title: Fluorene Conjugated Polymer/Nickel Oxide Nanocomposite Hole Transport Layer Enhances the Efficiency of Organic Photovoltaic Devices.
abstract: A nanocomposite layer comprising the conjugated polymer poly[(9,9-bis(3'-(N,N-dimethylamino)propyl)-2,7-fluorene)-alt-2,7-(9,9-dioctyl)fluorene] (PFN) and nickel oxide (NiOx) has been employed as the hole transport layer (HTL) in organic photovoltaics (OPVs) featuring PBDTTBO-C8and [6,6]-phenyl-C71-butyric acid methyl ester (PC71BM) as the active layer. The optimal device incorporating the PFN:NiOxnanocomposite as the HTLs displayed a power conversion efficiency (PCE) to 6.2%, up from 4.5% for the corresponding device incorporating pristine NiOxas the HTL layer: a nearly 40% improvement in PCE. X-ray photoelectron spectroscopy (XPS) was used to determine the types of chemical bonding, ultraviolet photoelectron spectroscopy (UPS) to measure the change in work function, and atomic force microscopy (AFM) to examine the morphology of the composite layers. The growth of nickel trioxide, Ni2O3, in the PFN:NiOxlayer played a key role in producing the p-doping effect and in tuning the work function, thereby improving the overall device performance.
authors.affiliation: Department of Materials Science and Engineering, National Chiao Tung University , Hsinchu 30010, Taiwan, R.O.C.
authors.forename: Guan-Chiun
authors.initials: GC
authors.lastname: Chiou
authors.affiliation: National Synchrotron Radiation Research Center , Hsinchu 30076, Taiwan, R.O.C.
authors.forename: Ming-Wei
authors.initials: MW
authors.lastname: Lin
authors.affiliation: National Synchrotron Radiation Research Center , Hsinchu 30076, Taiwan, R.O.C.
authors.forename: Yu-Ling
authors.initials: YL
authors.lastname: Lai
authors.affiliation: Department of Materials Science and Engineering, National Chiao Tung University , Hsinchu 30010, Taiwan, R.O.C.
authors.forename: Chiao-Kai
authors.initials: CK
authors.lastname: Chang
authors.affiliation: Department of Materials Science and Engineering, National Chiao Tung University , Hsinchu 30010, Taiwan, R.O.C.
authors.forename: Jian-Ming
authors.initials: JM
authors.lastname: Jiang
authors.affiliation: Department of Materials Science and Engineering, National Chiao Tung University , Hsinchu 30010, Taiwan, R.O.C.
authors.forename: Yu-Wei
authors.initials: YW
authors.lastname: Su
authors.affiliation: Department of Materials Science and Engineering, National Chiao Tung University , Hsinchu 30010, Taiwan, R.O.C.
authors.forename: Kung-Hwa
authors.identifier: http://orcid.org/0000-0001-5332-2757
authors.initials: KH
authors.lastname: Wei
authors.affiliation: National Synchrotron Radiation Research Center , Hsinchu 30076, Taiwan, R.O.C.|Department of Photonics, National Cheng Kung University , Tainan 70101, Taiwan, R.O.C.
authors.forename: Yao-Jane
authors.identifier: http://orcid.org/0000-0001-7687-4351
authors.initials: YJ
authors.lastname: Hsu
keywords: X-ray photoelectron spectroscopy (XPS); charge transfer; hole transport layer (HTL); nanocomposite; nickel oxide (NiOx); nickel trioxide (Ni2O3); organic photovoltaics (OPVs); poly[(9,9-bis(3′-(N,N-dimethylamino)propyl)-2,7-fluorene)-alt-2,7-(9,9-dioctyl)fluorene] (PFN)