Rational manipulation of nonradiative decay channels is of crucial significance to improve photothermal conversion efficiency (PCE) and design photothermal agents. We first used the “internal and external combined” nonradiative decay strategy to enhance PCE. Specifically, organic IR-Y6 NPs with strong NIR absorption and high molar extinction coefficient were prepared and characterized. By means of TD-DFT calculations and fs-TA spectroscopy, the dual nonradiative decay channels composed of the free rotor (external strategy) and ultrafast dark excited states (DESs) between S₀ and S₁ states (internal strategy) were proved, which significantly enhanced PCE, up to 66%. IR-Y6 NPs were applied to a mice tumor model for photoacoustic image-guided photothermal therapy, showing complete tumor ablation ability and good biocompatibility for the normal organs. This work is of significance to deeply understand the nonradiation decay mechanism and rational design of high-performance PTT agents.

中文翻译：

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用于光声图像引导的高效光热治疗的“内外结合”非辐射衰减纳米剂

合理操控非辐射衰变通道对于提高光热转换效率（PCE）和设计光热剂具有重要意义。我们首先使用“内外结合”的非辐射衰减策略来增强 PCE。具体而言，制备并表征了具有强近红外吸收和高摩尔消光系数的有机IR-Y6 NPs。通过 TD-DFT 计算和 fs-TA 光谱，由自由转子（外部策略）和 S ₀和 S _{1之间的超快暗激发态（DES）组成的双非辐射衰变通道}状态（内部策略）被证明，这显着提高了 PCE，高达 66%。IR-Y6 NPs应用于小鼠肿瘤模型进行光声图像引导光热治疗，显示出完全的肿瘤消融能力和对正常器官的良好生物相容性。该工作对于深入了解高性能PTT代理的非辐射衰减机制和合理设计具有重要意义。