Ternary System with Controlled Structure: A New Strategy toward Efficient Organic Photovoltaics

Pei Cheng; Rui Wang; Jingshuai Zhu; Wenchao Huang; Sheng-Yung Chang; Lei Meng; Pengyu Sun; Hao-Wen Cheng; Meng Qin; Chenhui Zhu; Xiaowei Zhan; Yang Yang

doi:10.1002/adma.201705243

Ternary System with Controlled Structure: A New Strategy toward Efficient Organic Photovoltaics

Adv Mater. 2018 Feb;30(8). doi: 10.1002/adma.201705243. Epub 2018 Jan 10.

Authors

Pei Cheng¹, Rui Wang¹, Jingshuai Zhu², Wenchao Huang^{1

3}, Sheng-Yung Chang¹, Lei Meng¹, Pengyu Sun¹, Hao-Wen Cheng^{1

3}, Meng Qin¹, Chenhui Zhu⁴, Xiaowei Zhan², Yang Yang^{1

3}

Affiliations

¹ Department of Materials Science and Engineering, University of California, Los Angeles, CA, 90095, USA.
² Department of Materials Science and Engineering, College of Engineering, Key Laboratory of Polymer Chemistry and Physics of Ministry of Education, Peking University, Beijing, 100871, P. R. China.
³ California NanoSystems Institute, University of California, Los Angeles, CA, 90095, USA.
⁴ Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.

PMID: 29318665
DOI: 10.1002/adma.201705243

Abstract

Recently, a new type of active layer with a ternary system has been developed to further enhance the performance of binary system organic photovoltaics (OPV). In the ternary OPV, almost all active layers are formed by simple ternary blend in solution, which eventually leads to the disordered bulk heterojunction (BHJ) structure after a spin-coating process. There are two main restrictions in this disordered BHJ structure to obtain higher performance OPV. One is the isolated second donor or acceptor domains. The other is the invalid metal-semiconductor contact. Herein, the concept and design of donor/acceptor/acceptor ternary OPV with more controlled structure (C-ternary) is reported. The C-ternary OPV is fabricated by a sequential solution process, in which the second acceptor and donor/acceptor binary blend are sequentially spin-coated. After the device optimization, the power conversion efficiencies (PCEs) of all OPV with C-ternary are enhanced by 14-21% relative to those with the simple ternary blend; the best PCEs are 10.7 and 11.0% for fullerene-based and fullerene-free solar cells, respectively. Moreover, the averaged PCE value of 10.4% for fullerene-free solar cell measured in this study is in great agreement with the certified one of 10.32% obtained from Newport Corporation.

Keywords: non-fullerene; organic photovoltaics; organic solar cells; sequential process; ternary.