Impact of the Solvation State of Lead Iodide on Its Two-Step Conversion to MAPbI3\n: An In Situ Investigation
Liu, Shengzhong Frank
Anthopoulos, Thomas D.
KAUST DepartmentKAUST Solar Center (KSC)
Material Science and Engineering Program
Office of the VP
Organic Electronics and Photovoltaics Group
Physical Science and Engineering (PSE) Division
Permanent link to this recordhttp://hdl.handle.net/10754/630962
MetadataShow full item record
AbstractProducing high efficiency solar cells without high-temperature processing or use of additives still remains a challenge with the two-step process. Here, the solution processing of MAPbI3 from PbI2 films in N,N-dimethylformamide (DMF) is investigated. In-situ grazing incidence wide-angle X-ray scattering (GIWAXS) measurements reveal a sol–gel process involving three PbI2-DMF solvate complexes—disordered (P0) and ordered (P1, P2)—prior to PbI2 formation. When the appropriate solvated state of PbI2 is exposed to MAI (methylammonium Iodide), it can lead to rapid and complete room temperature conversion into MAPbI3 with higher quality films and improved solar cell performance. Complementary in-situ optical reflectance, absorbance, and quartz crystal microbalance with dissipation (QCM-D) measurements show that dry PbI2 can take up only one third of the MAI taken up by the solvated-crystalline P2 phase of PbI2, requiring additional annealing and yet still underperforming. The perovskite solar cells fabricated from the ordered P2 precursor show higher power conversion efficiency (PCE) and reproducibility than devices fabricated from other cases. The average PCE of the solar cells is greatly improved from 13.2(±0.53)% (from annealed PbI2) to 15.7(±0.35)% (from P2) reaching up to 16.2%. This work demonstrates the importance of controlling the solvation of PbI2 as an effective strategy for the growth of high-quality perovskite films and their application in high efficiency and reproducible solar cells.
CitationBarrit D, Cheng P, Tang M-C, Wang K, Dang H, et al. (2019) Impact of the Solvation State of Lead Iodide on Its Two-Step Conversion to MAPbI3\n: An In Situ Investigation. Advanced Functional Materials: 1807544. Available: http://dx.doi.org/10.1002/adfm.201807544.
SponsorsD.B. and P.C. contributed equally to this work. This work was supported by the King Abdullah University of Science and Technology (KAUST), National Natural Science Foundation of China (61604092), and National University Research Fund (GK201802005). CHESS is supported by the NSF via NSF award DMR-1332208. A.A. conceived the project. A.A., K.Z., and T.D.A. supervised the work. D.B. and P.C. performed all of the experiments. M.T., K.W., H.D., and D.-M.S. helped to acquire the GIWAXS measurements. S.(F.)L. helped with useful discussions of device fabrication. All the authors contribute to the writing of the Manuscript.
JournalAdvanced Functional Materials