Inhibiting Li+ migration by thenoyltrifluoroacetone toward efficient and stable perovskite solar cells†
Abstract
Lithium bis(trifluoromethanesulfonyl)imide is commonly employed as a dopant to improve the hole mobility of hole transport layers. However, undesired Li+ migration impedes the development of highly efficient and stable perovskite solar cells because the voids left by Li+ migration will accelerate the penetration of oxygen and moisture. Here, thenoyltrifluoroacetone (TTA) modifies the perovskite/spiro-OMeTAD interface. TTA can passivate the undercoordinated Pb2+ defects via the coordination between carbonyl/thiophenic sulfur and Pb2+. TTA can also inhibit the annoying Li+ migration by the coordination interaction between carbonyl and Li+. Besides, TTA can promote hole extraction by adjusting the energy level matching at the perovskite/hole transport layer interface. A TTA-modified device yields a power conversion efficiency of over 22% and has improved humidity and thermal stability. This finding paves a novel way to suppress undesired Li+ migration for highly efficient and stable PSCs.
- This article is part of the themed collection: 2023 Inorganic Chemistry Frontiers HOT articles