TY - JOUR
T1 - High-Performance Organic Solar Cells Containing Pyrido[2,3-b]quinoxaline-Core-Based Small-Molecule Acceptors with Optimized Orbit Overlap Lengths and Molecular Packing
AU - Xu, Tongle
AU - Luo, Zhenghui
AU - Ma, Ruijie
AU - Chen, Zhanxiang
AU - Dela Peña, Top Archie
AU - Liu, Heng
AU - Wei, Qi
AU - Li, Mingjie
AU - Zhang, Cai'e
AU - Wu, Jiaying
AU - Lu, Xinhui
AU - Li, Gang
AU - Yang, Chuluo
N1 - Publisher Copyright:
© 2023 Wiley-VCH GmbH.
PY - 2023/7/24
Y1 - 2023/7/24
N2 - The central core in A-DA1D-A-type small-molecule acceptor (SMAs) plays an important role in determining the efficiency of organic solar cells (OSCs), while the principles governing the efficient design of SMAs remain elusive. Herein, we developed a series of SMAs with pyrido[2,3-b]quinoxaline (PyQx) as new electron-deficient unit by combining with the cascade-chlorination strategy, namely Py1, Py2, Py3, Py4 and Py5. The introduction of chlorine atoms reduces the intramolecular charge transfer effects but elevates the LUMO values. Density functional theory (DFT) reveals that Py2 with ortho chlorine substituted PyQx and Py5 with two chlorine atoms yield larger dipole moments and smaller π⋅⋅⋅π stacking distances, as compared with the other three acceptors. Moreover, Py2 shows the strongest light absorption capability induced by extended orbit overlap lengths and more efficient packing structures in the dimers. These features endow the best device performance of Py2 due to the better molecular packing and aggregation behaviors, more suitable domain sizes with better exciton dissociation and charge recombination. This study highlights the significance of incorporating large dipole moments, small π⋅⋅⋅π stacking distances and extended orbit overlap lengths in dimers into the development of high-performance SMAs, providing insight into the design of efficient A-DA1D-A-type SMAs for OSCs.
AB - The central core in A-DA1D-A-type small-molecule acceptor (SMAs) plays an important role in determining the efficiency of organic solar cells (OSCs), while the principles governing the efficient design of SMAs remain elusive. Herein, we developed a series of SMAs with pyrido[2,3-b]quinoxaline (PyQx) as new electron-deficient unit by combining with the cascade-chlorination strategy, namely Py1, Py2, Py3, Py4 and Py5. The introduction of chlorine atoms reduces the intramolecular charge transfer effects but elevates the LUMO values. Density functional theory (DFT) reveals that Py2 with ortho chlorine substituted PyQx and Py5 with two chlorine atoms yield larger dipole moments and smaller π⋅⋅⋅π stacking distances, as compared with the other three acceptors. Moreover, Py2 shows the strongest light absorption capability induced by extended orbit overlap lengths and more efficient packing structures in the dimers. These features endow the best device performance of Py2 due to the better molecular packing and aggregation behaviors, more suitable domain sizes with better exciton dissociation and charge recombination. This study highlights the significance of incorporating large dipole moments, small π⋅⋅⋅π stacking distances and extended orbit overlap lengths in dimers into the development of high-performance SMAs, providing insight into the design of efficient A-DA1D-A-type SMAs for OSCs.
KW - Chlorination
KW - Molecular Packing
KW - Pyrido[2,3-b]Quinoxaline
KW - Small-Molecule Acceptor
KW - Solar Cells
UR - http://www.scopus.com/inward/record.url?scp=85161987993&partnerID=8YFLogxK
U2 - 10.1002/anie.202304127
DO - 10.1002/anie.202304127
M3 - Journal article
C2 - 37232174
AN - SCOPUS:85161987993
SN - 1433-7851
VL - 62
JO - Angewandte Chemie - International Edition
JF - Angewandte Chemie - International Edition
IS - 30
M1 - e202304127
ER -