Synthesis And Properties Of Organic-inorganic Hybrid Lead Iodide

The photoelectric conversion efficiency of perovskite based solar cells applied with organic-inorganic hybrid lead iodides can be up to 20%,which is comparable with silicon based solar cells.It can greatly reduce the production cost and energy consumption of solar cells,and can improve its cost performance.Therefore,great interest has been stimulated.However,current material of the solar cells-CH3NH3PbX3 has a deadly deficiency,being easily hydrolyzed in moist atmosphere.In order to improve the stability and the controllability,it is necessary to prepare new perovskite-like materials.In this thesis,several new stable layered lead iodides were synthesized and the properties were investigated,here is the main content:In introduction,the development history and the latest research progress of perovskite based solar cells were reviewed briefly.Then the synthesis methods and the structures of solar cells materials were introduced,and the improvement directions of perovskite based solar cells were summarized.Finally,the significance and the main contents of the thesis were introduced.In chapter 2,two new layered lead iodides,(H2Aepz)3Pb4I14(1)and(H2Aepz)PbI4(2)were synthesized by solvothermal method.As far as we know,only small organic cations such as methylammonium can incorporate into the multi-layered perovskite structure except the cations sandwiched between the inorganic layers at present.We first discovered compound 1,where larger organic cations,bis-protonated 2-(2-aminoethyl)pyrazole(Aepz),not only sandwiched between the inorganic layers,but also incorporated within the perovskite-like PbI layered structure.Another 2-D compound(H2Aepz)PbI4(2)was also prepared that is a single layer perovskite.A simple schottky device was prepared to investigate the photoelectro-responsive properties of the compounds.Finally the relationship of their photocurrent densities with the crystal structures and band energy gaps was also discussed.In chapter 3,three new compounds C6H5NH2(CH3)Pbl4(3),C6H5NH2(CH2CH3)PbI3(4)and C6H5NH(CH3)2PbI3(5),whose organic cations were N-methylaminobenzene,N-ethylaminobenzene and N,N-dimethylaniline,respectively,were synthesized by solvothermal method.The crystal structures of these compounds were determined by single crystal X-ray diffraction.Compound 3 is a 2-D single layer perovskite,compounds 4 and 5,who share the same chemical formula,have 1-D chains.Finally the photocurrent response properties of these compounds were measured.