Novel Oligomer Enables Green Solvent Processed 17.5% Ternary Organic Solar Cells: Synergistic Energy Loss Reduction and Morphology Fine-Tuning

Hao Xia; Ying Zhang; Wanyuan Deng; Kuan Liu; Xinxin Xia; Chun-Jen Su; U-Ser Jeng; Miao Zhang; Jiaming Huang; Jingwei Huang; Cenqi Yan; Wai-Yeung Wong; Xinhui Lu; Weiguo Zhu; Gang Li

doi:10.1002/adma.202107659

Novel Oligomer Enables Green Solvent Processed 17.5% Ternary Organic Solar Cells: Synergistic Energy Loss Reduction and Morphology Fine-Tuning

Adv Mater. 2022 Mar;34(10):e2107659. doi: 10.1002/adma.202107659. Epub 2022 Jan 31.

Authors

Hao Xia^{1

2}, Ying Zhang¹, Wanyuan Deng³, Kuan Liu¹, Xinxin Xia⁴, Chun-Jen Su⁵, U-Ser Jeng⁵, Miao Zhang⁶, Jiaming Huang², Jingwei Huang¹, Cenqi Yan¹, Wai-Yeung Wong⁶, Xinhui Lu⁴, Weiguo Zhu², Gang Li¹

Affiliations

¹ Department of Electronic and Information Engineering, Research Institute for Smart Energy (RISE), The Hong Kong Polytechnic University, Hung Hum Kowloon, Hong Kong, 999077, China.
² School of Materials Science and Engineering, Jiangsu Engineering Laboratory of Light-Electricity-Heat Energy-Converting Materials and Applications Jiangsu Collaborative Innovation Center of Photovoltaic Science and Engineering National Experimental Demonstration Center for Materials Science and Engineering, Changzhou University, Changzhou, 213164, China.
³ State Key Laboratory of Luminescent Materials and Devices, Institute of Polymer Optoelectronic Materials and Devices, South China University of Technology, Guangzhou, 510640, China.
⁴ Department of Physics, The Chinese University of Hong Kong, New Territories, Hong Kong, 999077, China.
⁵ National Synchrotron Radiation Research Center, Hsinchu Science Park, Hsinchu, 30076, Taiwan.
⁶ Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hum Kowloon, Hong Kong, 999077, China.

PMID: 34997631
DOI: 10.1002/adma.202107659

Abstract

The large non-radiative recombination is the main factor that limits state-of-the-art organic solar cells (OSCs). In this work, two novel structurally similar oligomers (named 5BDTBDD and 5BDDBDT) with D-A-D-A-D and A-D-A-D-A configuration are synthesized for high-performance ternary OSCs with low energy loss. As third components, these PM6 analogue oligomers effectively suppress the non-radiative recombination in OSCs. Although the highest occupied molecular orbital (HOMO) levels of 5BDTBDD and 5BDDBDT are higher than that of PM6, the oligomers enabled ultra-high electroluminescence quantum efficiency (EQE_EL ) of 0.05% and improved V_OC , indicating suppressing non-radiative recombination overweighs the common belief of deeper HOMO requirement in third component selection. Moreover, the different compatibility of 5BDTBDD and 5BDDBDT with PM6 and BTP-BO4Cl fine-tunes the active layer morphology with synergistic effects. The ternary devices based on PM6:5BDTBDD:BTPBO4Cl and PM6:5BDDBDT:BTP-BO4Cl achieve a significantly improved PCEs of 17.54% and 17.32%, representing the state-of-the art OSCs processed by green solvent of o-xylene. The strategy using novel oligomer as third component also has very wide composition tolerance in ternary OSCs. This is the first work that demonstrates novel structurally compatible D-A type oligomers are effective third components, and provides new understanding of synergetic energy loss mechanisms towards high performance OSCs.

Keywords: green solvents; low energy loss; oligomers; ternary organic solar cells; wide composition tolerance.

Abstract

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