Study On The Properties Of Halogenated Perovskite And Its Application

In recent years,metal halide perovskite materials have received widespread attention in the field of photovoltaic cells,and their excellent optical properties and lower costs have promoted the application and development of metal halide perovskite materials.In 2009,organic-inorganic hybrid perovskites were first applied to solar cells as light-absorbing materials,and their photoelectric conversion efficiency increased from 3.8%to 25.4%.However,different halogen perovskites have different properties,and only by combining their properties can they be made into devices with higher requirements.This article starts from the performance of halogen perovskite materials,compares the performance of different halogen perovskites,selects different crystals and different preparation methods to prepare materials and make corresponding devices.Successfully produced photodetectors,high-brightness and wide-gamut LEDs,and photocells.Through a series of structural characterization and performance testing methods,the morphology,phase,composition,photoelectric properties,optical properties,and electrochemical properties of the perovskite materials were analyzed and studied.The main research contents and successes are as follows:(1)Halogen perovskite prepared by thermal deposition method and its applicationIn this chapter,CsPbBr₃ and Cs₄PbBr₆ crystals were successfully prepared by thermal deposition.And by washing with DMSO,the single crystal of Cs₄PbBr₆ was successfully separated.The differences in morphology of the two were studied by optical microscope and SEM,and the detailed optical and electrical properties of the two were studied by PL and equipment built by ourselves.It is concluded that there is a negative correlation between the photocurrent and PL.Both CsPbBr₃ perovskite has better photo-electric properties and Cs₄PbBr₆ perovskite has better photoluminescence properties.In addition,the applicable perovskite light sensor device is manufactured,and its detector head is only micron level,and it can visually show whether the measured light source exists or the strength of the light source through the software we write.(2)Study on the properties of zero-dimensional perovskite(A₄BX₆)prepared by trace solvents and its applicationIn this chapter,single crystals of Cs₄PbBr₆ were prepared by ultrasound-assisted methods and extended to other A₄BX₆ perovskites.Using a simple one-step synthesis method.And proved the superiority of the method.In the early stage of the experiment,by choosing different solvents,we found that Cs₄PbBr₆ with different crystal forms can be obtained.It was proved that the crystal performance of Cs₄PbBr₆ was quickly synthesized by using DMSO in trace amounts by sonication.It is known from PL that it shows strong fluorescence at 519 nm and has a lifetime of 10 ns.A green light-emitting device based on this was produced,and a maximum brightness of 3.8×10₉ cd m_-2 was achieved.By combining with a commercially available phosphor,a white LED was produced,which can cover 32.3%of the color gamut,respectively.It accounted for 107.3%of CIE1931 and 84.8%of CIE1976.(3)Study on electrochemical performance of lithium ion-doped perovskite and its applicationIn this chapter,perovskite obtained by thermal deposition is used as a raw material,and a lithium perchlorate solution is used as an electrolyte for electrochemical doping.A perovskite material with superior photoelectric properties was obtained.We found that the electrochemically doped perovskite can maintain its crystal structure while still undergoing electrochromic phenomena.Our absorbance test shows that the absorbance of the crystal has increased significantly.And the results of the PL test found that the blue emission of the crystal's emission spectrum was caused by the Burstein-Moss effect.It was determined that the lithium ion electrochemical doping was N-doped,and we also found that it also had a fluorescence enhancement effect and could The crystal can realize the characteristics of single crystal light emission under the condition of low voltage.Later,using the equipment built by ourselves to conduct photoelectric performance test analysis,we found that the light conversion performance of the doped perovskite crystal has been greatly improved,and has been improved by many orders of magnitude in different aspects.And a crystal with an external quantum efficiency of 0.24%and a continuous discharge of 21 min under the condition of photo-charging for 18 s was obtained.In addition to the light conversion performance,the obtained crystal also has a certain capacitance performance,with a capacity of 100-250F/g,which is 6orders of magnitude higher than that of an undoped crystal.And comparative experiments also prove that Cs₄PbBr₆ crystal is also suitable for electrochemical doping of lithium ions.In the end,through real-time electrochemical testing of perovskite crystals with different doping levels,we proved that electrochemical doping needs to reach a certain level to cause changes in the photoelectric properties of perovskite.