Guo YuJia, Su Jie, Wang Lu, Lin Zhenhua, Hao Yue, Chang Jingjing
State Key Discipline Laboratory of Wide Band Gap Semiconductor Technology, Shaanxi Joint Key Laboratory of Graphene, School of Microelectronics, Xidian University, Xi'an 710071, China.
Advanced Interdisciplinary Research Center for Flexible Electronics, Xidian University, Xi'an 710071, China.
J Phys Chem Lett. 2021 Apr 8;12(13):3393-3400. doi: 10.1021/acs.jpclett.1c00611. Epub 2021 Mar 31.
Reducing the toxic Pb component in perovskites is an important step to realize environment-friendly perovskite optoelectronic devices. Herein, the structural, electronic, and optical properties of Zn and Mn codoped CsPbBr have been investigated based on first-principle calculations and experimental verifications. Although the Zn dopant could reduce the optical band gap and exciton binding energy and enhance the optical absorption and defect tolerance for CsPbBr, the maximum reduction of the toxic Pb component was just about 12.5% in the experiment because the Zn dopant enlarges the formation energy of CsPbZnBr. For the stable CsPbMnZnBr perovskite, the largest and corresponding ( + ) could reach up to 25% and 83% respectively, since the Mn dopant could reduce the structural disorder. Especially when ( + ) < 50%, CsPbMnZnBr exhibits a comparable carrier lifetime and exciton binding energy with a lower band gap to those of the CsPbBr, since the Zn dopant supplies a charge to CsPbBr to counteract the variation of Pb-Br bonds induced by the Mn dopant. Meanwhile, the d orbitals of the dopant increase the optical absorption. These suggest that a 50% reduction of toxic Pb could be realized for stable CsPbMnZnBr with negligibly deteriorated optoelectronic properties. This work provides an alternative approach to achieve a Pb-less perovskite with a high performance.
降低钙钛矿中有毒的铅成分是实现环境友好型钙钛矿光电器件的重要一步。在此，基于第一性原理计算和实验验证，研究了锌和锰共掺杂的CsPbBr的结构、电子和光学性质。虽然锌掺杂剂可以降低CsPbBr的光学带隙和激子结合能，并增强其光吸收和缺陷容忍度，但在实验中有毒铅成分的最大降低量仅约为12.5%，因为锌掺杂剂增大了CsPbZnBr的形成能。对于稳定的CsPbMnZnBr钙钛矿，最大的 和相应的( + )分别可达25%和83%，因为锰掺杂剂可以减少结构无序。特别是当( + ) < 50%时，CsPbMnZnBr表现出与CsPbBr相当的载流子寿命和激子结合能，且带隙更低，因为锌掺杂剂向CsPbBr提供电荷以抵消锰掺杂剂引起的Pb - Br键变化。同时，掺杂剂的d轨道增加了光吸收。这些表明，对于稳定的CsPbMnZnBr，可以实现有毒铅成分降低50%，且光电性能的恶化可忽略不计。这项工作为实现高性能无铅钙钛矿提供了一种替代方法。
