Abstract：
Modulating the assembly pathway is an indispensable strategy for optimizing the performance of optical materials. However, implementing this strategy is nontrivial for metal nanocluster building blocks, due to the limited functional modification of nanoclusters and complexity of their emission mechanism. In this report, we demonstrate that a gold nanocluster modified by 4,6-diamino-2-pyrimidinethiol (DPT-AuNCs) self-assembles into two distinct aggregation structures in methanol (MeOH)/water mixed solvent, thus exhibiting pathway complexity. Kinetic studies show that DPT-AuNCs firstly assembles into non-luminescent nanofibers (kinetically controlled), which further transforms into strongly luminescent microflowers (thermodynamicallycontrolled). In-depth analysis of the assembly mechanism reveals that the transformation of aggregation structures involves the disassembly of nanofibers and a subsequent nucleation-growth process. Temperature-dependent photoluminescence (PL) spectroscopy and infrared (IR) measurements reveal that inter-cluster hydrogen bonding bridged by solvent molecules and C-H···π interaction are the key factors for emission enhancement. The photoluminescent property of DPT-AuNCs can be controlled by varying the cosolvent in water, enabling DPT-AuNCs to distinguish different kind of alcohols, particularly the isomerism n-propanol (NPA) and isopropanol (IPA). Additionally, he addition of seeds effectively regulate the assembly kinetics of DPT-AuNCs. This study advances our understanding of assembly pathways and improves the luminescent performance of nanoclusters (NCs).
摘要：
调制组装路径是优化光学材料性能不可或缺的策略。然而,实施这一策略对于金属纳米簇构建块来说是不平凡的，由于纳米团簇的有限的功能修饰和其发射机理的复杂性。在这份报告中,我们证明了由4,6-二氨基-2-嘧啶硫醇（DPT-AuNC）修饰的金纳米簇在甲醇（MeOH）/水混合溶剂中自组装成两个不同的聚集结构，因此表现出路径复杂性。动力学研究表明，DPT-AuNC首先组装成非发光纳米纤维（动力学控制），进一步转化为强烈发光的微花（热力学控制）。对组装机理的深入分析表明，聚集结构的转变涉及纳米纤维的分解和随后的成核-生长过程。温度依赖性光致发光（PL）光谱和红外（IR）测量表明，由溶剂分子桥接的簇间氢键和C-H···π相互作用是增强发射的关键因素。DPT-AuNC的光致发光特性可以通过改变水中的共溶剂来控制，使DPT-AuNC能够区分不同种类的醇，特别是异构正丙醇(NPA)和异丙醇(IPA)。此外,种子的添加有效地调节了DPT-AuNC的组装动力学。这项研究促进了我们对组装途径的理解，并改善了纳米簇（NC）的发光性能。
