title: Highly efficient low-bandgap polymer solar cells with solution-processed and annealing-free phosphomolybdic acid as hole-transport layers.
abstract: We demonstrate a novel solution-processed method to fabricate a stable anode buffer layer without any annealing process. As we know, buffer layers in polymer solar cells (PSCs) are always prepared by the traditional high-vacuum thermal evaporation or annealing-treated spin-coating methods, but the fabricating processes are complicated and time-consuming. Here, a solution method without any annealing to fabricate phosphomolybdic acid (PMA) as anode buffers is presented, which brings an obvious improvement of power conversion efficiency (PCE) from 1.75% to 6.57% by optimizing the PMA concentrations and interface pretreatment with device structure shown as ITO/TiO2/PCDTBT:PC70BM/PMA/Ag. The improvement is ascribed to the fine energy-level matching and perfect surface modification. This annealing-free method greatly simplifies the device fabrication process and supplies a wide way to achieve a large area fabrication for PSCs.
authors.affiliation: State Key Laboratory on Integrated Optoelectronics, ‡College of Electronic Science and Engineering, and §Key Laboratory of Bionic Engineering (Ministry of Education), Jilin University , Changchun 130012, People's Republic of China.
authors.forename: Xu
authors.initials: X
authors.lastname: Jia
authors.forename: Liang
authors.initials: L
authors.lastname: Shen
authors.forename: Mengnan
authors.initials: M
authors.lastname: Yao
authors.forename: Yan
authors.initials: Y
authors.lastname: Liu
authors.forename: Wenjuan
authors.initials: W
authors.lastname: Yu
authors.forename: Wenbin
authors.initials: W
authors.lastname: Guo
authors.forename: Shengping
authors.initials: S
authors.lastname: Ruan
keywords: PCDTBT; isopropyl alcohol; phosphomolybdic acid; polymer solar cell