelectric material.Its characteristics are excellent,such as high photoluminescence quantum yield,high color gamut coverage and continuous adjustable emission wavelength.So it has great potential application value in the fields of display and solar cells.However,currently the research on all inorganic perovskite quantum dots mainly focus on green and blue perovskite quantum dots,red perovskite quantum dots which is one of the three original lig hts and its inkjet printing is still relative lack.In this paper,CsPbBrI₂red light quantum dots with good properties were prepared by improving the synthesis conditions,raw materials and passivation treatment,and the ink based on improved CsPbBrI₂red light quantum dots is mixed for inkjet printing and down conversion membrane.In this paper,CsPbBrI₂ red quantum dots solution were prepared by thermal injection method,then its crystal morphology,optical properties and stability were characterized.It was found that the initial quantum dots had some shortcomings,such as low fluorescence quantum yield and poor stability.On the basis of thermal injection method,the preparation process parameters were improved.The optimum synthesis temperature was 180℃and the optimum reaction time was 5 s;The effects of synthetic raw materials were studied.The preparation effects of cesium acetate and lead acetate trihydrate in the precursor were better than cesium carbonate and lead oxide respectively.Quantum dot s with photoluminescence characteristics could be generated only when the molar number of lead source was greater than cesium source,and the photoluminescence intensity of CsPbBrI₂ red perovskite quantum dots was the highest when the molar ratio of cesium source to lead source was 1:2;The effects of different reaction solvents and dispersion solvents were studied.Octadecene was the best solvent;Different dispersants have little effect on the fluorescence intensity of CsPbBrI₂ red quantum dots.Based on the improved preparation process,potassium ion doping and halogen-rich passivation were used to improve the photoluminescence intensity of quantum dots.Finally,CsPbBrI₂ red quantum dots with good stability,92.01%high fluorescence quantum yield and 23.5 nm narrow half peak width were obtained.On the basis of high-performance quantum dots,the light curing red quantum dot ink was prepared.The quenching mechanism of Cs Pb Br I ₂perovskite quantum dots under UV irradiation was studied.Cs Pb Br I ₂ perovskite quantum dots with good UV stability were prepared by using lauryl methacrylate as the reaction solvent.The dispersion solvent was adjusted to optimize the ink deposition,and the well adapted light curing oligomer and initiator were configured for the quantum dots,the down conversion film was formed by inkjet printing quantum dot ink on the pixel of RGB device.The preparation processes of down conversion films by spin coating and pouring methods were studied.The red quantum dot down conversion films obtained by dropping 20 wt.%PMMA polymer onto PMMA glass substrate and pouring directly had a high PLQY of 70.24%.