Surface defects have been a key constraint for perovskite photovoltaics. Herein, 1,3-dimethyl-3-imidazolium hexafluorophosphate (DMIMPF6) ionic liquid (IL) is adopted to passivate the surface of a formamidinium-cesium lead iodide perovskite (Cs0.08FA0.92PbI3) and also reduce the energy barrier between the perovskite and hole transport layer. Theoretical simulations and experimental results demonstrate that Pb-cluster and Pb-I antisite defects can be effectively passivated by [DMIM]+ bonding with the Pb2+ ion on the perovskite surface, leading to significantly suppressed non-radiative recombination. As a result, the solar cell efficiency was increased to 23.25 % from 21.09 %. Meanwhile, the DMIMPF6-treated perovskite device demonstrated long-term stability because the hydrophobic DMIMPF6 layer blocked moisture permeation.
Bibliographical noteFunding Information:
Z.X. acknowledges support from the National Natural Science Foundation of China (61975106) and the Shaanxi Technical Innovation Guidance Project (2018HJCG‐17). S.L. acknowledges the Strategic Priority Research Program of Chinese Academy of Sciences (Grant No. XDA17040506), the National Key Research and Development Program of China (2016YFA0202403), the National University Research Fund (GK261001009), the Innovative Research Team (IRT_14R33), the 111 Project (B14041), the Chinese National 1000‐Talents‐Plan Program, and the Shanxi Science and Technology Department (20201101012). The unfunded collaborative work of S.P. and D.Y. was supported through the International Institute of Biosensing (IIB) headquartered at Penn State University.
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- energy levels
- ionic liquids
PubMed: MeSH publication types
- Journal Article