title: Influence of Weak Base Addition to Hole-Collecting Buffer Layers in Polymer:Fullerene Solar Cells.
abstract: We report the effect of weak base addition to acidic polymer hole-collecting layers in normal-type polymer:fullerene solar cells. Varying amounts of the weak base aniline (AN) were added to solutions of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS). The acidity of the aniline-added PEDOT:PSS solutions gradually decreased from pH = 1.74 (AN = 0 mol% ) to pH = 4.24 (AN = 1.8 mol %). The electrical conductivity of the PEDOT:PSS-AN films did not change much with the pH value, while the ratio of conductivity between out-of-plane and in-plane directions was dependent on the pH of solutions. The highest power conversion efficiency (PCE) was obtained at pH = 2.52, even though all devices with the PEDOT:PSS-AN layers exhibited better PCE than those with the pristine PEDOT:PSS layers. Atomic force microscopy investigation revealed that the size of PEDOT:PSS domains became smaller as the pH increased. The stability test for 100 h illumination under one sun condition disclosed that the PCE decay was relatively slower for the devices with the PEDOT:PSS-AN layers than for those with pristine PEDOT:PSS layers.
authors.affiliation: Organic Nanoelectronics Laboratory and KNU Institute for Nanophotonics Applications (KINPA), Department of Chemical Engineering, School of Applied Chemical Engineering, Kyungpook National University, Daegu 41566, Korea. jyseo@knu.ac.kr.
authors.forename: Jooyeok
authors.initials: J
authors.lastname: Seo
authors.affiliation: Advanced Composites Materials Technical Center, Toray Advanced Materials Korea, Gumi-Si, Gyeongbook 39422, Korea. soohyeong@torayamk.com.
authors.forename: Soohyeong
authors.initials: S
authors.lastname: Park
authors.affiliation: Organic Nanoelectronics Laboratory and KNU Institute for Nanophotonics Applications (KINPA), Department of Chemical Engineering, School of Applied Chemical Engineering, Kyungpook National University, Daegu 41566, Korea. msong@knu.ac.kr.
authors.forename: Myeonghun
authors.initials: M
authors.lastname: Song
authors.affiliation: Organic Nanoelectronics Laboratory and KNU Institute for Nanophotonics Applications (KINPA), Department of Chemical Engineering, School of Applied Chemical Engineering, Kyungpook National University, Daegu 41566, Korea. jh-jeong@knu.ac.kr.
authors.forename: Jaehoon
authors.initials: J
authors.lastname: Jeong
authors.affiliation: Organic Nanoelectronics Laboratory and KNU Institute for Nanophotonics Applications (KINPA), Department of Chemical Engineering, School of Applied Chemical Engineering, Kyungpook National University, Daegu 41566, Korea. lcyyeon@knu.ac.kr.
authors.forename: Chulyeon
authors.initials: C
authors.lastname: Lee
authors.affiliation: Organic Nanoelectronics Laboratory and KNU Institute for Nanophotonics Applications (KINPA), Department of Chemical Engineering, School of Applied Chemical Engineering, Kyungpook National University, Daegu 41566, Korea. khj217@knu.ac.kr.|Priority Research Center, Research Institute of Advanced Energy Technology, Kyungpook National University, Daegu 41566, Korea. khj217@knu.ac.kr.
authors.forename: Hwajeong
authors.initials: H
authors.lastname: Kim
authors.affiliation: Organic Nanoelectronics Laboratory and KNU Institute for Nanophotonics Applications (KINPA), Department of Chemical Engineering, School of Applied Chemical Engineering, Kyungpook National University, Daegu 41566, Korea. ykimm@knu.ac.kr.
authors.forename: Youngkyoo
authors.initials: Y
authors.lastname: Kim
mesh_terms: D000814:Aniline Compounds / Q000737:chemistry; D002021:Buffers; D037741:Fullerenes / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D018625:Microscopy, Atomic Force; D011108:Polymers / Q000737:chemistry*; D012993:Solar Energy
chemical_list: D000814:Aniline Compounds; D002021:Buffers; D037741:Fullerenes; D011108:Polymers; C023650:aniline
keywords: PEDOT:PSS; aniline; hole-collecting layer; pH; polymer:fullerene solar cells; power conversion efficiency; stability; weak base