Photoelectric Properties And Property Research Of Two-dimensional Perovskite Material (PEA)₂PbBr₄

Currently,various emerging optoelectronic information technologies are developing rapidly,and the development of new efficient and intelligent optoelectronic devices and systems has become the goal of researchers.Guided by this goal,the selection and design of advanced device architectures and novel optoelectronic materials has become a major trend in the development of future information technologies.Among them,two-dimensional organic-inorganic hybrid perovskite have become one of the outstanding candidates for various optoelectronic devices.It combines the unique advantages of 2D and perovskite materials,such as the unique layered structure properties of 2D materials,excellent material tunability,high light absorption coefficient,high mobility of perovskite,etc.,which injects new vitality into the field of optoelectronic devices in terms of performance enhancement,functional expansion,high integration and flexible wearability.Currently,there are relatively few studies on materials and devices for two-dimensional organic-inorganic hybrid perovskite,and there are still a large number of problems that need to be explored and solved.This thesis hopes to make some useful exploration in this direction:taking two-dimensional organic-inorganic hybrid perovskite as the main research object,through two-dimensional organic-inorganic hybrid chalcogenide material design and synthesis,related device architecture design,heterojunction interface regulation and other methods,to master the performance characteristics and optimization laws of two-dimensional perovskite optoelectronic devices for different application scenarios,to complete the research from basic material synthesis,device architecture design to The research work will be completed from basic material synthesis,device architecture design to device performance optimization.Specifically,the main contents of this thesis include the following aspects:(1)Synthesis of two-dimensional(PEA)₂Pb Br₄ nanosheets and application of optoelectronic propertiesTwo-dimensional(PEA)₂Pb Br₄ nanosheets were successfully synthesized by anti-solvent dispersion method.The effects of different ligands and volume factors on the optoelectronic properties of nanosheets were explored by UV-vis and PL characterization.It was concluded that(PEA)₂Pb Br₄ nanosheets had the highest absorption and photoluminescence properties when 10?L of octylamine ligand was selected,and ultrathin(PEA)₂Pb Br₄ nanosheets with a thickness of only 40 nm were measured by AFM characterization.This is due to the fact that octylamine,as a commonly used surfactant,participates in the regulation of precursors,and long-chain alkylamines also play a key role in controlling the crystallization kinetics to obtain small-sized nanoparticles,which can promote the perovskite microparticles.The crystals are exfoliated and reduced to nanoscale crystals,resulting in the exfoliation of the layered nanosheets,so the nanosheets have good optoelectronic properties.On this basis,a photoconductive device with(PEA)₂Pb Br₄ nanosheets as the light absorbing layer was synthesized.The IV curve It shows that the device has obvious photoresponse characteristics under the irradiation of 405nm ultraviolet light(power is 1.33 m W).The photoresponse exceeds two orders of magnitude,indicating that the fabricated photoconductive device has good photodetection performance.(2)Two-dimensional perovskite(PEA)₂Pb Br₄ thin film/organic semiconductor heterojunction transistor device application researchTwo-dimensional(PEA)₂Pb Br₄ and(PEA)₂Pb Br₄/PVP hybrid films were prepared by one-step solution spin coating,and the crystalline properties of the as-prepared films were verified by XRD characterization.As a film former,PVP was introduced into perovskite to make the film smoother.(PEA)₂Pb Br₄-PVP/pentacene heterojunction transistors were prepared when the mixed solutions were prepared in a volume ratio of3:1.But the conductivity of the mixed film was reduced,resulting in a device performance degrades rapidly,and when its memory behavior is tested,efficient memory cannot be achieved.On this basis,(PEA)₂Pb Br₄/PDPPBTT heterojunction transistors were studied and fabricated.The transistors have typical P-channel transfer and output characteristics,and the switching ratio of the devices is greater than 10~2A.We tested the optical properties of the transistor devices.Based on the transfer characteristic curves under both 405 nm and 800 nm illumination,obvious photoresponse appeared.This non-overlapping absorption peak broadened the photoresponse behavior of the device.On the other hand,transistor-type devices are designed for storage applications.We tested the transfer cycle curves in the high gate voltage scan range,as well as the switching retention time and the read-write-erase cycle.It was found that the device has obvious hysteresis behavior,and the obtained The storage window is greater than 160V;the storage on-off ratio can reach 102 A in a holding time of 100 seconds,and there is a little instability in 100 read-write-erase cycles,which may be caused by the instability of the(PEA)2Pb Br4 film under air of.