Controlled Vapor Deposition Synthesis Of Perovskite Nanomaterials And Their Optoelectronic Properties

Lead halide perovskite nanomaterials have excellent optoelectronic properties,which lead to many applications in this field.The precise and controllable preparation of high-quality perovskite nanomaterials is the basis for the research of perovskite properties and applications.There are two methods to synthesize perovskite nanomaterials:liquid phase method and vapor phase method.The liquid phase method is inexpensive,but it is usually difficult to avoid the introduction of impurity ions,resulting in poor crystallinity and degrading its performance.While for the vapor phase method,it can completely avoid impurity ion pollution to preserve good crystallinity.Besides,both the morphology and composition can be precisely regulated by vapor deposition.Therefore,vapor phase method is the first choice for the preparation of high-quality perovskite nanomaterials.However,the high cost and difficulty in mass produce of nanomaterials greatly limit the further application of this method.To further improve the controllability of the product,or to reduce the cost are two aims in vapor deposition method.Through the design of a new preparation process,this paper aims to achieve the controllable preparation of perovskite nanomaterials and reduce the cost of vapor deposition method.The main results list as follows:1.Controllable synthesis of uniform perovskite precursor PbI₂ nanosheets and MAPbI₃nanosheets.By introducing the confined space into physical vapor deposition method,we synthesized PbI₂ nanosheets with uniform shape and size.The confined space provided a relatively stable growth environment and avoided the kinetic instability during the growth process,thereby achieving its controlled uniform growth of PbI₂ nanosheets.Using PbI₂nanoplatelets as the precursor,the MAPbI₃ nanosheets were prepared by vapor deposition method.Corresponding characterization demonstrated that the MAPbI₃ nanosheets have high crystallinity and excellent optical properties.2.Synthesis of CsPbBr₃ nanowire arrays with high-efficiency and low cost.A hot plate assisted vapor deposition method was used to prepare perovskite nanomaterials for the first time.CsPbBr₃ nanowire arrays with uniform morphology and size were successfully obtained.Perovskite nanowire arrays of arbitrary composition with controllable length and diameter can be easily prepared just by changing the ratio of the source,the growth temperature and time.In addition,a laser based on CsPbBr₃ nanowires is tested,which showed a low threshold of27.4μJ/cm² and high quality factor about 1330.These parameters indicated that the perovskite with high crystallinity.We synthesized CsPbBr₃ nanowire arrays by a low cost vapor deposition method as well as maintain its high crystallinity.