The transition between plasmon resonance and photoluminescence in coinage metal and alloy nanoclusters (NC) is controlled by surface charge, core composition, and surface ligand type

造币金属和合金纳米团簇 (NC) 中等离子共振和光致发光之间的转变由表面电荷、核心组成和表面配体类型控制

• 批准号: 320907882
• 负责人: Professor Dr.-Ing. Stephan Barcikowski
• 金额: --
• 依托单位: Lehrstuhl für Technische Chemie I
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/320907882?language=en
• 关键词: transition; between; plasmon; resonance; photoluminescence

The transition regime from plasmon resonant nanoparticles to photoluminescent nanoclusters (NC) in gold is at a size 2-3 nm, where neither of these optical features is pronounced, is still poorly understood. All previous studies on this topic focused on metal-organic NC, capped with organic ligands and primarily discussed particle size effects. However, to which extent this phenomenon is also ruled by I) the number of valence electrons in the cluster, II) the energy of the contributing orbitals, or III) the polarizability of the electronic system is still scarcely understood. Thereto, size-controlled ligand-free, fully inorganic colloidal NC derived from laser fragmentation in liquids are ideal model materials. We will elucidate how electron-injecting and electron-withdrawing agents affect the transition regime discriminating A) weak charge transfer effects by ions B) strong but delocalized charge transfer from electron-rich supports like graphene, and C) strong, localized but ambivalent effects from covalently bound (Au-S) organic ligands. Additionally, element-specific features like bandgap energy and polarizability will be varied within a homologous coinage metal NC series of Au, Ag, and Cu, including AgAu and CuAu alloy NCs with of solid solution and segregated metal core ultrastructure. We will examine how doping of gold with another coinage metal with different orbital energy and polarizability affects the transition regime and how it is correlated with molar fraction and elemental mixing.

从等离子体共振纳米颗粒到金中的光致发光纳米团簇（NC）的过渡状态是在2-3 nm的尺寸，其中这些光学特征都不明显，仍然知之甚少。以往的研究都集中在金属有机NC，与有机配体封端，主要讨论了粒径效应。然而，这种现象在多大程度上也受I）团簇中价电子的数量，II）贡献轨道的能量，或III）电子系统的极化率的支配仍然很少被理解。因此，尺寸可控的无配体的，完全无机的胶体NC衍生的激光裂解在液体中是理想的模型材料。我们将阐明电子注入剂和吸电子剂如何影响过渡态，区分A）离子的弱电荷转移效应B）来自富含电子的载体如石墨烯的强但离域的电荷转移，以及C）来自共价结合的（Au-S）有机配体的强、局部但矛盾的效应。此外，带隙能和极化率等元素特定特征将在Au、Ag和Cu的同源铸币金属NC系列中发生变化，包括具有固溶体和分离金属芯超微结构的AgAu和CuAu合金NC。我们将研究如何掺杂金与另一种钴金属具有不同的轨道能量和极化率的影响过渡制度，以及它是如何与摩尔分数和元素混合。