title: Conjugated Polymer-Small Molecule Alloy Leads to High Efficient Ternary Organic Solar Cells.
abstract: Ternary organic solar cells are promising candidates for bulk heterojunction solar cells; however, improving the power conversion efficiency (PCE) is quite challenging because the ternary system is complicated on phase separation behavior. In this study, a ternary organic solar cell (OSC) with two donors, including one polymer (PTB7-Th), one small molecule (p-DTS(FBTTH2)2), and one acceptor (PC71BM), is fabricated. We propose the two donors in the ternary blend forms an alloy. A notable averaged PCE of 10.5% for ternary OSC is obtained due to the improvement of the fill factor (FF) and the short-circuit current density (J(sc)), and the open-circuit voltage (V(oc)) does not pin to the smaller V(oc) of the corresponding binary blends. A highly ordered face-on orientation of polymer molecules is obtained due to the formation of an alloy structure, which facilitates the enhancement of charge separation and transport and the reduction of charge recombination. This work indicates that a high crystallinity and the face-on orientation of polymers could be obtained by forming alloy with two miscible donors, thus paving a way to largely enhance the PCE of OSCs by using the ternary blend strategy.
authors.affiliation: †Key Laboratory of Nanosystem and Hierarchical Fabrication, National Center for Nanoscience and Technology, Beijing 100190, P. R. China.
authors.forename: Jianqi
authors.initials: J
authors.lastname: Zhang
authors.affiliation: †Key Laboratory of Nanosystem and Hierarchical Fabrication, National Center for Nanoscience and Technology, Beijing 100190, P. R. China.
authors.forename: Yajie
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: †Key Laboratory of Nanosystem and Hierarchical Fabrication, National Center for Nanoscience and Technology, Beijing 100190, P. R. China.
authors.forename: Jin
authors.initials: J
authors.lastname: Fang
authors.affiliation: †Key Laboratory of Nanosystem and Hierarchical Fabrication, National Center for Nanoscience and Technology, Beijing 100190, P. R. China.
authors.forename: Kun
authors.initials: K
authors.lastname: Lu
authors.affiliation: ‡State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an 710049, P. R. China.
authors.forename: Zaiyu
authors.initials: Z
authors.lastname: Wang
authors.affiliation: ‡State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an 710049, P. R. China.
authors.forename: Wei
authors.initials: W
authors.lastname: Ma
authors.affiliation: †Key Laboratory of Nanosystem and Hierarchical Fabrication, National Center for Nanoscience and Technology, Beijing 100190, P. R. China.
authors.forename: Zhixiang
authors.initials: Z
authors.lastname: Wei