Laser wavelength effect on laser-induced photo-thermal sintering of silver nanoparticles

This work is concerned with the laser wavelength effect on the electrical properties and surface morphology of laser-sintered nanoparticle thin films. Silver nanoparticle thin films spin-coated on soda lime glass substrates were irradiated with lasers of three different wavelengths (near ultraviolet 405 nm, green 514.5 nm, near infrared 817 nm) at varied laser intensities and scanning speeds. Scanning electron microscopy images and ex situ resistivity measurements show that the photo-thermal sintering alters significantly the film surface morphology and electrical properties, depending on the processing parameters (laser wavelength, laser intensities and scanning speed). While the optical response of the material is determined largely by the processing laser wavelength, the laser beam intensity and scanning speed regulate the induced temperature field. Examination of the optical properties of as-deposited silver nanoparticle thin film in conjunction with scanning electron microscopy images taken from the laser-sintered lines helps elucidate how the processing laser wavelength modulates the optical response of silver nanoparticle thin film and therefore affects the thermal response.