Stable High-Performance Perovskite Solar Cells via Grain Boundary Passivation
Liu, Shengzhong Frank
KAUST DepartmentKAUST Solar Center (KSC)
Material Science and Engineering Program
Organic Electronics and Photovoltaics Group
Physical Science and Engineering (PSE) Division
Online Publication Date2018-03-12
Print Publication Date2018-04
Permanent link to this recordhttp://hdl.handle.net/10754/627469
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AbstractThe trap states at grain boundaries (GBs) within polycrystalline perovskite films deteriorate their optoelectronic properties, making GB engineering particularly important for stable high-performance optoelectronic devices. It is demonstrated that trap states within bulk films can be effectively passivated by semiconducting molecules with Lewis acid or base functional groups. The perovskite crystallization kinetics are studied using in situ synchrotron-based grazing-incidence X-ray scattering to explore the film formation mechanism. A model of the passivation mechanism is proposed to understand how the molecules simultaneously passivate the Pb-I antisite defects and vacancies created by under-coordinated Pb atoms. In addition, it also explains how the energy offset between the semiconducting molecules and the perovskite influences trap states and intergrain carrier transport. The superior optoelectronic properties are attained by optimizing the molecular passivation treatments. These benefits are translated into significant enhancements of the power conversion efficiencies to 19.3%, as well as improved environmental and thermal stability of solar cells. The passivated devices without encapsulation degrade only by ≈13% after 40 d of exposure in 50% relative humidity at room temperature, and only ≈10% after 24 h at 80 °C in controlled environment.
CitationNiu T, Lu J, Munir R, Li J, Barrit D, et al. (2018) Stable High-Performance Perovskite Solar Cells via Grain Boundary Passivation. Advanced Materials: 1706576. Available: http://dx.doi.org/10.1002/adma.201706576.
SponsorsK.Z. and T.N. designed and performed most of the experiments. R.M., D.B., and A.A. acquired in situ GIWAXS measurements and analyzed the data. J.L., J.L., and Z.Y. helped SEM test and TRPL measurements. H.H. performed TEM measurements. X.Z. helped trap density measurements. K.Z., A.A., S.(F.)L., and T.N. contributed to the writing of the paper. This work was supported by the National Key Research and Development Program of China (2017YFA0204800, 2016YFA0202403), National Natural Science Foundation of China (61604092, 61674098), National University Research Fund (Grant Nos. GK261001009, GK201603055), the 111 Project (B14041), and National 1000-talent-plan program (1110010341). GIWAXS measurements were performed at D-line in the Cornell High Energy Synchrotron Source (CHESS) and helped by the King Abdullah University of Science and Technology (KAUST). CHESS is supported by the NSF Award DMR-1332208.