CH3NH3HgI3晶体的生长及光电性能研究

Growth and Photoelectric Properties of CH3NH3HgI3 Crystal

为探究有机金属卤化物CH3NH3HgI3的结构与光电性能间的内在规律,采用溶剂挥发法以甲基碘化胺(CH3NH3I)和碘化汞(HgI2)为反应物,以N,N-二甲基甲酰胺(DMF)为溶剂合成CH3NH3HgI3多晶粉末;以甲醇(CH3OH)为溶剂在氧化铟锡(ITO)导电玻璃上生长了CH3NH3HgI3薄膜。利用X射线衍射仪(XRD)、紫外-可见-近红外分光光度计(UV-VIS-NIR)及电流电压测试仪(CVIV)表征其结构及光电性能。研究结果表明:制备的CH3NH3HgI3粉体为单一晶相结构;CH3NH3HgI3晶体存在多个范德华键作用面。薄膜的电阻率约为10^9Ω·cm;薄膜的禁带宽度为2.8 eV,其可见-近红外波段存在多个吸收峰,与薄膜中大量的结构缺陷有关。分析认为CH3NH3HgI3可应用于紫光探测领域。

The relationship between the structure and photoelectric properties of the organometallic halide methylamine mercuric iodine(CH3NH3HgI3)is investigated.The polycrystalline powder was synthesized by the solvent volatilization method with methylamine iodide(CH3NH3I)and mercuric iodide(HgI2)as reactants and N,N-dimethylformamide(DMF)as solvent;CH3NH3HgI3 thin films grew on the Indium Tin Oxide(ITO)conductive glass with methanol(CH3OH)as solvent.The structures of both the powder and thin films were analyzed with an XRD.The optical properties of the thin films were investigated with an Ultraviolet-Visible-Near-Infrared Spetrophotometer,and their electrical properties were measured with a CVIV instrument.The test showed that CH3NH3HgI3 powder had the pure crystalline phase structure.The analysis of its structure showed that there existed several weak bonding surfaces of van der Waals bond in CH3NH3HgI3 crystal structure.The thin films had a resistivity of about 10^9Ω·cm and a bandgap of about 2.8 eV,and several absorption peaks occurred in the visible-near infrared region,which is related to the presence of a large number of structural defects in the films.It is concluded that CH3NH3HgI3 can be used in the field of violet ray detection.