带隙
钙钛矿(结构)
电子能带结构
原子轨道
材料科学
光电子学
电子结构
有效质量(弹簧-质量系统)
直接和间接带隙
凝聚态物理
化学
物理
结晶学
电子
量子力学
作者
Gang Tang,Vei Wang,Yajun Zhang,Philippe Ghosez,Jiawang Hong
标识
DOI:10.1016/j.jpowsour.2021.230546
摘要
The electronic orbital characteristics at the band edges play an important role in determining the electrical, optical and defect properties of perovskite photovoltaic materials. It is highly desirable to establish the relationship between the underlying atomic orbitals and the optoelectronic properties as a guide to maximize the photovoltaic performance. Here, using first-principles calculations and taking Ruddlesden-Popper (RP) phase layered perovskites Csn+1GenIn+1Cl2n as examples, we demonstrate how to rationally optimize the optoelectronic properties (e.g., band gap, transition dipole matrix elements, carrier effective masses, bandwidth) through a simple band structure parameter. Our results show that reducing the splitting energy |Δc| between the in-plane px,y and out-of-plane pz orbitals at the conduction band minimum (CBM) can effectively reduce the band gap and carrier effective masses while greatly improving the optical absorption in the visible region. Thereby, the orbital-property relationship with Δc is well established through biaxial compressive strain. Finally, it is shown that this approach can be reasonably extended to several other non-cubic halide perovskites with similar p orbitals characteristics at the conduction band edge. Therefore, we believe that our proposed orbital engineering approach will provide atomic-level guidance for understanding the performance limits of layered perovskite solar cells.
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