Enhancement of fluorescence emission in a flexible and free-standing fluorescing film is a key requirement for sensing platforms with augmented sensitivity. In this context, a study on the enhanced fluorescence emission from nitrogen-doped carbon dots (NCDs) embedded on a flexible free-standing photonic crystal hydrogel film prepared via photopolymerization, is presented. The composite structure utilizes the photonic crystal enhanced fluorescence (PCEF) technique and incorporates a self-assembled 3D photonic crystal (3D PC) onto a photopolymerizable hydrogel matrix containing the NCDs. The 3D PC template is prepared through vertical deposition self-assembly using monodisperse polystyrene (PS) spheres. By leveraging the enhanced excitation and extraction effect in a PC-fluorophore composite, the authors’ structure exhibits a fourfold enhancement in fluorescence emission compared to the control sample. The relative positioning of the photonic stopband with the excitation and emission spectra of the fluorophore (NCDs) is thoroughly studied by selecting four different 3D PCs with varied lattice parameters. In addition, the hydrogel matrix offers improved photostability and enhanced lifetime for the NCDs. This structure can be further modified into an efficient sensor through appropriate functionalization.

中文翻译：

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一种柔性独立式光子晶体水凝胶薄膜，用于增强氮掺杂碳点的荧光

增强柔性独立式荧光薄膜中的荧光发射是具有增强灵敏度的传感平台的关键要求。在此背景下，提出了一项关于嵌入通过光聚合制备的柔性自支撑光子晶体水凝胶薄膜上的氮掺杂碳点（NCD）增强荧光发射的研究。该复合结构利用光子晶体增强荧光（PCEF）技术，并将自组装3D光子晶体（3D PC）整合到含有NCD的光聚合水凝胶基质上。 3D PC 模板是使用单分散聚苯乙烯 (PS) 球通过垂直沉积自组装制备的。通过利用 PC-荧光团复合材料中增强的激发和提取效应，作者的结构与对照样品相比，荧光发射增强了四倍。通过选择四种具有不同晶格参数的不同 3D PC，深入研究了光子阻带与荧光团 (NCD) 激发和发射光谱的相对定位。此外，水凝胶基质还提高了非传染性疾病的光稳定性并延长了使用寿命。通过适当的功能化，可以将该结构进一步修改为高效的传感器。