New advances in printed circuit boards have yielded promising applications, especially concerning sensors and wireless identification devices. However, such devices require improved high-κ dielectric capacitors that avoid high temperature treatments. Barium titanate (BaTiO3) is a ferroelectric material commonly used as a dielectric material in existing capacitors. Without excessive heating, the dielectric properties of barium titanate can be improved with the addition of conductive nanoparticles to the BaTiO3 surface. Gold nanoparticles are ideal for their ability to disperse in water without agglomerating over time.
Starting with commercially available 100 nm barium titanate nanoparticles and smaller (15-20 nm) gold nanoparticles, a composite was produced via heterocoagulation. Modification of the BaTiO3 and gold surfaces creates electrostatically attractive forces that maintain order and avoids the self-agglomeration of gold particles into connective pathways. Characterization of the particles included single-point and pH-dependent Zeta-potential measurements. SEM images of the dry material revealed the presence of well-dispersed gold nanoparticles on the surface of the 100 nm barium titanate particles. The dielectric constant was measured on freeze-dried and pressed pellets. Optimization of the dielectric constant by varying the gold concentration was also explored.