Photo-induced excited-state dynamics within organic materials fundamentally determine their photophysical properties for various applications, and thus understanding the primary excited-state dynamics behavior is of fundamental and practical significance. Until recently, the excited-state dynamics of organic materials towards biophotonics have been rarely studied, although numerous endeavors have been devoted to the design of organic materials for biophotonics. Herein, various spectroscopy technologies including femtosecond transient absorption (fs-TA) spectroscopy clearly reveal a totally different excited state dynamics behavior within Bodipy monomer (2B-BDP dye) and aggregates (2B-BDP NPs), indicating strongly morphology dependent character. 2B-BDP dye undergoes an ultrafast conversion from S₁ to intramolecular charge transfer (ICT) state for subsequent photoluminescence (PL) and nonradiative (NR) decay, while 2B-BDP NPs show an accelerated excited-state deactivation mainly through S₁→S₀ NR decay. The potential bioapplications based on the corresponding excited state dynamics behavior are discussed together with experimental results. Interestingly, the accelerated NR decay in 2B-BDP NPs does not yield a stronger photoacoustic (PA) signal than that in 2B-BDP dye, which violates the conventional wisdom that faster NR decay would benefit the photothermal effects for better photoacoustic imaging (PAI). These insightful and fundamental observations of the excited-state dynamics may contribute an alternative approach at the molecular level towards the future design of functional Bodipy-based organic molecules with desirable performances.

有机材料中的光致激发态动力学从根本上决定了它们在各种应用中的光物理性质，因此了解主要的激发态动力学行为具有根本和实际意义。直到最近，很少有人研究有机材料对生物光子的激发态动力学，尽管人们已经为生物光子有机材料的设计做出了许多努力。在本文中，包括飞秒瞬态吸收（fs-TA）光谱在内的各种光谱技术清楚地揭示了Bodipy单体（2B-BDP染料）和聚集体（2B-BDP NP）内完全不同的激发态动力学行为，表明其强烈依赖于形态。2B-BDP染料从S _1开始经历超快转化到分子内电荷转移（ICT）状态，随后发生光致发光（PL）和非辐射（NR）衰减，而2B-BDP NP主要通过S ₁ →S ₀表现出加速的激发态失活NR衰减。讨论了基于相应的激发态动力学行为的潜在生物应用以及实验结果。有趣的是，与2B-BDP染料相比，在2B-BDP NP中加速的NR衰减不会产生更强的光声（PA）信号，这违背了传统的观点，即更快的NR衰减将有益于光热效应，以实现更好的光声成像（PAI） 。这些对激发态动力学的深刻见解和基础性观察可能会在分子水平上为实现具有理想性能的功能性基于Bodipy的有机分子的未来设计提供一种替代方法。