Efficient and stabilized molecular doping of hole-transporting materials driven by a cyclic-anion strategy for perovskite solar cells.
Chem Sci
; 15(25): 9814-9822, 2024 Jun 26.
Article
em En
| MEDLINE
| ID: mdl-38939142
ABSTRACT
Bis(trifluoromethane)sulfonimide lithium salt (Li-TFSI) is commonly used as an effective dopant to improve the performance of the hole-transporting material (HTM) in n-i-p perovskite solar cells (PSCs). However, the ultra-hygroscopic and migratory nature of Li-TFSI leads to inferior stability of PSCs. Here, we report on a strategy to regulate the anion unit in Li-TFSI from linear to cyclic, constructing a new dopant, lithium 1,1,2,2,3,3-hexafluoropropane-1,3-disulfonimide (Li-CYCLIC), for the state-of-the-art poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA). Mechanistic and experimental results reveal that the cyclic anion CYCLIC- exhibits stronger interaction with Li+ and PTAAË+ compared with the linear anion TFSI-, thus significantly restraining the moisture absorption and migration of Li+ and improving the thermodynamic stability of PTAAË+CYCLIC-. With this molecular engineering, the resulting PSCs based on Li-CYCLIC obtained an improved efficiency, along with remarkably enhanced stability, retaining 96% of the initial efficiency after over 1150 hours under continuous 1 sun illumination in an N2 atmosphere, yielding an extrapolated T 80 of over 12 000 hours. In a broader context, the proposed strategy of linear-to-cyclic doping provides substantial guidance for the subsequent advancement in the development of effective dopants for photoelectric devices.
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MEDLINE
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En
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Chem Sci
Ano de publicação:
2024
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Article