V. Lashkaryov Institute of Semiconductor Physics NAS of Ukraine, pr. Nauki 41, Kyiv 03028, Ukraine.
Institute of Physics NAS of Ukraine, pr. Nauki 46, Kyiv 03028, Ukraine.
J Phys Chem Lett. 2022 Jul 28;13(29):6619-6627. doi: 10.1021/acs.jpclett.2c00805. Epub 2022 Jul 14.
Anti-Kasha emission (i.e., the emission from S ( > 1) excited levels) of infrared chromophores which possess intensive absorption and S emission in the near-infrared region, but which are spectrally silent in the visible, is a challenging task for relevant applications such as energy conversion, bioimaging, sensitization of solar cells, optical sensors, and so on. Here we demonstrate a dual emission of near-infrared tricarbocyanine dyes with a bright green S fluorescence, whose quantum yield increases by 2-4 times together with a strong enhancement of the spontaneous rate of S fluorescence, whereas the quantum yield of S emission decreases by 2-7 times, respectively, as a result of immobilization of the dye molecule via interaction with carbon quantum dots. The enhanced immobilization-induced S emission is shown to occur because of planarization of the molecule and freezing its rotational degrees of freedom as indicated by suppression of the dye hot-band absorption-assisted anti-Stokes S emission.
具有强近红外吸收和 S 发射但在可见光谱中无光谱响应的红外发色团的反卡沙（Kasha）发射（即来自 S（>1）激发态的发射），对于能量转换、生物成像、太阳能电池敏化、光学传感器等相关应用来说是一项极具挑战性的任务。在这里，我们展示了近红外三碳菁染料的双发射，具有明亮的绿色 S 荧光，其量子产率增加了 2-4 倍，同时 S 荧光的自发速率增强了 2-4 倍，而 S 发射的量子产率分别降低了 2-7 倍，这是由于染料分子通过与碳量子点相互作用而固定化的结果。增强的固定化诱导的 S 发射被证明是由于分子的平面化和旋转自由度的冻结，这是由于抑制了染料热带吸收辅助的反斯托克斯 S 发射。
