Auxiliary sequential deposition enables 19%-efficiency organic solar cells processed from halogen-free solvents

Siwei Luo; Chao Li; Jianquan Zhang; Xinhui Zou; Heng Zhao; Kan Ding; Hui Huang; Jiali Song; Jicheng Yi; Han Yu; Kam Sing Wong; Guangye Zhang; Harald Ade; Wei Ma; Huawei Hu; Yanming Sun; He Yan

doi:10.1038/s41467-023-41978-0

Auxiliary sequential deposition enables 19%-efficiency organic solar cells processed from halogen-free solvents

Nat Commun. 2023 Oct 31;14(1):6964. doi: 10.1038/s41467-023-41978-0.

Authors

Siwei Luo^#¹, Chao Li^#^{1

2}, Jianquan Zhang^#³, Xinhui Zou^#^{1

4}, Heng Zhao⁵, Kan Ding⁶, Hui Huang⁷, Jiali Song², Jicheng Yi¹, Han Yu¹, Kam Sing Wong⁴, Guangye Zhang⁷, Harald Ade⁶, Wei Ma⁵, Huawei Hu⁸, Yanming Sun⁹, He Yan^{10

11}

Affiliations

¹ Department of Chemistry, Guangdong-Hong Kong-Macao Joint Laboratory of Optoelectronic and Magnetic Functional Materials, Energy Institute and Hong Kong Branch of Chinese National, Engineering Research Center for Tissue Restoration and Reconstruction, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, 999077, China.
² School of Chemistry, Beihang University, 100191, Beijing, China.
³ School of Science and Engineering, Shenzhen Institute of Aggregate Science and Technology, The Chinese University of Hong Kong, 518172, Shenzhen, Guangdong, China.
⁴ Department of Physics, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, 999077, China.
⁵ State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, 710049, Xi'an, China.
⁶ Department of Physics and Organic and Carbon Electronics Laboratories (ORaCEL), North Carolina State University, Raleigh, NC, 27695, USA.
⁷ College of New Materials and New Energies, Shenzhen Technology University, 518118, Shenzhen, Guangdong, China.
⁸ State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, 201620, Shanghai, China.
⁹ School of Chemistry, Beihang University, 100191, Beijing, China. sunym@buaa.edu.cn.
¹⁰ Department of Chemistry, Guangdong-Hong Kong-Macao Joint Laboratory of Optoelectronic and Magnetic Functional Materials, Energy Institute and Hong Kong Branch of Chinese National, Engineering Research Center for Tissue Restoration and Reconstruction, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, 999077, China. hyan@ust.hk.
¹¹ Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, 510640, Guangzhou, Guangdong Province, China. hyan@ust.hk.

^# Contributed equally.

Abstract

High-efficiency organic solar cells are often achieved using toxic halogenated solvents and additives that are constrained in organic solar cells industry. Therefore, it is important to develop materials or processing methods that enabled highly efficient organic solar cells processed by halogen free solvents. In this paper, we report an innovative processing method named auxiliary sequential deposition that enables 19%-efficiency organic solar cells processed by halogen free solvents. Our auxiliary sequential deposition method is different from the conventional blend casting or sequential deposition methods in that it involves an additional casting of dithieno[3,2-b:2',3'-d]thiophene between the sequential depositions of the donor (D18-Cl) and acceptor (L8-BO) layers. The auxiliary sequential deposition method enables dramatic performance enhancement from 15% to over 18% compared to the blend casting and sequential deposition methods. Furthermore, by incorporating a branched-chain-engineered acceptor called L8-BO-X, device performance can be boosted to over 19% due to increased intermolecular packing, representing top-tier values for green-solvent processed organic solar cells. Comprehensive morphological and time-resolved characterizations reveal that the superior blend morphology achieved through the auxiliary sequential deposition method promotes charge generation while simultaneously suppressing charge recombination. This research underscores the potential of the auxiliary sequential deposition method for fabricating highly efficient organic solar cells using environmentally friendly solvents.

Grants and funding

No.51825301/National Natural Science Foundation of China (National Science Foundation of China)