Construction Of Perovskite Microstructure Arrays And Application Of Light-Emitting

Halide perovskites（HPs）are emerging as candidates for next-generation optoelectronic devices due to their excellent optoelectronic properties,ease of processing,and good compatibility with flexible substrates.Structured HPs with periodic micro-or nano-patterns have recently attracted significant interest due to their potential to not only improve the efficiency of an individual device via the controlled arrangement of HP crystals into a given geometry,but also to technologically pixelate the device into arrays suitable for future commercialization.At present,the photoelectric properties of HPs have been deeply studied,and the preparation of patterned perovskite arrays is gradually diversified.The applications in laser arrays and phosphor-converted light-emitting diode have been developed rapidly.However,the reported HPs arrays still have some problems,such as complicated preparation method or high cost,the performance of optoelectronic devices still need to be optimized,and the toxicity of lead,which limit their further promotion.Based on this,this thesis focuses on the preparation of HPs microstructure arrays and the light-emitting applications.The main research contents are as follows:Firstly,we reported for the first-time halide perovskite micro-ring arrays.Using 2D colloidal crystals as templates,spin-coating perovskite precursor solutions on them,drying,removing the templates,and annealing to prepare CsPb Br₃ perovskite micro-ring arrays with highly ordered arrangement and uniform size.The diameters of the as-prepared perovskite rings can be controlled continuously by selection of template spheres with different sizes or additional annealing treatments.Dynamics analysis indicates that the shrinking of the precursor towards template spheres before perovskite crystallization is key for the formation of ring arrays.Besides,by controlling the shrink rate and crystallization rate,it is possible to obtain perovskite arrays with much more complex structures.The internal mechanism of regulating the size the micro-ring was revealed by scanning electron microscope characterization.The as-prepared CsPb Br₃ micro-ring array can be used in whispering gallery mode laser array with low threshold（～7.3μJ/cm²）.Secondly,Mn doped C₄N₂H₁₄Pb Br₄ micro-ring arrays and micro-rods with tunable size were grown in situ by using the above colloidal crystal template assisted growth method.Besides,the PL spectra of the as-prepared Mn-doped perovskite show three emission peaks,which are derived from intrinsic,self-trapping and Mn impurity respectively.The white emission can be obtained by adjusting the relative intensity of the emission peaks.The white LED device based on the as-prepared perovskite exhibits excellent parameters related to white light.The correlated color temperature,color rendering index and CIE color coordinates of the device are 5645 K,85 and（0.32,0.32）,respectively,and the color deviation value is less than0.009.Thirdly,to assemble HP nanocrystals（NCs）with better photoluminescence performance,a groove template-assisted assembly method was proposed.Using this method,HP NCsmicrorods,microrings and microdisk arrays with high photoluminescence efficiency,uniform size and highly ordered arrangement are successfully assembled.Besides,the successful patterning of two different kinds of HP NCssynthesized by surface engineering or doping strategies suggests the universality of this method.Compared with the 2D colloidal crystal template method,the HP array obtained by using the groove template show better order,more array morphology,and wider application range.Finally,to solve the toxicity problem of lead-based HP,lead-free copper doped halide NCswere prepared by ultrasonic method.As-prepared NCsshow good size uniformity,high photoluminescence quantum yield,good environmental and ultraviolet light stability.In addition,the emission wavelength of NCscan be adjusted by changing the halogen composition.It is analyzed that the luminescence of NCsis caused by monovalent copper and the charge transfer process from ligand to metal.Such NCscan be used to build phosphor-converted LED.