Synthesis And Photoelectric Performance Study Of Bismuth And Manganese Based Organic-inorganic Hybrids Perovskite Molecular Materials

With the development of science and technology,people have higher requirements for functional materials,and the single-performance materials can no longer meet daily needs.Compared with the traditional single component inorganic/organic materials,organic-inorganic hybrid materials had become research focus in materials,chemical,medical and cross-disciplinary research due to its simple manufacturing process,superior performance combining organic materials and inorganic materials.Based on these,our resrach selected low-toxicity trivalent bismuth ions and low-cost divalent manganese ions as the inorganic framework.And the benzylamine,ethylenediamine and 2-amino-4 methylpyridine were used as organic groups.Six types of organic-inorganic hybrid monocrystals were synthesized by solvent volatile method and hydrothermal synthesis method.A series of characterizations of the crystal structure,morphology and photoelectrochemical stability were carried out,and its application in thin-film solar cells was explored.This paper mainly includes three parts as follows:?1?Bismuth oxide was used as the basic inorganic skeleton of the trivalent bismuth ion source and reacted with benzylamine and hydrohalic acid.Three organic-inorganic hybrids werepreparedbyhydrothermalcrystallization:?C₆H₅CH₂NH₃?₂Bi₂Cl₁₀,?C₆H₅CH₂NH₃?₂Bi₂Br₁₁1 and?C₆H₅CH₂NH₃?BiI₄.The single crystal diffraction results showed that the?C₆H₅CH₂NH₃?₂Bi₂Cl₁₀0 had a typical 2D layered structure at room temperature and belonged to P2_1/c space group with monoclinic system;The?C₆H₅CH₂NH₃?₂Bi₂Br₁₁ space group was P-1 and belonged to triclinic crystal system with a 0-dimensional point structure;?C₆H₅CH₂NH₃?Bi I₄ space group was P2_1/n and belonged to monoclinic crystal system with a1D chain structure.UV-vis and TGA indicated that the optical band gap value was 3.21 eV and the thermal stability reached 250?for?C₆H₅CH₂NH₃?₂Bi₂Cl₁₀;?C₆H₅CH₂NH₃?₂Bi₂Br₁₁had a optical band gap of 2.55 eV and the thermal stability was up to 230?;and the thermal stability of?C₆H₅CH₂NH₃?BiI₄ can reach 290?with a band gap value of 1.67 eV.?2?Reacting with hydrobromic acid by using manganese carbonate as a source of divalent manganese ions,2-amino-4-picoline and ethylenediamine as organic groups,respectively.Two Mn-based organic-inorganic hybrids were prepared by the slow evaporation method:?C₆H₉N₂?₂MnBr₄ and?NH₃CH₂CH₂NH₃?₂MnBr₆.?C₆H₉N₂?₂MnBr₄ was the triclinic system with P-1 space group,and had a 0D point structure.?NH₃CH₂CH₂NH₃?₂MnBr₆ had a center symmetric structure with the orthorhombic system,Pnma space group,and also had a0D point structure.TGA and UV-vis showed that?C₆H₉N₂?₂MnBr₄ was stable below 200?with a band gap value of 2.18 eV;?NH₃CH₂CH₂NH₃?₂MnBr₆ had higher thermal stability,which can reach 288?and the optical band gap value was 2.61 e V.The PL test results showed that?C₆H₉N₂?₂MnBr₄ exhibited strong fluorescence at 525 nm under the 350 nm excitation and its relative intensity was 817860 cps.When?NH₃CH₂CH₂NH₃?₂MnBr₆ was irradiated with excitation light at 350 nm,the fluorescence emission peak was at 537 nm,and the relative fluorescence intensity was 8362 cps.?3?On the basis of our previous work,the?NH₃CH₂CH₂NH₃?Bi_xSb_1-xI₁₀ single crystal was prepared by hydrothermal crystallization with B-site doping.Compared with the undoped?NH₃CH₂CH₂NH₃?Bi₂I₁₀,crystal volume and size was significantly increased with 1.8*0.8mm of?NH₃CH₂CH₂NH₃?Bi_xSb_1-x-x I₁₀.?NH₃CH₂CH₂NH₃?Bi_xSb_1-xI₁₀0 was crimson with the irregular lumpy.The TGA results proved that the thermal stability can reach 330?with a bandgap value of 1.70 eV.Based on that,the?NH₃CH₂CH₂NH₃?Bi_xSb_1-xI₁₀ thin films was prepared on the ITO/NiO substrate by a one-step spin coating method of precursor dissolution,and its photoelectric thermal stability was preliminary studied.The?NH₃CH₂CH₂NH₃?Bi_xSb_1-xI₁₀ thin films prepared under this optimal process condition had good compactness and high coverage with about 1?m thickness.EDX results showed that the I:?Bi+Sb?ratio was 4.60 of?NH₃CH₂CH₂NH₃?Bi_xSb_1-x-x I₁₀ thin films sample,which was consistent with the ratio of the?NH₃CH₂CH₂NH₃?Bi_xSb_1-xI₁₀ single crystal sample.Finally,the voltage value of the NiO/?NH₃CH₂CH₂NH₃?Bi_xSb_1-x-x I₁₀ half-cell structure was measured to be 70 mV.