Understanding the Impact of Hierarchical Nanostructure in Ternary Organic Solar Cells

Advanced Science

Jin Fang¹  Zaiyu Wang¹  Jianqi Zhang¹  Yajie Zhang¹  Dan Deng¹  Zhen Wang¹  Kun Lu¹  Wei Ma² 

[1] CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, National Center for Nanoscience and Technology, Beijing, P. R. China;State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, P. R. China

关键词: conjugated polymers;    conjugated small molecules;    hierarchical nanostructures;    morphology;    ternary organic solar cells;   

DOI  :  10.1002/advs.201500250

来源: Wiley

【 摘 要 】

Abstract

Ternary organic solar cells (OSCs), which blend two donors and fullerene derivatives with different absorption ranges, are a promising potential strategy for high-power conversion efficiencies (PCEs). In this study, inverted ternary OSCs are fabricated by blending a highly crystalline small molecule BDT-3T-CNCOO in a low band gap polymer PBDTTT-C-T:PC₇₁BM. As the small molecule is introduced, the overall PCEs increase from 7.60% to 8.58%. The morphologies of ternary blends are studied by combining transmission electron microscopy and X-ray scattering techniques at different length scales. Hierarchical phase separation is revealed in the ternary blend, which is composed of domains with sizes of ≈88, ≈50, and ≈20 nm, respectively. The hierarchical phase separation balances the charge separation and transport in ternary OSCs. As a result, the fill factors of the devices significantly improve from 58.4% to 71.6%. Thus, ternary blends show higher hole mobility and higher fill factor than binary blends, which demonstrates a facile strategy to increase the performance of OSCs.

【 授权许可】

CC BY   
© 2015 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.