Quantum Beats in Fluorescence Dynamics Generated from Multiple Pulse Excitations to Reveal the Degenerate Excited States in Bovine Serum Albumin-Protected Au25(SR)18 Nanoclusters
Quantum Beats in Fluorescence Dynamics Generated from Multiple Pulse Excitations to Reveal the Degenerate Excited States in Bovine Serum Albumin-Protected Au25(SR)18 Nanoclusters
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多次脉冲激发产生的荧光动力学中的量子拍揭示牛血清白蛋白保护的 Au25(SR)18 纳米团簇的简并激发态
DOI：
10.1021/acs.jpcc.1c09790
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发表时间：
2022
期刊：
影响因子：
--
通讯作者：
Lijun Guo
中科院分区：
文献类型：
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作者：
Zhongran Wei;Yatao Pan;Xiangyu Huo;Yulu He;Yanmin Kuang;Xia Ran;Lijun Guo
硫代稳定的金纳米团簇(NCS)因其独特的性质和广阔的应用前景而引起了人们的极大兴趣。然而，在充分了解它们的电子结构和光学性质的相关机理方面仍然存在挑战。在这里，我们主要关注牛血清白蛋白(BSA)保护的AU25(SR)18NC，通过在多脉冲激发下在荧光动力学中创建量子拍子来深入了解它们的电子结构。成功地产生了简并激发态之间的电子振荡，并对其进行了系统的研究。量子拍子的能见度对激发波长、激发功率和溶液温度不敏感，但对发射波长、三重态布居数和Au原子数非常敏感。序列脉冲激发产生的荧光动力学振荡清楚地揭示了AU25(SR)18NCs电子结构中存在长寿命简并三重态。由振荡剖面的傅里叶变换分析得到了三个典型频率：1.79±0.01 GHz、2.64±0.05 GHz和3.87±0.03 GHz，表明简并三重态之间存在电子叠加和能量差异。这些发现对于深入理解BSA保护的AU25(SR)18NC的电子结构和光物理性质之间的关系具有重要意义。
Thiolate-stabilized Au nanoclusters (NCs) have attracted considerable interest because of their unique properties and promising applications. However, there are still challenges in fully understanding the involved mechanisms of their electronic structure and optical properties. Here, we have focused primarily on bovine serum albumin (BSA)-protected Au25(SR)18NCs to gain deep insight into their electronic structure by creating quantum beats in fluorescence dynamics with multiple pulse excitations. The electronic oscillations among degenerate excited states have been successfully generated and systematically investigated. The visibility of quantum beats demonstrates an insensitivity to the excitation wavelength, excitation power, and solution temperature but is very sensitive to the emission wavelength, the population of triplet states, and the number of Au atoms. The generated oscillations in fluorescence dynamics by sequential pulse excitations clearly reveal the existence of long-lived degenerate triplet states in the electronic structure of Au25(SR)18NCs. There are three typical frequencies of 1.79 ± 0.01 GHz, 2.64 ± 0.05 GHz, and 3.87 ± 0.03 GHz determined from the Fourier transform analysis of the oscillation profile, suggesting the electronic superimpositions and energetic differences among the degenerate triplet states. These findings are significant for deep understanding of the relationship between the electronic structure and photophysical properties of BSA-protected Au25(SR)18NCs.