系统间交叉
超快激光光谱学
化学
光化学
三重态
分子内力
接受者
光激发
单重态
吸收光谱法
激发态
光谱学
原子物理学
分子
立体化学
量子力学
物理
有机化学
凝聚态物理
作者
Xi Chen,А. А. Суханов,Maria Letizia Taddei,Bernhard Dick,Jianzhang Zhao,В. К. Воронкова,Mariangela Di Donato
标识
DOI:10.1021/acs.jpclett.2c02118
摘要
Three anthracene (An)–naphthalenediimide (NDI) compact electron donor–acceptor dyads were prepared. Femtosecond transient absorption (fs-TA) spectra show fast charge separation (ca. 0.9–1.7 ps) and relatively slow charge recombination (ca. 8–565 ps) upon photoexcitation; moreover, the 3An state was observed for 9-An-NDI, whereas the final state is 3NDI for both 9-An-Ph-NDI and 2-An-Ph-NDI, which have an intervening phenyl linker between the An and NDI units. Nanosecond transient absorption (ns-TA) spectra indicate that the lowest triplet state of all the dyads is 3An, with triplet lifetimes of 139–354 μs. An unusually slow intramolecular triplet–triplet energy transfer (TTET) was observed for 9-An-Ph-NDI and 2-An-Ph-NDI (32–85 ns). Time-resolved electron paramagnetic resonance (TREPR) spectroscopy confirms that the intersystem crossing (ISC) mechanism is spin orbit charge transfer ISC (SOCT-ISC) for all the dyads; for 9-An-NDI, only the 3An state was observed, while for the other two dyads, both 3NDI and 3An states were observed, with their relative population changing with increasing delay time, which supports TTET.
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