Effect of light intensity on nanoparticle nucleation during printing of silver micropatterns via superluminescent light projection

Although photoreduction-based printing of metallic micropatterns makes these structures widely accessible, their use in functional devices is limited by the poor electrical and optical properties. These properties can be optimized by tuning the size and density of the nanoparticles in the structures. However, such optimization is slow and resource-intensive because the underlying mechanisms are not well understood. Here, we investigate the nanoparticle nucleation behavior in the superluminescent light projection technique. We demonstrate that optical dosage, which is widely used to specify and standardize processing conditions in printers, is a poor predictor of the nanoparticle size and density. Instead, the intensity of light and the duration of exposure have distinct effects even when their product (i.e., dosage) is identical. We further demonstrate that the empirically observed nucleation behavior can be qualitatively explained by the classical nucleation theory, but a more complex model is required to satisfactorily explain the onset of nucleation.