Photoelectric Properties Of Inorganic Perovskite And Its Applications

Due to its characteristics of high optical anisotropy,high optical absorption coefficient and excellent stability,inorganic perovskite materials have been used to prepare photoelectric response devices with high efficiency,low cost,low dark current and long service life,which have attracted wide attention in recent years.However,it is difficult to control the crystallinity of perovskite materials during the crystallization process,resulting in many defects,poor morphology,interface carrier recombination and other shortcomings,which seriously limit the development and application of perovskite materials in commercial development.In this paper,two kinds of cesium-based materials,inorganic lead-free perovskite Cs Pb Br3 and inorganic lead-free double perovskite Cs2 Ag Sb Br6 materials,were systematically studied.The effects of the introduction of natural dyes and ion doping on the performance of two kinds of photoresponse devices,solar cells and photodetectors,were respectively investigated.The perovskite films were modified by introducing additives and doping elements respectively.The main contents are as follows:(1)The natural dyes turmeric and carotene were added as additives to the precursor solution of Cs Pb Br3 perovskite for film optimization.The energy level of perovskite layer was adjusted to optimize the energy level matching of each layer of the device,which is conducive to carrier transmission;The surface and cross section of the film were characterized.It was found that the grain size of perovskite increased with the introduction of dye,and the pores of the film were improved obviously.The current density and voltage curve(J-V)showed that the photoelectric conversion efficiency(PCE)of the device with turmeric and carotene were 9.78% and 7.81%,respectively.Compared with pristine Cs Pb Br3,the PCE(5.35%)is improved.This is because the dye itself has good light absorption performance and can make the perovskite level more match with other levels of the device.At the same time,the prepared device has high stability and can still maintain good photoelectric efficiency after 90 days without packaging in the air.(2)The effect of Bi ion doping ratio on the photoelectric response performance of Cs2 Ag Sb Br6 perovskite thin films was studied by regulating Bi ion doping ratio.The introduction of different Bi atomic ratio(at%)can reduce the energy gap of double perovskite.It is found through morphology and phase analysis and other characterization methods that doping ions are beneficial to the crystallinity of grains,which is conducive to the migration of carrier.Then electrochemical tests are carried out,and the results of the timing current and time curve(I-t)curve show that,compared with the pristine Cs2 Ag Sb Br6,the response parameters of Bi devices doped with 0.35 at% are slightly improved.The current switching ratio increases from 50.57 to 94.36,and the response time decreases from 13.23 ms and 24.01 ms to 5.98 ms and 8.88 ms.The responsivity increased from 11.06 m A/W to 19.34 m A/W,and the specific detection rate increased from 1.42×108 Jones to 2.47×108 Jones.,which verifies the feasibility of single doping Bi ions in double perovskite system.(3)On the basis of the previous part of the study,further doping Co ion,perovskite composition is Cs2Bi0.35 Ag Sb0.65-x Cox Br6.Firstly,the single-doping experiment of Co ion was carried out,and it was found that the performance of the doped device will be improved.But the enhancement effect of the doped device of 0.03 at% and 0.06 at% was close,and the optimal ratio was not obtained.Subsequently,Co ion with different atomic ratio was introduced on the basis of Cs2 Ag Bi0.35Sb0.65Br6.The I-t curve shows that when0.03 at% Co is doped,the device prepared by co-doping method has higher photoelectric performance.The switching ratio is 117.98,the response time is 1.96 ms,4.51 ms,the responsivity is 22.64 m A/W and the specific detection rate of 3.05×108 Jones,which are superior to the optimal parameters of Bi ion single doping.This fully verifies the feasibility of co-doping elements to improve the performance of photodetector devices.