摘要
运用第一性原理研究了MAPbI_(2)Cl/RbPbI_(3)、MAPbI_(2)Cl/RbSnI_(3)和MAPbI_(3)/RbSnI_(2)Cl异质结构(MA=CH_(3)NH_(3))的电子和光学性能。结果表明MAPbI_(3)/RbSnI_(2)Cl和MAPbI_(2)Cl/RbSnI_(3)结构具有半导体特性,其带隙分别为0.19和0.97 eV。通过有效质量计算表明,MAPbI_(2)Cl/RbSnI_(3)和MAPbI_(3)/RbSnI_(2)Cl可应用于光伏元件。此外,能态密度图显示在MAPbI_(3)/RbSnI_(2)Cl的结构中有二维电子气在结处形成。通过绘制z轴上的阴阳离子键长度变化及电势表面的分布情况,表明在MAPbI_(2)Cl/RbSnI_(3)和MAPbI_(3)/RbSnI_(2)Cl结构中存在类铁体。在三种物质中,反射率函数都具有较大的值且其性质类似于闪亮金属。此外,MAPbI_(2)Cl/RbSnI_(3)和MAPbI_(3)/RbSnI_(2)Cl异质结构在可见光范围内的吸收峰分别位于412和701 nm。
Electronic and optical properties of MAPbI_(2)Cl/RbPbI_(3),MAPbI_(2)Cl/RbSnI_(3) and MAPbI_(3)/RbSnI_(2)Cl heterostructures(MA=CH_(3)NH_(3)),were studied by first principle approach.Our calculations show that the MAPbI_3/RbSnI_(2)Cl and MAPbI_(2)Cl/RbSnI_(3) structures have semiconductor properties with gaps of 0.19 and 0.97 eV,respectively.The effective masses calculations show that the MAPbI_(2)Cl/RbSnI_(3) and MAPbI_(3)/RbSnI_(2)Cl can be used in photovoltaic devices.Also,the partial density of energy states(PDOS)diagrams show that in structure of MAPbI_(3)/RbSnI_(2)Cl,the twodimensional electron gas is formed at the junction.In the following,by plotting the changes in the length of anion-cation bonds in the z direction and analyzing the local distribution of electrical potential surfaces,a ferroelectric-like behavior can be seen in the MAPbI_(2)Cl/RbSnI_(3) and MAPbI_(3)/RbSnI_(2)Cl structures.Finally,in all cases,the reflectivity functions have large values and behave similar to shiny metals.Also,both MAPbI_(2)Cl/RbSnI_(3) and MAPbI_(3)/RbSnI_(2)Cl heterostructures have absorption peaks in the visible range that are located at 412 and 701 nm,respectively.
关键词
第一性原理
异质结构
钙钛矿
电子特性
二维电气
铁电行为
first principle calculations
heterostructure
perovskites
electronic properties
two-dimensional electron gas
ferroelectric behavior
