Approaching 18% efficiency of ternary organic photovoltaics with wide bandgap polymer donor and well compatible Y6 : Y6-1O as acceptor

Xiaoling Ma; Anping Zeng; Jinhua Gao; Zhenghao Hu; Chunyu Xu; Jae Hoon Son; Sang Young Jeong; Caixia Zhang; Mengyang Li; Kai Wang; He Yan; Zaifei Ma; Yongsheng Wang; Han Young Woo; Fujun Zhang

doi:10.1093/nsr/nwaa305

Approaching 18% efficiency of ternary organic photovoltaics with wide bandgap polymer donor and well compatible Y6 : Y6-1O as acceptor

Natl Sci Rev. 2020 Dec 31;8(8):nwaa305. doi: 10.1093/nsr/nwaa305. eCollection 2021 Aug.

Authors

Xiaoling Ma¹, Anping Zeng², Jinhua Gao¹, Zhenghao Hu¹, Chunyu Xu¹, Jae Hoon Son³, Sang Young Jeong³, Caixia Zhang¹, Mengyang Li⁴, Kai Wang¹, He Yan², Zaifei Ma⁴, Yongsheng Wang¹, Han Young Woo³, Fujun Zhang¹

Affiliations

¹ Key Laboratory of Luminescence and Optical Information, Ministry of Education, Beijing Jiaotong University, Beijing 100044, China.
² Departmentof Chemistry, The Hong Kong University of Science and Technology, Hong Kong, China.
³ Organic Optoelectronic Materials Laboratory, Department of Chemistry, College of Science, Korea University, Seoul 02841, South Korea.
⁴ Center for Advanced Low-Dimension Materials, State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai 201620, China.

Abstract

A series of ternary organic photovoltaics (OPVs) are fabricated with one wide bandgap polymer D18-Cl as donor, and well compatible Y6 and Y6-1O as acceptor. The open-circuit-voltage (V_OC ) of ternary OPVs is monotonously increased along with the incorporation of Y6-1O, indicating that the alloy state should be formed between Y6 and Y6-1O due to their excellent compatibility. The energy loss can be minimized by incorporating Y6-1O, leading to the V_OC improvement of ternary OPVs. By finely adjusting the Y6-1O content, a power conversion efficiency of 17.91% is achieved in the optimal ternary OPVs with 30 wt% Y6-1O in acceptors, resulting from synchronously improved short-circuit-current density (J_SC ) of 25.87 mA cm^-2, fill factor (FF) of 76.92% and V_OC of 0.900 V in comparison with those of D18-Cl : Y6 binary OPVs. The J_SC and FF improvement of ternary OPVs should be ascribed to comprehensively optimal photon harvesting, exciton dissociation and charge transport in ternary active layers. The more efficient charge separation and transport process in ternary active layers can be confirmed by the magneto-photocurrent and impedance spectroscopy experimental results, respectively. This work provides new insight into constructing highly efficient ternary OPVs with well compatible Y6 and its derivative as acceptor.

Keywords: morphology regulation; organic photovoltaics; photon harvesting; power conversion efficiency; ternary strategy.