Fluorescence probes emitting in the second near-infrared (NIR-II, 1000–1700 nm) window with the ability for deep-tissue imaging in mammals herald a new era in surgical methodology. However, the brightness of these NIR-II probes is still far from satisfactory due to their low fluorescence quantum yields (QYs), preventing the observation of high-resolution images such as whole-organ vascular networks in real time. Described here is the molecular engineering of a series of semiconducting polymer dots (Pdots) incorporated with aggregation-induced emission moieties to exhibit the QYs as high as 14% in the NIR-II window. Benefiting from the ultrahigh brightness, a 1400 nm long-pass filter is utilized to realize in vivo 3D tumor mapping in mice. To further understand how the geometrical and electron structures of the semiconducting polymers affect their optical properties, the in-depth and thorough density-functional theory calculations are performed to interpret the experimental results. This study lays the groundwork for further molecular design of highly bright NIR-II Pdots.

中文翻译：

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用于 3D 肿瘤映射的具有高 NIR-II 荧光的超亮半导体聚合物点的分子设计

在第二个近红外（NIR-II，1000-1700 nm）窗口中发射的荧光探针能够对哺乳动物进行深层组织成像，这预示着外科方法学的新时代。然而，由于荧光量子产率 (QY) 较低，这些 NIR-II 探针的亮度仍远不能令人满意，无法实时观察全器官血管网络等高分辨率图像。这里描述的是一系列半导体聚合物点 (Pdots) 的分子工程，这些点与聚集诱导的发射部分结合，在 NIR-II 窗口中表现出高达 14% 的 QY。受益于超高亮度，利用1400 nm长通滤光片实现小鼠体内3D肿瘤映射。为了进一步了解半导体聚合物的几何结构和电子结构如何影响其光学性质，进行了深入而彻底的密度泛函理论计算来解释实验结果。该研究为进一步分子设计高亮度 NIR-II Pdots 奠定了基础。