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zhangkun232

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专业: 催化化学

[交流] 贵金属纳米团簇的分子发光机制已有2人参与

金属纳米团簇的发光一直以来存在非常大的争议，有两个核心机制：贵金属纳米团簇的量子尺寸限域效应和表面配体主导的空间电子效应，越来越多的证据证明表面配体对发光的调控起到决定性作用，但是发光的中心是表面的保护性配体还是其它吸附的化学组分。结合各种稳态谱学以及飞秒超快技术，我们在国际上率先提出了，贵金属纳米团簇的发光中心来源于界面吸附的结构水分子，这正结构水分子不同于传统的氢键水分子，并且提出了拓扑激发的概念。论文发表在Nanoscale（Nanoscale, 2021,13, 15058-15066；DOI https://doi.org/10.1039/D1NR02389F）上，欢迎大家留言讨论。文章链接如下：https://pubs.rsc.org/en/content/articlelanding/2021/nr/d1nr02389f
Caged structural water molecules emit tunable brighter colors by topological excitation†

bstract
Intrinsically, free water molecules are a colourless liquid. If it is colourful, why and how does it emit the bright colours? We provided direct evidence that when water was trapped into the sub-nanospace of zeolites, the structural water molecules (SWs) exhibited strong tunable photoluminescence (PL) emissions from blue to red colours with unprecedented ultra-long lifetimes up to the second scale at liquid nitrogen temperature. Further controlled experiments and combined characterizations by time-resolved steady-state and ultra-fast femtosecond (fs) transient optical spectroscopy showed that the singly adsorbed hydrated hydroxide complex {OH−·H2O} as SWs in the confined nanocavity is the true emitter centre, whose PL efficiency strongly depends on the type and stability of the SWs, which is dominated by H-bond interactions, such as the solvent effect, pH value and operating temperature. The emission of SWs exhibits the characteristic of topological excitations (TAs) due to the many-body quantum electron correlations in confined nanocavities, which differs from the local excitation of organic chromophores. Our model not only elucidates the origin of the PL of metal nanoclusters (NCs), but also provides a completely new insight to understand the nature of heterogeneous catalysis and interface bonding (or state) at the molecule level, beyond the metal-centred d band theory.

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