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Strategic Synthesis of Ultrasmall NiCo 2 O 4 NPs as Hole Transport Layer for Highly Efficient Perovskite Solar Cells
Author(s) -
Ouyang Dan,
Xiao Junyan,
Ye Fei,
Huang Zhanfeng,
Zhang Hong,
Zhu Lu,
Cheng Jiaqi,
Choy Wallace C. H.
Publication year - 2018
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.201702722
Subject(s) - perovskite (structure) , materials science , ternary operation , energy conversion efficiency , spinel , chemical engineering , layer (electronics) , nanoparticle , nanotechnology , photovoltaic system , oxide , optoelectronics , ecology , computer science , engineering , metallurgy , biology , programming language
This study proposes a novel strategy of controllable deamination of Co–NH 3 complexes in a system containing Ni(OH) 2 to synthesize ultrasmall ternary oxide nanoparticles (NPs), NiCo 2 O 4 . Through this approach, ultrasmall (5 nm on average) and well‐dispersed NiCo 2 O 4 NPs without exotic ligands are obtained, which enables the formation of uniform and pin‐hole free films. The tightly covered NiCo 2 O 4 films also facilitate the formation of large perovskite grains and thus reduce film defects. The results show that with the NiCo 2 O 4 NPs as the hole transport layer (HTL), the perovskite solar cells reach a high power conversion efficiency (PCE) of 18.23% and a promising stability (maintained ≈90% PCE after 500 h light soaking). To the best of the author's knowledge, it is the first time that spinel NiCo 2 O 4 NPs have been applied as hole transport layer in perovskite solar cells successfully. This work not only demonstrates the potential applications of ternary oxide NiCo 2 O 4 as HTLs in hybrid perovskite solar cells but also provides an insight into the design and synthesis of ultrasmall and ligand‐free NPs HTLs to enable cost‐effective photovoltaic devices.