We describe the synthesis of optical quality thin film materials with high refractive index, employing zirconium based
hybrid sol-gel precursors. As the zirconium propoxide precursor is unstable in the presence of a strong nucleophilic agent
such as water, two synthesis routes have been performed employing a chelating agent and an organosilane precursor to
avoid the formation of any undesired ZrO2 agglomerates, leading to organo-zirconate complexes and silicato-zirconate
copolymers, respectively. The prepared hybrid sol-gel materials were deposited by spin-coating to form a transparent
thin film on silicon substrates, and heat treated at 100 °C for the final stabilisation of the layer.
The effect of the two synthesis routes on the optical properties of zirconium based hybrid sol-gel material is discussed. It
was found that the nature and concentration of the organosilane precursor can significantly affect the structural properties
of the deposited films. A correlation was also demonstrated between the concentration of the organosilane precursor and
the refractive index of the material. By reducing the concentration of organosilane precursor, high refractive index
materials were obtained. Similar behaviour was observed for the materials synthesised via chelating agent. The synthesis
employing an organosilane precursor produces films with higher refractive index. A maximum refractive index of 1.746
was measured at 635nm for the deposited thin films.