Thermal conductivity estimation of inkjet-printed silver nanoparticle ink during continuous wave laser sintering

We determined the thermal conductivity of silver nanoparticle ink during laser sintering by applying the Wiedemann–Franz law to two-dimensional heat conduction equations. Ink with 34wt% silver (Ag) nanoparticles with an average size of approximately 50nm was printed on Eagle-XG (Samsung–Corning) glass substrate by inkjet printing. Inkjet-printed patterns were irradiated with a 532nm continuous wave laser at various laser intensities. To obtain a transient thermal conductivity trace of the ink during the laser sintering process, in-situ electrical resistance data were measured to estimate the thermal conductivity of the inkjet-printed ink using the Wiedemann–Franz law. Two-dimensional heat conduction equations were iteratively solved to obtain transient temperature information about the sintered ink. As the laser sintering temperature increased, the surface morphology of the sintered ink affected the thermal conductivity of the laser-sintered ink. Thermal conductivity of the laser-sintered Ag nanoparticle ink was estimated by considering the thermal conductivity of the air confined in pores.