A hybrid dewetting approach to generate highly sensitive plasmonic silver nanoparticles with a narrow size distribution

Laser dewetting is a simple and efficient method for transforming a metal thin film into nanoparticles. However, the particles obtained via laser dewetting typically exhibit a wide size distribution. This study shows that a combination of thermal and laser dewetting processes can be used to generate more uniform metal nanoparticles. A 10-nm-thick Ag film deposited on glass was irradiated by an Nd:YAG laser pulse to produce nanoparticles with sizes in the range of 35-145 nm. When the film was thermally annealed at 250 degrees C in an Ar atmosphere before laser irradiation, Ag nanoparticles with a much narrower size distribution were obtained (mean size = 48 nm and standard deviation = 10.5 nm), which was attributed to the island structure formed by the pre-annealing step. Xray photoelectron spectroscopy confirmed the absence of particle oxidation. An important feature associated with this hybrid dewetting approach was that the obtained Ag nanoparticles showed a strong single plasmonic resonance peak owing to their narrow size distribution. As a plasmonic sensing platform, they exhibited much enhanced refractive index sensitivity and figure of merit than the particles produced via laser dewetting.

Automated summary

The study demonstrates that combining thermal and laser dewetting processes can generate more uniform metal nanoparticles, with pre-annealing leading to narrower size distribution. The obtained silver nanoparticles exhibit a strong single plasmonic resonance peak due to their narrow size distribution, showing enhanced refractive index sensitivity and figure of merit as a plasmonic sensing platform compared to particles produced via laser dewetting.