Structural, Electronic, and Optical Characterizations of the Interface between CH3NH3PbI3 and BaSnO3 Perovskite: A First-Principles Study

• Published in: Journal of physical chemistry. C 2019-07, Vol.123 (26), p.16075-16082
• Main Authors: Guo, Yao, Xue, Yuanbin, Geng, Cuihuan, Li, Chengbo, Li, Xianchang, Niu, Yongsheng
• Format: Article
• Language: English
• ISSN: 1932-7447; 1932-7455
• DOI: 10.1021/acs.jpcc.9b01088

The interfaces play a significant role in enhancing the photoelectric properties and stability of the perovskite solar cells (PSCs). In this work, we performed first-principles density-functional-theory (DFT) calculations to examine the interaction between CH3NH3PbI3 and BaSnO3 perovskite. The interfacial structure–property relationships of pristine CH3NH3PbI3/BaSnO3 have been thoroughly explored by theoretical computations. The results of interfacial binding strength and electronic structure indicate that the combination of SnO2/PbI2 has the strongest interfacial interaction and charge transfer capability. The enhanced interfacial interaction between CH3NH3PbI3 and BaSnO3 is beneficial for electron–hole separation. Moreover, the lanthanum-doped CH3NH3PbI3/BaSnO3 interfaces are also investigated to explore the impact of lanthanum doping on the properties of CH3NH3PbI3/BaSnO3. The geometric, electronic, and optical characteristics of the CH3NH3PbI3/BaSnO3 interface with lanthanum dopant at different positions have been evaluated. We found that lanthanum dopant was energetically stable at the subsurface layer. The doping depth has a negligible influence on the interfacial charger transfer. Lanthanum doping has been demonstrated to be workable for enhancing the n-type conductivity in BaSnO3 while the excellent transport property is preserved. La incorporations effectively reduce the conduction band level of BaSnO3, which will make the interfacial band alignment more suitable for the electron transfer. Finally, the absorption coefficients and interband transitions are well estimated to understand the light trapping capacity. This work provides an atomic insight into the interfacial interaction between CH3NH3PbI3 and BaSnO3, which can help us to obtain to new strategies for optimizing the PSCs interfaces.