Abstract:
The work presented in this thesis focuses on the synthesis of nanomaterials, formulation and
printing of Ag nanoparticle and nanowire inks for two distinct applications: a) inkjet printing
of Ag nanoparticle films on ceramic substrates with the aim of providing a smaller size of
printed feature at lower cost than that can be obtained with the conventionally used screen
printing, and b) Ag nanowires films prompted by the wide quest of electronics industry for
materials with increased flexibility, lower cost and higher transmittance to replace indium tin
oxide.
Ag nanoparticles with a size of 50 nm were successfully synthesized and dispersed in
aqueous medium. Two preparation routes were compared in order to distinguish the effects of
solvents treatment of particles and their influence on the suspension characteristics including
Ag loading, rheology, surface tension and later the electrical film properties. The co-polymer
Pluronic F127 was found to be an effective as a stabiliser leading to the formulation of high
silver loading in inks.
The processing and characterization of silver films was performed. The aim was to
reduce the number of layers in the silver nanoparticles film by increasing the thickness of a
single layer with the goal of obtaining a dense and conductive film. An increase in the Ag
loading, from 5 wt % to 45 wt % favoured the achievement of denser and thicker film with
one layer printing. Addition of SiO2 to the ink formula resulted in denser structure and better
adhesion of the printed track then the one without SiO2.
A new method for improving the morphology of inkjet printed tracks has been
proposed by printing the ink into the structured channels with predefined topography.
Silver nanowires were synthesised and dispersed in methanol with help of copolymer
F127. They were subsequently deposited on plastic and glass substrates forming conductive
and transparent films.
