Li Ma, Zhuoran Kuang, Hao Zhang, Yan Wan, Yuanyuan Guo, Andong Xia, Yang Li
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引用次数: 0
Abstract
To mimic the excitation energy conversion mechanisms observed in natural light-harvesting systems, we have extensively investigated photoinduced symmetry-breaking charge separations (SBCSs) in various multichromophoric model systems have been extensively investigated. However, designing multichromophoric model systems capable of simultaneously achieving ultrafast and complete SBCS remains a significant challenge. In this study, we employed benzene, thiophene, and furan as π-bridges to develop a series of boron dipyrromethene (BODIPY) homodimers. Spectral analysis, together with an estimation of the π-bridge-dependent charge transfer (CT) coupling using the fragment charge difference method, reveals that π-bridge units with different electron-donating abilities can effectively modulate the CT coupling between chromophores. Notably, the furan-based π-bridge, exhibiting the most pronounced electron-donating character, facilitates symmetry-breaking charge transfer (SBCT), i.e., excimer formation with a time constant of about 12 ps in weak polar toluene. Furthermore, a dramatic increase in the SBCS rate constant was observed in highly polar acetonitrile, improving from 60.4 ps for the benzene-bridged homodimer to 2.9 ps for the furan-bridged counterpart. These findings underscore the potential of π-bridge units in tuning the photophysical properties of covalent molecular aggregates by optimizing such systems for specific applications such as organic photovoltaics and photocatalysis.
期刊介绍:
An essential criterion for acceptance of research articles in the journal is that they provide new physical insight. Please refer to the New Physical Insights virtual issue on what constitutes new physical insight. Manuscripts that are essentially reporting data or applications of data are, in general, not suitable for publication in JPC B.