TY - JOUR
T1 - Efficient small-molecule donor with improved structural order and molecular aggregation enabled by side-chain modification
AU - Chen, Haiyan
AU - Yang, Ke
AU - Huang, Peihao
AU - Hu, Dingqin
AU - Tang, Hua
AU - Lv, Jie
AU - Li, Gang
AU - Lu, Shirong
N1 - Publisher Copyright:
© 2021 Chongqing Xixin Tianyuan Data & Information Co., Ltd
PY - 2021/11
Y1 - 2021/11
N2 - Side-chain modification is a proven effective approach for morphology manipulation in organic solar cells (OSCs). However, in-depth analysis and investigation involving side-chain modification towards morphology improvement, including molecular microstructure, orientating packing and aggregation are urgent for all-small-molecule (ASM) systems. Herein, employing a fluorine-modified two-dimension benzodithiophene (BDT) as central unit, we contrastively synthesized two small-molecule donors, namely BDT-F-SR and BDT-F-R, each welding alkylthio side-chains on thienyl of central BDT unit and the other grafted non-sulfuric alkyl side-chains. As predicted, the synergetic side-chain modification of fluorination and alkyl changeover triggers diverse molecular dipole moments and orientations, resulting in different molecular energy levels, thermal stabilities, molecular planarity and order. Eventually, together with the preeminent small-molecule acceptor Y6, BDT-F-R-based ASM OSCs obtain enhanced power conversion efficiency (PCE) of 13.88% compared to BDT-F-SR-based devices (PCE of 12.75%) with more suitable phase-separation and balanced carrier mobilities. The contrast results reveal that alkyl side-chains seem to be a more satisfactory partner for fluorine-modified 2D BDT-based small-molecule donors compared to alkylthio pendants, and highlight the significance of subtle side-chain modification for molecular structural order fun-tuning and morphology control, laying the foundation for efficient ASM OSCs.
AB - Side-chain modification is a proven effective approach for morphology manipulation in organic solar cells (OSCs). However, in-depth analysis and investigation involving side-chain modification towards morphology improvement, including molecular microstructure, orientating packing and aggregation are urgent for all-small-molecule (ASM) systems. Herein, employing a fluorine-modified two-dimension benzodithiophene (BDT) as central unit, we contrastively synthesized two small-molecule donors, namely BDT-F-SR and BDT-F-R, each welding alkylthio side-chains on thienyl of central BDT unit and the other grafted non-sulfuric alkyl side-chains. As predicted, the synergetic side-chain modification of fluorination and alkyl changeover triggers diverse molecular dipole moments and orientations, resulting in different molecular energy levels, thermal stabilities, molecular planarity and order. Eventually, together with the preeminent small-molecule acceptor Y6, BDT-F-R-based ASM OSCs obtain enhanced power conversion efficiency (PCE) of 13.88% compared to BDT-F-SR-based devices (PCE of 12.75%) with more suitable phase-separation and balanced carrier mobilities. The contrast results reveal that alkyl side-chains seem to be a more satisfactory partner for fluorine-modified 2D BDT-based small-molecule donors compared to alkylthio pendants, and highlight the significance of subtle side-chain modification for molecular structural order fun-tuning and morphology control, laying the foundation for efficient ASM OSCs.
KW - Molecular dipole moment
KW - Morphology
KW - Organic solar cell
KW - Side-chain modification
KW - Small-molecule donor
UR - http://www.scopus.com/inward/record.url?scp=85129294053&partnerID=8YFLogxK
U2 - 10.1016/j.matre.2021.100061
DO - 10.1016/j.matre.2021.100061
M3 - Journal article
AN - SCOPUS:85129294053
SN - 2666-9358
VL - 1
JO - Materials Reports: Energy
JF - Materials Reports: Energy
IS - 4
M1 - 100061
ER -