Halogen-Free Donor Polymers Based on Dicyanobenzotriazole with Low Energy Loss and High Efficiency in Organic Solar Cells

Lei Wang; Lifu Zhang; Seoyoung Kim; Tingting Wang; Zhongyi Yuan; Changduk Yang; Yu Hu; Xiaohong Zhao; Yiwang Chen

doi:10.1002/smll.202206607

Halogen-Free Donor Polymers Based on Dicyanobenzotriazole with Low Energy Loss and High Efficiency in Organic Solar Cells

Small. 2023 May;19(18):e2206607. doi: 10.1002/smll.202206607. Epub 2023 Jan 30.

Authors

Lei Wang¹, Lifu Zhang², Seoyoung Kim³, Tingting Wang¹, Zhongyi Yuan¹, Changduk Yang^{4

5}, Yu Hu¹, Xiaohong Zhao¹, Yiwang Chen^{1

2}

Affiliations

¹ College of Chemistry and Chemical Engineering/Institute of Polymers and Energy Chemistry, Nanchang University, 999 Xuefu Avenue, Nanchang, 330031, P. R. China.
² National Engineering Research Center for Carbohydrate Synthesis/Key Lab of Fluorine and Silicon for Energy Materials and Chemistry of Ministry of Education, Jiangxi Normal University, 99 Ziyang Avenue, Nanchang, 330022, P. R. China.
³ School of Energy and Chemical Engineering, Perovtronics Research Center, Low Dimensional Carbon Materials Center, Ulsan National Institute of Science and Technology (UNIST), 50 UNIST-gil, Ulju-gun, Ulsan, 44919, South Korea.
⁴ Department of Energy Engineering, School of Energy and Chemical Engineering, Perovtronics Research Center, Low Dimensional Carbon Materials Center, Ulsan National Institute of Science and Technology (UNIST), 50 UNIST-gil, Ulju-gun, Ulsan, 44919, South Korea.
⁵ Graduate School of Carbon Neutrality, Ulsan National Institute of Science and Technology (UNIST), 50 UNIST-gil, Ulju-gun, Ulsan, 44919, South Korea.

PMID: 36717277
DOI: 10.1002/smll.202206607

Abstract

Halogenation of organic semiconductors is an efficient strategy for improving the performance of organic solar cells (OSCs), while the introduction of halogens usually involves complex synthetic process and serious environment pollution problems. Herein, three halogen-free ternary copolymer donors (PCNx, x = 3, 4, 5) based on electron-withdrawing dicyanobenzotriazole are reported. When blended with the Y6, PCN3 with strong interchain interactions results in appropriate crystallinity and thermodynamic miscibility of the blend film. Grazing-incidence wide-angle X-ray scattering measurements indicate that PCN3 has more ordered arrangement and stronger π-π stacking than previous PCN2. Fourier-transform photocurrent spectroscopy and external quantum efficiency of electroluminescence measurements show that PCN3-based OSCs have lower energy loss than PCN2, which leads to their higher open-circuit voltage (0.873 V). The device based on PCN3 reaches power conversion efficiency (PCE) of 15.33% in binary OSCs, one of the highest values for OSCs with halogen-free donor polymers. The PCE of 17.80% and 18.10% are obtained in PM6:PCN3:Y6 and PM6:PCN3:BTP-eC9 ternary devices, much higher than those of PM6:Y6 (16.31%) and PM6:BTP-eC9 (17.33%) devices. Additionally, this ternary OSCs exhibit superior stability compared to binary host system. This work gives a promising path for halogen-free donor polymers to achieve low energy loss and high PCE.

Keywords: dicyanobenzotriazole; halogen-free semiconductors; low energy loss; organic solar cells; ternary copolymers.

Abstract

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