Suppressed Blinking and Polarization-Dependent Emission Enhancement of Single ZnCdSe/ZnS Dot Coupled with Au Nanorods
Suppressed Blinking and Polarization-Dependent Emission Enhancement of Single ZnCdSe/ZnS Dot Coupled with Au Nanorods
复制标题
与金纳米棒耦合的单个 ZnCdSe/ZnS 点的抑制闪烁和偏振相关发射增强
DOI：
10.1021/acsami.2c00207
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发表时间：
2022
期刊：
影响因子：
--
通讯作者：
Xia Ran
中科院分区：
文献类型：
--
作者：
Yulu He;Jin Chen;Renming Liu;Yulong Weng;Cong Zhang;Yanmin Kuang;Xiaojuan Wang;Lijun Guo;Xia Ran
荧光量子点在量子光学、光电子学、固态照明、生物成像等领域具有广阔的应用前景，引起了人们的广泛关注。然而，荧光量子点器件具有光闪烁、发射效率低、不稳定等缺点，影响了其光学性能和实际应用。在这里，我们报道了组装在Au纳米棒(NRS)表面的单个锌镉硒/硫化锌量子点的闪烁抑制、辐射速率增强和偏振相关的发射特性。我们发现Au NRS的局域表面等离子体激元(LSP)显著地调节了复合的ZnCd Se/ZnS QD-Au NRS(QD-Au NRS)的激发和发射性质。与盖片上的单量子点相比，单QD-Au NRS的单位时间平均发射光子数显著增加，寿命显著缩短，闪烁受到抑制。根据实验和模拟分析，Au NRS的光生LSP场显著增加了QD-Au NRS的激发跃迁和辐射速率。虽然发射效率略有提高，但激发和辐射速率的协同增强充分竞争了非辐射过程，以补偿量子点的低发射效率，最终抑制QD-Au NRS的光闪烁。此外，还观察到了偏振相关的发射增强，并对其进行了理论分析，证明了很好的一致性，证实了激发增强的贡献。我们的发现为提高单一QD-Au-NR复合材料的光学性能和稳定性提供了一种实用的策略，并为深入理解发射体与金属纳米颗粒的LSP场之间的相互作用提供了必要的信息。
Fluorescent quantum dots (QDs) have attracted extensive attention because of their promising applications in many fields such as quantum optics, optoelectronics, solid-state lighting, and bioimaging. However, photo-blinking, low emission efficiency, and instability are the drawbacks of fluorescent QD-based devices, affecting their optical properties and practical applications. Here, we report suppressed blinking, enhanced radiative rate, and polarization-dependent emission properties of single ZnCdSe/ZnS QDs assembled on the surface of Au nanorods (NRs). We found that the local surface plasmon (LSP) of Au NRs significantly regulates the excitation and emission properties of the composite ZnCdSe/ZnS QD-Au NRs (QD-Au NRs). The average number of photons emitted per unit time from single QD-Au NRs has been significantly enhanced compared with that of single ZnCdSe/ZnS QDs on the coverslip, accompanied by a drastically shortened lifetime and suppressed blinking. According to the experimental and simulation analysis, the photogenerated LSP field of Au NRs remarkably increases the excitation transition and the radiative rates of QD-Au NRs. Although the emission efficiency is slightly increased, the synergetic enhancement of excitation and radiative rates sufficiently competes with the nonradiative process to compensate for the low emission efficiency of QDs and ultimately suppress the photo-blinking of QD-Au NRs. Moreover, the polarization-dependent emission enhancement has also been observed and theoretically analyzed, demonstrating good consistency and confirming the contribution of excitation enhancement. Our findings present a practical strategy to improve the optical properties and stability of single QD-Au NR composite and provide essential information for a deep understanding of the interaction between emitters and the LSP field of metal nanoparticles.