Zhao Fei, Hu Jialing, Guan Daoming, Liu Jinyang, Zhang Xuebo, Ling Huan, Zhang Yunxiang, Liu Qian
Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, Shanghai, 200438, China.
Adv Mater. 2023 Dec;35(51):e2304907. doi: 10.1002/adma.202304907. Epub 2023 Nov 12.
Dye-sensitization can enhance lanthanide-based upconversion luminescence, but is hindered by interfacial energy transfer from organic dye to lanthanide ion Yb . To overcome these limitations, modifying coordination sites on dye conjugated structures and minimizing the distance between fluorescence cores and Yb in upconversion nanoparticles (UCNPs) are proposed. The specially designed near-infrared (NIR) dye, disulfo-indocyanine green (disulfo-ICG), acts as the antenna molecule and exhibits a 2413-fold increase in luminescence under 808 nm excitation compared to UCNPs alone using 980 nm irradiation. The significant improvement is attributed to the high energy transfer efficiency of 72.1% from disulfo-ICG to Yb in UCNPs, with majority of energy originating from triplet state (T ) of disulfo-ICG. Shortening the distance between the dye and lanthanide ions increases the probability of energy transfer and strengthens the heavy atom effect, leading to enhanced T generation and improved dye-triplet sensitization upconversion. Importantly, this approach also applies to 730 nm excitation Cy7-SO sensitization system, overcoming the spectral mismatch between Cy7 and Yb and achieving a 52-fold enhancement in luminescence. Furthermore, the enhancement of upconversion at single particle level through dye-sensitization is demonstrated. This strategy expands the range of NIR dyes for sensitization and opens new avenues for highly efficient dye-sensitized upconversion systems.
染料敏化可以增强基于镧系元素的上转换发光，但受到从有机染料到镧系离子Yb的界面能量转移的阻碍。为了克服这些限制，提出了修饰染料共轭结构上的配位位点并最小化上转换纳米颗粒（UCNP）中荧光核与Yb之间的距离。特别设计的近红外（NIR）染料二磺酸吲哚菁绿（disulfo-ICG）充当天线分子，与单独使用980nm辐照的UCNP相比，在808nm激发下发光增加了2413倍。这一显著改善归因于UCNP中从二磺酸吲哚菁绿到Yb的72.1%的高能量转移效率，大部分能量来自二磺酸吲哚菁绿的三重态（T）。缩短染料与镧系离子之间的距离增加了能量转移的概率并增强了重原子效应，导致T生成增强和染料三重态敏化上转换得到改善。重要的是，这种方法也适用于730nm激发的Cy7-SO敏化系统，克服了Cy7与Yb之间的光谱失配并实现了52倍的发光增强。此外，还证明了通过染料敏化在单颗粒水平上增强上转换。该策略扩展了用于敏化的近红外染料范围，并为高效染料敏化上转换系统开辟了新途径。
