Room-Temperature Partial Conversion of α-FAPbI 3 Perovskite Phase via PbI 2 Solvation Enables High-Performance Solar Cells
Liu, Shengzhong (Frank)
Anthopoulos, Thomas D.
KAUST DepartmentKAUST Solar Center (KSC)
Material Science and Engineering
Material Science and Engineering Program
Physical Science and Engineering (PSE) Division
Online Publication Date2020-01-31
Print Publication Date2020-03
Embargo End Date2021-01-31
Permanent link to this recordhttp://hdl.handle.net/10754/661442
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AbstractThe two-step conversion process consisting of metal halide deposition followed by conversion to hybrid perovskite has been successfully applied toward producing high-quality solar cells of the archetypal MAPbI3 hybrid perovskite, but the conversion of other halide perovskites, such as the lower bandgap FAPbI3, is more challenging and tends to be hampered by the formation of hexagonal nonperovskite polymorph of FAPbI3, requiring Cs addition and/or extensive thermal annealing. Here, an efficient room-temperature conversion route of PbI2 into the α-FAPbI3 perovskite phase without the use of cesium is demonstrated. Using in situ grazing incidence wide-angle X-ray scattering (GIWAXS) and quartz crystal microbalance with dissipation (QCM-D), the conversion behaviors of the PbI2 precursor from its different states are compared. α-FAPbI3 forms spontaneously and efficiently at room temperature from P2 (ordered solvated polymorphs with DMF) without hexagonal phase formation and leads to complete conversion after thermal annealing. The average power conversion efficiency (PCE) of the fabricated solar cells is greatly improved from 16.0(±0.32)% (conversion from annealed PbI2) to 17.23(±0.28)% (from solvated PbI2) with a champion device PCE > 18% due to reduction of carrier recombination rate. This work provides new design rules toward the room-temperature phase transformation and processing of hybrid perovskite films based on FA+ cation without the need for Cs+ or mixed halide formulation.
CitationBarrit, D., Cheng, P., Darabi, K., Tang, M., Smilgies, D., Liu, S. (Frank), … Amassian, A. (2020). Room-Temperature Partial Conversion of α-FAPbI 3 Perovskite Phase via PbI 2 Solvation Enables High-Performance Solar Cells. Advanced Functional Materials, 1907442. doi:10.1002/adfm.201907442
SponsorsThis work was supported by the King Abdullah University of Science and Technology (KAUST), Key Program project of the National Natural Science Foundation of China (51933010), the National Natural Science Foundation of China (61974085, 61604092), and the Natural Science Basic Research Plan in Shaanxi Province of China (Program No. 2017JQ6040). CHESS is supported by the NSF award DMR-1332208.
JournalAdvanced Functional Materials