Study of titanium phosphate gels and their application to the synthesis of KTiOPO4 films

Abstract

Phosphoric acid esters PO(OR)3–x(OH)x(with 0<x<3 and R = Et, Bu, Pri, 2-methylbutane) have been studied as precursors for polycondensation reactions with titanium alkoxides. These precursors are easily synthesized by reaction of P2O5 with alcohols. Both the POH : Ti ratio and the hydrolysis ratio (H2O : Ti) have an effect on the condensation and gelation. Also, thermolysis of phosphate esters of tertiary alcohols causes the in situ generation of free H3PO4 and the condensation of titanium phosphate. The precursors and the colloidal solutions have been characterized through 31P nuclear magnetic resonance (NMR) and dynamic light scattering. The use of these colloidal solutions for the thin-film synthesis of KTiOPO4 is demonstrated.