Fluorescent hyperbranched polysiloxane (HBPSi) has attracted increasing attention due to its good biocompatibility. However, its emission mechanism remains an open question. Unfortunately, the excitation spectra of HBPSi are rarely systematically investigated and show a narrow excitation band, which hinders the emission mechanism study. Herein, we synthesized a series of novel HBPSi containing l-glutamic acid (HBPSi-GA). Surprisingly, these polymers have four excitation peaks and two emission peaks, which are caused by the energy transfer from free functional groups to heterogeneous electron delocalizations in different clusters. Meanwhile, the fluorescence and biocompatibility of HBPSi-GA are significantly improved with increasing l-glutamic acid. Furthermore, HBPSi-GA exhibits dual stimuli-responsive fluorescence to temperature and Fe³⁺ as well as potential application in cell imaging. This research possesses important guidance to develop multiexcitation unconventional fluorescent polymers.

中文翻译：

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能量转移引起的多激发和超支化聚硅氧烷的增强排放。

荧光超支化聚硅氧烷（HBPSi）由于其良好的生物相容性而受到越来越多的关注。但是，其排放机制仍然是一个悬而未决的问题。不幸的是，很少有系统地研究HBPSi的激发光谱，并且显示出窄的激发带，这阻碍了发射机理的研究。本文中，我们合成了一系列新型的含有1-谷氨酸的HBPSi（HBPSi-GA）。令人惊讶地，这些聚合物具有四个激发峰和两个发射峰，这是由于能量从自由官能团转移到不同簇中的异质电子离域而引起的。同时，HBPSi-GA的荧光和生物相容性随l的增加而显着提高。-谷氨酸。此外，HBPSi-GA对温度和Fe ³⁺表现出双重刺激响应荧光，并在细胞成像中具有潜在的应用。该研究为开发多激发非常规荧光聚合物提供了重要指导。