The Study On Photoelectric Properties Of Inorganic Perovskite Prepared By Pulsed Laser Deposition And Enhanced By Plasmon

In recent years,inorganic perovskite material CsPb X₃（X=Cl,Br,I）has attracted much attention which is driven by the high-performance optoelectronic devices.It not only has excellent carrier diffusion length,but also has very high light quantum yield,so it is widely used in solar cells and LED light emitting devices.At the same time,the different aspects of inorganic perovskite improvement directions are inspired for different needs.For photoelectric devices such as solar cells,photodetectors,developing a film of good quality,and the preparation technology of high stability performance is particularly important for the LED and laser devices.Fluorescence wave length is adjustable,Fluorescence intensity enhancement is the primary consideration.Therefore,in this paper,the preparation process of inorganic perovskite film and its performance improvement are studied,and the achievements are listed as following:A solid-phase reaction method for CsPb I_xBr_3-x（x=0,1,2,3）thin films has been developed by using pulsed laser deposition（PLD）.The ratio of halogen elements x（x=0,1,2,3）in CsPb I_xBr_3-xthin films can be changed by selecting the two targets.Through the characterization of thin films,it is proved that the solid-phase reaction method has been successfully applied in the preparation of thin films,which have good crystallinity and small roughness.The effect of deposition sequence in solid phase reaction is explained by the calculated results of surface energy,and the Csprecursor film should be deposited first.The prepared film is applied to photoelectric detectors,achieving a good on-off ratio and long time stability under ultra-high humidity（90-95%）.By studying the grain size of the prepared films,it is found that the grain size of the films varies with the thickness of the films in the range of 40-150 nm,and bright fluorescence can be achieved in the case of small grains.By using the advantages of PLD and by designing metal mask,the fabrication of low cost and low pollution,high precision micron array（9.6μm）is realized.At the same time,it can also be used to prepare fluorescent patterns to realize the application in different scenes.By preparing films with large area（3 cm×3 cm）and high thickness（2.535μm）,it is proved that solid-phase reaction with PLD can be used in devices with different requirements.CsPb I₃quantum dots are prepared by thermal injection method and show bright red color under fluorescence meter.TEM test shows that the particles are evenly dispersed and have relatively uniform size,concentrated at about 15 nm.The fluorescence properties of the film are verified by absorption spectra and photoluminescence（PL）tests.The PL peak is about690 nm,which overlaps with the absorption band edge,and the half-width is about 35 nm,showing good fluorescence properties.The plasmonic crystals cavity structure Si O₂/Ag is further introduced,which is composed of Si O₂pellets with a diameter of 400 nm and 40 nm thick Ag plated on them.The insulating layer Al₂O₃is then plated on them to prevent direct contact between Ag and CsPb I₃.Finally,the CsPb I₃quantum dots are spun on it.The comparison of absorption spectra and PL tests shows that Si O₂/Ag/Al₂O₃/CsPb I₃film’s light absorption at 532 nm is about 10 times stronger than that of pure CsPb I₃film,resulting in about 10 times stronger fluorescence.Through Si O₂/Ag/Al₂O₃structure,the fluorescence enhancement of CsPb I₃is successfully realized,which lays a good foundation for its further application in LED or laser devices.