Research Projects

Silver(I) chalcogenolate nanoclusters have garnered significant interest in recent years due to their unique photophysical characteristics, making them promising candidates for photo-functional applications. To address the limitations of intrinsic instability and low quantum yields, our research focuses on assembling these nanoclusters into extended frameworks using organic linker molecules — a strategy aimed at improving both their structural stability and photoluminescence properties. We investigated how inter- and intra-cluster distances, linker rigidity, and framework dimensionality influence the emission behaviour. So, the design of cluster nodes with varying ligands and appropriate choice of linkers provides great promise to reinforce the relationship between the electronic structure and photoluminescence, which can help to customize the function of CAMs for solid-state applications. Objectives: 1. Synthesis and characterization: (a) molecular clusters (NCs) with varying ligands; (b) cluster-assembled materials (CAMs) with a hierarchy of structures; 2. Photoluminescence properties: (a) UV-vis and photoluminescence properties at solution, thin film, and solid-state of NC and CAM; (b) Temperature-dependent photoluminescence and lifetimes to understand the mechanistic pathway; 3. Structure-property relationship: Structural information of NC and CAM in atomic label, and the detailed photo-physical phenomena will elucidate the origin of the photoluminescence; 4. The proposed project is to define how the properties of cluster-assembled materials evolve and differ from their molecular units and bulk; 5. Our goal is to bridge the gap between fundamental photophysics and device-level applications based on these atomically precise quantum cluster-assembled materials, enabling the construction of superior nanomaterials tailored for LEDs, sensors, and other optoelectronic platforms. Synthesis of Clusters and CAMs: Atom-precise metal nanoclusters are generally synthesized in a facile one-pot bottom-up approach where the metal salts and protecting ligands are added in a mixture of solvents and the reducing agents are added to prepare the nanoclusters capped by the ligands. Using bidentate or multidentate linkers to construct higher-dimensional cluster-assembled framework materials (CAMs) is facile and convenient. All these clusters and cluster assemblies will be characterized thoroughly. Photoluminescence studies: It’s important to highlight that the clusters themselves are the emissive centers, or luminophores. Therefore, any change in their environment — such as packing or orientation in the framework — directly alters their emission. To probe these effects in greater depth, temperature-dependent photoluminescence (PL) spectroscopy and time-resolved lifetime measurements are essential. The temperature-dependent PL studies will have valuable information about singlet-triplet energy gaps, which strongly depend on the rigidity of the framework in cluster-assembled structures. Similarly, lifetime analyses can underscore the change of excited states properties from cluster to cluster-assembled materials. Structure-property relationship: These precisely track and tune emission properties — whether through linker design, framework rigidity, or inter-cluster spacing —will provide proof of principle to make these materials highly versatile for advanced applications. Moving forward, the integration of experimental insights with theoretical modeling will be crucial in building a predictive understanding of these systems. Our goal is to bridge the gap between fundamental photophysics and device-level applications based on these atomically precise quantum cluster-assembled materials, enabling the construction of superior nanomaterials tailored for LEDs, sensors, and other optoelectronic platforms.