Environmentally-friendly solvent processed fullerenefree organic solar cells enabled by screening halogenfree solvent additives

作     者：赵文超 叶龙 李荪荪 刘晓宇 张少青 张赟 Masoud Ghasemi 何畅 Harald Ade 侯剑辉 

作者机构：State Key Laboratory of Polymer Physics and Chemistry Beijing National Laboratory for Molecular Sciences CAS Research/Education Center forExcellence in Molecular Sciences Institute of Chemistry Chinese Academy of Sciences University of Chinese Academy of Sciences Department of Physics and Organic and Carbon Electronics Lab (ORa CEL) North Carolina State University 

出 版 物：《Science China Materials》 (中国科学（材料科学（英文版）)

年 卷 期：2017年第60卷第8期

页      面：697-706页

核心收录：

学科分类：08[工学] 080502[工学-材料学] 0805[工学-材料科学与工程（可授工学、理学学位）] 

基　　金：financial support from the National Natural Science Foundation of China (91333204, 21325419 and 51673201) the Chinese Academy of Sciences (XDB12030200, KJZD-EW-J01) the National Basic Research Program 973 (2014CB643501) the CAS-Croucher Funding Scheme for Joint Laboratories (CAS14601) supported by the US Office of Naval Resea (ONR) grant N00141512322 supported by a Research Opportunity Initiative grant by the UNC General Administatrtion 

主　　题：organic solar cells halogen-free solvent morphology high-efficiency 

摘      要：Though the power conversion efficiencies（PCEs） of organic solar cells（OSCs） have been boosted to 12%,the use of highly pollutive halogenated solvents as the processing solvent significantly hinders the mass production of OSCs. It is thus necessary to achieve high-efficiency OSCs by utilizing the halogen-free and environmentally-friendly solvents. Herein, we applied a halogen-free solvent system（oxylene/1-phenylnaphthalene, XY/PN） for fabricating fullerene-free OSCs, and a high PCE of 11.6% with a notable fill factor（FF） of 72% was achieved based on the PBDB-T：IT-M blend, which is among the top efficiencies of halogen-free solvent processed OSCs. In addition, the influence of different halogen-free solvent additives on the blend morphology and device performance metrics was studied by synchrotron-based tools and other complementary methods. Morphological results indicate the highly ordered molecular packing and highest average domain purity obtained in the blend films prepared by using XY/PN co-solvent are favorable for achieving increased FFs and thus higher PCEs in the ***, a lower interaction parameter（χ） of the IT-M：PN pair provides a good explanation for the more favorable morphology and performance in devices with PN as the solvent additive, relative to those with diphenyl ether and Nmethylpyrrolidone. Our study demonstrates that carefully screening the non-halogenated solvent additive plays a vital role in realizing the efficient and environmentally-friendly solvent processed OSCs.