Francisco Alexandra P, Botequim David, Prazeres Duarte M F, Serra Vanda V, Costa Sílvia M B, Laia César A T, Paulo Pedro M R
LAQV@REQUIMTE, Chemistry Department, Faculty of Science and Technology , Universidade NOVA de Lisboa , 2829-516 Caparica , Portugal.
J Phys Chem Lett. 2019 Apr 4;10(7):1542-1549. doi: 10.1021/acs.jpclett.9b00373. Epub 2019 Mar 20.
Porphyrins are typically weak emitters, which presents challenges to their optical detection by single-molecule fluorescence microscopy. In this contribution, we explore the enhancement effect of gold nanodimer antennas on the fluorescence of porphyrins in order to enable their single-molecule optical detection. Four meso-substituted free-base porphyrins were evaluated: two cationic, one neutral, and one anionic porphyrin. The gold nanodimer antennas are able to enhance the emission from these porphyrins by a factor of 10-10 increase in the maximum detected photon rates. This extreme enhancement is due to the combination of an antenna effect on the excitation rate that is estimated to be above 10-fold and an emission efficiency that corresponds to an increase of 2-10 times in the porphyrin's fluorescence quantum yield.
卟啉通常是弱发射体，这给通过单分子荧光显微镜对其进行光学检测带来了挑战。在本论文中，我们探索了金纳米二聚体天线对卟啉荧光的增强作用，以便能够对其进行单分子光学检测。评估了四种中位取代的游离碱卟啉：两种阳离子卟啉、一种中性卟啉和一种阴离子卟啉。金纳米二聚体天线能够将这些卟啉的发射增强10 - 10倍，即最大检测光子速率增加。这种极端增强是由于天线对激发速率的影响（估计超过10倍）和发射效率的综合作用，发射效率对应于卟啉荧光量子产率提高2 - 10倍。
