Plasmon-Coupled Resonance Energy Transfer II: Exploring the Peaks and Dips in the Electromagnetic Coupling Factor
Plasmon-Coupled Resonance Energy Transfer II: Exploring the Peaks and Dips in the Electromagnetic Coupling Factor
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DOI：
10.1021/acs.jpcc.8b07210
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发表时间：
2018-10-04
影响因子：
3.7
通讯作者：
Schatz, George C.
中科院分区：
文献类型：
--
作者：
Ding, Wendu;Hsu, Liang-Yan;Schatz, George C.
我们研究了位于球形银纳米颗粒的相对两侧的供体-受体对之间的共振能量转移，并利用我们以前开发的量子电动力学理论探索了能量转移速率对纳米颗粒尺寸的依赖性。该理论表明，该速率由供体发射光谱、受体吸收光谱和电子耦合因子（CF）的乘积决定，电子耦合因子（CF）由与作为纳米颗粒附近的偶极发射体的供体相关的电动力学决定。我们发现，CF光谱显示与局部表面等离子体共振相关的峰，但最显著的峰的位置与纳米颗粒的尺寸的相关性小于对于相同颗粒的消光光谱所发现的。对于偶极等离子体激元激发占主导地位的小纳米颗粒（小于或类似于30 nm），准静态分析得到分析公式，其中CF峰和谷涉及供体电场与纳米颗粒的散射偶极场之间的干扰。对于较大的纳米颗粒（60-210 nm），CF在接近355 nm的波长处最大化，而与颗粒尺寸无关，该颗粒尺寸由对消光光谱有显著贡献的最高多极等离子体决定，仅由较低的多极等离子体（例如偶极等离子体）产生小的贡献。此外，对于可激发银的体等离子体共振的325 nm附近的波长，不能激发表面等离子体，因此来自供体的激发不能通过表面等离子体传输到受体，导致CF中的显著下降。这项工作提供了关于等离子体介导的能量转移的新概念，这些概念与传统的（福斯特）理论完全不同，但当供体和受体充分分离时，这些概念应该主导能量转移行为。
We study resonance energy transfer between a donor-acceptor pair located on opposite sides of a spherical silver nanoparticle and explore the dependence of energy-transfer rate on nanoparticle size using a quantum electrodynamics theory we developed previously. This theory indicates that the rate is determined by the product of donor emission spectra, acceptor absorption spectra, and an electronic coupling factor (CF) that is determined by electrodynamics associated with the donor as a dipole emitter near the nanoparticle. We find that the CF spectra show peaks that are associated with localized surface plasmon resonances, but the locations of the most significant peaks are less correlated to the size of the nanoparticle than is found for extinction spectra for the same particle. For small nanoparticles (less than or similar to 30 nm), where dipole plasmon excitation dominates, a quasi-static analysis leads to an analytical formula, in which the CF peaks and dips involve interference between donor electric field and the scattered dipolar field of the nanoparticle. For larger nanoparticles (60-210 nm), the CF maximizes at a wavelength near 355 nm independent of particle size that is determined by the highest multipole plasmon that contributes significantly to the extinction spectrum, with only small contributions arising from lower multipole plasmons, such as the dipole plasmon. Also, for wavelengths near 325 nm where the bulk plasmon resonance of silver can be excited, surface plasmons cannot be excited, so excitation from the donor cannot be transmitted by surface plasmons to the acceptor, leading to a pronounced dip in the CF. This work provides new concepts concerning plasmon-mediated energy transfer that are quite different from conventional (Forster) theory, but which should dominate energy-transfer behavior when donor and acceptor are sufficiently separated.