Research On Low Defect Ion Exchange And Photoelectric Properties Of All-inorganic Perovskite Nanowires

The general formula of metal halide perovskite is ABX₃,where A is methylammonium,formamidine or Cs,B is Pb or Sn,and X is usually Cl,Br or I.Due to their remarkable photophysical properties and a wide range of adjustable components,these compounds have shown great prospects in various optoelectronic applications.Among them,the size and morphology of the crystallites may have a significant impact on its chemical and physical properties,thus affecting its optoelectronic applications.One-dimensional halide perovskite nanowires have excellent carrier transport in one dimension,high crystalline quality and other characteristics,their interesting physical properties and their use in various applications in electronics,optoelectronics,sensing,and nanoscale The potential has been extensively studied.Perovskite nanomaterials are used in various applications including optics,electricity,optoelectronics and other fields.The physical and chemical tunable properties of this material have prompted us to pursue simultaneous synthesis and control of material composition and nanowire morphology.Experimental studies have found that chemical transformations,such as liquid-phase ion exchange and solid-phase ion exchange,are simple and versatile methods that can achieve fine control of material composition and create new materials and nanostructures.Here,we demonstrated the successful synthesis of luminescent cesium lead halide(CsPb X₃,X=Cl,Br,I)nanowires with uniform diameter(100?2000 nm)and tunable composition ratio.Using CsPbBr3 nanowires as a template,the composition of the nanowires can be independently controlled by the method of liquid-phase ion exchange.The obtained mixed halogen perovskite nanowire has a well-preserved morphology and crystal structure,and its tunable photoluminescence covers the visible spectral region(430?700 nm).Scanning electron microscope(SEM),photoluminescence(PL)and time-resolved photoluminescence decay(TRPL)show that anion exchange does not significantly increase the defect density in nanowires.The experiment studied the electrical properties of the mixed halogen perovskite nanowires through the photocurrent measurement test.Its excellent optoelectronic properties will play a huge potential in applications in the field of optoelectronics.The solid-phase ion exchange method has also been used to control the composition of the nanowires.The yellow phase CsPbI₃ nanowires and CsPbBr₃ nanowires undergo a solid-phase ion exchange reaction at a certain temperature(150?200?)to obtain hybrid CsPb(Br/I)₃nanowires.The effects of temperature and humidity on the obtained hybrid CsPb(Br/I)₃nanowires were systematically studied.The experiment found that the CsPb(Br/I)₃ nanowires transformed from the yellow phase CsPbI₃ nanowires have the cubic structure of the perovskite phase.The occurrence of this phase transition was confirmed by studying its fluorescence characteristics,and thus a mutant heterojunction of yellow phase CsPbI₃ nanowires combined with CsPb(Br/I)₃ nanowires was obtained.The mechanism and phenomenon of this phase transition provide a basis for the future application of yellow phase CsPbI₃ nanowires in optoelectronic devices.