Abstract
The mechanism responsible for visible photoluminescence (PL) emission from gold nanoparticles (AuNPs) needs an in-depth understanding for various practical applications. In this spirit, we proposed an analytical model to calculate and predict the visible PL from AuNPs. The developed phenomenological model integrated the influences of LSSs, oscillator strength, binding energy of excitons, and the quantum confinement (QC) to achieve the mathematical expression of PL spectral intensity. The influence of NPs sizes, shapes, size distribution and pump energy on the PL spectra of AuNPs was evaluated. The experimental PL spectra were fitted to the analytical model to determine its robustness. The authenticity of the model was validated with the state of the art simulation and experimental findings. The rudimentary insight of PL mechanism of AuNPs was demonstrated based on the electronic structures calculations. Model predicted values of band gap energy for AuNPs in the size range of 2 to 50 nm agreed well with the experimental and DFT simulation results when compared. The selected model parameters that significantly influenced the PL calculations can further be extended to other nanostructures morphologies.