Förster resonance energy transfer (FRET) has been widely applied in fluorescence imaging, sensing and so on, while developing useful strategy of boosting FRET efficiency becomes a key issue that limits the application. Except optimizing spectral properties, promoting orientation factor (κ2) has been well discussed but rarely utilized for boosting FRET. Herein, we constructed binary nano‐assembling of two thermally activated delayed fluorescence (TADF) emitters (2CzPN and DMAC‐DPS) with J‐type aggregate of cyanine dye (C8S4) as doping films by taking advantage of their electrostatic interactions. Time‐resolved spectroscopic measurements indicated that 2CzPN/Cy‐J films exhibit an order of magnitude higher kFRET than DMAC‐DPS/Cy‐J films. Further quantitative analysing on kFRET and kDET indicated higher orientation factor (κ2) in 2CzPN/Cy‐J films play a key role for achieving fast kFRET, which was subsequently confirmed by anisotropic measurements. Corresponding DFT/TDDFT calculation revealed strong “two‐point” electrostatic anchoring in 2CzPN/Cy‐J films that is responsible for highly orientated transitions. We provide a new strategy for boosting FRET in nano‐assemblies, which might be inspired for designing FRET‐based devices of sensing, imaging and information encryption.

中文翻译：

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通过在二元热激活延迟荧光/J-聚集体中锚定偶极子方向来促进激发态能量转移

福斯特共振能量转移（FRET）已广泛应用于荧光成像、传感等领域，而开发有效的提高FRET效率的策略成为限制其应用的关键问题。除了优化光谱特性之外，促进定向因子 (κ2) 已被充分讨论，但很少用于增强 FRET。在此，我们利用两种热激活延迟荧光（TADF）发射器（2CzPN和DMAC-DPS）的静电相互作用，以J型花青染料（C8S4）聚集体作为掺杂膜，构建了二元纳米组装体。时间分辨光谱测量表明，2CzPN/Cy-J 薄膜的 kFRET 比 DMAC-DPS/Cy-J 薄膜高一个数量级。对 kFRET 和 kDET 的进一步定量分析表明，2CzPN/Cy-J 薄膜中较高的取向因子 (κ2) 对于实现快速 kFRET 起着关键作用，随后各向异性测量证实了这一点。相应的 DFT/TDDFT 计算揭示了 2CzPN/Cy-J 薄膜中强大的“双点”静电锚定，它负责高度定向的转变。我们提供了一种在纳米组件中增强 FRET 的新策略，这可能会启发设计基于 FRET 的传感、成像和信息加密设备。