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High‐Performance Inverted Perovskite Solar Cells with Operational Stability via n‐Type Small Molecule Additive‐Assisted Defect Passivation
Author(s) -
Koo Donghwan,
Cho Yongjoon,
Kim Ungsoo,
Jeong Gyujeong,
Lee Junghyun,
Seo Jihyung,
Yang Changduk,
Park Hyesung
Publication year - 2020
Publication title -
advanced energy materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.08
H-Index - 220
eISSN - 1614-6840
pISSN - 1614-6832
DOI - 10.1002/aenm.202001920
Subject(s) - materials science , perovskite (structure) , passivation , energy conversion efficiency , grain size , perovskite solar cell , chemical engineering , grain boundary , nanotechnology , optoelectronics , microstructure , composite material , layer (electronics) , engineering
Significant efforts have been devoted to modulating the grain size and improving the film quality of perovskite in perovskite solar cells (PSCs). Adding materials to the perovskite is especially promising for high‐performance PSCs, because the additives effectively control the crystal structure. Although the additive engineering approach has substantially boosted the efficiency of PSCs, instability of the perovskite film has remained a primary bottleneck for the commercialization of PSCs. Herein, a newly conceived bithiophene‐based n‐type conjugated small molecule (Y‐Th2) is introduced to PSCs, which simultaneously enhances the performance and stability of the cell. The Y‐Th2 effectively passivates the defect states in perovskite through Lewis acid–base interactions, increasing the grain size and quality of the perovskite absorber. An inverted PSC containing the Y‐Th2 additive achieves a power conversion efficiency of 21.5%, versus 18.3% in the reference device. The operational stability is also considerably enhanced by the improved hydrophobicity and intermolecular hydrogen bonds in the perovskite.