Mechanistic insights on sulfur functionalization of Ag nanoflowers†

The morphological evolution of nanomaterials plays a crucial role in sensing-based quantum applications. Functionalizing the nanomaterials induces appropriate morphology and chemistry for specific adsorption and subsequent detection of targeted analytes. This study presents a method for synthesizing Ag nanoflower (NF) and sulfur functionalized analogs using a solution phase approach. Sulfur functionalization via thiourea not only reduces nanoflower size by 23 nm but also enhances structural uniformity and stability, as confirmed through a combined experimental and computational approach, including TD-DFT and SAPT0 analysis. The as-synthesized NFs are characterized using X-ray diffraction, energy dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, FT-IR, Thermogravimetric analysis, UV-visible, and photoluminescence spectroscopy. We used molecular dynamics simulations to gain insights into experimental measurements. Radial distribution function analysis of simulated trajectories demonstrated that the oxygen atom of polyvinyl pyrrolidone and sulfur atom of thiourea are the key elements responsible for stabilization and functionalization, respectively. We also used density functional theory to simulate theoretical absorbance spectra and electronic structures. Quantum chemical calculations revealed the energetic contributions of noncovalent interactions, particularly the electrostatic interaction responsible for stabilizing AgNFs.