title: An ultra-thin, un-doped NiO hole transporting layer of highly efficient (16.4%) organic-inorganic hybrid perovskite solar cells.
abstract: NiO is a wide band gap p-type oxide semiconductor and has potential for applications in solar energy conversion as a hole-transporting layer (HTL). It also has good optical transparency and high chemical stability, and the capability of aligning the band edges to the perovskite (CH3NH3PbI3) layers. Ultra-thin and un-doped NiO films with much less absorption loss were prepared by atomic layer deposition (ALD) with highly precise control over thickness without any pinholes. Thin enough (5-7.5 nm in thickness) NiO films with the thickness of few time the Debye length (LD = 1-2 nm for NiO) show enough conductivities achieved by overlapping space charge regions. The inverted planar perovskite solar cells with NiO films as HTLs exhibited the highest energy conversion efficiency of 16.40% with high open circuit voltage (1.04 V) and fill factor (0.72) with negligible current-voltage hysteresis.
authors.affiliation: Department of Energy Science, Sungkyunkwan University, Suwon 440-746, Republic of Korea. hshin@skku.edu.
authors.forename: Seongrok
authors.initials: S
authors.lastname: Seo
authors.affiliation: Photo-Electronic Hybrids Research Center, Korea Institute of Science and Technology (KIST), Seoul 136-791, Korea and Department of Materials Science and Engineering, Seoul National University, Seoul 151-742, Korea. jykim.mse@snu.ac.kr.
authors.forename: Ik Jae
authors.initials: IJ
authors.lastname: Park
authors.affiliation: Department of Energy Science, Sungkyunkwan University, Suwon 440-746, Republic of Korea. hshin@skku.edu.
authors.forename: Myungjun
authors.initials: M
authors.lastname: Kim
authors.affiliation: Department of Energy Science, Sungkyunkwan University, Suwon 440-746, Republic of Korea. hshin@skku.edu.
authors.forename: Seonhee
authors.initials: S
authors.lastname: Lee
authors.affiliation: Department of Energy Science, Sungkyunkwan University, Suwon 440-746, Republic of Korea. hshin@skku.edu and Integrated Energy Center for Fostering Global Creative Researcher (BK 21 Plus) Sungkyunkwan University, Suwon 440-746, Republic of Korea.
authors.forename: Changdeuck
authors.initials: C
authors.lastname: Bae
authors.affiliation: School of Materials Science and Engineering, Sungkyunkwan University, Suwon 440-746, Republic of Korea.
authors.forename: Hyun Suk
authors.initials: HS
authors.lastname: Jung
authors.affiliation: School of Chemical Engineering and Department of Energy Science, Sungkyunkwan University, Suwon 440-746, Republic of Korea.
authors.forename: Nam-Gyu
authors.initials: NG
authors.lastname: Park
authors.affiliation: Department of Materials Science and Engineering, Seoul National University, Seoul 151-742, Korea. jykim.mse@snu.ac.kr.
authors.forename: Jin Young
authors.initials: JY
authors.lastname: Kim
authors.affiliation: Department of Energy Science, Sungkyunkwan University, Suwon 440-746, Republic of Korea. hshin@skku.edu.
authors.forename: Hyunjung
authors.initials: H
authors.lastname: Shin