Optical properties of furnace-sintered silver nanoparticles with different sizes

The laser heating of silver nanoparticles (NPs) has been studied extensively in the field of printed electronics. The optical properties of reflectivity and optical penetration depth are important parameters in the analysis of the laser heating process. These determine the absorption of laser energy by the target. Therefore, we studied the optical properties of Ag NPs with different particle sizes. Two types of Ag NPs with average particle sizes of 50 and 10 nm were used in this study. The Ag NPs were sintered in a furnace at different sintering temperatures of 50, 100, 150, 200, 250, and 300 °C. The refractive indices and extinction coefficients for each case were measured using an ellipsometer. The 50 and 10 nm Ag NPs exhibited different trends in their optical properties. These differences were explained based on the effective medium theory. The reflectivity and optical penetration depth for each case were calculated based on the measured refractive indices and extinction coefficients.