Photophysics and photostability of 9,10-bis(phenylethynyl)anthracene revealed by single-molecule spectroscopy
Photophysics and photostability of 9,10-bis(phenylethynyl)anthracene revealed by single-molecule spectroscopy
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DOI：
10.1039/c2ra21100a
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发表时间：
2012-01-01
期刊：
影响因子：
3.9
通讯作者：
Fukui, Hiroki
中科院分区：
文献类型：
--
作者：
Mitsui, Masaaki;Kawano, Yuya;Fukui, Hiroki
用单分子光谱学方法研究了9，10-二(苯乙炔基)菲(BPEA)在40 nm厚的Zeonex聚合物薄膜中的光物理和光稳定性。通过记录荧光强度轨迹、荧光寿命和荧光光谱，验证了BPEA的单分子检测。光强轨迹显示出频繁的开/关闪烁和一步光漂白行为。观察到的闪烁归因于通过系间交叉(ISC)暂时占据激发三重态T-1。在三态模型(如S-0、S-1和T-1)的假设下，通过对闪烁统计和强度自相关的分析，得到了BPEA的三重态寿命分布和S-1-T-1ISC量子产额的分布。我们发现了极低的ISC产额(在10(-5)-10(-4)数量级)，这是由于B-3(2U)和S-1(B-1(1U))/T-1(B-3(1U))态之间的大能隙在理论上是合理的。为了深入了解氧对光漂白的影响，还在空气和Ar气氛下进行了SMS测量。结果表明，尽管氧气的存在大大降低了BPEA的光稳定性，但在脱氧条件下，BPEA在光漂白之前会释放10(7)个以上的光子，并且具有相当低的光漂白产率(10(-9)-10(-8))。本研究表明，BPEA在室温下具有较高的光稳定性，可以作为一种有用的绿色荧光探针用于短信的研究。
The photophysics and photostability of 9,10-bis(phenylethynyl) anthracene (BPEA) diluted in a 40-nm-thick Zeonex polymer film have been investigated by single-molecule spectroscopy (SMS). The single-molecule detection of BPEA was verified by recording fluorescence intensity trajectories, fluorescence lifetimes, and fluorescence spectra. The intensity trajectories showed frequent on/off blinking and one-step photobleaching behaviors. The observed blinking was attributed to the temporary occupation of the excited triplet state T-1 via intersystem crossing (ISC). Assuming a three-state model (e.g., S-0, S-1, and T-1), the distributions of triplet lifetime and S-1 -> T-1 ISC quantum yield of BPEA were both derived from the analyses of the blinking statistics and the intensity autocorrelation. We found extremely low ISC yields (on the order of 10(-5)-10(-4)), which were theoretically rationalized by the large energy gap between B-3(2u) and S-1(B-1(1u))/T-1(B-3(1u)) states. SMS measurements were also conducted under both air and Ar atmospheres in order to gain insight into the influence of oxygen on photobleaching. The results reveal that, although the presence of oxygen considerably degraded the photostability of BPEA, under deoxygenated conditions, BPEA delivers more than 10(7) photons before photobleaching and possesses an appreciably low photobleaching yield of 10(-9)-10(-8). This study shows that BPEA has a relatively high degree of photostability at room temperature and can serve as a useful green fluorescent probe for SMS studies.