Estimation of the aspect-ratio distribution in chemically synthesized gold nanorods solution using UV-visible absorption spectroscopy

A rapid and ubiquitous method to characterize samples of chemically synthesized Gold Nano Rods (GNRs) is by measuring their UV-visible spectra. The presence of transverse and longitudinal surface plasmon resonance peaks in UV-visible spectra indicate the presence of GNRs. However, the quality of the synthesised sample, and thus their performance in various sensor applications, depends on the geometrical variations of the GNRs present in the solution. As a result, an algorithm has been developed to estimate the Aspect Ratio (AR) variation of the GNRs present by theoretically fitting to the longitudinal surface plasmon resonance peak of the UV-visible spectrum. After numerically benchmarking has been undertaken, the developed algorithm has been used to calculate the mean and standard deviation of the ARs in two synthesized samples, showing that this method offers a fast and cost-effective alternative to Transmission Electron Microscopy. (paper)