Structured Excitation Energy Transfer: Tracking Exciton Diffusion below Sunlight Intensity
Structured Excitation Energy Transfer: Tracking Exciton Diffusion below Sunlight Intensity
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DOI：
10.1021/acsphotonics.4c00004
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发表时间：
2024-02
期刊：
影响因子：
7
通讯作者：
Guillermo D. Brinatti Vazquez;Giulia Lo;Gerfo Morganti;Cvetelin Vasilev;C. N. Hunter;N. V. Hulst
中科院分区：
文献类型：
--
作者：
Guillermo D. Brinatti Vazquez;Giulia Lo;Gerfo Morganti;Cvetelin Vasilev;C. N. Hunter;N. V. Hulst
随着对用于光捕获应用的新材料的需求的增加，时空显微镜技术正受到越来越多的关注，因为它们允许直接观察激子的纳米级扩散。然而，使用脉冲和紧密聚焦的激光束产生的光强度远高于在阳光照射下预期的光强度，导致光损伤和非线性效应，严重限制了这些技术的准确性和适用性，特别是在生物或原子薄材料中。在这项工作中，我们提出了一种新的时空显微镜技术，利用结构化激发，以显着降低激发强度，高达10,000倍时，与以前报道的时空光致发光显微镜实验。我们在两个不同的系统中测试了我们的方法，报告了在低于太阳光的照明条件下的第一次激子扩散测量，这两个测量都考虑了有机光伏样品（Y 6）中的平均功率和峰值激子密度，在该样品中，我们跟踪了激子长达五个复合寿命。接下来，在来自紫色细菌的捕光复合物2的印刷单层中，首次在空间和时间上直接观察到纳米级的能量传输。
With the increasing demand for new materials for light-harvesting applications, spatiotemporal microscopy techniques are receiving increasing attention as they allow direct observation of the nanoscale diffusion of excitons. However, the use of pulsed and tightly focused laser beams generates light intensities far above those expected under sunlight illumination, leading to photodamage and nonlinear effects that seriously limit the accuracy and applicability of these techniques, especially in biological or atomically thin materials. In this work, we present a novel spatiotemporal microscopy technique that exploits structured excitation in order to dramatically decrease the excitation intensity, up to 10,000-fold when compared with previously reported spatiotemporal photoluminescence microscopy experiments. We tested our method in two different systems, reporting the first exciton diffusion measurement at illumination conditions below sunlight, both considering average power and peak exciton densities in an organic photovoltaic sample (Y6), where we tracked the excitons for up to five recombination lifetimes. Next, nanometer-scale energy transport was directly observed for the first time in both space and time in a printed monolayer of the light-harvesting complex 2 from purple bacteria.