钙钛矿CH₃NH₃PbBr₃电子结构和光吸收特性的第一性原理研究  

First-Principle Study of Electronic Structure and Optical Absorption of Perovskite CH3NH3PbBr3

作　　者：刘洪飞 王娜 张众维 

机构地区：[1]天津城建大学理学院,天津 [2]天津城建大学计算机与信息工程学院,天津

出　　处：《材料科学》2017年第1期64-71,共8页Material Sciences

基　　金：国家自然科学基金(批准号:11547123);天津城建大学科研启动项目(05140704,05147001).

摘　　要：本文采用基于密度泛函理论的第一性原理方法,研究了正交晶系(Pnma) CH3NH3PbBr3的电子结构和光吸收性质。结果表明,采用optB86b+vdWDF交换关联泛函计算得到的晶格结构和带隙宽度,与实验结果符合的很好,说明包含范德瓦尔斯作用的vdW-DF泛函能够更好的描述该体系的物理性质。态密度分析表明,有机分子CH3NH3对于价带顶和导带底的贡献较小,价带顶主要是由Br 4p轨道组成,导带底是由Pb 6p轨道组成。吸收系数计算结果表明材料在360 nm和430 nm附近出现两个吸收峰,且随着波长的增加,吸收强度呈现下降的趋势,以上结果为CH3NH3PbBr3在光电领域的应用提供可靠的理论基础。Using first-principle calculations based on density functional theory (DFT), we have studied the electronic structure and optical properties of orthorhombic perovskite CH3NH3PbBr3 (Pnma). The structural properties and band gap value calculated with the optB86b+vdWDF functional are in good agreement with experimental results. Thus, consideration of the vdW interactions is im-portant for theoretical investigation of CH3NH3PbBr3. The analysis of partial density of states shows that the organic CH3NH3 makes little contribution to the top valence (VBM) and bottom conduction bands (CBM). The VBM is mainly composed of Br 4p states, while the CBM is dominated by Pb 6p states. Calculated absorption coefficient of CH3NH3PbBr3 shows an absorption peak around 360 nm and a weak one around 430 nm. Meanwhile, absorption intensity decreases with the increase of wavelength. The above results can provide reliable guidance for its experimental application in optoelectronics.

关 键 词：第一性原理 CH₃NH₃PbBr₃ 电子性质 光吸收 

分 类 号：G6[文化科学—教育学]