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Graded 2D/3D Perovskite Heterostructure for Efficient and Operationally Stable MA‐Free Perovskite Solar Cells
Author(s) -
Yao Qin,
Xue Qifan,
Li Zhenchao,
Zhang Kaicheng,
Zhang Teng,
Li Ning,
Yang Shihe,
Brabec Christoph J.,
Yip HinLap,
Cao Yong
Publication year - 2020
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.202000571
Subject(s) - materials science , perovskite (structure) , heterojunction , energy conversion efficiency , optoelectronics , grain boundary , nanotechnology , chemical engineering , composite material , microstructure , engineering
Almost all highly efficient perovskite solar cells (PVSCs) with power conversion efficiencies (PCEs) of greater than 22% currently contain the thermally unstable methylammonium (MA) molecule. MA‐free perovskites are an intrinsically more stable optoelectronic material for use in solar cells but compromise the performance of PVSCs with relatively large energy loss. Here, the open‐circuit voltage ( V oc ) deficit is circumvented by the incorporation of β‐guanidinopropionic acid (β‐GUA) molecules into an MA‐free bulk perovskite, which facilitates the formation of quasi‐2D structure with face‐on orientation. The 2D/3D hybrid perovskites embed at the grain boundaries of the 3D bulk perovskites and are distributed through half the thickness of the film, which effectively passivates defects and minimizes energy loss of the PVSCs through reduced charge recombination rates and enhanced charge extraction efficiencies. A PCE of 22.2% (certified efficiency of 21.5%) is achieved and the operational stability of the MA‐free PVSCs is improved.