title: An Obvious Improvement in the Performance of Ternary Organic Solar Cells with "Guest" Donor Present at the "Host" Donor/Acceptor Interface.
abstract: A small-molecule material, 7,7-(4,4-bis(2-ethylhexyl)-4H-silolo[3,2-b:4,5-b']dithiophene-2,6-diyl)bis(6-fluoro-4-(5'-hexyl-[2,2'-bithiophen]-5-yl)benzo-[c] [1,2,5]thiadiazole) (p-DTS(FBTTH2)2), was used to modify the morphology and electron-transport properties of the polymer blend of poly(3-hexythiophene) (P3HT) and [6,6]-phenyl-C71-butyric acid methyl ester (PC71BM) bulk heterojunctions. As a result, a 24% increase in the power-conversion efficiency (PCE) of the p-DTS(FBTTH2)2:P3HT:PC71BM ternary organic solar cells (OSCs) is obtained. The improvement in the performance of OSCs is attributed to the constructive energy cascade path in the ternary system that benefits an efficient Förster resonance energy/charge transfer process between P3HT and p-DTS(FBTTH2)2, thereby improving photocurrent generation. It is shown that p-DTS(FBTTH2)2 molecules engage themselves at the P3HT/PC71BM interface. A combination of absorption enhancement, efficient energy transfer process, and ordered nanomorphology in the ternary system favors exciton dissociation and charge transportation in the polymer bulk heterojunction. The finding of this work reveals that distribution of the appropriate "guest" donor at the "host" donor/acceptor interface is an effective approach for attaining high-performance OSCs.
authors.affiliation: School of Physics, State Key Laboratory of Crystal Materials, Shandong University , Jinan, Shandong 250100, China.
authors.forename: Peng-Qing
authors.initials: PQ
authors.lastname: Bi
authors.affiliation: Department of Physics, Institute of Advanced Materials and Institute of Research and Continuing Education (Shenzhen), Hong Kong Baptist University , Kowloon Tong 999077, Hong Kong.
authors.forename: Bo
authors.initials: B
authors.lastname: Wu
authors.affiliation: School of Physics, State Key Laboratory of Crystal Materials, Shandong University , Jinan, Shandong 250100, China.
authors.forename: Fei
authors.initials: F
authors.lastname: Zheng
authors.affiliation: School of Physics, State Key Laboratory of Crystal Materials, Shandong University , Jinan, Shandong 250100, China.
authors.forename: Wei-Long
authors.initials: WL
authors.lastname: Xu
authors.affiliation: School of Physics, State Key Laboratory of Crystal Materials, Shandong University , Jinan, Shandong 250100, China.
authors.forename: Xiao-Yu
authors.initials: XY
authors.lastname: Yang
authors.affiliation: School of Physics, State Key Laboratory of Crystal Materials, Shandong University , Jinan, Shandong 250100, China.
authors.forename: Lin
authors.initials: L
authors.lastname: Feng
authors.affiliation: Department of Physics, Institute of Advanced Materials and Institute of Research and Continuing Education (Shenzhen), Hong Kong Baptist University , Kowloon Tong 999077, Hong Kong.
authors.forename: Furong
authors.initials: F
authors.lastname: Zhu
authors.affiliation: School of Physics, State Key Laboratory of Crystal Materials, Shandong University , Jinan, Shandong 250100, China.|School of Chemistry, The University of Melbourne , Parkville, Victoria 3010, Australia.
authors.forename: Xiao-Tao
authors.initials: XT
authors.lastname: Hao
keywords: charge collection; energy/charge transfer; morphology control; synergistic effect; ternary organic solar cells