title: Effect of nanoscale SubPc interfacial layer on the performance of inverted polymer solar cells based on P3HT/PC71BM.
abstract: The effect of a nanoscale boron subphthalocyanine chloride (SubPc) interfacial layer on the performance of inverted polymer solar cells based on poly (3-hexyl thiophene) (P3HT) and [6,6]-phenyl-C(71)-butyric acid methyl ester (PC(71)BM) was studied. When a 1 nm SubPc layer was introduced between the active layer (P3HT:PC(71)BM) and MoO(x) in the device with ITO/ZnO/P3HT:PC(71)BM/SubPc/MoO(x)/Al configuration, the power conversion efficiency (PCE) was increased from 3.42 (without SubPc) to 3.59%. This improvement is mainly attributed to the enhanced open-circuit voltage from 0.62 to 0.64 V. When the Flory-Huggins interaction parameters were estimated from the solubility parameters through the contact angle measurement, it revealed that the interaction between SubPc and PC(71)BM is more attractive than that between SubPc and P3HT at the interface of P3HT:PC(71)BM/SubPc, through which charges are well transported from the active layer to the anode. This is supported by a decrease of the contact resistance from 5.49 (SubPc 0 nm) to 0.94 MΩ cm (SubPc 1 nm). The photoelectron spectra provide another evidence for the enhanced PCE, exhibiting that the 1 nm thick SubPc layer extracts more photoelectrons from the active layer than other thicknesses.
authors.affiliation: Department of Materials Science and Engineering, Seoul National University, 599 Gwanak-ro, Gwanak-gu, Seoul 151-742, Republic of Korea.
authors.forename: Jung Yong
authors.initials: JY
authors.lastname: Kim
authors.forename: Seunguk
authors.initials: S
authors.lastname: Noh
authors.forename: Young Min
authors.initials: YM
authors.lastname: Nam
authors.forename: Jun Young
authors.initials: JY
authors.lastname: Kim
authors.forename: Jeongkyun
authors.initials: J
authors.lastname: Roh
authors.forename: Myeongjin
authors.initials: M
authors.lastname: Park
authors.forename: Jason J
authors.initials: JJ
authors.lastname: Amsden
authors.forename: Do Y
authors.initials: DY
authors.lastname: Yoon
authors.forename: Changhee
authors.initials: C
authors.lastname: Lee
authors.forename: Won Ho
authors.initials: WH
authors.lastname: Jo