title: Atomic Layer Deposition of TiO2 for a High-Efficiency Hole-Blocking Layer in Hole-Conductor-Free Perovskite Solar Cells Processed in Ambient Air.
abstract: In this study we design and construct high-efficiency, low-cost, highly stable, hole-conductor-free, solid-state perovskite solar cells, with TiO2 as the electron transport layer (ETL) and carbon as the hole collection layer, in ambient air. First, uniform, pinhole-free TiO2 films of various thicknesses were deposited on fluorine-doped tin oxide (FTO) electrodes by atomic layer deposition (ALD) technology. Based on these TiO2 films, a series of hole-conductor-free perovskite solar cells (PSCs) with carbon as the counter electrode were fabricated in ambient air, and the effect of thickness of TiO2 compact film on the device performance was investigated in detail. It was found that the performance of PSCs depends on the thickness of the compact layer due to the difference in surface roughness, transmittance, charge transport resistance, electron-hole recombination rate, and the charge lifetime. The best-performance devices based on optimized TiO2 compact film (by 2000 cycles ALD) can achieve power conversion efficiencies (PCEs) of as high as 7.82%. Furthermore, they can maintain over 96% of their initial PCE after 651 h (about 1 month) storage in ambient air, thus exhibiting excellent long-term stability.
authors.forename: Hang
authors.initials: H
authors.lastname: Hu
authors.forename: Binghai
authors.initials: B
authors.lastname: Dong
authors.affiliation: Institute of Physical Chemistry, University of Münster , Corrensstr. 28/30, 48149 Münster, Germany.
authors.forename: Huating
authors.initials: H
authors.lastname: Hu
authors.forename: Fengxiang
authors.initials: F
authors.lastname: Chen
authors.forename: Mengqin
authors.initials: M
authors.lastname: Kong
authors.forename: Qiuping
authors.initials: Q
authors.lastname: Zhang
authors.forename: Tianyue
authors.initials: T
authors.lastname: Luo
authors.forename: Li
authors.initials: L
authors.lastname: Zhao
authors.forename: Zhiguang
authors.initials: Z
authors.lastname: Guo
authors.forename: Jing
authors.initials: J
authors.lastname: Li
authors.forename: Zuxun
authors.initials: Z
authors.lastname: Xu
authors.forename: Shimin
authors.initials: S
authors.lastname: Wang
authors.affiliation: Institute of Physical Chemistry, University of Münster , Corrensstr. 28/30, 48149 Münster, Germany.
authors.forename: Dominik
authors.initials: D
authors.lastname: Eder
authors.forename: Li
authors.initials: L
authors.lastname: Wan
keywords: atomic layer deposition; carbon counter electrode; hole-blocking layer; hole-conductor-free perovskite solar cells; long-term stability