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The Introduction of Fluorine and Sulfur Atoms into Benzotriazole‐Based p‐Type Polymers to Match with a Benzotriazole‐Containing n‐Type Small Molecule: “The Same‐Acceptor‐Strategy” to Realize High Open‐Circuit Voltage
Author(s) -
Tang Ailing,
Xiao Bo,
Chen Fan,
Zhang Jianqi,
Wei Zhixiang,
Zhou Erjun
Publication year - 2018
Publication title -
advanced energy materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.08
H-Index - 220
eISSN - 1614-6840
pISSN - 1614-6832
DOI - 10.1002/aenm.201801582
Subject(s) - benzotriazole , acceptor , materials science , polymer , open circuit voltage , molecule , energy conversion efficiency , short circuit , crystallography , chemistry , voltage , organic chemistry , optoelectronics , physics , metallurgy , composite material , condensed matter physics , quantum mechanics
“The Same‐Acceptor‐Strategy” (SAS) adopts benzotriazole (BTA)‐based p‐type polymers paired with a new BTA based non‐fullerene acceptor BTA13 to minimize the trade‐off between the open‐circuit voltage ( V OC ) and short circuit current ( J SC ). The fluorination and sulfuration are introduced to lower the highest occupied molecular orbitals (HOMO) of the polymers. The fluorinated polymer of J52‐F shows the higher power conversion efficiency (PCE) of 8.36% than the analog polymer of J52, benefited from a good balance between an improved V OC of 1.18 V and a J SC of 11.55 mA cm −2 . Further adding alkylthio groups on J52‐F, the resulted polymer, J52‐FS, exhibits the highest V OC of 1.24 V with a decreased energy loss of 0.48 eV, compared with 0.67 eV for J52 and 0.54 eV for J52‐F. However, J52‐FS shows an inferior PCE (3.84%) with a lower J SC of 6.74 mA cm −2 , because the small Δ E HOMO between J52‐FS and BTA13 (0.02 eV) gives rise to the inefficient hole transfer and high charge recombination, as well as low carrier mobilities. The results of this study clearly demonstrate that the introduction of different atoms in p‐type polymers is effective to improve the SAS and realize the high ( V OC ) and PCE.