title: High-Performance Perovskite Solar Cells Engineered by an Ammonia Modified Graphene Oxide Interfacial Layer.
abstract: The introduction of an ammonia modified graphene oxide (GO:NH3) layer into perovskite-based solar cells (PSCs) with a structure of indium-tin oxide (ITO)/poly(3,4-ethylene-dioxythiophene):poly(4-styrenesulfonate) (
  PSS)-GO: NH3/CH3NH3PbI3-xClx/phenyl C61-butyric acid methyl ester (PCBM)/(solution Bphen) sBphen/Ag improves their performance and perovskite structure stability significantly. The fabricated devices with a champion PCE up to 16.11% are superior in all the performances in comparison with all the reference devices without the GO:NH3 layer. To understand the improved device performances, synchrotron-based grazing incidence X-ray diffraction (GIXRD), scanning electron microscopy (SEM), ultraviolet photoelectron spectroscopy (UPS), X-ray photoelectron spectroscopy (XPS), and UV-visible absorption measurements have been conducted on perovskite films on different substrates. It was found that these improvements should be partially attributed to the improved crystallization and preferred orientation order of peovskite structure, partially to the improved morphology with nearly complete coverage, partially to the enhanced optical absorption caused by the
  PSS-GO:NH3 layer, and partially to the better matched energy-level-alignment at the perovskite interface. Furthermore, the device was shown to be more stable in the ambient condition, which is clearly associated with the improved peovskite structure stability by the GO:NH3 layer observed by the GIXRD measurements. All these achievements will promote more applications of chemically modified graphene oxide interfacial layer in the PSCs as well as other organic multilayer devices.
authors.affiliation: Shanghai Institute of Applied Physics, Chinese Academy of Sciences , 2019 Jialuo Road, Shanghai 201800, China.|Shanghai Synchrotron Radiation Facility(SSRF), Shanghai Institute of Applied Physics, Chinese Academy of Sciences , 239 Zhangheng Road, Pudong New Area, Shanghai 201204, China.
authors.forename: Shanglei
authors.initials: S
authors.lastname: Feng
authors.affiliation: Shanghai Institute of Applied Physics, Chinese Academy of Sciences , 2019 Jialuo Road, Shanghai 201800, China.|Shanghai Synchrotron Radiation Facility(SSRF), Shanghai Institute of Applied Physics, Chinese Academy of Sciences , 239 Zhangheng Road, Pudong New Area, Shanghai 201204, China.
authors.forename: Yingguo
authors.initials: Y
authors.lastname: Yang
authors.affiliation: Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University , 199 Ren'ai Road, Suzhou, 215123, China.
authors.forename: Meng
authors.initials: M
authors.lastname: Li
authors.affiliation: Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University , 199 Ren'ai Road, Suzhou, 215123, China.
authors.forename: Jinmiao
authors.initials: J
authors.lastname: Wang
authors.affiliation: Shanghai Institute of Applied Physics, Chinese Academy of Sciences , 2019 Jialuo Road, Shanghai 201800, China.|Shanghai Synchrotron Radiation Facility(SSRF), Shanghai Institute of Applied Physics, Chinese Academy of Sciences , 239 Zhangheng Road, Pudong New Area, Shanghai 201204, China.
authors.forename: Zhendong
authors.initials: Z
authors.lastname: Cheng
authors.affiliation: Shanghai Institute of Applied Physics, Chinese Academy of Sciences , 2019 Jialuo Road, Shanghai 201800, China.|Shanghai Synchrotron Radiation Facility(SSRF), Shanghai Institute of Applied Physics, Chinese Academy of Sciences , 239 Zhangheng Road, Pudong New Area, Shanghai 201204, China.
authors.forename: Jihao
authors.initials: J
authors.lastname: Li
authors.affiliation: Shanghai Institute of Applied Physics, Chinese Academy of Sciences , 2019 Jialuo Road, Shanghai 201800, China.|Shanghai Synchrotron Radiation Facility(SSRF), Shanghai Institute of Applied Physics, Chinese Academy of Sciences , 239 Zhangheng Road, Pudong New Area, Shanghai 201204, China.
authors.forename: Gengwu
authors.initials: G
authors.lastname: Ji
authors.affiliation: Shanghai Institute of Applied Physics, Chinese Academy of Sciences , 2019 Jialuo Road, Shanghai 201800, China.|Shanghai Synchrotron Radiation Facility(SSRF), Shanghai Institute of Applied Physics, Chinese Academy of Sciences , 239 Zhangheng Road, Pudong New Area, Shanghai 201204, China.
authors.forename: Guangzhi
authors.initials: G
authors.lastname: Yin
authors.affiliation: Shanghai Institute of Applied Physics, Chinese Academy of Sciences , 2019 Jialuo Road, Shanghai 201800, China.|Shanghai Synchrotron Radiation Facility(SSRF), Shanghai Institute of Applied Physics, Chinese Academy of Sciences , 239 Zhangheng Road, Pudong New Area, Shanghai 201204, China.
authors.forename: Fei
authors.initials: F
authors.lastname: Song
authors.affiliation: Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University , 199 Ren'ai Road, Suzhou, 215123, China.
authors.forename: Zhaokui
authors.initials: Z
authors.lastname: Wang
authors.affiliation: Shanghai Institute of Applied Physics, Chinese Academy of Sciences , 2019 Jialuo Road, Shanghai 201800, China.|Shanghai Synchrotron Radiation Facility(SSRF), Shanghai Institute of Applied Physics, Chinese Academy of Sciences , 239 Zhangheng Road, Pudong New Area, Shanghai 201204, China.
authors.forename: Jingye
authors.initials: J
authors.lastname: Li
authors.affiliation: Shanghai Institute of Applied Physics, Chinese Academy of Sciences , 2019 Jialuo Road, Shanghai 201800, China.|Shanghai Synchrotron Radiation Facility(SSRF), Shanghai Institute of Applied Physics, Chinese Academy of Sciences , 239 Zhangheng Road, Pudong New Area, Shanghai 201204, China.|Institute of Materials Genome , Shanghai, 200444, China.|Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences , Shanghai 201800, China.
authors.forename: Xingyu
authors.initials: X
authors.lastname: Gao
keywords: ammonia modified graphene oxide; device performance; energy-level-match; hole transfer layer; perovskite solar cells; perovskite structure