Formulation of Sol−Gel Derived Bismuth Silicate Dielectric Ink for Flexible Electronics Applications

Abstract

An agile method is demonstrated for the development of a low dielectric constant ink made from nanostructured bismuth silicate (nBSO), synthesized by a sol− gel method. The viscous ink, suitable for screen-printing, was formulated by controlling the organic additives. The viscosity as well as the dynamic viscoelastic properties of the formulated ink was tuned to yield ideal flow characteristics. The microstructure and surface roughness of the printed film were characterized, and the film shows minimum average and root-mean-square surface roughness values (Ra = 80.3 nm and Rq = 102 nm). Microwave dielectric properties of the printed dielectric film were εr = 4.36 and tan δ = 1.6 × 10−2 at 10 GHz. The apparent leakage current density of the film is of the order of 10−5 A/cm2. The improved dielectric and thermal properties, combined with low leakage current, make nBSO dielectric ink a suitable candidate for use in printed electronics