Preparation And Properties Of Zn-doped CsPbI₃ Perovskite Quantum Dot Electrospinning Fibrous Membranes

All-inorganic halide perovskite materials（CsPbX₃,X=Cl,Br,I）have the characteristics of tunable elemental composition and particle size.At the same time,they have excellent optical properties such as long carrier mobility,high optical absorption coefficient,and narrow emission spectrum.In addition,the uniform morphology,large exciton binding energy and low trap density of CsPbX₃can achieve high photoluminescence quantum efficiency.uniform morphology,large exciton binding energy and low trap density can achieve high photoluminescence quantum efficiency.However,all-inorganic perovskite quantum dots are particularly sensitive to the external environment such as water and air,which is not conducive to the application of all-inorganic perovskite quantum dots.Therefore,how to improve the stability of all-inorganic perovskite quantum dots is the key to its commercialization.In this thesis,quantum dot films were prepared by ion doping,polymer coating,and electrospinning to improve the stability of CsPbI₃ perovskite.The main results are as follows:（1）By doping Zn²⁺（0.1 mmol,0.2 mmol,0.3 mmol）to replace part of Pb²⁺,polystyrene（PS）was selected as the polymer coating material,CsPbI₃ nanocrystals were grown in situ in polymer fibers by electrospinning to prepare Zn²⁺doping CsPbI₃@PS film（named Zn-CsPbI₃@PS）.The optimal Zn²⁺doping amount is 0.3 mmol,the diameter of the Zn-CsPbI₃@PS fiber is 500 nm-1.5μm.The contact angle of the film is 125°-131°,and the film can maintain fluorescence emission for 1 week in water.（2）By doping Zn²⁺（0.1 mmol,0.2 mmol,0.3 mmol）to replace part of Pb²⁺,polymethyl methacrylate（PMMA）was selected as the polymer coating material,CsPbI₃ nanocrystals were grown in situ in polymer fibers by electrospinning to prepare Zn²⁺doping CsPbI₃@PMMA film（named Zn-CsPbI₃@PMMA）.The optimal Zn²⁺doping amount for Zn-CsPbI₃@PMMA is 0.3 mmol.The diameters of the Zn-CsPbI₃@PMMA fibers ranged from 300 nm to 700 nm,and the film contact angles were 121°to 137°.The films could maintain fluorescence emission for 2 weeks in water and 5 months in air.The WLED devices constructed with thin films have emission peaks corresponding to 466 nm（blue light）,530 nm（green light）and 674 nm（red light）,respectively,with CIE color coordinates of（0.2954,0.3103）and color temperature of 7707 K.（3）Zn-CsPbI₃@PMMA EFs were prepared by additional passivation with phthalimide ligands.The PL intensity of Zn-CsPbI₃@PMMA EFs is 1.6 times higher than that of Zn-CsPbI₃@PMMA.The photocatalytic degradation rates of Zn-CsPbI₃@PMMA EFs for p-methylene blue（MB）and methyl orange（MO）reach 87.48%and 77.03%,respectively.The catalytic degradation rates of Zn-CsPbI₃@PMMA EFs for MB and MO were 0.1623 min^-1and 0.1421 min^-1,respectively.（4）Zn-CsPbI₃@PS EFs were prepared by additional passivation with phthalimide ligands.The PL intensity of the passivated Zn-CsPbI₃@PS EFs is 3.2 times higher than that of Zn-CsPbI₃@PS.The photocatalytic degradation rates of Zn-CsPbI₃@PS EFs for MB and MO reach 75.49%and 77.31%,respectively.The catalytic degradation rates of Zn-CsPbI₃@PMMA EFs for MB and MO were 0.0374 min^-1 and 0.0351 min^-1,respectively.