Dopant-Free Hole Transport Materials Based on a Large Conjugated Electron-Deficient Core for Efficient Perovskite Solar Cells |
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Authors: | Jiefeng Hai Hao Wu Xinxing Yin Jiaxing Song Lin Hu Yingzhi Jin Ling Li Zhen Su Zhiguang Xu Hao Wang Zaifang Li |
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Affiliation: | 1. Guangxi Key Laboratory of Electrochemical and Magneto-Chemical Functional Materials, Guilin University of Technology, Guilin, 541004 China;2. China-Australia Institute for Advanced Materials and Manufacturing (IAMM), Jiaxing University, Jiaxing, 314001 China;3. Center for Future Materials, University of Southern Queensland, Springfield, QLD, 4300 Australia |
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Abstract: | Hole transport materials (HTMs) play a significant role in device efficiencies and long-term stabilities of perovskite solar cells (PSCs). In this work, two simple dopant-free HTMs are designed with a large conjugated electron-deficient core. On the one hand, a large coplanar backbone endows enhanced π–π stacking and reduced hole hopping distance. On the other hand, the incorporation of electron-deficient unit can easily tune the energy levels as well as increase hole mobilities. Combining these two advantages together, 12,13-bis(2-ethylhexyl)-3,9-diundecyl-12,13-dihydro1,2,5]thiadiazole3,4-e]thieno2″,3″:4,5]thieno2′,3′:4,5]pyrrolo3,2-g]thieno2′,3′:4,5]thieno3,2-b]indole is chosen as the large electron-deficient core to construct two novel dopant-free HTMs, Y6-T and Y-T. Both Y6-T and Y-T behave suitable highest occupied molecular orbital levels, good hole mobilities, as well as strong hydrophobicities. After careful device optimization with a passivation agent, Y-T delivers an impressive power conversion efficiency of 20.29%, which is higher than that of Y6-T (18.82%) and doped spiro-OMeTAD (19.24%). Moreover, PSCs based on Y6-T and Y-T show much better long-term stabilities than spiro-OMeTAD due to the intrinsic hydrophobicity. Therefore, this work provides a promising candidate as well as a useful design strategy for exploring dopant-free HTMs, which may pave the way for the commercialization of PSCs. |
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Keywords: | dopant-free electron-deficient core hole transport materials perovskite solar cells |
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