title: Layer-by-Layer Self-Assembled Graphene Multilayers as Pt-Free Alternative Counter Electrodes in Dye-Sensitized Solar Cells.
abstract: Low cost, charged, and large scale graphene multilayers fabricated from nitrogen-doped reduced graphene oxide N-rGO(+), nitrogen and sulfur codoped reduced graphene oxide NS-rGO(+), and undoped reduced graphene oxide rGO(-) were applied as alternative counter electrodes in dye-sensitized solar cells (DSSCs). The neat rGO-based counter electrodes were developed via two types of layer-by-layer (LBL) self-assembly (SA) methods: spin coating and spray coating methods. In the spin coating method, two sets of multilayer films were fabricated on poly(diallyldimethylammonium chloride) (PDDA)-coated fluorine-doped tin oxide (FTO) substrates using GO(-) combined with N-GO(+) followed by annealing and denoted as [rGO(-)/N-rGO(+)]n or with NS-GO(+) and denoted as [rGO(-)/NS-rGO(+)]n for counter electrodes in DSSCs. The DSSCs employing new types of counter electrodes exhibited ∼7.0% and ∼6.2% power conversion efficiency (PCE) based on ten bilayers of [rGO(-)/N-rGO(+)]10 and [rGO(-)/NS-rGO(+)]10, respectively. The DSSCs equipped with a blend of one bilayer of [rGO(-):N-rGO(+)] and [rGO(-):NS-rGO(+)] on PDDA-coated FTO substrates were prepared from a spray coating and showed ∼6.4% and ∼5.6% PCE, respectively. Thus, it was demonstrated that a combination of undoped, nitrogen-doped, and nitrogen and sulfur codoped reduced graphene oxides can be considered as potentially powerful Pt-free electrocatalysts and alternative electrodes in conventional photovoltaic devices.
authors.affiliation: Department of Chemistry and Nano Science, Division of Molecular and Life Sciences, College of Natural Sciences, Ewha Womans University , 52, Ewhayeodae-gil, Seodaemun-gu, Seoul 120-750, Korea.
authors.forename: Adila
authors.initials: A
authors.lastname: Rani
authors.affiliation: Department of Chemistry and Nano Science, Division of Molecular and Life Sciences, College of Natural Sciences, Ewha Womans University , 52, Ewhayeodae-gil, Seodaemun-gu, Seoul 120-750, Korea.
authors.forename: Kyungwha
authors.initials: K
authors.lastname: Chung
authors.affiliation: School of Chemical Engineering and SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University , 2066, Seobu-ro, Jangan-gu, Suwon, Gyeonggi-do 440-746, Republic of Korea.
authors.forename: Jeong
authors.initials: J
authors.lastname: Kwon
authors.affiliation: School of Chemical Engineering and SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University , 2066, Seobu-ro, Jangan-gu, Suwon, Gyeonggi-do 440-746, Republic of Korea.
authors.forename: Sung June
authors.initials: SJ
authors.lastname: Kim
authors.affiliation: Department of Chemistry and Nano Science, Division of Molecular and Life Sciences, College of Natural Sciences, Ewha Womans University , 52, Ewhayeodae-gil, Seodaemun-gu, Seoul 120-750, Korea.
authors.forename: Yoon Hee
authors.initials: YH
authors.lastname: Jang
authors.affiliation: Department of Chemistry and Nano Science, Division of Molecular and Life Sciences, College of Natural Sciences, Ewha Womans University , 52, Ewhayeodae-gil, Seodaemun-gu, Seoul 120-750, Korea.
authors.forename: Yu Jin
authors.initials: YJ
authors.lastname: Jang
authors.affiliation: Department of Chemistry and Nano Science, Division of Molecular and Life Sciences, College of Natural Sciences, Ewha Womans University , 52, Ewhayeodae-gil, Seodaemun-gu, Seoul 120-750, Korea.
authors.forename: Li Na
authors.initials: LN
authors.lastname: Quan
authors.affiliation: Department of Chemistry and Nano Science, Division of Molecular and Life Sciences, College of Natural Sciences, Ewha Womans University , 52, Ewhayeodae-gil, Seodaemun-gu, Seoul 120-750, Korea.
authors.forename: Minji
authors.initials: M
authors.lastname: Yoon
authors.affiliation: Department of Chemical and Biomolecular Engineering, Yonsei University , 50, Yonsei-ro, Seodaemun-gu, Seoul 120-749, Republic of Korea.
authors.forename: Jong Hyeok
authors.initials: JH
authors.lastname: Park
authors.affiliation: Department of Chemistry and Nano Science, Division of Molecular and Life Sciences, College of Natural Sciences, Ewha Womans University , 52, Ewhayeodae-gil, Seodaemun-gu, Seoul 120-750, Korea.
authors.forename: Dong Ha
authors.initials: DH
authors.lastname: Kim
keywords: DSSCs; counter electrode; electrocatalyst; layer-by-layer self-assembly; nitrogen and sulfur codoped reduced graphene oxide; nitrogen-doped reduced graphene oxide