School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram, Kerala 695551, India.
Department of Chemistry, Indian Institute of Technology Indore, Madhya Pradesh 453552, India.
Nanoscale. 2023 May 11;15(18):8377-8386. doi: 10.1039/d3nr01107k.
Owing to the quantized size and associated discrete energy levels, atomically precise silver nanoclusters (Ag NCs) hold great potential for designing functional luminescent materials. However, the thermally activated non-radiative transition of Ag(I)-based NCs has faded the opportunities. To acquire the structurally rigid architecture of cluster nodes for constraining such transitions, a new synthetic approach is unveiled here that utilizes a neutral template as a cluster-directing agent to assemble twenty Ag(I) atoms that ensure the maximum number of surface-protecting ligand attachment possibilities in a particular solvent medium. The solvent polarity triggers the precise structural design to circumvent the over-reliance of the templates, which results in the formation of [CO@Ag(SAdm)(CFCOO)(DMA)] NC (where SAdm = 1-adamantanethiolate and DMA = ,-dimethylacetamide) exhibiting an unprecedented room-temperature photoluminescence emission. The high quantum yield of the generated blue emission ensures its candidature as an ideal donor for artificial light-harvesting system design, and it is utilized with the two-step sequential energy transfer process, which finally results in the generation of ideal white light. For implementing perfect white light emission, the required chromophores in the green and red emission regions were chosen based on their effective spectral overlap with the donor components. Due to their favorable energy-level distribution, excited state energy transfers occurred from the NC to β-carotene at the initial step, then from the conjugate of the NC and β-carotene to another chromophore, Nile Blue, at the second step a sequential Förster resonance energy transfer pathway.
由于原子精确的银纳米团簇（Ag NCs）的量子尺寸和相关的离散能级，它们在设计功能性发光材料方面具有巨大的潜力。然而，基于 Ag(I)的 NCs 的热激活非辐射跃迁使这些机会黯然失色。为了获得簇节点的结构刚性架构，以限制这种跃迁，这里揭示了一种新的合成方法，该方法利用中性模板作为簇导向剂来组装二十个 Ag(I)原子，从而确保在特定溶剂介质中具有最大数量的表面保护配体附着可能性。溶剂极性触发了精确的结构设计，以避免对模板的过度依赖，这导致了 [CO@Ag(SAdm)(CFCOO)(DMA)] NC（其中 SAdm = 1-金刚烷硫醇盐，DMA = ，-二甲基乙酰胺）的形成，表现出前所未有的室温光致发光发射。生成的蓝色发射的高量子产率确保了其作为人工光捕获系统设计的理想供体的候选资格，并且它与两步顺序能量转移过程一起使用，最终导致理想的白光的产生。为了实现完美的白光发射，根据与供体组件的有效光谱重叠，选择了绿光和红光发射区域所需的发色团。由于其有利的能级分布，激发态能量从 NC 转移到β-胡萝卜素在初始步骤，然后从 NC 和β-胡萝卜素的共轭物转移到另一个发色团尼罗蓝在第二步，依次进行Förster 共振能量转移途径。
