Optimization And Studies For The Performances Of Three And Quasi-Two Dimensional Bromide Based Organic-Inorganic Hybrid Perovskite Light Emitting Diodes

In this thesis,the bromine-based organic-inorganic hybrid perovskite used as the research subject to explore the photoelectric properties of three-dimensional perovskite materials and quasi-two-dimensional perovskite materials and the performance of perovskite light-emitting diode devices.We prepared and optimized light-emitting devices based on three-dimensional and quasi-two-dimensional perovskites,and we have done some work to study the dynamic transport of charge carriers and their photoelectric properties in such devices.The specific work is as follows:1.By adjusting the film thickness and annealing of perovskite,we prepared and optimized the three-dimensional bromo-based perovskite(CH3NH3PbBr3)LED device.A typical organic molecule bathocuproine(BCP)has been utilized during the preparation of methyl-ammonium lead tri-bromide(CH3NH3PbBr3)precursor,and a perovskite-based light emitting diode(PeLED)consisting of Glass/ITO/PEDOT:PSS/CH3NH3PbBr3:BCP/Bphen/Ag was fabricated.Owing to the participation of BCP,the PeLED exhibits excellent light emissive properties without any crystalline distortions of CH3NH3PbBr3,such as low turn-on voltage Vturn-on=2.5 V,high luminescent intensity L=1.4 × 104 cd/m2 and high efficiency ?=3.2 cd/A.Based on electronic transport and optically spectroscopic characterizations,it has been verified that such remarkable and desirable enhancements are attributed to three contributions,(?)a decrease of CH3NH3PbBr3 crystalline grain size,(?)a reduction of trap density(nt),and(?)an improvement of electronic charge mobility(?).2.We analyzed the photoelectric properties of bromine-based two-dimensional perovskite materials(PEA2(MAPbBr3)n-1PbBr4)under different n values by means of spectroscopy,ultraviolet absorption and XRD.A quasi-two-dimensional perovskite light-emitting diode device with n=4 was prepared and optimized.In the device preparation,the solvent vapor annealing optimization treatment method is introduced,which can reduce the film formation roughness of the quasi-two-dimensional perovskite and effectively suppress the leakage current of the device,thereby further improving the device performance.The brightness of the device optimized by solvent vapor annealing can be up to 3.6 x 103 cd/m2,and the current efficiency can reach 11.36 cd/A.We used an AC impedance spectroscopy test to analyze the effects of solvent atmosphere annealing on two-dimensional perovskite devices,which is beneficial to device carrier injection and improved exciton radiation recombination.It provides a new method for optimizing the film quality of quasi-two-dimensional perovskite...