单层Cs_(2)PbI_(2)Cl_(2)中点缺陷的形成与稳定性  

Formation and stability of point defects in monolayer Cs_(2)PbI_(2)Cl_(2)

作　　者：何诗颖 赵宇清 邹代峰[1,2] 许英 廖雨洁[1,2] 禹卓良 HE Shi-Ying;ZHAO Yu-Qing;ZOU Dai-Feng;XU Ying;LIAO Yu-Jie;YU Zhuo-Liang(School of Physics and Electronic Science,Hunan University of Science and Technology,Xiangtan 411201,China;Hunan Provincial Key Laboratory of Intelligent Sensors and Advanced Sensor Materials,Xiangtan 411201,China;School of Physics and Electronic Science,Hunan Institute of Science and Technology,Yueyang 414006,China)

机构地区：[1]湖南科技大学物理与电子科学学院,湘潭411201 [2]智能传感器与新型传感器材料湖南省重点实验室,湘潭411201 [3]湖南理工学院物理与电子科学学院,岳阳414006

出　　处：《原子与分子物理学报》2025年第5期130-136,共7页Journal of Atomic and Molecular Physics

基　　金：国家自然科学基金(12204166);湖南省教育厅青年基金(20B219);湖南科技大学科研启动基金(E51996)。

摘　　要：Cs_(2)PbI_(2)Cl_(2)是卤化铅钙钛矿材料的新成员,由于其高的光吸收系数和长的载流子迁移距离等优异的光电物理性能,在太阳能电池、光电探测器、场效应晶体管以及发光二极管等领域受到广泛的关注.其中光电材料及器件的优良特性由电子结构决定,而钙钛矿的点缺陷对电子结构具有重要的调控,且单层Cs_(2)PbI_(2)Cl_(2)中点缺陷的研究尚且缺乏.本文基于密度泛函理论的第一性原理计算,对单层Cs_(2)PbI_(2)Cl_(2)的铯空位、碘空位、氯空位、铯替代铅、碘替代铯、碘替代铅、碘替代氯、氯替代铯、氯替代铅和氯替代碘的缺陷形成能和稳定性进行了研究.结果表明:在富铅和缺铅条件下,碘替代氯和氯替代碘的缺陷形成能偏低,且氯替代碘能有效降低体系总能,提高体系稳定性.在缺铅条件下铯空位缺陷形成能低于富铅条件,在缺铅条件下更易形成铯空位;富铅和缺铅条件下对碘替代氯和氯替代碘的缺陷形成能基本无影响.上述研究结果有助于理解点缺陷对钙钛矿材料稳定性的影响,同时也为未来实验上设计基于Cs_(2)PbI_(2)Cl_(2)的高效的光电子器件提供理论依据.Cs_(2)PbI_(2)Cl_(2) is a new member of lead halide perovskite materials.Due to its excellent photoelectric physical properties such as high optical absorption coefficient and long carrier migration distance,Cs_(2)PbI_(2)Cl_(2) has received extensive attention in the fields of solar cells,photodetectors,field-effect transistors and light-emitting diodes.Among them,the excellent properties of photoelectric materials and devices are determined by the electronic structure.The point defects of perovskite play an important role in regulating the electronic structure,and the research on the point defects of monolayer Cs_(2)PbI_(2)Cl_(2) is still lacking.The defect formation energy and stability of cesium vacancy,iodine vacancy,chlorine vacancy,cesium replacing lead,iodine replacing cesium,iodine replacing lead,iodine replacing chlorine,chlorine replacing lead,chlorine replacing cesium,chlorine replacing lead and chlorine replacing iodine in monolayer Cs_(2)PbI_(2)Cl_(2) are studied based on the first principles of density functional theory.The results show that the defect formation energies of iodine replacing chlorine and chlorine replacing iodine are low under the conditions of lead rich and lead poor.Chlorine replacing iodine can effectively reduce the total energy of the system and improve the stability of the system.The formation of cesium vacancy defects under lead poor conditions is lower than that under lead rich conditions,and it is easier to form cesium vacancy under lead poor conditions.There is no effect on the defect formation of iodine replacing chlorine and chlorine replacing iodine under the conditions of lead rich and lead poor.These results help to understand the effect of point defects on the stability of perovskite materials,and also provide theoretical basis for the future experimental design of high-efficiency optoelectronic devices based on Cs_(2)PbI_(2)Cl_(2).

关 键 词：单层Cs_(2)PbI_(2)Cl_(2) 形成能 点缺陷 稳定性 

分 类 号：O474[理学—半导体物理]